[Effect of nifedipine on canine LESP (author's transl)]

Nifedipine acts on smooth muscle cells to prevent the influx of calcium ions. The present study was undertaken to see whether a relaxatory effect of nifedipine is present on esophageal smooth muscle as well as on vascular smooth muscle. The experiment was performed on anesthetized dog's lower esophageal sphincter pressure (LESP). Nifedipine (0.5 mg/kg) administered sublingually caused rapid and marked depression of LESP. LESP response to either ACO-tetragastrin (0.5 microgram/kg) or bethanechol (5 microgram/kg) was inhibited partially but markedly. This inhibition might be caused by prevention of calcium-ion influx. This depressant effect of nifedipine on LESP both in resting state and in stimulated state is able to apply to therapy of hypermotile disorders of the esophagus.