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.
Valeyev
A Y
AY
Laboratory of Neurophysiology, NINDS, National Institutes of Health, Bethesda, MD 20892.
Cruciani
R A
RA
Lange
G D
GD
Smallwood
V S
VS
Barker
J L
JL
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