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Volume 16, Number 14, Issue of July 15, 1996 pp. 4479-4490
Copyright ©1996 Society for Neuroscience

Immunocytochemical Localization of the GABAC Receptor rho  Subunits in the Mammalian Retina

Ralf Enz, Johann Helmut Brandstätter, Heinz Wässle, and Joachim Bormann

Max-Planck-Institut für Hirnforschung, Neuroanatomische Abteilung, Deutschordenstrasse 46, D-60528 Frankfurt, Germany

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
FOOTNOTES
REFERENCES

ABSTRACT

Polyclonal antibodies against the N terminus of the rat rho 1 subunit were generated to study the distribution of GABAC receptors in the mammalian retina. The specificity of the antibodies was tested in Western blots and transfected HEK-293 cells. No cross-reactivity with the GABAA receptor subunits alpha 1-3, beta 1-3, gamma 2, delta  or with the glycine receptor subunits alpha 1 and beta  could be detected. In contrast, the rho 1, rho 2, and rho 3 subunits were all recognized by the antibodies. In vertical sections of rat, rabbit, cat, and macaque monkey retinae, strong punctate immunoreactivity was present in the inner plexiform layer. Weaker immunoreactivity was also present in the outer plexiform layer, and cell bodies of bipolar cells were faintly labeled. Double immunostaining of vertical sections and immunostaining of dissociated rat retinae showed the punctate immunofluorescence to colocalize with bipolar cell axon terminals. The puncta possibly represent clustering of the rho  subunits at postsynaptic sites.

Key words: GABAC receptor; rho subunits; rat retina; rabbit retina; cat retina; macaque monkey retina; bipolar cell; immuno-cytochemistry; antibodies

INTRODUCTION

GABA is the major inhibitory neurotransmitter in the vertebrate CNS (Sivilotti and Nistri, 1991). Three types of pharmacologically and physiologically distinct GABA receptors have been described. Activation of bicuculline-sensitive GABAA receptors causes the opening of integral membrane channels selectively permeable to chloride (Bormann et al., 1987; Macdonald and Olsen, 1994; Sieghart, 1995). By contrast, GABAB receptors couple to either K+ or Ca2+ channels via G-proteins and second-messenger systems (Bormann, 1988; Bowery, 1989). They are activated by baclofen and are resistant to drugs that modulate the GABAA receptor. Early studies by Johnston and colleagues (1975) indicated that the partially folded GABA analog cis-4-aminocrotonic acid might activate selectively a third class of GABA receptor in the mammalian CNS. These receptors, which were tentatively designated GABAC (Drew et al., 1984), are insensitive to both bicuculline and baclofen (for review, see Bormann and Feigen- span, 1995).

GABAC receptors reportedly are present in various parts of the vertebrate brain, including spinal cord (Johnston et al., 1975), optic tectum (Nistri and Sivilotti, 1985; Sivilotti and Nistri, 1989), cerebellum (Drew et al., 1984; Drew and Johnston, 1992), and hippocampus (Strata and Cherubini, 1994; Martina et al., 1995). GABAC receptors first were observed in retina by Miledi and colleagues after expressing mRNA from bovine retina in Xenopus oocytes (Polenzani et al., 1991). Native GABAC receptors with similar properties were identified later on subpopulations of neurons in rat (Feigenspan et al., 1993; Feigenspan and Bormann, 1994b), fish (Qian and Dowling, 1993, 1994, 1995; Dong et al., 1994), and tiger salamander retinae (Lukasiewicz et al., 1994; Zhang and Slaughter, 1995).

Accumulating evidence indicates that GABAC receptors are composed of rho  subunits, which were originally cloned in man (Cutting et al., 1991, 1992). The human rho 1 and rho 2 subunits share 74% amino acid sequence identity, but only 30-38% when compared with GABAA receptor subunits (Cutting et al., 1991, 1992). When expressed in Xenopus oocytes, the rho  subunits form homo-oligomeric channels with the characteristic GABAC pharmacology (Cutting et al., 1991; Shimada et al., 1992; Kusama et al., 1993a,b; Wang et al., 1994).

The counterparts of the human rho  subunits now have been cloned in chick (rho 1-2; Albrecht and Darlison, 1995) and in rat (rho 1-3; Enz et al., 1995; Ogurusu et al., 1995; Zhang et al., 1995a; Ogurusu and Shingai, 1996), revealing a high degree of similarity at the protein level with the respective human sequences. In contrast to the receptors formed by the human rho 1 or rho 2 subunits (Shimada et al., 1992; Wang et al., 1994), GABAC receptors in the rat are almost insensitive to the Cl- channel antagonist picrotoxinin (Feigenspan et al., 1993; Feigenspan and Bormann, 1994a; Pan and Lipton, 1995). This functional difference appears to reside in a single amino acid of the rat rho 2 subunit (Zhang et al., 1995a). The use of PCR and in situ hybridization has demonstrated a high expression of rho 1 and rho 2 subunits in rat bipolar cells (Enz et al., 1995), supporting the idea that rho  subunits are part of the GABAC receptor, because bipolar cells exhibit bicuculline-resistant GABAC responses. Although rho 1 appears to be restricted to the retina, the rho 2 subunit is expressed significantly in other parts of the CNS, most notably in the hippocampus and cortex (Enz et al., 1995).

The strong expression of rho 1/rho 2 subunits in the rat bipolar cell implies a possible role of GABAC receptors in mediating lateral inhibitory interaction in the mammalian retina. However, better spatial resolution than that of PCR and in situ hybridization is required to elucidate the synaptic mechanisms involving GABAC receptors. Therefore, we have raised polyclonal antibodies against the rat rho 1 subunit and studied the localization of GABAC receptors on mammalian retinal neurons.

MATERIALS AND METHODS

Preparation of antibodies. Total RNA was extracted from the retinae of an 8-week-old Wistar rat, and reverse transcription-polymerase chain reaction (RT-PCR) was performed as described (Chomczynski and Sacchi, 1987; Enz and Bormann, 1995). Specific oligonucleotide primers for the rat GABA receptor rho 1 subunit were synthesized (sense 5'-CGGGATCCGCTGAGAGCACAGTGCACT-3' pos. 46-64; antisense 5'-GAAGATCTGACGTTGTCTGTGGTGGTG-3' pos. 513-495) using our own unpublished cDNA sequence data. Restriction sites for BamHI and BglII were added to the primers (bold letters) to facilitate cloning of the PCR products. The PCR reaction (94°C, 5 min; 35 cycles at 94°C, 45 sec; 60°C, 40 sec; 72°C, 45 sec) was performed on a programmable thermocycler (Perkin-Elmer Cetus, Norwalk, CT) as described previously (Enz and Bormann, 1995). The PCR product was fused to an N-terminal histidine affinity tag in the BamHI/BglII site of the bacterial expression vector pQE13 (Diagen, Hilden, Germany). After transformation in E.coli (strain M15[pREP4]), positive recombinants were analyzed by dideoxy sequencing (Sanger, 1977). Protein expression in one positive clone was induced by the addition of 2 mM isopropyl-beta -D-thiogalactosid (Stratagene, La Jolla, CA), and after 5 hr incubation at 37°C, bacteria were lysed in 6 M guanidinium hydrochloride, pH 8. The fusion protein was purified using a Ni2+-nitrilotriacetic acid resin column (Diagen) and dialysed against PBS, pH 7.4. The precipitated protein was lyophilized and used for antibody production in rabbits according to standard immunization procedures (Eurogentec, Seraing, Belgium). Briefly, rabbits were injected subcutaneously with 0.5 mg antigen emulsified in 0.5 ml of complete Freund's adjuvant, followed by injections in incomplete adjuvant after 2, 4, and 8 weeks. Obtained serum was affinity-purified using the diethyl aminoethylether (DEAE) column of the Econo-Pac IgG purification kit (Biorad, Richmond, CA). The eluate was further purified by an antigen-coupled column (Kem-En-Tec, Copenhagen, Denmark).

Other immunsera. The following polyclonal antisera against the GABAA receptor (GABAAR) subunits (gift of H. Möhler) were used: alpha 1, residues 1-16; alpha 2, residues 1-9; alpha 3, residues 1-15 (Benke et al., 1991a; Gao et al., 1993; Marksitzer et al., 1993); beta 1, residues 381-389 (Greferath et al., 1995); gamma 2, residues 1-15 (Stephenson et al., 1990); delta , residues 1-17 (Benke et al., 1991b). The mouse monoclonal antibodies bd17 (GABAAR beta 2,3; Boehringer Mannheim, Mannheim, Germany) (Schoch et al., 1985; Ewert et al., 1992) and mAb4a recognizing glycine receptor (GlyR) subunits (alpha 1-3 and beta ; gift of J. Kirsch) (Pfeiffer et al., 1984; Schröder et al., 1991) also were used. Mouse monoclonal antibodies for the protein kinase C (PKC) alpha -isoenzyme (clone MC5; Amersham, Arlington Heights, IL) (Greferath et al., 1990; Walker et al., 1990) and calbindin-D (Sigma Aldrich, Deisenhofen, Germany) were used to label bipolar cells (Grünert et al., 1994).

Immunocytochemistry. Adult albino rats were deeply anesthetized with 4% halothane and decapitated. After enucleation, the eye was opened by an encircling cut and the eyecup was immersion-fixed in 4% paraformaldehyde in 0.1 M phosphate buffer (PB), pH 7.4 for 15-60 min, depending on the primary antibodies used. The eyecup was washed in 0.1 M PB, and the retina was dissected out and cryoprotected by immersion in increasing sucrose concentrations (10-30%) in PB. Pieces of retina were sectioned vertically at 12 µm thickness on a cryostat, and the sections were collected on chrome-alum/gelatin-coated slides. Immunostaining was performed using the indirect fluorescence method. The primary antibodies and their dilutions used for receptor immunocytochemistry were: GABAAR alpha 1 (1:10,000), alpha 2 (1:2000), alpha 3 (1:5000), beta 1 (1:50), beta 2,3 (1:50), gamma 2 (1:5000), GlyR alpha 1-3, beta  (1:500), GABACR rho 1 (1:100). The binding sites of the primary antibodies were revealed by secondary antibodies: goat anti-guinea pig conjugated to Cy3 (1:1000, Dianova, Hamburg, Germany), goat anti-mouse conjugated to Cy3 (1:1000; Dianova), goat anti-rabbit conjugated to Cy3 (1:1000; Dianova), goat anti-mouse conjugated to fluorescein isothiocyanate (FITC; 1:50; Dianova), and goat anti-rat conjugated to FITC (1:50; Dianova). In double-labeling experiments, sections were incubated in a mixture of the primary antibodies, and subsequently in a mixture of secondary antibodies. Controls were prepared by omitting the incubation with one of the two primary antibodies. In this case, only the immunoreactivity of the remaining primary antibody could be specifically detected.

Dissociated cells were prepared from adult rat retinae as described (Huba and Hofmann, 1988; Karschin and Wässle, 1990). Cells were fixed for 5 min in methanol/acetic acid (95:5/v:v) at -79°C, dryed for 15 min at room temperature, and preincubated for 20 min with 2.5% (w/v) goat serum in PB. Cells were incubated with the rho 1 antibodies diluted in preincubation buffer (1:100) for 5 hr, followed by the secondary antibody goat anti-rabbit conjugated to Cy3 (1:1000) for 30 min.

Human embryonic kidney cells (HEK-293 cells, ATCC CRL 1573) were transfected (Chen and Okayama, 1987) with cDNAs encoding GABAAR subunits alpha 1-3, beta 1-3, and gamma 2 (gift of P.H. Seeburg), GlyR subunits alpha 1 and beta  (gift of H. Betz), or rho 1 subunits (gift of G. R. Uhl). Proteins were expressed under control of the cytomegalovirus-promotor. Fixation of transfected HEK-293 cells and immunostaining was performed using the same procedure as described above for dissociated cells.

Immunofluorescence was examined and photographed with a Zeiss photomicroscope using the appropriate filter combinations (FITC: 450-490, FT 510, LP 520; CY3: BP 546, FT 580, LP 590). The fluorescence filters were wedge-corrected, so shifting from one filter to the other did not cause any displacement of the image. In some instances, very strong Cy3 fluorescence was also visible with the FITC filter. This could be blocked by an additional green interference filter (515-565) inserted into the microscope tube. Black-and-white photomicrographs were taken on Kodak TMY 400 film.

Gel electrophoreses and Western blot analysis. Membranes of HEK-293 cells expressing GABAAR-subunits alpha 1, alpha 3, GlyR subunits alpha 1 and beta , or the rho 1 subunit were prepared as follows. Briefly, cells were homogenized in buffer (4 mM HEPES, 220 mM mannose, 70 mM sucrose, 0.1% benzamidin, 0.025% benzethonium chloride, 1.25% aprotinin, 0.005% alpha 2-macroglobuline, pH 7.5) and sedimentated for 3 min at 1000 × g. To collect the membrane fraction, the supernatant was centrifuged at 20,000 × g.

Bacterial fusion proteins for the N termini of GABAAR subunits beta 3, gamma 2, delta , and rho 2,3 subunits were generated in E.coli strain M15[pREP4] using PCR cloning techniques as described. Oligonucleotide sequences were:

beta 3 sense 5'-GAAGATCTCAGAGCGTAAACGACCCCG-3' pos. 75-93,

antisense 5'-GAAGATCTCCCAATGTTTCTCTTCAACCG-3' pos. 732-711 (Ymer et al., 1989);

gamma 2 sense 5'-GAAGATCTCAAAAGTCAGATGATGACTATG-3' pos. 114-135,

antisense 5'-GAAGATCTCCCCATTCTTCTGCTCAGAT-3' pos. 816-796 (Shivers et al., 1989);

delta sense 5'-GAAGATCTCACCATGGCGCCAGAGCA-3' pos. 54-71,

antisense 5'-GAAGATCTACCCCGGTTCCTCCGAAG-3' pos. 744-726 (Shivers et al., 1989);

rho 2 sense 5'-GCGGATCCAGAAAACCCAGGAGGAAGAG-3' pos. 60-79,

antisense 5'-GCGGATCCGTGACGTCGCAGAGTGAAGT-3' pos. 779-760 (Ogurusu et al., 1995);

rho 3 sense 5'-GCGGATCCTGGATCACACTGATGCTGGA-3' pos. 40-59,

antisense 5'-GAAGATCTGTGCCTCCGTAGCACAAAG-3' pos. 789-771 (Ogurusu and Shingai, 1996).

Restriction sites for BamHI and BglII were added to the primers (bold letters) to facilitate cloning of the PCR products. Cloning of DNA, and expression and purification of fusion-proteins were performed as described.

Membrane proteins of HEK-293 cells and bacterial fusion proteins were subjected to SDS-PAGE gel electrophoresis (Laemmli, 1970), transferred to nitrocellulose sheets (Schleicher and Schüll, Dassel, Germany), and detected using the enhanced chemiluminescence system (Amersham). The following dilutions of antisera were used: GABAAR alpha 1 (1:20,000), alpha 3 (1:20,000), beta 2,3 (1:100), gamma 2 (1:10,000), delta  (1:500); GlyR alpha 1-3, beta  (1:1000); GABACR rho 1 (1:300 for HEK cell membranes; 1:1000 for E.coli fusion proteins). As secondary antisera, goat anti-guinea pig (Dianova), goat anti-mouse (Dianova), and goat anti-rabbit (Dianova), conjugated to horseradish peroxidase, were used in a dilution of 1:5000 each.

RESULTS

Characterization of the rho 1 antibodies

We raised polyclonal antibodies against the GABAC receptor rho 1 subunit by synthesizing a fusion protein corresponding to the N-terminal region (position 16-171) of the rat rho 1 subunit. The specificity of the polyclonal antibodies obtained in rabbits after injection of the fusion protein was tested on Western blots and with transfected HEK-293 cells. Figure 1A shows specific signals of the expected size for the rho 1 antigen incubated with the DEAE- and antigen-affinity-purified antibodies (lanes I and rho 1), which are inhibited by preincubation with the antigen (lane rho 1p). No signal is present after incubation of the antigen with DEAE-purified preimmunserum (lane P). The N termini of the rho 2 and rho 3 subunits were also recognized by the antibodies (lanes rho 2 and rho 3). In crude membrane fractions of HEK-293 cells transfected with the human rho 1 cDNA, a specific signal of ~50 kDa could be detected (Fig. 1B, lane rho 1). This signal is prevented by preincubating the immunserum with the antigen (Fig. 1B, lane rho 1p). Membrane fractions of untransfected cells showed no signal (not illustrated). Immunostaining of HEK-293 cells expressing rho 1 with our polyclonal antibodies revealed specific labeling (Fig. 1C, rho 1) that could be blocked by the antigen (Fig. 1C, rho 1p), whereas untransfected cells were not stained (not illustrated).
Fig. 1. Characterization of rho 1 polyclonal antibodies. A, Detection of 20 ng antigen with DEAE-purified (lane I) and antigen affinity-purified (lane rho 1) immunsera. Preincubation with the antigen (1 mg antigen per ml serum) inhibits the signal (lane rho 1p). Incubation with the DEAE-purified preimmunserum does not show any specific signal (lane P). The N termini of the rat rho 2 and rho 3 subunits were also detected by the rho 1 antibodies (lanes rho 2 and rho 3). The low molecular weight marker (Biorad) is indicated on the left. B, Crude membrane fractions with human rho 1 subunit transfected HEK-293 cells showed a specific signal of 50 kDa after incubation with the affinity-purified polyclonal antibodies (lane rho 1) that can be inhibited by preincubation with the antigen (lane rho 1p). Low molecular weight marker as in A. C, HEK-293 cells expressing the human rho 1 subunit labeled with rho 1 polyclonal antibodies (rho 1). Staining is prevented by preincubation with the antigen (rho 1p). Scale bar, 10 µm.
[View Larger Version of this Image (25K GIF file)]

Because the primary sequence of the antigen has several regions identical to other GABAAR and GlyR subunits, we tested the cross-reactivity of the rho 1 polyclonal antibodies for some of those subunits. Western blot analysis of HEK cell membranes containing GABAAR alpha 1 and alpha 3 or GlyR alpha 1 and beta  subunits showed no detectable signal after incubation with the polyclonal rho 1 antibodies (Fig. 2A, - lanes). The same result was obtained with fusion proteins for the N terminus of GABAAR subunits beta 3, gamma 2, and delta  (Fig. 2B, - lanes), whereas the rho 1 antigen could easily be detected under the applied conditions (Fig. 2B, lane A). In both experiments, however, specific signals were obtained with the antibodies against GABAAR and GlyR subunits (Fig. 2, + lanes). Cross-reactivity was absent also in intact HEK-293 cells transfected with GABAAR subunits alpha 1-3, beta 1-3, gamma 2, and GlyR subunits alpha 1 and beta , whereas clear labeling was seen after staining the cells with the specific GABAAR or GlyR antibodies (not shown). Finally, when antibodies against GABAAR or GlyR subunits were preincubated with rho 1 antigen, labeling of HEK-293 cells transfected with those subunits was not prevented (not shown), indicating specific inhibition of our rho 1 antibodies by the antigen. In conclusion, our polyclonal antibodies recognize the three rho  subunits known to date, and staining can be blocked by preincubation with the antigen. Cross-reactivity to GABAAR or GlyR subunits could not be detected under various conditions.

Fig. 2. Cross-reactivity of rho 1 polyclonal antibodies with GABAAR and GlyR subunits. A, Western blots of HEK-293 cell membranes containing GABAAR alpha 1, alpha 3, or GlyR alpha 1, beta  subunits. Expression of these proteins is detected after incubation with subunit-specific antibodies (+ lanes), whereas incubation with the rho 1 polyclonal antibodies shows no signal (- lanes). The low molecular weight marker (Biorad) is indicated on the left. B, Western blots of bacterial fusion proteins of GABAAR beta 3, gamma 2, and delta  subunit N termini showing specific labeling with subunit-specific antibodies (+), but no signal for the rho 1 polyclonal antibodies (-). Under these conditions, 20 ng of the rho 1 antigen can be detected (lane A). Signals lower than the expected molecular weight of a subunit are probably attributable to cleavage of the protein by proteases. Low molecular weight marker as in A.
[View Larger Version of this Image (34K GIF file)]

Localization of the rho  subunits in mammalian retinae

Vertical sections of rat, rabbit, cat, and monkey retinae were immunostained with the antibodies against the rho 1 subunit. Figure 3 shows fluorescence micrographs of rat (Fig. 3A), macaque monkey (Fig. 3B), and rabbit (Fig. 3C) retinae. The general labeling pattern is similar, and strong punctate immunoreactivity is found throughout the inner plexiform layer (IPL). Weaker, but specific, immunoreactivity is also present in the outer plexiform layer (OPL). The labeling pattern of the cat retina (not shown) is in close agreement with the results from rat, rabbit, and monkey retinae. The punctate immunofluorescence is not homogeneously distributed within the IPL of the rat retina (Fig. 3A). Rather, several distinct bands can be recognized.
Fig. 3. Fluorescence micrographs of vertical cryostat sections through rat, monkey, and rabbit retinae that were immunolabeled for the rho  subunits (Cy3-coupled secondary antibodies). The Nomarski micrographs to the right show the retinal layering. IS, Inner segments; ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer. Scale bar, 50 µm. A, In the rat retina, strong punctate immunolabeling is found in discrete bands in the IPL. There is also distinct fluorescence in the OPL, and some cell bodies in the outer part of the INL are faintly labeled. B, In the macaque monkey retina, strong punctate immunoreactivity is found throughout the IPL. Close to the GCL, a band of more brightly labeled, larger puncta becomes apparent. In the OPL, faint dashed labeling can be observed; single dashes probably represent the dendritic tops of cone bipolar cells at the position of individual cone pedicles. Some bipolar cell bodies are faintly labeled. C, In the rabbit retina, strong punctate immunofluorescence can be observed in the IPL, and there is a slight indication of lamination. In the OPL, dashed labeling can be observed. The punctate label of inner/outer segments is nonspecific and has been observed with many rabbit antisera.
[View Larger Version of this Image (137K GIF file)]

Our previous light microscopic studies of the localization of glycine and GABA receptors also revealed a punctate immunofluorescence that was shown by electron microscopy to correspond to a clustering of the receptors at postsynaptic sites (Grünert and Wässle, 1993; Sassoè-Pognetto et al., 1994; Greferath et al., 1995). The punctate labeling of the IPL in Figure 3 is closely similar, and we interpret the puncta as an aggregation of rho  subunits at postsynaptic sites. However, only electron microscopy will be able to show this convincingly. The question is at which processes the immunoreactive puncta might be localized. The previous finding by in situ hybridization that rod bipolar (RB) cells express rho 1 and rho 2 messages (Enz et al., 1995) indicates that the immunoreactive puncta might be localized on RB cells. We investigate this possibility in the following section.

RB cells express punctate immunoreactivity for the rho  subunits

Double-immunofluorescence experiments were performed on vertical sections of the rat retina (Fig. 4). Labeling for the rho  subunits (Fig. 4A) was revealed with secondary antibodies coupled to Cy3. RB cells (Fig. 4B) were labeled with an antibody against the alpha -isoform of PKC and visualized with secondary antibodies coupled to FITC. Their cell bodies are in the outer part of the inner nuclear layer (INL), and their axons descend to the inner margin of the IPL where they terminate in a broad band of varicose swellings. The RB cell dendrites form the outer margin of the OPL. Comparison of the staining pattern in the OPL of Figure 4, A and B, suggests that the RB cell dendrites express weak immunoreactivity for the rho  subunits (arrowheads). Closer inspection with high-power objectives suggests an aggregation of the rho  subunits on the dendritic tips of RB cells. Enlarged micrographs of the inner half of the IPL of Figure 4, A and B, are shown, respectively, in Figure 4, C and D. The punctate immunofluorescence becomes apparent in Figure 4C. A point-by-point comparison between C and D of Figure 4 (arrows) shows that the immunoreactive puncta form aggregates that correspond to the varicose swellings of RB cell axon terminals. Inspection with high- power objectives and changing the focus of the microscope shows convincingly that the puncta coincide with the axon terminal membrane of RB cells. However, only electron microscopy can prove this definitely.
Fig. 4. Fluorescence micrographs of a vertical cryostat section through a rat retina that was double-immunolabeled for the rho  subunits and for PKC. A, The strong punctate fluorescence specific for the rho  subunits becomes apparent in the IPL. Note also the weaker and partly punctate label in the OPL (arrowheads). B, PKC immunoreactive RB cells and some few amacrine cells can be seen (retinal layers as in Fig. 3). C, Part of the IPL in A shown at higher magnification. D, Part of the IPL in B shown at higher magnification. Many puncta at the lower half of C colocalize with RB axon terminals in D. Scale bar, 10 µm in C and D.
[View Larger Version of this Image (138K GIF file)]

Dissociated rat retinae were investigated to corroborate the localization of the immunoreactive puncta on the RB axons. It has been shown previously that all cells in the dissociates that have the typical appearance of bipolar cells are RB cells (Karschin und Wässle, 1990). Nomarski micrographs of typical dissociated RB cells are shown in Figure 5, A and C. These cells have small cell bodies and long axons that terminate in varicose swellings. Most of the dendritic processes have been lost during dissociation. The culture dish was immunostained for the rho  subunits, and the corresponding fluorescence micrographs (Fig. 5B,D) show a concentration of the label at the axon terminal. Punctate immunofluorescence is present in Figure 5D along the descending axon (arrows) and on the varicose axon terminal system.

Fig. 5. Micrographs of dissociated RB cells of the rat retina. A and C are Nomarski micrographs of two RB cells. B and D are the corresponding fluorescence micrographs showing immunoreactivity for the rho  subunits. Labeling is strongest in the axon terminals. Puncta of stronger immunofluorescence possibly represent clustering of the subunits at postsynaptic sites. Scale bar, 10 µm.
[View Larger Version of this Image (65K GIF file)]

Do cone bipolar cells express punctate immunoreactivity for the rho  subunits?

Punctate immunofluorescence within the IPL (Figs. 3, 4) is not restricted to the inner part where RB cells terminate, but exists across the entire IPL. This suggests localization of the puncta not only on RB cell axon terminals, but also on cone bipolar (CB) cell axon terminals. Most of the markers, such as recoverin, that specifically label CB cells of the rat retina (Milam et al., 1993; Euler and Wässle, 1995) could not be applied here because they were raised in the same species (rabbit) as the rho 1 antibodies. Therefore, we addressed this question for the macaque monkey retina, where PKC immunoreactivity is found in RB cells and in the type DB4 cone bipolar cell (Grünert et al., 1994). A vertical section through parafoveal monkey retina is shown in Figure 6A. Strong labeling of RB cell dendrites in the OPL, of RB cell perikarya in the INL, and of RB cell axon terminals at the inner margin of the IPL is apparent. However, as indicated by the two horizontal arrows in Figure 6A, there is also a band of small varicosities more toward the center of the IPL. These have been shown previously to correspond to the axon terminals of DB4 cone bipolar cells (Grünert et al., 1994). Figure 6, B and C, shows, respectively, a section of a macaque monkey retina that was double-labeled for PKC immunoreactivity (Fig. 6B) and for rho  subunit immunoreactivity (Fig. 6C). Comparison of the labeling of the OPL in Figure 6, B and C, reveals differences. Only the flat tops of putative CB cells are significantly labeled in Figure 6C (arrowheads); no labeling of RB cell dendrites can be observed. It is possible that the density of GABAC receptors at RB cell dendrites in the monkey retina is low. The IPL of Figure 6, B and C, is shown at higher magnification in Figure 6, D and E, respectively. The axons of RB cells terminate in large varicosities at the inner margin of the IPL (Fig. 6E, bottom). Comparison with Figure 6D shows that many of the immunoreactive puncta coincide with such RB cell axon terminals. Toward the center of the IPL in Figure 6E, several axonal varicosities of putative DB4 cells are shown (small arrows). Immunoreactive puncta that would be colocalized with these varicosities are depicted in Figure 6D (small arrows). This suggests that rho  immunoreactive puncta are present on RB as well as on DB4 cell axon terminals. However, punctate immunoflurescence is also present in the outer part of the IPL, suggesting that other bipolar cells express clusters of rho  subunits.
Fig. 6. Fluorescence micrographs of vertical cryostat sections through the parafoveal retina of a macaque monkey. A, PKC immunoreactivity is found in RB cells. As indicated by the two horizontal arrows, there is a second band of smaller varicosities slightly below the center of the IPL. This has been shown previously (Grünert et al., 1994) to represent the axon terminals of cone bipolar cell DB4. B and C show a section that was double-labeled for PKC and the rho  subunits, respectively. Note that the RB cells that are prominently labeled in B have many dendritic terminals in the OPL. These terminals are not labeled in C. Instead, as indicated by the arrowheads, flat tops of putative CB cells are labeled. D is a magnified print of C, and E is a magnified print of B. Comparison of the lower parts of D and E shows that many rho  immunoreactive puncta colocalize with RB axon terminals. Colocalizations can also be observed (small arrows) for the smaller axonal varicosities of DB4 cells, which are found more toward the center of the IPL. Scale bar, 10 µm in D and E.
[View Larger Version of this Image (143K GIF file)]

This possibility was investigated more directly by double labeling monkey retinae with an antibody against calbindin (CaBP-D28K) and with the antisera against the rho 1 subunit. It was shown previously that antibodies against calbindin label the diffuse bipolar cell type DB3 (Grünert et al., 1994). Figure 7A shows the calbindin immunofluorescence. Cones and DB3 cells are strongly labeled; horizontal cells and some amacrine cells are weakly labeled. The axons of the DB3 cells terminate in a narrow stratum in the outer half of the IPL, where they form a sparse band of varicosities (arrowheads in Fig. 7A). Figure 7B shows the rho  immunofluorescence. Strong punctate label is present throughout the IPL, and (as indicated by the arrowheads) punctate label is also present in the stratum where DB3 axons terminate. However, higher resolution is needed to find immunoreactive puncta on the DB3 axon terminals. Figure 7, D and E, shows the IPL of a double-labeled section at higher magnification. Several DB3 axonal varicosities can be seen in Figure 7D (three of them are marked by small white arrows). The distribution of rho  immunoreactive puncta in the IPL is shown in Figure 7E, where there are several examples of colocalizations of immunoreactive puncta and DB3 axonal varicosities (arrows).

Fig. 7. Fluorescence micrographs of vertical cryostat sections through the parafoveal retina of a macaque monkey. The sections were double-immunolabeled for the rho  subunits and for calbindin. A, Cones and some DB3 cone bipolars are strongly immunoreactive for calbinden. The axon terminals of DB3 cells form a narrow band of varicosities in the outer part of the IPL (arrowheads). The retinal layers are indicated in the Nomarski micrograph (C). Abbreviations as in Figure 3. B, Same section as in A, but revealing the localization of the rho  subunits. Strong punctate fluorescence is found throughout the IPL, including the stratum where DB3 cells have their axon terminals (arrowheads). D and E show the IPL of a double-immunolabeled section at higher magnification. Some calbindin-immunoreactive DB3 axonal varicosities are in focus in D (small arrows). The arrows in E show rho -immunoreactive puncta that would be colocalized with these varicosities. Scale bar, 50 µm in A-C and 20 µm in D and E.
[View Larger Version of this Image (111K GIF file)]

This result was further quantified. High-power prints of 13 sections double-labeled for calbindin and the rho  subunits were made. The axon terminals of DB3 cells were traced onto acetate foil, and the number of rho  immunoreactive puncta coinciding with the axonal varicosities were counted. Of the 157 varicosities encountered, 97 did not coincide with a rho  punctum; 47 coincided with one rho  punctum, and only 13 coincided with two or more puncta. The average number of puncta per varicosity was 0.5. The same analysis was also performed for PKC/rho double-labeling experiments (Fig. 6). Only axonal varicosities of RB cells terminating close to the ganglion cell layer were considered. RB cell axonal varicosities are comparable in size to those of DB3 cells. Of the 189 RB cell varicosities, 9 did not coincide with a rho  punctum; 59 coincided with one punctum and 121 coincided with two or more puncta. The average number of puncta per varicosity was 2.2. Thus, there are approximately four times as many rho  puncta on RB axonal varicosities as on DB3 cells. The bright immunofluorescence at the inner margin of the IPL in Figures 3B and 7B is in accordance with the strong expression of the rho  subunits by RB cells in the primate retina.

DISCUSSION

Specificity of the antibodies

We have raised polyclonal antibodies against the rho 1 subunit to study the localization of GABAC receptors in the mammalian retina. The antibodies were directed against the N-terminal region (position 16-171) of the rat rho 1 subunit. This region is different from that of the well known GABAA receptor or glycine receptor subunits: <60% sequence similarity is present. The specificity of the antibodies was confirmed on Western blots and with HEK-293 cells transfected against GABAA R subunits alpha 1-3, beta 1-3, gamma 2, and delta , or GlyR alpha 1 and beta  subunits. Most of these subunits previously had been localized to different cell types of the retina (Hughes et al., 1991; Brecha, 1992; Vardi et al., 1992; Greferath et al., 1993, 1995; Grigorenko and Yeh, 1994; Enz and Bormann, 1995). Both of the experiments with transfected cells and with Western blots (Figs. 1, 2), as well as the staining pattern of the retina (Figs. 3, 4, 5, 6, 7), show that the antibodies against the rho 1 subunit do not recognize GABAAR or GlyR subunits. However, the N-terminal region (position 16-171) of the rho 1 subunit is highly similar to the rho 2 (82%) and to the rho 3 (78%) subunits. From position 78-171, this similarity reaches 94% (rho 2) and 93% (rho 3), respectively. Therefore, it is not surprising that our antibodies recognize the rho 1, rho 2, and rho 3 subunits (Fig. 1). We also tried to raise antibodies against shorter parts of the N-terminal as well as the cytoplasmic region, where rho 1, rho 2, and rho 3 show less similarities. However, these attempts were unsuccessful.

Localization of the rho  subunit to rod bipolar cells

The double-labeling experiments using an antibody against PKC and the antibodies against the rho 1 subunit showed convincingly the localization of rho  subunit immunoreactive puncta on the axon terminals of RB cells in the inner part of the IPL. Previous electron microscopic studies of the RB axon terminals in the cat (Sterling and Lampson, 1986), macaque monkey (Grünert and Martin, 1991), rabbit (Strettoi et al., 1990), and rat retina (Chun et al., 1993) showed that they receive their major input from amacrine cells in the inner third of the IPL. Most of this input actually is localized on the axonal varicosities. The great number of rho -immunoreactive puncta on the varicosities is in accordance with these ultrastructural results. There was also a weak but distinct labeling of the extrasynaptic membranes of RB cells. Their cell bodies and dendrites seem to express low amounts of rho  subunits. In well stained sections, dendritic tips of rod bipolar cells that are inserted into the rod spherules could be observed. This suggests that GABA released from horizontal cells might influence RB cells in the OPL through rho  subunits. However, the strong punctate immunofluorescence in the IPL suggests that the density of rho  subunits in these ``hot spots'' is substantially higher. Electrophysiological results are in accordance with this differential distribution of the rho  subunits. When GABA was applied to dissociated RB cells (Karschin and Wässle, 1990; Suzuki et al., 1990; Gillette and Dacheux, 1995), responses from the axon terminals were considerably larger than somatic or dendritic responses.

There is evidence from electrophysiology (Feigenspan et al., 1993; Feigenspan and Bormann, 1994a) and from histology (for review, see Greferath et al., 1995) that RB cells also express conventional bicuculline-sensitive GABAA receptors in addition to GABAC receptors. The evidence is strong for the expression of the alpha 1 and gamma 2 subunits and less so for the beta 2/3 subunits. Immunoreactivity for the alpha 1 and gamma 2 subunits is punctate, suggesting that these subunits are concentrated at postsynaptic sites comparable to the rho  subunits described here. This raises the interesting question of whether the rho  subunits and the alpha 1 or gamma 2 subunits occur in the same puncta, or whether they are expressed at different synapses. One also would like to know whether the rho  subunits form homomeric receptors or whether they coassemble with specific subunits of the GABAA receptor. It has been shown that GABAA receptor subunits alpha 1, beta 1, and gamma 2 do not coassemble with the rho 1 subunit (Shimada et al., 1992).

Localization of the rho  subunit to cone bipolar cells

There is no evidence that amacrine or ganglion cells express the rho  subunits. Extrasynaptic, diffuse labeling of amacrine or ganglion cell bodies was not observed in the present immunocytochemical study, and immunoreactive puncta did not decorate their cell body outlines. Such labeling has been observed with antibodies against certain subunits of the GABAA receptor (Greferath et al., 1995). In a previous in situ hybridization experiment, message for the rho 1 or rho 2 subunits was largely restricted to bipolar cell bodies (Enz et al., 1995). Finally, GABA-induced currents of amacrine and ganglion cells could be reliably blocked by the application of bicuculline (Ishida, 1992; Boos et al., 1993; Feigenspan et al., 1993) and thus are mediated by GABAA receptors. We therefore interpret the punctate label found throughout the IPL as expression of the rho  subunits by CB cell axons and not as labeling of amacrine or ganglion cell processes. There are approximately 10 types of CB cells in the mammalian retina (cat: Famiglietti, 1981; Kolb et al., 1981; McGuire et al., 1984; Pourcho and Goebel, 1987; Cohen and Sterling, 1990a,b; rabbit: Famiglietti, 1981; Mills and Massey, 1992; Jeon and Masland, 1995; monkey: Boycott and Wässle, 1991; rat: Euler and Wässle, 1995). Their axons terminate in different strata of the IPL: those of OFF-CB cells in the outer part, and those of ON-CB cells in the inner part. Because rho  immunoreactivity is present throughout the IPL, both ON- and OFF-CB cells must be labeled. This was shown here directly for two types of CB cells of the macaque monkey retina. Puncta of rho  immunoreactivity were found both on DB3 cells, which are putative OFF-bipolars, and on DB4 cells, which are putative ON-bipolars. Patch-clamp recordings from different types of CB cells in a rat retina slice preparation (Euler et al., 1996) have revealed bicuculline-resistant GABAC responses in both RB and in different types of CB cells.

As in the case of RB cells, there was also a weak diffuse labeling of the extrasynaptic membranes of CB cells. This also holds for their dendrites in the OPL. The dashed labeling, found in the OPL of rabbit and monkey retinae (Figs. 3B,C), suggests that more labeling might be present on dendritic terminals contacted by cone pedicles. Hence, GABA released from horizontal cells would have access to GABAC receptor there.

The question of whether all CB cells express the rho  subunits cannot be answered at present. Punctate labeling of the IPL of the monkey retina is not particularly strong in the strata where midget bipolar cells terminate, and it is possible that midget bipolar cells express only low amounts of the rho  subunit.

Physiological role of GABAC receptors

GABAC receptors are 10 times more sensitive to GABA than GABAA receptors (Polenzani et al., 1991; Feigenspan and Bormann, 1994a), and they show a weaker steady-state desensitization than the GABAA subtype (Polenzani et al., 1991; Qian and Dowling, 1993). Thus, gating of GABAC receptors on dendrites and axon terminals of bipolar cells is expected to occur at very low GABA concentrations and to be more efficacious than that of GABAA receptors (Bormann and Feigenspan, 1995). GABAA receptors are upregulated by substances such as dopamine, adenosine, histamine, enkephalin, somatostatin (Feigenspan and Bormann, 1994c), or vasoactive intestinal peptide (Veruki and Yeh, 1992, 1994; Feigenspan and Bormann, 1994c). The signal chain involves protein kinase A. GABAC receptors are downregulated by serotonin or glutamate via activation of PKC (Feigenspan and Bormann, 1994b; Kusama et al., 1995). The preferential labeling by PKC immunoreactivity of RB cells might be important in this context.

GABAergic amacrine cells are presynaptic to GABA receptor clusters in the IPL. They comprise many different morphological types (Vaney, 1990) and colocalize with many other neuroactive substances, which they perhaps corelease with GABA (Brecha et al., 1984, 1988; Massey and Redburn, 1987; Kosaka et al., 1988; Vaney and Young, 1988; Vaney, 1990; Wässle and Boycott, 1991). It is possible that there is a close match between the type of amacrine cell that provides the presynaptic terminal and the type of GABA receptor that is clustered at the postsynaptic site. More ultrastructural information is needed to determine, for instance, whether rho  subunits are clustered at the postsynaptic sites of certain types of amacrine cells. Further questions concern the distribution of rho 1, rho 2, and rho 3 subunits. RT-PCR studies with single RB cells in the rat retina indicated that the rho 2 subunit is expressed at a much higher level than the rho 1 subunit (Enz et al., 1995). This result was confirmed by Zhang et al. (1995b) using Northern hybridization and primer extension techniques. Preferential expression of the rho 2 subunit over the rho 1 subunit in rat bipolar cells raises the question of how oligomeric GABAC receptors are composed of these two proteins. Clearly, subunit-specific antibodies for all three rho  subunits are needed to understand the synaptic details of GABAC receptor localization.

FOOTNOTES

Received Feb. 16, 1996; revised April 19, 1996; accepted April 24, 1996.

  

This work was supported by the Deutsche Forschungsgemeinschaft (SFB 269) and the Fonds der Chemischen Industrie. We thank Anja Leihkauf, Ursula Arbogast, and Felicitas Boij for excellent technical assistance, Irmgard Odenthal for typing, Joachim Kirsch for providing the mAb4a antibody and for help with transfected cells, Hanns Möhler for supplying GABAA receptor antibodies, George R. Uhl for the gift of the human rho 1 cDNA, Peter H. Seeburg and Heinrich Betz for providing GABAA and glycine receptor subunit cDNAs, and David Calkins for reading and improving this manuscript.

Correspondence should be addressed to Joachim Bormann, Max-Planck-Institut für Hirnforschung, Deutschordenstrasse 46, D-60528 Frankfurt, Germany.


REFERENCES

  • Albrecht BE, Darlison MG (1995) Localization of the rho 1- and rho 2-subunit messenger RNAs in chick retina by in situ hybridization predicts the existence of gamma -aminobutyric acid type C receptor subtypes. Neurosci Lett 189:155-158 . [Web of Science][Medline]
  • Benke D, Cicin-Sain A, Mertens S, Möhler H (1991a) Immunochemical identification of the alpha 1- and alpha 3-subunits of the GABAA-receptor in rat brain. J Recept Res 11:407-424 . [Web of Science][Medline]
  • Benke D, Mertens S, Trzeciak A, Gillessen D, Möhler H (1991b) Identification and immunohistochemical mapping of GABAA receptor subtypes containing the delta -subunit in rat brain. FEBS Lett 283:145-149 . [Web of Science][Medline]
  • Boos R, Schneider H, Wässle H (1993) Voltage- and transmitter-gated currents of AII-amacrine cells in a slice preparation of the rat retina. J Neurosci 13:2874-2888 . [Abstract]
  • Bormann J (1988) Electrophysiology of GABAA and GABAB receptor subtypes. Trends Neurosci 11:112-116 . [Web of Science][Medline]
  • Bormann J, Feigenspan A (1995) GABAC receptors. Trends Neurosci 12:515-521.
  • Bormann J, Hamill OP, Sakmann B (1987) Mechanism of anion permeation through channels gated by glycine and gamma -aminobutyric acid in mouse cultured spinal neurones. J Physiol (Lond) 385:243-286 . [Abstract/Free Full Text]
  • Bowery N (1989) GABAB receptors and their significance in mammalian pharmacology. Trends Pharmacol Sci 10:401-407 . [Medline]
  • Boycott BB, Wässle H (1991) Morphological classification of bipolar cells in the macaque monkey retina. Eur J Neurosci 3:1069-1088. [Web of Science][Medline]
  • Brecha NC (1992) Expression of GABAA receptors in the vertebrate retina. Prog Brain Res 90:3-28 . [Web of Science][Medline]
  • Brecha NC, Oyster CW, Takahashi ES (1984) Identification and characterization of tyrosine hydroxylase immunoreactive amacrine cells. Invest Ophthalmol Vis Sci 25:66-70 . [Abstract]
  • Brecha NC, Johnson D, Peichl L, Wässle H (1988) Cholinergic amacrine cells of the rabbit retina contain glutamate decarboxylase and gamma -aminobutyrate immunoreactivity. Proc Natl Acad Sci USA 85:6187-6191. [Abstract/Free Full Text]
  • Chen C, Okayama H (1987) High-efficiency transformation of mammilian cells by plasmid DNA. Mol Cell Biol 7:2745-2752 . [Abstract/Free Full Text]
  • Chomczynski P, Sacchi N (1987) Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem 162:156-159 . [Web of Science][Medline]
  • Chun M-H, Han S-H, Chung J-W, Wässle H (1993) Electron microscopic analysis of the rod pathway of the rat retina. J Comp Neurol 332:421-432 . [Web of Science][Medline]
  • Cohen E, Sterling P (1990a) Demonstration of cell types among cone bipolar neurons of cat retina. Philos Trans R Soc Lond Biol 330:305-321 . [Web of Science][Medline]
  • Cohen E, Sterling P (1990b) Convergence and divergence of cones onto bipolar cells in the central area of the cat retina. Philos Trans R Soc Lond Biol 330:323-328 . [Web of Science][Medline]
  • Cutting GR, Lu L, O'Hara BF, Kasch LM, Montrose-Rafizadeh C, Donovan DM, Shimada S, Antonarakis SE, Guggino WB, Uhl GR, Kazazian HH Jr (1991) Cloning of the gamma -aminobutyric acid (GABA) rho 1 cDNA: a GABA receptor subunit highly expressed in the retina. Proc Natl Acad Sci USA 88:2673-2677 . [Abstract/Free Full Text]
  • Cutting GR, Curristin S, Zoghbi H, O'Hara B, Seldin MF, Uhl GR (1992) Identification of a putative gamma -aminobutyric acid (GABA) receptor subunit rho2 cDNA and colocalization of the genes encoding rho2 (GABRR2) and rho1 (GABRR1) to human chromosome 6q14-q21 and mouse chromosome 4. Genomics 12:801-806 . [Web of Science][Medline]
  • Dong C-J, Picaud SA, Werblin FS (1994) GABA transporters and GABAC-like receptors on catfish cone- but not rod-driven horizontal cells. J Neurosci 14:2648-2658 . [Abstract]
  • Drew CA, Johnston GAR (1992) Bicuculline- and baclofen-insensitive gamma -aminobutyric acid binding to rat cerebellar membranes. J Neurochem 58:1087-1092 . [Web of Science][Medline]
  • Drew CA, Johnston GAR, Weatherby RP (1984) Bicuculline-insensitive GABA receptors: studies on the binding of (-)-baclofen to rat cerebellar membranes. Neurosci Lett 52:317-321 . [Web of Science][Medline]
  • Enz R, Bormann J (1995) Expression of glycine receptor subunits and gephyrin in single bipolar cells of the rat retina. Vis Neurosci 12:501-507 . [Web of Science][Medline]
  • Enz R, Brandstätter JH, Hartveit E, Wässle H, Bormann J (1995) Expression of GABA receptor rho 1 and rho 2 subunits in the retina and brain of the rat. Eur J Neurosci 7:1495-1501 . [Web of Science][Medline]
  • Euler T, Wässle H (1995) Immunocytochemical identification of cone bipolar cells in the rat retina. J Comp Neurol 361:461-478 . [Web of Science][Medline]
  • Euler T, Schneider H, Wässle H (1996) Glutamate responses of bipolar cells in a slice preparation of the rat retina. J Neurosci 16:2934-2944 . [Abstract/Free Full Text]
  • Ewert M, deBlas AL, Möhler H, Seeburg PH (1992) A prominent epitope on GABAA receptors is recognized by two different monoclonal antibodies. Brain Res 569:57-62 . [Web of Science][Medline]
  • Famiglietti EV (1981) Functional architecture of cone bipolar cells in mammalian retina. Vision Res 21:1559-1563 . [Web of Science][Medline]
  • Feigenspan A, Bormann J (1994a) Differential pharmacology of GABAA and GABAC receptors on rat retinal bipolar cells. Eur J Pharmacol Mol Pharmacol Sect 288:97-104 . [Web of Science][Medline]
  • Feigenspan A, Bormann J (1994b) Modulation of GABAC receptors in rat retinal bipolar cells by protein kinase C. J Physiol (Lond) 481:325-330 . [Abstract/Free Full Text]
  • Feigenspan A, Bormann J (1994c) Facilitation of GABAergic signaling in the retina by receptors stimulating adenylate cyclase. Proc Natl Acad Sci USA 91:10893-10897 . [Abstract/Free Full Text]
  • Feigenspan A, Wässle H, Bormann J (1993) Pharmacology of GABA receptor Cl- channels in rat retinal bipolar cells. Nature 361:159-162 . [Medline]
  • Gao B, Fritschy JM, Benke D, Möhler H (1993) Neuron specific expression of GABAA-receptor subtypes: differential association of the alpha 1- and alpha 3- subunits with serotonergic and GABAergic neurons. Neuroscience 54:881-892 . [Web of Science][Medline]
  • Gillette MA, Dacheux RF (1995) GABA- and glycine-activated currents in the rod bipolar cell of the rabbit retina. J Neurophysiol 74:856-875 . [Abstract/Free Full Text]
  • Greferath U, Grünert U, Wässle H (1990) Rod bipolar cells in the mammalian retina show protein kinase C-like immunoreactivity. J Comp Neurol 301:433-442 . [Web of Science][Medline]
  • Greferath U, Müller F, Wässle H, Shivers B, Seeburg P (1993) Localization of GABAA receptors in the rat retina. Vis Neurosci 10:551-561 . [Web of Science][Medline]
  • Greferath U, Grünert U, Fritschy JM, Stephenson A, Möhler H, Wässle H (1995) GABAA receptor subunits have differential distributions in the rat retina: in situ hybridization and immunohistochemistry. J Comp Neurol 353:553-571 . [Web of Science][Medline]
  • Grigorenko EV, Yeh HH (1994) Expression profiling of GABAA receptor beta -subunits in the rat retina. Vis Neurosci 11:379-387 . [Web of Science][Medline]
  • Grünert U, Martin PR (1991) Rod bipolar cells in the macaque monkey retina: immunoreactivity and connectivity. J Neurosci 11:2742-2758 . [Abstract]
  • Grünert U, Wässle H (1993) Immunocytochemical localization of glycine receptors in the mammalian retina. J Comp Neurol 335:523-537 . [Web of Science][Medline]
  • Grünert U, Martin PR, Wässle H (1994) Immunocytochemical analysis of bipolar cells in the macaque monkey retina. J Comp Neurol 348:607-627 . [Web of Science][Medline]
  • Huba R, Hofmann HD (1988) Tetanus toxin binding to isolated and cultured rat retinal glial cells. Glia 1:156-164 . [Web of Science][Medline]
  • Hughes TE, Grünert U, Karten HJ (1991) GABAA receptors in the retina of the cat: an immunohistochemical study of wholemounts, sections, and dissociated cells. Vis Neurosci 6:229-238 . [Web of Science][Medline]
  • Ishida AT (1992) The physiology of GABAA receptors in retinal neurons. In: Progress in brain research (Mize, RR, Marc, RE, Sillito, AM, eds) , p. 29. Amsterdam: Elsevier.
  • Jeon C-J, Masland RH (1995) A population of wide-field bipolar cells in the rabbit's retina. J Comp Neurol 360:403-412 . [Web of Science][Medline]
  • Johnston GAR, Curtis DR, Beart PM, Game CJA, McCulloch RM, Twitchin B (1975) Cis- and trans-4-aminocrotonic acid as GABA analogues of restricted conformation. J Neurochem 24:157-160. [Web of Science][Medline]
  • Karschin A, Wässle H (1990) Voltage- and transmitter-gated currents in isolated rod bipolar cells of the rat retina. J Neurophysiol 63:860-876 . [Abstract/Free Full Text]
  • Kolb H, Nelson R, Mariani A (1981) Amacrine cells, bipolar cells and ganglion cells of the cat retina. Vision Res 21:1081-1114 . [Web of Science][Medline]
  • Kosaka T, Tauchi M, Dahl JL (1988) Cholinergic neurons containing GABA-like and/or glutamic acid decarboxylase-like immunoreactivities in various brain regions of the rat. Exp Brain Res 70:605-617 . [Web of Science][Medline]
  • Kusama T, Spivak CE, Whiting P, Dawson VL, Schaeffer JC, Uhl GR (1993a) Pharmacology of GABA rho 1 and GABA alpha /beta receptors expressed in Xenopus oocytes and COS cells. Br J Pharmacol 109:200-206 . [Web of Science][Medline]
  • Kusama T, Wang T-L, Guggino WB, Cutting GR, Uhl GR (1993b) GABA rho 2 receptor pharmacological profile: GABA recognition site similarities to rho 1. Eur J Pharmacol 245:83-84 . [Web of Science][Medline]
  • Kusama T, Sakurai M, Kizawa Y, Uhl GR, Murakami H (1995) GABA rho 1 receptor: inhibition by protein kinase C activators. Eur J Pharmacol Mol Pharmacol Sect 291:431-434. [Web of Science][Medline]
  • Laemmli UK (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680-685 . [Medline]
  • Lukasiewicz PD, Maple BR, Werblin FS (1994) A novel GABA receptor on bipolar cell terminals in the tiger salamander retina. J Neurosci 14:1202-1212 . [Abstract]
  • Macdonald RL, Olsen RW (1994) GABAA receptor channels. Annu Rev Neurosci 17:569-602 . [Web of Science][Medline]
  • Marksitzer R, Benke D, Fritschy J-M, Trzeciak A, Bannwarth W, Möhler H (1993) GABAA-receptors: drug binding profile and distribution of receptors containing the alpha 2-subunit in situ. J Recept Res 13:467-477 . [Web of Science][Medline]
  • Martina M, Strata F, Cherubini E (1995) Whole cell and single channel properties of a new GABA receptor transiently expressed in the hippocampus. J Neurophysiol 73:902-906 . [Abstract/Free Full Text]
  • Massey SC, Redburn DA (1987) Transmitter circuits in the vertebrate retina. Prog Neurobiol 28:55-96 . [Medline]
  • McGuire BA, Stevens JK, Sterling P (1984) Microcircuitry of bipolar cells in the cat retina. J Neurosci 4:2920-2938 . [Abstract]
  • Milam AH, Dacey DM, Dizhoor AM (1993) Recoverin immunoreactivity in mammalian cone bipolar cells. Vis Neurosci 10:1-12 . [Web of Science][Medline]
  • Mills SL, Massey SC (1992) Morphology of bipolar cells labeled by DAPI in the rabbit retina. J Comp Neurol 321:133-149 . [Web of Science][Medline]
  • Nistri A, Sivilotti L (1985) An unusual effect of gamma -aminobutyric acid on synaptic transmission of frog tectal neurones in vitro. Br J Pharmacol 85:917-922 . [Web of Science][Medline]
  • Ogurusu T, Shingai R (1996) Cloning of a putative gamma -aminobutyric acid (GABA) receptor subunit rho 3 cDNA. Biochim Biophys Acta 1305:15-18 . [Medline]
  • Ogurusu T, Taira H, Shingai R (1995) Identification of GABAA receptor subunits in rat retina: cloning of the GABAA receptor rho 2-subunit cDNA. J Neurochem 65:964-968 . [Web of Science][Medline]
  • Pan Z-H, Lipton SA (1995) Multiple GABA receptor subtypes mediate inhibition of calcium influx at rat retinal bipolar cell terminals. J Neurosci 15:2668-2679 . [Abstract]
  • Pfeiffer F, Simler R, Grenningloh G, Betz H (1984) Monoclonal antibodies and peptide mapping reveal structural similarities between the subunits of the glycine receptor of rat spinal cord. Proc Natl Acad Sci USA 81:7224-7227 . [Abstract/Free Full Text]
  • Polenzani L, Woodward RM, Miledi R (1991) Expression of mammalian gamma -aminobutyric acid receptors with distinct pharmacology in Xenopus oocytes. Proc Natl Acad Sci USA 88:4318-4322 . [Abstract/Free Full Text]
  • Pourcho RG, Goebel DJ (1987) A combined Golgi and autoradiographic study of 3H-glycine-accumulating cone bipolar cells in the cat retina. J Neurosci 7:1178-1188 . [Abstract]
  • Qian H, Dowling JE (1993) Novel GABA responses from rod-driven retinal horizontal cells. Nature 361:162-164 . [Medline]
  • Qian H, Dowling JE (1994) Pharmacology of novel GABA receptors found on rod horizontal cells of the white pearch retina. J Neurosci 14:4299-4307 . [Abstract]
  • Qian H, Dowling JE (1995) GABAA and GABAC receptors on hybrid bass retinal bipolar cells. J Neurophysiol 74:1920-1928 . [Abstract/Free Full Text]
  • Sanger F (1977) Determination of nucleotide sequences in DNA. Science 214:1205-1210 .
  • Sassoè-Pognetto M, Wässle H, Grünert U (1994) Glycinergic synapses in the rod pathway of the rat retina: cone bipolar cells express the alpha 1 subunit of the glycine receptor. J Neurosci 14:5131-5146 . [Abstract]
  • Schoch P, Richards J, Häring P, Takacs B, Stähli C, Staehelin T, Haefely W, Möhler H (1985) Co-localization of GABAA receptors and benzodiazepine receptors in the brain shown by monoclonal antibodies. Nature 314:168-171 . [Medline]
  • Schröder S, Hoch W, Becker C-M, Grenningloh G, Betz H (1991) Mapping of antigenic epitopes on the alpha 1 subunit of the inhibitory glycine receptor. Biochemistry 30:42-47 . [Medline]
  • Shimada S, Cutting G, Uhl GR (1992) gamma -Aminobutyric acid A or C receptor? gamma -Aminobutyric acid rho 1 receptor RNA induces bicuculline-, barbiturate-, and benzodiazepine-insensitive gamma -aminobutyric acid responses in Xenopus oocytes. Mol Pharmacol 41:683-687 . [Abstract]
  • Shivers BD, Killisch I, Sprengel R, Sontheimer H, Köhler M, Schofield PR, Seeburg PH (1989) Two novel GABAA receptor subunits exist in distinct neuronal subpopulations. Neuron 3:327-337 . [Web of Science][Medline]
  • Sieghart W (1995) Structure and pharmacology of gamma -aminobutyric acidA receptor subtypes. Pharmacol Rev 47:181-234 . [Web of Science][Medline]
  • Sivilotti L, Nistri A (1989) Pharmacology of a novel effect of gamma -aminobutyric acid on the frog optic tectum in vitro. Eur J Pharmacol 164:205-212 . [Web of Science][Medline]
  • Sivilotti L, Nistri A (1991) GABA receptor mechanism in the central nervous system. Prog Neurobiol 36:35-92 . [Web of Science][Medline]
  • Stephenson FA, Duggan MJ, Pollard S (1990) The gamma 2 subunit is an integral component of the gamma -aminobutyric acidA receptor but the alpha 1 polypeptide is the principal site of the agonist benzodiazepine photoaffinity labelling reaction. J Biol Chem 265:21160-21165 . [Abstract/Free Full Text]
  • Sterling P, Lampson LA (1986) Molecular specificity of defined types of amacrine synapse in cat retina. J Neurosci 6:1314-1324 . [Abstract]
  • Strata F, Cherubini E (1994) Transient expression of a novel type of GABA response in rat CA3 hippocampal neurones during development. J Physiol (Lond) 480:493-503 . [Abstract/Free Full Text]
  • Strettoi E, Dacheux RF, Raviola E (1990) Synaptic connections of rod bipolar cells in the inner plexiform layer of the rabbit retina. J Comp Neurol 295:449-466 . [Web of Science][Medline]
  • Suzuki S, Tachibana M, Kaneko A (1990) Effects of glycine and GABA on isolated bipolar cells of the mouse retina. J Physiol (Lond) 421:645-662 . [Abstract/Free Full Text]
  • Vaney DI (1990) The mosaic of amacrine cells in the mammalian retina. In: Progress in retinal research, (Osborne, NN, Chader, G, eds) , Vol 9, p. 49. Oxford: Pergamon.
  • Vaney DI, Young HM (1988) GABA-like immunoreactivity in cholinergic amacrine cells of the rabbit retina. Brain Res 438:369-373 . [Web of Science][Medline]
  • Vardi N, Masarchia P, Sterling P (1992) Immunoreactivity to GABAA receptor in the outer plexiform layer of the cat retina. J Comp Neurol 320:394-397 . [Web of Science][Medline]
  • Veruki ML, Yeh HH (1992) Vasoactive intestinal polypeptide modulates GABAA receptor function in bipolar cells and ganglion cells of the rat retina. J Neurophysiol 67:791-797 . [Abstract/Free Full Text]
  • Veruki ML, Yeh HH (1994) Vasoactive intestinal polypeptide modulates GABAA receptor function through activation of cyclic AMP. Vis Neurosci 11:899-908 . [Web of Science][Medline]
  • Walker JM, Homan EC, Sando JJ (1990) Differential activation of protein kinase C isozymes by short chain phosphatidylserines and phosphatidylcholines. J Biol Chem 265:8016-8021 . [Abstract/Free Full Text]
  • Wang T-L, Guggino WB, Cutting GR (1994) A novel gamma -aminobutyric acid receptor subunit (rho 2) cloned from human retina forms bicuculline-insensitive homo-oligomeric receptors in Xenopus oocytes. J Neurosci 14:6524-6531 . [Abstract]
  • Wässle H, Boycott BB (1991) Functional architecture of the mammalian retina. Physiol Rev 71:447-480 . [Free Full Text]
  • Ymer S, Schofield PR, Draguhn A, Werner P, Köhler M, Seeburg PH (1989) GABAA receptor beta  subunit heterogeneity: functional expression of cloned cDNAs. EMBO J 8:1665-1670 . [Web of Science][Medline]
  • Zhang J, Slaughter MM (1995) Preferential suppression of the ON pathway by GABAC receptors in the amphibian retina. J Neurophysiol 74:1583-1592. [Abstract/Free Full Text]
  • Zhang D, Pan Z-H, Zhang X, Brideau AD, Lipton SA (1995a) Cloning of a gamma -aminobutyric acid type C receptor subunit in rat retina with a methionine residue critical for picrotoxinin channel block. Proc Natl Acad Sci USA 92:11756-11760 . [Abstract/Free Full Text]
  • Zhang D, Pan Z-H, Brideau AD, Lipton SA (1995b) GABA rho  subunits in rat retina: structure and function. Soc Neurosci Abstr 21:1035.
Copyright ©1996 Society for Neuroscience   0270-6474/1996/164479-12$05.00/0



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[Abstract] [Full Text] [PDF]

Home page
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Home page
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Home page
 J. Neurophysiol.Home page
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J Neurophysiol, March 1, 1998; 79(3): 1384 - 1395.
[Abstract] [Full Text] [PDF]

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[Abstract] [Full Text] [PDF]

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J. Neurosci., August 15, 1997; 17(16): 6075 - 6085.
[Abstract] [Full Text] [PDF]

Home page
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J. Biol. Chem., May 23, 1997; 272(21): 13750 - 13757.
[Abstract] [Full Text] [PDF]

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