Nicardipine and vascular hypertrophy.

The effects of nicardipine administration on the morphology of coronary, renal, and pulmonary vascular trees were studied in spontaneously hypertensive rats (SHRs). Male 10-week-old SHRs received 1 mg/kg/day of nicardipine or vehicle orally for 12 weeks. Age-matched Wistar-Kyoto rats were used as normotensive reference animals. Blood pressure, heart weight, heart/body weight ratio, the area occupied by the medial layer, and area occupied by the vascular wall/area of lumen ratio increased significantly (p less than 0.001) in SHRs compared with normotensive Wistar-Kyoto rats. Nicardipine reduced blood pressure, as well as relative heart weight, the area occupied by vascular smooth muscle, and the area occupied by the vascular wall/area of lumen ratio. In addition, the size of laminae of smooth muscle of the pulmonary artery was reduced in nicardipine-treated SHRs; coronary artery branches were the most sensitive. The results of the study provide direct evidence that nicardipine reduces not only blood pressure but is also able to counteract the development of hypertension-dependent changes in the morphology of the cardiovascular system.