title: Extended mepyramine treatment and histamine H1-receptors in guinea-pig brain.
abstract: Treatment of guinea-pigs for 24 days with a single daily dose of mepyramine, 5 mg/kg i.p. had no consistent significant effect on the number of histamine H1-receptors, determined from the promethazine-sensitive binding of [3H]mepyramine, in cerebellum, cerebral cortex, hippocampus, hypothalamus or intestinal smooth muscle. Measurement of the time course of the block of H1-mediated blood pressure responses in conscious guinea pigs following a single i.p. injection of mepyramine, 5 mg/kg, suggested that some degree of block persisted for up to 16 h. Treatment of guinea pigs with two daily doses of 5 mg mepyramine/kg, i.p., for 10 days had no consistent effect on the KD or capacity of promethazine-sensitive [3H]mepyramine binding to cerebellum or hypothalamus.
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects*; D006168:Guinea Pigs; D008297:Male; D011738:Pyrilamine / Q000378:metabolism / Q000494:pharmacology*; D011968:Receptors, Histamine / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000032:analysis / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000631:Aminopyridines; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011738:Pyrilamine