Examination of the bronchoconstrictor response of guinea-pig isolated lung to β-phenylethylamine

1. 1. β-Phenylethylamine (PEA) produced a contraction of the guinea-pig isolated lung parenchymal strip and bronchoconstriction of perfused lungs. 2. 2. Reserpine pretreatment had little effect on these responses indicating a substantial direct effect. 3. 3. Phentolamine (10 −6 and 10 −5M) had minimal effect on PEA in the lung strip compared with that on noradrenaline, eliminating involvement of α-adrenoceptors. 4. 4. PEA was unaffected by atropine (10 −7M) or a mepyramine (10 −7M); metiamide (10 −4M) mixture. The contraction was not therefore mediated via muscarinic or histaminergic receptors. 5-HT and dopamine receptors were also discounted. 5. 5. Possible stimulation of a phenylethylaminergic receptor and its relevance to bronchial asthma is discussed.