Rapid accumulation of inositol phosphates in isolated rat superior cervical sympathetic ganglia exposed to V1-vasopressin and muscarinic cholinergic stimuli.
An accumulation of 3H-labelled inositol phosphates is observed when prelabelled rat superior cervical sympathetic ganglia are exposed to [8-arginine]vasopressin or to muscarinic cholinergic stimuli. The response to vasopressin is much greater than the response to cholinergic stimuli. The response to vasopressin is blocked by a V1-vasopressin antagonist, and oxytocin is a much less potent agonist than vasopressin. Vasopressin causes no increase in the cyclic AMP content of ganglia. These ganglia therefore appear to have functional V1-vasopressin receptors that are capable of activating inositol lipid breakdown, but no V2-receptors coupled to adenylate cyclase. The first [3H]inositol-labelled products to accumulate in stimulated ganglia are inositol trisphosphate and inositol bisphosphate, suggesting that the initiating reaction in stimulated inositol lipid metabolism is a phosphodiesterase-catalysed hydrolysis of phosphatidylinositol 4,5-bisphosphate (and possibly also phosphatidylinositol 4-phosphate). This response to exogenous vasopressin occurs in ganglia incubated in media of reduced Ca2+ concentration. The physiological functions of the V1-vasopressin receptors of these ganglia remain unknown.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology*; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D005728:Ganglia, Sympathetic / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism*; D008297:Male; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013403:Sugar Phosphates / Q000378:metabolism*
D001626:Bethanechol Compounds; D007295:Inositol Phosphates; D013403:Sugar Phosphates; D018723:Bethanechol; D001127:Arginine Vasopressin; D010121:Oxytocin; D001285:Atropine; D000242:Cyclic AMP; D002118:Calcium; D004837:Epinephrine