An in vitro study of various drugs on central and peripheral airways of the rat: a comparison with human airways.

1 The effect of histamine and other drugs on the central and peripheral airways of the rat was studied by applying them directly to isolated tracheal and lung strip preparations. These effects were then compared with those observed on human isolated bronchial muscle preparations. 2 Acetylcholine and 5-hydroxytryptamine (5-HT) both contracted the lung strip and trachea of the rat, and both were more potent on the trachea than the lung strip. 3 Histamine and prostaglandins E2 (PGF2) or F2 tau (PGF2 tau) produced no effect on either the lung strip or trachea of the rat. 4 On the human isolated bronchial preparation, in contrast to the rat airways, both histamine and PGF2 tau produced marked concentration-dependent contractions and 5-HT either produced no response or a slight relaxation. 5 In view of these results, the use of anaphylactic bronchoconstriction in the rat as a model for the study of asthma in man is questioned.