delapril and nilvadipine

We examined the effects of a calcium antagonist and an angiotensin converting enzyme (ACE) inhibitor on contractile and non-contractile protein metabolism and cardiac function in a monocrotaline-induced right ventricular hypertrophy model, in order to define the effects of these drugs on cardiac hypertrophy.. One week after monocrotaline injection, male Sprague-Dawley rats were given either a calcium antagonist (nilvadipine; 3 mg/kg per day) or an ACE inhibitor (delapril-HCl; 30 mg/kg per day) for 2 weeks. Right ventricular pressure, the right ventricle: (left ventricle + interventricular septum) ratio, myosin isoenzymes, collagen concentration, collagen types and contractility of right ventricular free wall were examined.. In untreated rats significant monocrotaline-induced right ventricular hypertrophy with an increase in the proportion of collagen types III and V was observed. There were no significant changes in collagen concentration. Both drugs reduced right ventricular pressure to the same degree and decreased right ventricular hypertrophy. However, the inhibitory effect of delapril on right ventricular hypertrophy was stronger than that of nilvadipine. Nilvadipine reduced the collagen concentration and reversed changes in collagen types, whereas delapril did not have any significant effect on collagen concentration or collagen types. Cardiac contractility was improved by delapril, but not by nilvadipine.. The results show that a calcium antagonist disproportionately inhibited contractile and non-contractile protein metabolism, whereas an ACE inhibitor proportionally inhibited them and improved cardiac function in a model of right ventricular hypertrophy. The improvement in cardiac function may be due partly to the proportional inhibition of contractile and non-contractile proteins elicited by an ACE inhibitor.

Topics: Absorptiometry, Photon; Angiotensin-Converting Enzyme Inhibitors; Animals; Calcium Channel Blockers; Collagen; Electrophoresis; Heart Ventricles; Hypertrophy, Right Ventricular; Indans; Male; Myocardial Contraction; Myocardium; Myosins; Nifedipine; Organ Size; Rats; Rats, Sprague-Dawley; Ventricular Pressure

The aim was to examine the effects of an angiotensin converting enzyme (ACE) inhibitor and a calcium antagonist on intracellular calcium transients in isolated cardiac myocytes from a monocrotaline induced right ventricular hypertrophy model.. One week after monocrotaline injection, Sprague-Dawley rats were given either an ACE inhibitor (delapril-HCl) or a calcium antagonist (nilvadipine) for two weeks. Using fura-2/AM, calcium transients were measured in single myocytes separated from the right ventricle.. The severe right ventricular hypertrophy observed in untreated rats was significantly reduced in drug treated animals. The inhibitory effects of delapril were more prominent than those of nilvadipine, although both drugs reduced right ventricular pressure to the same extent. Calcium transients in delapril treated rats were similar to those in control rats. On the other hand, the calcium transient in nilvadipine treated rats was decreased and its time course was prolonged. The changes were similar to those found in monocrotaline treated rats. The responsiveness of calcium transients to isoprenaline in delapril treated rats was similar to that in control rats. The responsiveness in nilvadipine treated rats was decreased, and was similar to that in monocrotaline treated rats. Delapril improved developed tension and the beta adrenoreceptor responsiveness of developed tension to isoprenaline.. Although delapril and nilvadipine inhibited cardiac hypertrophy in monocrotaline treated rats, significant improvement of contractile function and beta adrenoreceptor responsiveness was observed only in the delapril treated rats. This improvement was partially due to the improvement in calcium transients and the restoration of the beta adrenoreceptor responsiveness of the calcium transient to beta adrenergic stimulation.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Calcium; Calcium Channel Blockers; Cells, Cultured; Hypertrophy, Right Ventricular; Indans; Male; Monocrotaline; Myocardial Contraction; Myocardium; Nifedipine; Rats; Rats, Sprague-Dawley; Receptors, Adrenergic, beta