Effects of inhibitor of endothelium-derived relaxing factor on hypoxic contraction of isolated pig coronary artery.
Exposure of isolated pig coronary artery with endothelium intact to hypoxia Krebs-Henseleit solution aerated with 95% N2 + 5% CO2 caused a transient contractile response, and the coronary artery without endothelium exhibited a gradual decrease in basal tension. The endothelium-dependent contractile response to hypoxia was almost completely blocked by nitro-L-arginine (0.2 mmol.L-1), and inhibited by methylthioninium chloride (10 mumol.L-1). The inhibitory effect of the NLA was partially reversed by L-arginine (2 mmol.L-1). Sodium nitroprusside (10 mumol.L-1) was also completely antagonized and nicorandil (0.3 mol.L-1) remarkably reduced the hypoxic contractile response. Tetraethylammonium (10 mmol.L-1) and glibenclamide (1 mumol.L-1) had little effect on hypoxia-induced vascular contraction, whereas cromakalim (1 mumol.L-1) produced obvious relaxing effect on hypoxic response. These results suggest that suppression of basally released nitric oxide (NO) is an important mechanism of coronary vasoconstriction induced by hypoxia.
Yang
X P
XP
Department of Pharmacology, Hebei Medical College, Shijiazhuang, China.
Wu
Z J
ZJ
Xu
Y F
YF
Dong
W
W
Yang
W
W
Fu
S X
SX
Li
Y S
YS
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D015687:Cell Hypoxia; D003331:Coronary Vessels / Q000187:drug effects; D019806:Cromakalim; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D019335:Nitroarginine; D011758:Pyrroles / Q000494:pharmacology; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D001578:Benzopyrans; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine