Effects of early onset of nimodipine treatment on microvascular integrity in the aging rat brain.

Abstract

We studied the effects of long-term treatment with 1,4-dihydropyridine nimodipine on age-related changes of the cerebral microvasculature in layers I, III, and V of the frontoparietal motor cortex of aged (30 months) male Wistar rats. Ultrastructural alterations of microvessels can either be attributed to degeneration or to deposition processes. Nimodipine application, irrespective of the time of onset, did not interfere with the degeneration of microvascular pericytes. However, nimodipine treatment from 24-30 months significantly reduced the amount of microvascular deposition products in cortical layers I and III, while an earlier onset (16 months) of the drug application resulted in a significant reduction in all motor cortex layers studied. This indicates a different susceptibility of microvessels in layer V of the frontoparietal motor cortex. These results show a beneficial effect of nimodipine on the integrity of cerebral microvasculature during aging and may provide a morphologic basis for the improved motor and cognitive performance in aged rats after chronic nimodipine application.