Prostaglandin D2 (PGD2) potentiates cholinergic responsiveness in guinea-pig trachea

PGD2 dose dependently potentiated the parasympathetic-induced contraction in guinea-pig trachea in vitro. This phenomenon was much more evident in ovalbumin-sensitized guinea-pig trachea. Indomethacin pretreatment enhanced the capacity of PGD2 to potentiate cholinergic-induced contraction in normal but not in ovalbumin-sensitized guinea-pig. PGD2 shifted to the left the curve of the exogenous acetylcholine-induced contraction in guinea-pig trachea, indicating a postsynaptic site of action of PGD2. These data suggest a role of PGD2 in the genesis of hyperreactivity of tracheal smooth muscles, particularly in a model of pulmonary anaphylaxis.