S.I. Sofronova, M.E. Ilatovskaya, O.S. Tarasova, V.F. Pozdnev, N.A. Medvedeva
Endothelin (ET-1) is produced in the vascular endothelium under endothelin converting enzyme (ECE) action. In overphysiological concentration ET-1 has an evident vasoconstrictor activity but the ET-1 role in circulation control in health is poorly known. In this work we investigated the changes of rat pulmonary and renal arteries reactivity after endothelin converting enzyme inhibition by substance PP-36 (consumption with drinking water in dosage of 1.8 mg/kg per day during two weeks). PP-36 consumption had no influence on systemic arterial pressure. PA constriction in response to α1-adrenoreceptor agonist phenylephrine didn’t change while RA sensitivity to phenylephrine significantly increased. PA endothelium-independent relaxation (to sodium nitroprusside) didn’t change but endothelium-dependent relaxation (to acetylcholine) significantly increased which can be due to increase in nitric oxide production by the endothelium. RA responses to both sodium nitroprusside and acetylcholine increased which can be due to alteration of endothelial secretion and/or higher smooth muscle sensitivity to NO. Therefore ECE inhibition may be accompanied by enhancement of arterial constriction as well as relaxation. Probably in health ET-1 action contributes to vessel resistance stabilization.