QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ma, J. Y. Articles by Narahashi, T. Search for Related Content PubMed PubMed Citation Articles by Ma, J. Y. Articles by Narahashi, T.

 Previous Article  |  Next Article 

Journal of Neuroscience, Vol 14, 3835-3841, Copyright © 1994 by Society for Neuroscience

ARTICLE

Terbium modulation of single gamma-aminobutyric acid-activated chloride channels in rat dorsal root ganglion neurons

JY Ma, E Reuveny and T Narahashi
Department of Pharmacology, Northwestern University Medical School, Chicago, Illinois 60611.

We have previously reported that lanthanides markedly potentiate the GABA-induced chloride current by acting at a distinct site on the GABAA receptor-channel complex (Ma and Narahashi, 1993a,b). These studies have now been extended to the single-channel level and changes in gating kinetics of GABAA receptor currents caused by 100 microM terbium (Tb3+) are reported. The GABA-induced currents were recorded from outside-out membrane patches isolated from rat dorsal root ganglion neurons in primary culture at a holding potential of -60 mV. At least two conductance levels were recorded, a main conductance of about 26 pS (70-80% of events) and a subconductance of about 19 pS (20-30% of events). These two conductances and the ratio of main- and subconductance state currents with respect to the number of events were not changed by Tb3+. The frequency of channel openings was also unchanged in the presence of Tb3+. The frequency histograms of open, close, and burst durations of the main-conductance state were best fitted by a sum of three exponential functions. All of the time constants remained unchanged by application of Tb3+ while the relative proportions of the longest open and burst duration time constants were increased and the relative proportion of longest closed time constant was decreased. We suggest that Tb3+ binds to an allosteric site on the GABAA receptor-channel complex to increase the apparent mean open time of the channel by increasing the affinity of GABA for the GABA binding site, and/or by shifting the distribution toward the open states so that the frequency of occurrence of longer open states is stabilized.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				A. Meir, S. Ginsburg, A. Butkevich, S. G. Kachalsky, I. Kaiserman, R. Ahdut, S. Demirgoren, and R. Rahamimoff Ion Channels in Presynaptic Nerve Terminals and Control of Transmitter Release Physiol Rev, July 1, 1999; 79(3): 1019 - 1088. [Abstract] [Full Text] [PDF]

				Q.-Y. Liu, A. E. Schaffner, Y.-X. Li, V. Dunlap, and J. L. Barker Upregulation of GABAA Current by Astrocytes in Cultured Embryonic Rat Hippocampal Neurons J. Neurosci., May 1, 1996; 16(9): 2912 - 2923. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help