Role of endothelium in the response to prostaglandin H2 in isolated dog arteries.
Prostaglandin (PG) H2 produced a transient contraction followed by a relaxation in helical strips of dog coronary, mesenteric and renal arteries contracted with PGF2 alpha. The contraction was in the order of mesenteric greater than renal greater than coronary artery. Removal of endothelium abolished the contraction in these arteries and significantly potentiated the relaxation only in mesenteric arteries. The relaxation was greater in mesenteric arteries than in renal and coronary arteries, denuded of endothelium. PGI2-induced relaxations were not influenced by endothelium denudation. In the arteries contracted with K+, PGH2-induced relaxations were attenuated, compared to those contracted with PGF2 alpha. Treatment with ONO3708, an antagonist of vasoconstrictor PGs, abolished the PGH2-induced contraction and potentiated the relaxation in the K+-contracted arteries. The relaxant response was suppressed by diphloretin phosphate, a PG receptor antagonist, as was the response to PGI2. PGH2-induced contractions in dog coronary, mesenteric and renal arteries would be due to vasoconstrictor PGs produced preferentially in the endothelium. However, production of PGI2 from PGH2 in endothelial and subendothelial tissues do not appear to differ.
Okamura
T
T
Department of Pharmacology, Shiga University of Medical Sciences, Ohtsu, Japan.
Inoue
S
S
Minami
Y
Y
Okunishi
H
H
Toda
N
N
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects; D004285:Dogs; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011449:Prostaglandin Endoperoxides / Q000494:pharmacology*; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology*; D044262:Prostaglandin H2; D011463:Prostaglandins H / Q000494:pharmacology*; D012077:Renal Artery / Q000187:drug effects
D011449:Prostaglandin Endoperoxides; D011450:Prostaglandin Endoperoxides, Synthetic; D011463:Prostaglandins H; D044262:Prostaglandin H2