β-Adrenoceptors involved in inhibition of histamine release from sensitized guinea-pig lung

Abstract

Selective β-adrenoceptor agonists and antagonists were used to study the type of β-adrenoceptors involved in inhibiting antigen-induced histamine release from actively sensitized guinea-pig lung. Results obtained with six non-catechol β-adrenergic agonists were compared with those found in guinea-pig atrial ( β 1) and tracheal ( β 2) preparations. In terms of rank order the relative activities of the compounds differed in the three preparations. Dissociation constants (K B values) for the cardioselective antagonist H93/26 were assessed using (−)-isoprenaline as an agonist. The K B value for inhibition of histamine release was significantly different from, and intermediate between, the K B values obtained in atria and trachea. In the guinea-pig tissues H35/25 was not a selective β-adrenoceptor antagonist; K B values were not significantly different in the three preparations. The results using the β-adrenoceptor agonists and antagonists suggest that the β-receptors involved in inhibition of antigen-induced histamine release in the guinea-pig lung differ from those found in guinea-pig atria and trachea.