Barium stimulation of esophageal smooth muscle.

Abstract

SummaryThis study reports the effect of BaCl2 on circular smooth muscle from the distal esophagus of the cat. The magnitude of the contractile response is dose-related; the threshold concentration varies from 5 × 10-5 to 5 × 10-4 gm/ml and irreversible contracture occurs at concentrations of 5 × 10-3 gm/ml or greater. The dose-response curve is not affected by atropine, hexamethonium, nicotine or the β-adrenergic stimulant, dl-isoproterenol. Thus, the response to barium is the result of a direct action on muscle rather than an indirect action through stimulation of motor elements of the esophageal intramural plexuses.