Comparison of relaxation responses of vascular and non-vascular smooth muscle to endothelium-derived relaxing factor (EDRF), acidified sodium nitrite (NO) and sodium nitroprusside. 1990

T M Cocks, and J A Angus
Baker Medical Research Institute, Prahran, Victoria, Australia.

Smooth muscle relaxant activity of endothelium-derived relaxing factor (EDRF) released from columns of cultured bovine endothelial cells by bradykinin (0.1-3 nmol/l) was measured in four non-vascular preparations: guinea-pig taenia caeci, guinea-pig trachea, rat stomach (fundus) and rat anococcygeus. Each preparation was contracted to a steady level of force with a variety of agonists such that they relaxed optimally to sodium nitroprusside (SNP). The EDRF-induced relaxations in each preparation were compared with those obtained in de-endothelialized ring preparations of greyhound coronary artery by means of paired bioassays run in parallel. EDRF released from the endothelial cell columns caused 80-100% relaxation of the coronary artery, 40-80% in the guinea-pig taenia caeci, 50-70% in the rat anococcygeus, 5-8% in the guinea-pig trachea and was undetectable in the rat stomach strip. By comparison, SNP caused maximal relaxation in all tissues compared with the coronary artery. In separate organ bath experiments the sensitivity to nitric oxide (NO: generated by adding acidified solutions of NaNO2) and SNP was compared in each preparation. SNP caused maximal relaxation in all tissues with the following order of potency: dog coronary artery greater than guinea-pig trachea greater than guinea-pig taenia = rat anococcygeus greater than rat stomach strip. In contrast, the concentration of acidified NaNO2 (NO, 300 nmol/l) that caused 96 +/- 4% relaxation in the dog coronary artery caused 84 +/- 7% and 48 +/- 1% relaxation in the taenia and anococcygeus respectively. No response attributable to NO was detected in either the trachea or rat stomach strip.(ABSTRACT TRUNCATED AT 250 WORDS)

UI MeSH Term Description Entries
D008297 Male Males
D009126 Muscle Relaxation That phase of a muscle twitch during which a muscle returns to a resting position. Muscle Relaxations,Relaxation, Muscle,Relaxations, Muscle
D009130 Muscle, Smooth Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed) Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009131 Muscle, Smooth, Vascular The nonstriated involuntary muscle tissue of blood vessels. Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D009569 Nitric Oxide A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP. Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D009599 Nitroprusside A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins. Nitroferricyanide,Sodium Nitroprusside,Cyanonitrosylferrate,Ketostix,Naniprus,Nipride,Nipruton,Nitriate,Nitropress,Nitroprussiat Fides,Nitroprusside, Disodium Salt,Nitroprusside, Disodium Salt, Dihydrate,Disodium Salt Nitroprusside,Nitroprusside, Sodium
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003106 Colon The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON. Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D003331 Coronary Vessels The veins and arteries of the HEART. Coronary Arteries,Sinus Node Artery,Coronary Veins,Arteries, Coronary,Arteries, Sinus Node,Artery, Coronary,Artery, Sinus Node,Coronary Artery,Coronary Vein,Coronary Vessel,Sinus Node Arteries,Vein, Coronary,Veins, Coronary,Vessel, Coronary,Vessels, Coronary
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog

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