Enhanced motility of the vagotomized canine stomach by electrical stimulation

Abstract

Functional impairment of the vagotomized stomach used as a substitute oesophagus seriously deteriorates the quality of life of patients following oesophageal cancer surgery. We speculated that if the enteric neurons of the reconstructed gastric tube survived functionally, the motility of the gastric tube could be facilitated and the recovery process after operation would improve as a consequence. In the present study we investigated whether direct electrical stimulation was effective for facilitating the motility of the canine vagotomized stomach. Dogs underwent truncal vagotomy by transabdominal approach and, in some cases, arteries to the upper stomach and the oesophagus were also ligated and resected to resemble the blood supply and surgical invasion of the reconstructed gastric tube. Electrical stimulation, a few minutes of positive rectangular current pulses, amplitude 20 V (or 15 mA), duration 0.5 ms and frequency between 0.2 and 7 Hz, was delivered on the greater curvature of the mid corpus. Changes in mechanical contractions were recorded using strain gauge force transducers. Electrical stimulation successfully enhanced the mechanical force of the phasic ring contractions of the vagotomized stomach in a frequency dependent manner. Aboral propagation and periodicity of the contractions, impaired by surgical procedures, were restored during stimulation. These excitatory effects were inhibited by atropine, hexamethonium and tetrodotoxin, suggesting that electrical stimulation acts on intramural cholinergic nerves that have survived functionally. These results suggest that electrical stimulation could be an effective method for improving the motility of the vagotomized stomach.