Ethanol and voltage- or receptor-mediated increases in cytosolic Ca2+ in brain cells.
Dissociated brain cells were isolated from newborn rat pups and loaded with fura-2. Different mechanisms for stimulating increased free intracellular Ca2+ concentrations [( Ca2+]i) were examined in the absence and presence of ethanol. KCl, carbachol, and kainate concentration-dependently increased [Ca2+]i. Quisqualate also elevated [Ca2+]i but did not produce clear concentration-dependent increases. KCl, carbachol, and quisqualate responses reached peak levels within 10-30 s and then desensitized within 90 s. However, kainate-stimulated increases in [Ca2+]i plateaued and did not decline after 90 s. Of these different [Ca2+]i-mediated processes, only 60 mM KCl stimulation was significantly inhibited by 100 mM ethanol, while lower KCl concentrations were not affected. Carbachol-induced release of intracellular Ca2+ and activation of non-NMDA (i.e., kainate, quisqualate) excitatory amino acid receptor-operated cation channels were also not significantly inhibited by 100 mM ethanol. Thus, in acutely dissociated brain cells from newborn rats, only Ca2+ influx via voltage- and, as reported previously, NMDA-operated Ca2+ channels were sensitive to ethanol inhibition.
Dildy-Mayfield
J E
JE
Division of Pharmacology, College of Pharmacy, University of Texas at Austin 78712.
Machu
T
T
Leslie
S W
SW
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004594:Electrophysiology; D000431:Ethanol / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2; D007608:Kainic Acid / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*
D005456:Fluorescent Dyes; D016194:Receptors, N-Methyl-D-Aspartate; D000431:Ethanol; D011189:Potassium Chloride; D016318:Quisqualic Acid; D002217:Carbachol; D007608:Kainic Acid; D002118:Calcium; D016257:Fura-2