Difference in the actions of calcitonin gene-related peptide on pig detrusor and vesical arterial smooth muscle.
Calcitonin gene-related peptide has been demonstrated in urinary bladder nerves, and suggested to play a role in local control of bladder motility. In isolated strips of pig detrusor muscle, calcitonin gene-related peptide did not affect spontaneous contractile activity, or contractions induced by high K+, carbachol, substance P, and electrical field stimulation. In contrast, calcitonin gene-related peptide elicited a concentration-dependent and pronounced (78-99%) relaxation of vesical arteries precontracted with endothelin-1, noradrenaline or prostaglandin F2 alpha. As a vasodilator, CGRP was approximately 50 times more potent than acetylcholine. Removal of the endothelium abolished acetylcholine-induced relaxation, but did not affect the relaxation produced by calcitonin gene-related peptide. Pretreatment with methylene blue, glibenclamide or indomethacin had no influence on CGRP's ability to relax the vessels. The inhibitor of NO-synthesis, NG-nitro-L-arginine, had no effect on the maximum vascular relaxation induced by calcitonin gene-relate peptide. It is concluded that in the pig, calcitonin gene-related peptide has no functionally important mechanical effects on isolated detrusor muscle strips, but is a potent dilator of vesical arteries. The vascular effects of the peptide are endothelium-independent, and seem to be exerted directly on the vascular smooth muscle.
Persson
K
K
Department of Clinical Pharmacology, University Hospital of Lund, Sweden.
Garcia-Pascual
A
A
Andersson
K E
KE
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology* / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D013552:Swine; D001743:Urinary Bladder / Q000098:blood supply / Q000187:drug effects* / Q000294:innervation; D014664:Vasodilation / Q000187:drug effects
D015740:Calcitonin Gene-Related Peptide