Interaction of formamidines with octopamine-sensitive adenylate cyclase receptor in the nerve cord of Periplaneta americana L.
Chlordimeform (CDM) and demethylchloridimeform (DCDM) mimic the action of octopamine in elevating adenylate cyclase activity in intact nerve cords of the American cockroach, Periplaneta americana. At a concentration of 1 x 10(-5)M, DCDM (13.5x increase within 20 minutes) is a more potent effector of the response than CDM (3x increase within 20 minutes), but both compounds show less efficacy than octopamine (23.5x increase within 15 minutes). DCDM also mimics the stimulatory effect of octopamine on adenylate cyclase activity in nerve cord homogenates whereas CDM has no demonstrable effect on this preparation. The octopamine- and DCDM-induced responses are competitively inhibited by phentolamine (1 x 10(-6)M) and cyproheptadine (1 x 10(-6)M) but not by propranolol (1 x 10(-6)M). DCDM and CDM inhibit the octopamine-induced activation of adenylate cyclase by 33% and 44% respectively. The results are discussed in light of the proposal that DCDM serves as a partial agonist and CDM as an antagonist of the octopamine receptor.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D002742:Chlorphenamidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D003533:Cyproheptadine / Q000494:pharmacology; D019204:GTP-Binding Proteins; D009420:Nervous System / Q000187:drug effects / Q000378:metabolism*; D009655:Octopamine / Q000494:pharmacology*; D010526:Periplaneta; D010646:Phentolamine / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism*
D000578:Amidines; D011956:Receptors, Cell Surface; D009655:Octopamine; C011741:demethylchlordimeform; D003533:Cyproheptadine; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D002742:Chlorphenamidine; D010646:Phentolamine