Characterization of contractile response to angiotensin in epididymal rat vas deferens

Pharmacology
C S Sum, W T Cheung

Abstract

Angiotensin had a dual action on the epididymal half of rat vas deferens. It potentiated electrical stimulated contraction and exerted a direct contractile effect on the muscle. The potentiation of electrically stimulated response may be mediated by presynaptic facilitation of neurotransmitter release. Muscular contractile response to angiotensin is concentration dependent. Angiotensin II was found to be much more potent than angiotensin III, and the order of potencies was angiotensin II > angiotensin I > angiotensin III. The presence of a mixture of protease inhibitors (10 microM chymostatin, 50 microM bacitracin, 10 microM leupeptin and 10 microM pepstatin) did not alter the contractile activity of angiotensin II. In contrast, angiotensin I (10 nM)-induced contraction was significantly reduced in the presence of ACE inhibitor SQ 20881 (500 nM). The angiotensin II induced contraction was not reduced by CGP 42112, a specific AT2 receptor antagonist, but was significantly inhibited by losartan, a specific AT1 receptor antagonist. Losartan shifted the dose-response curve of angiotensin II to the right with a pA2 value of 8.68. In addition, p-aminophenylalanine6 angiotensin II, which is proposed as an AT2 receptor agonist, did not...Continue Reading

Citations

Aug 28, 1998·European Journal of Pharmacology·L MaletínskáB Zelezná
Feb 4, 1999·Regulatory Peptides·R C SpethK L Grove
Jul 1, 1996·British Journal of Pharmacology·C S SumW T Cheung
Aug 27, 2013·Diabetes & Vascular Disease Research : Official Journal of the International Society of Diabetes and Vascular Disease·Diego C MusialNeide H Jurkiewicz
Oct 2, 2020·Microorganisms·Lorella PascoloGiuseppe Ricci
Jun 16, 1999·Gynecological Endocrinology : the Official Journal of the International Society of Gynecological Endocrinology·G P VinsonO Djahanbakhch
Oct 30, 2020·International Journal of Molecular Sciences·Marta Gianzo, Nerea Subirán

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