Effect of nilvadipine on the development of neurological deficits in stroke-prone spontaneously hypertensive rats.

BACKGROUND AND PURPOSE Several types of antihypertensive drugs have been reported to protect stroke-prone spontaneously hypertensive rats from stroke. However, the clinical relevance remains unclear. This study was performed to investigate the effect of nilvadipine, a calcium channel blocker, on the development of neurological deficits in stroke-prone spontaneously hypertensive rats. In addition, plasma levels of nilvadipine were measured to determine the clinical relevance. METHODS Salt-loaded stroke-prone spontaneously hypertensive rats were orally administered nilvadipine mixed with a powder diet (0.01% and 0.03%, wt/wt). Non-salt-loaded rats were maintained on tap water. Chronological changes in neurological deficit scores and systolic blood pressure were recorded. After 6 weeks of medication, measurement of plasma levels of nilvadipine, serum biochemical analysis, and pathological observation of both the brain and the kidney were performed. RESULTS In the salt-loaded control group, both severe hypertension and neurological deficit developed, and the final survival rate was 30%. Systolic blood pressure decreased significantly in the high-dose nilvadipine-treated group but not in the low-dose nilvadipine-treated group. However, the development of neurological deficit was almost completely inhibited in both nilvadipine-treated groups that had no deaths (P < .01). The mean plasma levels of nilvadipine in the low-dose group and in the high-dose group at the time of death were 0.21 ng/mL and 0.61 ng/mL, respectively. CONCLUSIONS Nilvadipine inhibited the development of neurological deficit in stroke-prone spontaneously hypertensive rats at plasma concentrations lower than that in clinical use. Thus, nilvadipine might prevent cerebral vascular disorders at doses routinely used for essential hypertension.