[Correction of cardiac functions in rats with experimental myocardial ischemia by chronic administration of endothelin-converting enzyme inhibitor].

Experiments on chronically instrumented Wistar rats demonstrated that 15 mm microsphere embolization of coronary arteries led to a significant decrease in the systemic (APsyst) and maximal left ventricular systolic pressures (LVSPmax) to 10.1 and 21.1%, respectively (p < 0.05). To evaluate the role of endothelin in this pathology, the inhibitor of endothelin-converting enzyme (ECE), PP-36, was used. PP-36 abolished hemodynamic changes caused by embolization after 4 days per os treatment (starting 2 days before surgical procedure). Dobutamine test revealed marked decrease of LVSPmax and +dP/dtmax responses in the embolized versus sham operated animals. PP-36 normalized ischemical heart response to beta-adrenergic stimulation. Maximal APsyst and LVSPmax increases were observed in embolized rats. PP-36 abolished this effect and led to parallel rising reaction to aminoguanidin in embolized (APsyst: +12.4 +/- 1.6 vs. +6.8 +/- 2.3 mmHg, p < 0.05) as well as in sham operated rats (APsyst: +8.5 +/- 1.1 vs. +5.6 +/- 0.7 mmHg, p < 0.05). Thus, the present research showed the possibility to correct ischemical heart disturbance by using a new ECE inhibitor, PP-36. One possible mechanism of this drugs action may include systemic or myocardial changes in NO contribution to the maintenance of normal arterial pressure.