Differential patterns of relaxation by synthetic atrial peptide (APII) in the pulmonary artery, ascending and distal abdominal aorta.
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| Abstract |
The vasodilatory effects of the synthetic rat atriopeptin (APII) have been studied in vitro in agonist-contracted, endothelium-denuded segments of the rat pulmonary artery, the ascending, and the distal abdominal aorta. In the pulmonary artery the contractures to methoxamine were inhibited more potently by APII (pD2 = 9.10 +/- 0.40, n = 6) than by the vasodilatory neuropeptide VIP (pD2 = 7.37 +/- 0.66, n = 6). The intrinsic activity of APII was 0.46 +/- 0.16 (n = 6). In segments previously exposed to either VIP or the beta 2-agonist salbutamol, APII was a near complete agonist (alpha = 0.82 +/- 0.17, n = 7 and 0.84 +/- 0.14, n = 6, respectively) without significant changes in the potencies. APII was a complete agonist also for the inhibition of the alpha-agonist-contracted segments of the aorta, however, with potencies 10-fold lower than in the pulmonary artery. VIP was without functionally significant effects in the aorta. The tachykinins (CGRP, SP, Neurokinins A and B) were without effects in all segments tested. In the ascending aorta, APII induced a long-lasting tachyphylaxis to the alpha-agonists, nearly completely abolishing the subsequent responsiveness to NA and methoxamine for more than 4 h.
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| Authors | S Aardal, M Bråtveit, K B Helle |
| Journal | Regulatory peptides (Regul Pept) Vol. 28 Issue 3 Pg. 283-92 (May 21 1990) ISSN: 0167-0115 [Print] Netherlands |
| PMID | 2377744 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
| Chemical References |
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