Journal article

ACETYLCHOLINE AND HISTAMINE INTERACT SUPRA-ADDITIVELY ON BRONCHOMOTOR TONE IN GUINEA-PIGS INVIVO - A POSSIBLE CONSEQUENCE OF THE RELATIONSHIP BETWEEN AIRWAYS RESISTANCE AND CALIBER

AG STEWART, DC THOMPSON, MR FENNESSY

ARCHIVES INTERNATIONALES DE PHARMACODYNAMIE ET DE THERAPIE | ARCH INT PHARMACODYNAMIE | Published : 1985

Abstract

Histamine and acetylcholine administered simultaneously to anaesthetized guinea-pigs result in a bronchoconstriction greater than that of the sum of the individual bronchoconstrictor effects of histamine and acetylcholine administered separately, i.e., a supra-additive interaction. In contrast, a supra-additive effect of acetylcholine and histamine on the isolated tracheal strip did not occur. At a pretreatment concentration of acetylcholine of 5 microM, histamine concentration-response curves were shifted rightwards, i.e., a less than additive interaction, suggesting that, at higher concentrations, histamine and acetylcholine do not act as independent agonists on guinea-pig tracheal smooth ..

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