ENALAPRIL, AN INHIBITOR OF ANGIOTENSIN CONVERTING ENZYME, INCREASES THE JUNCTIONAL CONDUCTANCE IN ISOLATED HEART CELL PAIRS

The effect of enalapril and angiotensin II on junctional conductance (gj) of isolated rat heart cell pairs was investigated. It was found that enalapril (1-mu-g/ml) increases gj by 106 +/- 3.1% (SEM) (n = 20) within 4 min. The effect of enalapril on gj was not suppressed by propranolol (10(-6) M) or by a cAMP-dependent protein kinase inhibitor. Angiotensin II (1-mu-g/ml) reduced gj by 55%. These observations might indicate that an intrinsic renin-angiotensin system in heart is involved in the control of gj in cardiac muscle.