Cl- channels are randomly activated by continuous GABA secretion in cultured embryonic rat hippocampal neurons.
Throughout the adult vertebrate central nervous system (CNS) gamma-aminobutyric acid (GABA) mediates transient Cl- conductances commonly identified as fast, Cl(-)-dependent inhibitory synaptic signals [Prog. Neurobiol., 36 (1991) 35-92]. In the rat hippocampus Cl(-)-dependent excitatory transients mediated by GABA emerge during the first postnatal week superimposed on a steady-state baseline that is also Cl(-)- and GABA-dependent [Int. J. Dev. Neurosci., 8 (1990) 481-490]. Here we report that many embryonic rat hippocampal neurons cultured for hours to days exhibit random fluctuations in Cl- channel activity that are mediated by continuous secretion of GABA in the absence of transients. Thus, GABA is broadcast tonically before it is released transiently.
Laboratory of Neurophysiology, NINDS, National Institutes of Health, Bethesda, MD 20892.
A Y
AY
Valeyev
R A
RA
Cruciani
G D
GD
Lange
V S
VS
Smallwood
J L
JL
Barker
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D002450:Cell Communication; D002478:Cells, Cultured; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D015640:Ion Channel Gating / Q000187:drug effects*; D008565:Membrane Proteins / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid