Effect of exposure in vitro to ethanol and hypoxia on gamma-aminobutyric acid efflux in the hippocampus of the fetal and adult guinea-pig.
The objective of this study was to determine the effects of acute direct exposure to ethanol, hypoxia or ethanol plus hypoxia on K+-stimulated gamma-aminobutyric acid (GABA) efflux (neuronal release minus uptake) in the hippocampus of the near-term fetal and adult guinea-pig. Transverse hippocampal slices were studied in a static-interface system. Exposure in vitro to ethanol or hypoxia involved 10-min incubation with 50 mM ethanol or 10-min incubation in a 95% N2/5% CO2 environment. GABA was quantitated by HPLC. Ethanol did not alter K+-stimulated GABA efflux; hypoxia augmented K+-stimulated GABA efflux three-fold in the near-term fetus and seven-fold in the adult; concurrent exposure to ethanol did not alter the effect of hypoxia. The data demonstrate that, for acute direct exposure to hypoxia and/or ethanol, only hypoxia increases K+-stimulated GABA efflux, the magnitude of which is dependent on the extent of development of the GABA system.
Catlin
M C
MC
Department of Pharmacology and Toxicology, Faculty of Medicine, Queen's University, Kingston, Ontario, Canada.
Penning
D H
DH
Brien
J F
JF
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D046508:Culture Techniques; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D005311:Fetal Hypoxia / Q000378:metabolism; D005865:Gestational Age; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism*; D008297:Male; D010100:Oxygen / Q000008:administration & dosage*; D011188:Potassium / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000431:Ethanol; D005680:gamma-Aminobutyric Acid; D011188:Potassium; D010100:Oxygen