Veratridine-induced depolarization caused a large increase in Ca uptak
e in the rat hippocampal slice (30.2 vs. 9.0 nM/mg dry weight). This u
ptake was reduced to 18.4 nM/mg when veratridine was combined with ano
xia. When compared with veratridine exposure alone, the combination of
anoxia and veratridine increased intracellular Na (460 vs. 380 mu M/g
), decreased intracellular K (30 vs. 40 mu M/g) and decreased ATP leve
ls (0.1 vs. 0.8 nM/mg). The changes in Na, K, and ATP should enhance n
et Ca uptake, yet Ca uptake was reduced. This suggests an effect of an
oxia to block Ca channels. In summary anoxia attenuates depolarization
-induced Ca uptake. This may represent a mechanism by which neurons ar
e partially protected against anoxic damage which could be more severe
if depolarization-induced Ca uptake was not limited.