Effect of manidipine on cardiac hypertrophy and coronary circulation in DOCA/salt hypertensive rats.

The effect of manidipine on cardiac hypertrophy, coronary circulation, left ventricular weight and maximal coronary flow in hypertension was measured in DOCA/salt treated systolic hypertensive rats with and without manidipine treatment. Normotensive rats were used as controls. After feeding with 0.05% manidipine-containing food, blood pressure was reduced only in DOCA/salt hypertensive rats, but not in control rats. After 3 weeks of treatment, sodium excretion was significantly increased in DOCA/salt-treated rats with or without manidipine treatment. Hearts were removed and perfused with modified Krebs-Henseleit solution with adenosine (5 x 10(-5) M) in a Langendorff apparatus. Maximal coronary flow (MCF) was significantly decreased only in DOCA/salt hypertensive rats without treatment, while manidipine treatment restored MCF. Left ventricular weight/body weight was also markedly greater in DOCA/salt-treated rats not given manidipine. Left ventricular weight in DOCA/salt-treated rats given manidipine was significantly reduced compared with DOCA/salt hypertensive rats without treatment, although it was heavier than in the control animals. Morphological examination showed that the increased wall/lumen ratio in DOCA/salt hypertensive rats was reduced by manidipine treatment. These findings suggest that treatment with manidipine in DOCA/salt hypertensive rats lowered high blood pressure and improved impaired coronary circulation with a reduction in left ventricular and vascular hypertrophy.