Influence of Respiratory Tract Viral Infection on Endothelin-1-Induced Modulation of Cholinergic Nerve-Mediated Contractions in Murine Airway Smooth Muscle

The effects of endothelin-1 (ET-1) and sarafotoxin S6c (S6c) on cholinergic contractions elicited by electrical field stimulation (EFS) were examined in mouse tracheal preparations from healthy animals and from animals infected with pa-rainfluenza-1 (P-1) virus. S6c (an ETB-selective agonist) and ET-1 caused marked ETA and/or ETB receptor-mediated potentiation of EFS-induced contraction in tracheal tissue from both groups. Despite the fact that such infection is known to markedly alter ET receptor density and function in mouse tracheal smooth muscle, no evidence for modulated neuronal ET receptor function was obtained. The reason for this differential sensitivity of smooth muscle and neuronal ET receptors to P-1 infection is unknown.