Vasoactive intestinal polypeptide-sensitive cyclic adenosine monophosphate generating system in the rat portal vein.
The effect of vasoactive intestinal polypeptide (VIP) on the 3'-5'-cyclic adenosine monophosphate (cAMP) generating system in membrane particles of rat portal vein was studied. In the presence of 10 microM GTP, VIP increased the concentration of cAMP in a dose-dependent manner. The removal of endothelium had no effect on cAMP production elicited by VIP. alpha- and beta-adrenergic as well as muscarinic receptor blocking agents did not inhibit VIP-dependent cAMP increase. Also various peptides, structurally analogous to VIP or active on portal vein smooth muscle, had no effect on cAMP production elicited by VIP. The present data, combined with those reported in the literature of an active relaxation of portal vein smooth muscle by VIP, suggest the existence of functionally active VIP receptors coupled to the adenylate cyclase system in the rat portal vein.
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Dipartimento di Scienze Neurologiche, Università La Sapienza, Roma, Italy.
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D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D011169:Portal Vein / Q000187:drug effects / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D006728:Hormones; D014660:Vasoactive Intestinal Peptide; D001285:Atropine; D006160:Guanosine Triphosphate; D011433:Propranolol; D000242:Cyclic AMP; D010646:Phentolamine