Fig. 1

Effect of capsaicin on vagally evoked contractions in the rat esophagus. Representative tracings of the effect of capsaicin (30 µM) on vagally mediated contractions in the esophagi of the intact rat (a) and capsaicin (Cap)-treated rat (b), respectively, are shown (n = 4). Electrical stimulations were applied to the vagus nerve using single pulses of 80 V (pulse duration 100 μs; between-pulse interval 1 min), and longitudinal mechanical responses were recorded isometrically. Filled circles under tracings Points of application of single-pulse electrical stimulation. Electrical stimulation of the vagus trunk induced monophasic (twitch-like) contractions of esophageal striated muscle. Capsaicin was added to the organ bath at a final concentration of 30 µM