Beneficial effect of nimodipine on peripheral nerve function in aged rats.

In aged rats neuromuscular function and motor coordination is gradually impaired. Major motor deficits were seen in rats of more than 2 years of age; with increasing age, the incidence of abnormal footprints increased sharply. Oral nimodipine, a Ca2(+)-entry blocker of the dihydropyridine type, treatment suppressed and/or delayed the appearance of these abnormal footprints. In aged rats that already displayed a considerable amount of abnormal footprints in the free walking pattern, oral nimodipine treatment was similarly effective. Nimodipine not only delays the onset of age-related motor deficits, but also may counteract these deficits once already present. In aged rats the nerve conduction velocities were severely diminished. Nimodipine treatment resulted in an enhancement of the sciatic and caudal nerve conduction velocities. Histological analysis revealed a lower fiber density in aged rats compared to aged nimodipine-treated rats. Whether nimodipine acts directly on the peripheral nervous system is currently unclear. Nevertheless, the present study lends further support for the beneficial effects of nimodipine in age-related motor deficits in the rat.