Inhibition of GABA release from slices prepared from several brain regions of rats at various times following a convulsion.
1 A method is described for the measurement of the K+-evoked release of endogenous gamma-aminobutyric acid (GABA) from slices of rat cortex, hippocampus and striatum. 2 In tissue prepared 30 min following an electroconvulsive shock, K+-evoked GABA release (above basal release) was inhibited by 45% in cortex, 50% in hippocampus and 75% in striatum. A similar inhibition of release was observed with slices prepared from rats in which a convulsion had been induced by flurothyl. There was no change in spontaneous (basal) release following either procedure. 3 An inhibition of K+-evoked endogenous GABA release was also seen in tissue prepared 4 min postictally but not 2 h after the seizure. 4 No difference was observed in the release of [3H]-GABA from preloaded cortical slices prepared from rats given a single electroconvulsive shock. 5 It is proposed that a convulsion results in an inhibition of GABA release and that this inhibition may in turn inhibit GABA synthesis as described in the preceding paper. 6 It is also proposed that changes in the endogenous releasable pool of GABA may not be detected by preloading slices with [3H]-GABA.
Green
A R
AR
MRC Clinical Pharmacology Unit, Radcliffe Infirmary, Oxford.
Minchin
M C
MC
Vincent
N D
ND
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003864:Depression, Chemical; D004597:Electroshock; D005481:Flurothyl / Q000633:toxicity; D007700:Kinetics; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid; D005481:Flurothyl; D011188:Potassium