title: Comparative effects of mast cell degranulators on perfused systemic blood vessels of Bufo melanostictus and Rana tigrina.
abstract: Three agents known to induce release of mast cell constituents, viz. polymyxin, compound 48/80 and polysorbate-80, were evaluated for effect on perfused blood vessels of R. tigrina and B. melanostictus. The mast cell degranulators caused vasoconstriction in frog and toad, except that for P-80 whose responses in toad were equivocal. Toads showed a general low responsiveness in comparison to frogs. Pharmacologic intervention with pheniramine, metergoline, hydergine, atropine and mecamylamine, respectively ruled out role of histamine, 5-HT, catecholamine or acetylcholine or even autonomic mechanisms in the above phenomena. The observations are suggestive of phylogenetic differences in biochemical profile of mast cells in amphibian species.
authors.affiliation: Department of Pharmacology, Banaras Hindu University, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Singh
authors.forename: S S
authors.initials: SS
authors.lastname: Gambhir
mesh_terms: D000818:Animals; D002025:Bufonidae; D006632:Histamine / Q000494:pharmacology; D006633:Histamine Antagonists; D066298:In Vitro Techniques; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D010477:Perfusion; D011113:Polymyxins / Q000494:pharmacology*; D011136:Polysorbates / Q000494:pharmacology*; D011898:Ranidae; D012701:Serotonin / Q000494:pharmacology; D013618:Tachyphylaxis; D014661:Vasoconstriction / Q000187:drug effects*; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology*
chemical_list: D006633:Histamine Antagonists; D011113:Polymyxins; D011136:Polysorbates; D012701:Serotonin; D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine