NIMODIPINES FUNCTIONAL BENEFITS DEPEND ON LESION COMPLETENESS IN MEDIAL SEPTAL AREA

The effects of a 4-day nimodipine treatment (70 mug/kg IP beginning on the day of surgery) given to rats with lesions directed at the medial septal area were monitored for 120 days. Body weight, water intake, o pen-field activity, rearing, hole-poking, and repetitive motor acts we re periodically measured through 120 postsurgical days. Although no di fferences were found in water intake between any of the groups, the bo dy weights of rats with any medial septal damage, whether treated with nimodipine or not, were lower than rats with control operations by po stsurgery day 120. Rats with any medial septal damage, whether treated with nimodipine or not, had lower rearing frequencies, rearing durati ons, and hole-poking frequencies than controls on all test days. Howev er, rats with complete medial septal lesions treated with nimodipine e xhibited movement in the open field and frequencies of stereotyped, sp ecies-typical acts similar to those of control rats by postsurgery day 60. This nimodipine effect was not observed in rats with partial lesi ons of the medial septal region. This study emphasizes that a brief ad ministration of nimodipine shortly after brain damage can influence be havioral changes 40-60 days after surgery, but that this effect was no t apparent in rats with only partial medial lesions.