Effect of captopril on some ventricular contractility indices in spontaneously hypertensive rats (SHR)

Two groups of SHR were treated with captopril (Squibb): the first group (1 month old)--30 mg/kg i.p. twice daily for 77 days, and the second group (8 months old)--20 mg/kg p.o. twice a day for 23 days. The recording of electrocardiogram (ECG), systolic blood pressure (SBP), diastolic blood pressure (DBP), and some isometric indices of the left-ventricular contractility indicate that in all treated animals the values of most of the parameters are considerably lowered compared to the controls. The ratio between velocity of pressure increase and intraventricular pressure/equal to 50 mmHg--(dP/dt)/ICP50/does not change significantly. It can be concluded that in SHR, captopril practically does not influence the inotropic condition of the myocardium.