[Properties of peroxynitrite-induced relaxation in rabbit pulmonary artery in vitro].
Vasodilatory properties of exogenous peroxynitrite (ONOO(-)) and effects of endothelial cells on ONOO(-) induced relaxation were investigated in isolated rabbit pulmonary arterial rings (PARs). In pre-contracted PARs, ONOO(-) gave rise to vasodilation in a dose-dependent manner, which was significantly higher than that of decomposed ONOO-. In contrast, relaxation of PARs to ONOO(-) was lower, as compared with sodium nitroprusside (SNP) or acetylcholine(ACh). ONOO(-) induced more significant relaxation in denuded endothelial PARs than in intact endothelial PARs. Relaxation of PARs to repetitively administered ONOO(-) appeared progressively decreased. Under this experimental condition, relaxation of PARs to ACh remained unchanged after administrating ONOO(-). These results suggest that ONOO(-) causes weak relaxation in pulmonary artery, which is down regulated by endothelium and is of tachyphylaxis.
Gu
Z Y
ZY
Department of Pathophysiology, Hebei Medical University, Shijiazhuang 050017.
Ling
Y L
YL
Li
S J
SJ
Meng
A H
AH
Zhang
J L
JL
D000818:Animals; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000502:physiology; D066298:In Vitro Techniques; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology / Q000502:physiology*; D011817:Rabbits; D013618:Tachyphylaxis; D014664:Vasodilation / Q000187:drug effects*
D030421:Peroxynitrous Acid