Effect of chronic hypoxia on endothelium-dependent relaxation and cGMP content in rat pulmonary artery.
This experiment was designed to determine whether chronic hypoxia affects endothelium-dependent relaxation and cGMP content of rat pulmonary artery (PA). Both Ach and ATP were found to induce endothelium-dependent relaxation of PA; and this relaxation was not prevented by indomethacin, but was completely abolished by methylene blue. Chronic hypoxia significantly depressed the endothelium-dependent relaxation: the relaxation responses of intra-PA (IPA) and extra-PA (EPA) to 10(-6) mol/L Ach in the hypoxic group were 61.3% and 59.2% of those in control, and the relaxation responses of IPA and EPA to 1.8 x 10(-5) mol/L ATP in the hypoxic group were 64.9% and 55.2% of those in the control, respectively. Chronic hypoxia significantly decreased the basic level and Ach-induced accumulation of cGMP in the PA. Our data suggest that chronic hypoxia might depress rat pulmonary artery endothelium-dependent relaxation through the inhibition of cytosolic soluble guanylate cyclase in vascular smooth muscle cells.
Rui
L
L
Institute of Basic Medical Sciences, CAMS, Beijing.
Cai
Y
Y
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D006152:Cyclic GMP / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology*; D011651:Pulmonary Artery / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D000255:Adenosine Triphosphate; D006152:Cyclic GMP; D000109:Acetylcholine