Distribution of Calbindin-D28K 1 (CaBP) in the cerebral cortex and hippocampus of the epileptic (El) mouse.

The distribution of Calbindin-D28K (CaBP), a calcium-binding protein that binds Ca2+ with high affinity, was measured by radioimmunoassay in various cortical regions of the epileptic strain of mice El. The El strain, in which seizures are induced by repeated vestibular stimulation, had significantly lower levels of CaBP in the hippocampus and dorsal occipital cortical areas than the control CF-1 strain. Following induction of seizures in the El strain, a further decrease in CaBP levels was observed in the hippocampal formation and ventral temporal cortical regions, areas where paroxysmal activity is generated in this strain. Considering the role of CaBP as an intraneuronal calcium buffer, the present findings indicate that neuronal calcium regulation is genetically altered in the El strain and is further disturbed during the events that lead to induction of seizures.