Aging: modulation of GABAA binding sites by ethanol and diazepam.
Modulation of gamma-aminobutyric acid (GABA) binding to the GABAA recognition site by ethanol and/or diazepam appears to change with the age of the animal. Brain tissue above the cerebellum of young, mature, and old rats was examined for an age-related change in the GABAA recognition sites 5 min after the rat was last habituated or received a single injection of the vehicle, ethanol and/or diazepam. The dose of ethanol injected was reduced in the senescent rats, so the brain levels of ethanol did not vary with age. An injection of ethanol and/or diazepam (180 micrograms/kg) did not significantly alter the GABAA recognition site in any age group relative to the habituated or vehicle-injected rats of that age group. However, the affinity of the GABAA recognition site was decreased by ethanol in mature and old rats relative to the affinity of the GABAA site after diazepam pretreatment in the presence and absence of ethanol, respectively. Finally, the combination of ethanol and diazepam elicited an increase in the number of GABAA binding sites relative to diazepam pretreatment in only the young rats. The present results indicate that the GABAA binding site is modulated by ethanol and diazepam in an age-dependent manner.
Komiskey
H L
HL
Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford 61107.
Raemont
L M
LM
Mundinger
K L
KL
D000375:Aging; D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D003975:Diazepam / Q000494:pharmacology*; D000431:Ethanol / Q000493:pharmacokinetics / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D012016:Reference Values
D011963:Receptors, GABA-A; D000431:Ethanol; D003975:Diazepam