Myogenic activity relationship between the lower esophageal sphincter and pylorus of the cat in normal peristalsis and provoked retroperistalsis.

Electrodes were chronically implanted in some of 14 cats and acutely inserted in others in the muscle of the high pressure zone of the lower esophagus (LEHPZ), in the duodenum, pylorus and antrum at identical location to register the myogenic electrical activity of the LEHPZ. Simultaneously the intraluminal pressure of the LEHPZ and swallowing contractions were recorded on a 6 channel Beckman R 611 ink-pen polygraph using stationary perfusion manometry. A clear basic electrical rhythm with slow wave activity was regularly found in the LEHPZ. Strong electrical changes (action potentials) were superimposed on the slow waves which were associated with relaxation in the LEHPZ and muscle contraction in the esophagus. Electric stimulation of the duodenum and pylorus with rectangular impulses produced retrograde peristalsis in the antrum but no response in the LEHPZ. Direct stimulation of the LEHPZ and gastric fundus, however, caused a strong transient contraction of the LEHPZ.