Calcium influence on neuronal sensitivity to ethanol in selectively bred mouse lines.

Sensitivity to ethanol, as measured by blood ethanol concentration at loss of righting reflex, was increased significantly in SS but not LS mice following intracerebroventricular (ICV) administration of calcium chloride or A23187, a calcium ionophore. Magnesium chloride or lanthanum chloride, ICV, did not alter sensitivity to ethanol in either SS or LS mice, further indicating a specificity for calcium cation. Calcium was without effect on sensitivity to halothane narcosis in LS or SS mice. Endogenous brain calcium content was similar in these mouse lines, and ethanol administration either in vivo or in vitro did not alter brain calcium concentration. These results indicate that differences in brain sensitivity to ethanol are mediated, in part, by genetic differences in calcium-related processes and support the hypothesis that ethanol-induced narcosis may be due to alterations in calcium metabolism in the CNS.