Ay. Valeyev et al., CL(-)CHANNELS ARE RANDOMLY ACTIVATED BY CONTINUOUS GABA SECRETION IN CULTURED EMBRYONIC RAT HIPPOCAMPAL-NEURONS, Neuroscience letters, 155(2), 1993, pp. 199-203
Throughout the adult vertebrate central nervous system (CNS) gamma-ami
nobutyric acid (GABA) mediates transient Cl- conductances commonly ide
ntified as fast, Cl--dependent inhibitory synaptic signals [Prog. Neur
obiol., 36 (1991) 35 92]. In the rat hippocampus Cl--dependent excitat
ory transients mediated by GABA emerge during the first postnatal week
superimposed on a steady-state baseline that is also Cl-- and GABA-de
pendent [Int. J.Dev. Neurosci., 8 (1990) 481-490]. Here we report that
many embryonic rat hippocampal neurons cultured for hours to days exh
ibit 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.