The nature of the β-adrenoceptor involved in the inhibition of antigen-induced histamine release

Antigen stimulated release of histamine from chopped sensitized guinea-pig lung is inhibited by the addition of β-adrenoceptor agonists in a manner indicating a β₂ response. Preaddition of β-adrenoceptor antagonists blocks this inhibition in a manner indicating a β₁ response. This apparent dichotomy probably results from a hybrid receptor, though the danger of the use of chemical analogues for classifying receptors is highlighted. Inhibition of histamine release by β-stimulation is shown to be species rather than organ specific.