Behavioral and anatomical consequences of unilateral fornix lesions and the administration of nimodipine

Male Wistar rats subjected to unilateral fimbria-fornix transection by mechanical knife cut or to sham operations were tested in a water maze and in an open field. Half the animals in each group were treated with either 0.06 mg/kg nimodipine or vehicle, administered i.p. for 7 days, beginning the day of surgery. Animals were sacrificed and brains were processed for acetylcholine esterase (AChE) histochemistry. In the water maze, lesioned rats showed a significant impairment relative to the sham-operated animals. Nimodipine treatment did not improve performance. There were no differences among the groups in the observed frequencies of the open field behaviors of locomotion, hole-poke, rearing and grooming. A significant reduction of AChE-positive cell bodies was found in the medial septal region on the side of the lesion. There were no differences in water maze performance among groups of rats treated with 0.0, 0.5, 1.0, or 5.0 mg/kg nimodipine for 7 days, beginning the day of fimbria-fornix transection, in an attempt to determine any dose-dependent effect of the drug.