NIMODIPINE PREVENTS EARLY LOSS OF HIPPOCAMPAL CA1 PARVALBUMIN IMMUNOREACTIVITY AFTER FOCAL CEREBRAL-ISCHEMIA IN THE RAT

The effect of focal cerebral ischemia induced by middle cerebral arter y occlusion on hippocampal interneurons containing the calcium-binding protein parvalbumin (PV) was studied in rats. Four hours after the on set of ischemia, a reduced number of PV-immunoreactive (-ir) neurons w as observed in the lateral part of the CA1 region, while PV-ir was not altered in the CA2 and CA3 areas. Pretreatment with the L-type Ca2+ c hannel blocker nimodipine prevented the ischemia-induced loss of PV-ir in the CA1, suggesting a role for L-type voltage sensitive calcium ch annels in the mechanism of early neuronal alterations in the hippocamp us CA1 region after focal cerebral ischemia.