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A spontaneous tonic chloride conductance in solitary glutamatergic hippocampal neurons

Authors :
Eisenman, Lawrence N.
Kress, Geraldine
Zorumski, Charles F.
Mennerick, Steven
Source :
Brain Research. Nov2006, Vol. 1118 Issue 1, p66-74. 9p.
Publication Year :
2006

Abstract

Abstract: GABA-A receptors mediate both phasic synaptic inhibition and more recently appreciated tonic currents in the vertebrate central nervous system. We addressed discrepancies in the literature regarding the pharmacology of tonic currents by examining tonic currents in a controlled environment of dissociated, solitary glutamatergic neurons. We describe a novel tonically active, bicuculline-sensitive chloride conductance that is insensitive to gabazine and to picrotoxin and thus not mediated by conventional GABA receptors. We exclude a significant contribution from small conductance calcium-gated potassium (SK) channels. We also pharmacologically exclude calcium-gated chloride channels, glycine receptors and the chloride current associated with glutamate transport. Finally, we demonstrate that, although small, this current modulates neuronal excitability. We speculate that this tonic current may provide a complementary mechanism for the regulation of neuronal excitability, particularly in regions with low ambient GABA concentrations. We conclude that this bicuculline-sensitive conductance needs to be accounted for in studies of GABA tonic currents, lest it be confused with currents associated with GABA overflow. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
00068993
Volume :
1118
Issue :
1
Database :
Academic Search Index
Journal :
Brain Research
Publication Type :
Academic Journal
Accession number :
22943549
Full Text :
https://doi.org/10.1016/j.brainres.2006.08.033