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Adenylate cyclase‐mediated vascular responses of rabbit aorta, mesenteric artery and skin microcirculation
Author(s) -
Wilson A.J.,
Warren J.B.
Publication year - 1993
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1993.tb13858.x
Subject(s) - adenylate kinase , microcirculation , medicine , aorta , cyclase , rabbit (cipher) , cardiology , mesenteric arteries , endocrinology , anatomy , artery , stimulation , computer science , receptor , computer security
1 The importance of adenylate cyclase‐mediated vascular relaxation in the macro and microcirculation was assessed in rabbit aortic and coeliac artery bioassay rings in vitro and skin microvessels in vivo.2 The neuropeptide pituitary adenylate cyclase‐activating polypeptide (PACAP38), the β‐agonist, isoprenaline, and the prostaglandins, PGE 1 and PGE 2 , were compared with the activity of nitroprusside, which acts by stimulating guanylate cyclase. 3 In aortic tissue the relative relaxant potencies were (−log m EC 50 , 100% = response to nitroprusside 10 −6 m ): nitroprusside 7.0, PACAP38 6.8, isoprenaline 6.3; PGE 1 and PGE 2 were weak constrictors. In coeliac artery rings relative potencies were (−log m EC 50 , 100% = response to nitroprusside 10 −5 m ): PACAP38 6.6, PGE 1 6.6, nitroprusside 6.5, PGE 2 4.9, and isoprenaline 4.3. 4 Comparative potencies when injected into anaesthetized rabbit skin in vivo were (−log mol/site required to increase blood red cell flux by 75%): PACAP38 13.0, PGE 2 10.7, isoprenaline 9.7, PGE 1 9.1, nitroprusside < 7. 5 Nitroprusside, the most effective relaxant tested in the aorta, was 10 7 fold less potent than PACAP in its effect on skin blood flow. PGE 1 and PGE 2 were constrictors of the aorta, of intermediate effect in the coeliac artery, but potent vasodilators of the microcirculation. 6 In this model, the importance of adenylate cyclase‐mediated vascular relaxation increases with decreasing vessel size.