Animal experiment:

Rats[1]Male SHR (11-15 weeks) are used. They are fasted for 16 h before the administration of drugs, and given Aranidipine (3, 10 mg/kg) orally through a gastric tube. Control animals are given the vehicle. At 1-24 h after drug administration, the SHR are killed by bleeding from the descending aorta under light anesthesia with ethyl ether, and the myocardium and brain are perfused with 0.9% saline from the aorta. Then, both tissues are removed, and blood vessels are trimmed away. Plasma from rat blood is isolated by centrifugation, and stored at -80℃ until the concentration of Aranidipine is determined.

Aranidipine (MPC1304) is a Ca2+ channel antagonist with potent and long-lasting antihypertensive effects.

Aranidipine (MPC-1304) is a new Ca2+ channel antagonist in spontaneously hypertensive rats. Following oral administration of Aranidipine at doses of 3 and 10 mg/kg to spontaneously hypertensive rats (SHR), there are significant decreases in Bmax values for specific [3H](+)-PN 200-110 binding to myocardial membranes compared to the control values. The Bmax values at 1 h (3 mg/kg), 1 and 6 h (10 mg/kg) are significantly decreased (47.7, 48.9 and 25.8%, respectively) compared to the control values. The effect is greatest at 1 h and decreases with time. The Bmax values at 6 h (3 mg/kg) and 12 or 24 h (10 mg/kg) after the oral administration of Aranidipine are not significantly different from the control values, suggesting the disappearance of the effect of Aranidipine. The Kd values for myocardial [3H](+)-PN 200-110 binding are unaltered by oral administration of Aranidipine[1].

[1]. Nozawa Y, et al. Receptor occupation and pharmacokinetics of MPC-1304, a new Ca2+ channel antagonist, in spontaneously hypertensive rats. Eur J Pharmacol. 1995 Dec 12;287(2):191-6.