Verapamil prevents the acute hypertensive response to intracerebroventricular cadmium in conscious normotensive rats.

Cadmium, a trace element from natural and industrial sources, may contribute to the pathogenesis of arterial hypertension. We evaluated the effect induced by acute intracerebroventricular (icv) administration of cadmium on mean blood pressure of normotensive conscious rats. Intracerebroventricular cadmium (1 to 10 micrograms) produced a dose-dependent, sustained increase in mean blood pressure. The hypertensive response to icv cadmium was significantly (P < .01) prevented by icv pretreatment with verapamil (10 to 100 micrograms). A preventive effect was exerted also by icv nifedipine (100 micrograms); however, this result was attributable, at least in part, to the antihypertensive action of the vehicle, polyethylene glycol. The hypertensive response to icv cadmium was blunted by icv administration of 10 ng clonidine, 10 micrograms vasopressin antagonist, or 10 micrograms bradykinin antagonist (P < .05), but it was not altered by icv enalaprilat (100 micrograms). These results indicate that brain calcium channels play a role in the hypertensive action induced by icv cadmium. Accumulation of cadmium in the brain caused by prolonged exposure to this heavy metal might lead to chronic arterial hypertension.