Studies were carried out on the action of nifedipine and nisoldipine on the contractile activity of human, isolated, coronary and mammary arteries and human, isolated, auricular and ventricular muscles. Nisoldipine depressed in a dose dependent manner the spontaneous rhythmic contractions displayed by the coronary artery preparations and at 1 nM abolished these contractions. Nisoldipine was twenty times more potent than nifedipine as an inhibitor of increase in tone induced by depolarization (100 mM K+). The rhythmic activity induced by serotonin (10μM) was more sensitive to nisoldipine than to nifedipine.
Nifedipine was five times (ventricular muscles) and ten times (auricular muscles) more potent than nisoldipine as negative inotropic agent.
From such observations in human isolated tissues, it appears that nisoldipine has a higher vascular selectivity than nifedipine. This indicates potential differences in the clinical use of these dihydropyridines.
- Contractile Activity
- Human Coronary Artery
- Ventricular Muscle
- Calcium Entry Blocker
- Cardiac Preparation
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