Calcium-dependent 86 Rb efflux and ethanol intoxication: studies of human red blood cells and rodent brain synaptosomes.
Effects of ethanol on calcium-dependent potassium efflux were investigated in red blood cells (RBC) from humans and brain synaptosomes from rats and mice. 86 Rb was used as a tracer for potassium. Synaptosomes and RBC were lysed and resealed with 86 Rb and calcium-EGTA buffers to regulate intracellular levels of ionized calcium. In vitro addition of ethanol (100 mM) stimulated the calcium-dependent 86 Rb efflux of synaptosomes. This stimulation was blocked by apamin, an inhibitor of the calcium-dependent potassium current of nerve cells. In addition, intracerebroventricular injection of apamin inhibited ethanol-induced narcosis in mice, providing behavioral evidence for the importance of calcium-stimulated potassium efflux in alcohol intoxication. In vitro addition of ethanol, propanol or butanol increased calcium-dependent 86 Rb efflux of human RBC at low concentrations of free calcium, but did not change the calcium-independent efflux of 86 Rb. These results suggest that the calcium-dependent 86 Rb efflux of nerve endings may have an important role in the pharmacological and toxicological effects of ethanol.
D000435:Alcoholic Intoxication / Q000378:metabolism*; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D004912:Erythrocytes / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
D001030:Apamin; D012413:Rubidium; D011188:Potassium; D002118:Calcium