Pre- and postjunctional effects of a thromboxane mimetic in canine bronchi

Thromboxane A2 is believed to participate in causation of hyperreactivity of airway smooth muscle (ASM). We therefore investigated the effects of a thromboxane mimetic (U-46619) on isolated ring segments of canine bronchial ASM (3rd to 5th order). U-46619 (10(-9)-10(-5) M) was found to elicit tonic contraction, membrane depolarization, and oscillations in membrane potential. These effects were sensitive to blockade of thromboxane receptors …