title: Contribution of cyclic GMP generation to the relaxation by nipradilol in the rabbit aorta.
abstract: 1. Contribution of cyclic GMP generation to the relaxation by nipradilol of vascular smooth muscle was studied in the isolated rabbit aorta contracted by phenylephrine (10(-7) M) or prostaglandin F2 alpha (PGF2 alpha, 3 x 10(-6) M). 2. Nipradilol-induced relaxation in both contractions and increase in cyclic GMP content were inhibited by methylene blue (10(-5) M). 3. The relations between the increase in cyclic GMP and the relaxation produced by nipradilol and nitroglycerin were fitted to sigmoid curves. The increase in cyclic GMP at 50% relaxation by nipradilol was smaller than that by nitroglycerin (1.2-fold increase as against 3-fold increase). 4. These results suggest a smaller contribution of cyclic GMP generation through activation of soluble guanylate cyclase to nipradilol-induced relaxation in the rabbit aorta.
authors.affiliation: Department of Pharmacology, Niigata University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sasage
authors.forename: M
authors.initials: M
authors.lastname: Nakazawa
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: S
authors.initials: S
authors.lastname: Imai
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D006152:Cyclic GMP / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008297:Male; D005996:Nitroglycerin / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology*; D011817:Rabbits; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D014665:Vasodilator Agents; C036089:nipradilol; D005996:Nitroglycerin; D006152:Cyclic GMP