Occlusion of hippocampal electrical junctions by intracellular calcium injection

doi:10.1016/0006-8993(87)90385-4

Brain Research

Volume 408, Issues 1–2, 7 April 1987, Pages 267-270

https://doi.org/10.1016/0006-8993(87)90385-4 Get rights and content

Abstract

Low-molecular weight dyes such as Lucifer yellow or car☐yfluorescein have been used to investigate the electrical connectivity of neurons via gap junctions. The interpretation that such dye passage is mediated through intercellular channels has been controversial and difficult to corroborate with direct techniques in mammalian brain. We report here that elevated intracellular free Ca²⁺, a treatment shown to cause gap junction occlusion in other tissues, significantly blocks dye transfer between hippocampal cells. Furthermore, intracellular injection of FITC-dextran (which is too large to cross gap junctions) never resulted in multiple hippocampal cell fills. These data lend strong support to the argument that the extent of dye-coupling provides a good estimate of the number of intercellular communication channels, and raises the possibility that these channels may be physiologically modulated.

Reference (27)

AlgerB.E. et al.
On the possibility of simultaneously recording from two cells with a single microelectrode in the hippocampal slice
Brain Research
(1983)
AndrewR.D. et al.
Coupling in rat hippocampal slices: dye transfer between CA₁ pyramidal cells
Brain Res. Bull.
(1982)
GraceA.A. et al.
Possible electronic coupling between sets of rat nigral dopaminergic neurons
Neuroscience
(1983)
GutnickM.J. et al.
Dye coupling and possible electrotonic coupling in the guinea pig neocortical slice
Neuroscience
(1985)
KaterS.B. et al.
Video monitoring of neuronal plasticity
TINS
(1982)
KimmelC.B. et al.
Cell lineage of zebrafish blastomeres. I. Cleavages pattern and cytoplasmic bridges between cells
Dev. Biol.
(1985)
KnowlesW.D. et al.
Electrotonic and dye coupling in hippocampal CA₁ pyramidal cells in vitro
Neuroscience
(1982)
MacVicarB.A. et al.
Dye-coupling between CA₃ pyramidal cells in slices of rat hippocampus
Brain Research
(1980)
MacVicarB.A. et al.
Uncoupling of CA₃ pyramidal neurons by propionate
Brain Research
(1985)
RaoG. et al.
Intracellular fluorescent staining with car☐yfluorescein: a rapid and reliable method for quantifying dye-coupling in mammalian central nervous system
J. Neurosci. Meth.
(1986)

SchmalbruchH. et al.

Gap junctions on CA₃ pyramidal cells of guinea pig hippocampus shown by freeze-fracture

Brain Research

(1981)

SkredeK.K. et al.

The transverse hippocampal slice: a well-defined cortical structure maintained in vitro

Brain Research

(1971)

StewartW.W.

Functional connection between cells as revealed by dye-coupling with a highly fluorescent napthalimide tracer

Cell

(1978)

Cited by (14)

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Citation Excerpt :
Ca2+]i elevation is generally considered to inhibit cell coupling in fibroblasts expressing CX43 (Dakin and Li, 2006) as well as in other cells (Baux et al., 1978). Furthermore, directly increasing the levels of cytosolic Ca2+ in hippocampal neurons leads to occlusion of dye coupling (Rao et al., 1987). These effects may be mediated directly via Ca2+-activated phosphorylation of the connexin subunits (Rorig and Sutor, 1996).
Intercellular communication through gap junctions plays an important role in fibroblast physiology. Here we report an activity-dependent neuronal control of gap-junctional communication (GJC) in rat dermal fibroblasts, which is associated with N-methyl-d-aspartate (NMDA) glutamate receptor-mediated elevations in intracellular Ca²⁺. Both spontaneous and induced activation of dorsal root ganglion (DRG) neurons, manifested by action potentials and TTX-dependent inward currents, significantly reduced fibroblast GJC in Neuron/Fibroblast (N/F) cocultures. Reduced fibroblast GJC by DRG neurons was prevented by blockade of NMDA receptors and decrease of intra- and intercellular Ca²⁺. Immunocytochemistry showed that the NR1 subunit of the NMDA receptor coexisted with CX43 at the plasma membrane of fibroblasts. Moreover, glutamate applied to fibroblast cultures triggered NMDA receptor-dependent intracellular Ca²⁺ elevations and decrease of GJC. These data demonstrate that NMDA receptor activation contributes to downregulation of GJC in fibroblasts. Since fibroblasts have been shown to facilitate DRG neurite growth and survival, our findings provide a glimpse at the impact that neuronal activation has on fibroblast networks.
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We examined the interactions of calmodulin with neuronal gap junction proteins connexin35 (Cx35) from perch, its mouse homologue Cx36, and the related perch Cx34.7 using surface plasmon resonance. Calmodulin bound to the C-terminal domains of all three connexins with rapid kinetics in a concentration- and Ca²⁺-dependent manner. Dissociation was also very rapid. K_d’s for calmodulin binding at a high-affinity site ranged from 11 to 72 nM, and K_1/2’s for Ca²⁺ were between 3 and 5 μM. No binding to the intracellular loops was observed. Binding competition experiments with synthetic peptides mapped the calmodulin binding site to a 10–30 amino acid segment at the beginning of the C-terminal domain of Cx36. The micromolar K_1/2’s and rapid on and off rates suggest that this interaction may change dynamically in neurons, and may occur transiently when Ca²⁺ is elevated to a level that would occur in the near vicinity of an activated synapse.
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A growing body of evidence suggests that highly correlated, spontaneous neural activity plays an important role in shaping connections in the developing nervous system prior to the maturation of sensory afferents. In this article we discuss the mechanisms involved in the generation and the regulation of spontaneous activity patterns in the developing retina and the developing neocortex. Spontaneous activity in the developing retina propagates across the ganglion cell layer as waves of action potentials and drives rhythmic increases in intracellular calcium in retinal neurons. Retinal waves are mediated by a combination of chemical synaptic transmission and gap junctions, and the circuitry responsible for generating retinal waves changes with age and between species. In the developing cortex, spontaneous calcium elevations propagate across clusters of cortical neurons called domains. Cortical domains are generated by a regenerative mechanism involving second messenger diffusion through gap junctions and subsequent calcium release from internal stores. The neocortical gap junction system is regulated by glutamate-triggered second messenger systems as well as neuromodulatory transmitters, suggesting extensive interactions between synaptic transmission and information flow through gap junctions. The interaction between gap junctions and chemical synaptic transmission observed in these developing networks represent a powerful mechanism by which activity across large groups of neurons can be correlated.
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: This work was supported by PHS Grants AG00243 and AG03376 to C.A.B., NS20331 to B.L.M. and BRSG Grant RR070B-86, Division of Research Resources, NIH to C.A.B.

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Occlusion of hippocampal electrical junctions by intracellular calcium injection

Abstract

Brain Research

Brain Res. Bull.

Neuroscience

Neuroscience

TINS

Dev. Biol.

Neuroscience

Brain Research

Brain Research

J. Neurosci. Meth.

Brain Research

Brain Research

Cell