Effect of oral bethanechol on parameters of esophageal peristalsis

It has been suggested that enhanced esophageal peristalsis may be an additional reason for the therapeutic effect of oral bethanechol (B) in reflux patients and for the improved acid clearing seen with B. This study was designed to determine the effect of oral B on various parameters of esophageal peristalsis. Healthy young adult males were studied with an intraesophageal transducer assembly. Amplitude, dp/dt, and velocity profiles for the smooth muscle portion of the esophagus were produced. Oral B, 25 mg, produced a significant increase (P less than 0.05) in amplitude in the distal esophagus from 15 to 45 min after drug administration. The effect on dp/dt was similar but not as marked. Oral bethanechol produced decreases in velocity at all points, reaching significance (P less than 0.05) at the most distal measuring site, 30 and 45 min after injection. Oral B produces a stronger but slower, perhaps more efficient, progression of the peristaltic wave in normal humans. Our findings may explain improved acid clearance found with this agent.

Pressure profile of esophageal peristalsis in normal humans as measured by direct intraesophageal transducers

The pressure profile of esophageal peristalsis was studied in healthy young adult males using an intraesophageal transducer assembly. The amplitude of peristaltic contractions following wet swallows was determined at intervals along the esophagus from the lower esophageal sphincter (LES) to the upper esophageal sphincter (UES). The amplitude profile revealed a trough of significantly decreased (P less than 0.05) amplitude at 17.5-20.0 cm above the LES. The change in pressure per unit time (dp/dt) produced a profile also with a significant decrease (P less than 0.01) in the upper esophagus, having good correlation (r = 0.91, P less than 0.001) with the amplitude profile. Mean velocity of the peristaltic wave in the upper esophagus varied from 2.92 +/- 0.19 (+/- SEM) to 3.29 +/- 0.36 cm/sec. In the distal esophagus, mean velocity increased significantly (P less than 0.01) to 4.98 +/- 0.38 cm/sec at 7.5 cm above the LES, and then fell significantly (P less than 0.05) to 2.15 +/- 0.27 cm/sec at 2.5 cm above the LES. This report establishes amplitude and velocity profiles in the human esophagus. The profile of the first derivative of the primary peristaltic wave (dp/dt) is also described, and its possible importance discussed.

Lower esophageal sphincter pressures and serum gastrin levels after cholinergic stimulation

To define the role of gastrin, if any, in the response of the lower esophageal sphincter (LES) to bethanechol, serum gastrin determinations and LES pressure measurements were made in controls, patients with vagotomy and antrectomy (V&A), and patients with vagotomy and pyloroplasty (V&P). Despite significant differences in mean basal serum gastrin levels no differences were found in mean resting LES pressures among these groups. In controls significant increases in LES pressure occurred after subcutaneous bethanechol, but serum gastrin levels did not change from basal values. Subcutaneous injections of bethanechol produced significantly greater increases in LES pressures in V&P patients than in V&A patients. Serum gastrin levels did not change in either group; however, background serum gastrin concentrations were significantly greater for V&P patients than V&A patients throughout the study. Intravenous infusion of human gastrin I heptadecapeptide in controls significantly increased sphincter responses to bethanechol. Thus, these studies provide evidence to suggest that the LES response to bethanechol is affected by background serum gastrin levels.