Bronchodilator activity of dimaprit in the guinea pig in vitro and in vivo.
The bronchodilator activity of the H2-recptor agonist, dimaprit, was assessed in vitro and in vivo. In vitro dimaprit relaxed guinea pig tracheal spirals and parenchymal strips that were constricted by the H1 receptor agonist, 2-PEA, or by carbachol. The H2-receptor antagonist, metiamide, inhibited this effect of dimaprit in vitro on both tissues constricted by 2-PEA but not on the carbachol constricted tracheal spiral. Intravenous infusion of dimaprit in the intact guinea pig resulted in reversal of bronchoconstriction induced by subcutaneous injection of 2-PEA. In vivo pretreatment with the H2-recptor antagonist, metiamide, resulted in a diminished sensitivity to the bronchodilating effects of intravenous dimaprit.
D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001993:Bronchodilator Agents; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000187:drug effects*; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D013890:Thiourea / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects
D001993:Bronchodilator Agents; D010627:Phenethylamines; D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D006632:Histamine; D013890:Thiourea