Modulation of cholinergic neurotransmission in canine airways by thromboxane mimetic U46619

We studied the effect of a thromboxane A2-mimetic, U46619, on the contractile responses of canine bronchial smooth muscle to cholinergic stimulation in vitro. U46619 (3 X 10(-10) M), at a concentration that did not cause contraction, enhanced the effect of electrical field stimulation at all frequencies; histamine (10(-7) M) and prostaglandin F2 alpha (10(-7) M) did not. U46619 (3 X 10(-10) M) did not affect methacholine-induced contractions. U46619 may therefore increase the prejunctional release of acetylcholine.