Study on vasodilatory properties of rabbit pulmonary artery induced by peroxynitrite in vitro / 中国病理生理杂志

ABSTRACT

This study was designed to invesigate vasodilatory action of exogenous peroxynitrite (ONOO-), and effect of endothelial cells on ONOO- -induced relaxation in isolated rabbit pulmonary arterial rings (PARs). Results were as follows (1) In precontracted PARs, ONOO- could give rise to vasodilation in a dose-dependent manner. Relaxations of PARs to ONOO- at doses of 10-5 mol/L, 5×10-5 mmol/L and 10-4 mol/L were 11.09%±1.84%, 31.10%±3.53% and 64.35%±3.83%, respectively, all of which were significantly higher than those of decomposed ONOO- with 5.88%±1.27%、16.15%±1.82% and 34.44%±3.26% at same concentrations, respectively. (2) Compared with SNP and ACh, ONOO- had weak relaxant action. (3) ONOO- induced more significantly enhanced relaxation in denuded endothelial PARs than in intact endothelial PARs. (4) In this experimental condition, the relaxation of PARs to 10-6 mol/L ACh remained unchanged before and after observation of relaxation to ONOO-. (5) The relaxations of PARs to 5×10-5 mol/L ONOO- in repetitively administered manner appeared progressively decreased. These results suggested that ONOO- might be implicated in pulmonary hypertension in the early stage of endotoxic shock.