Stimulatory role of the dorsal motor nucleus of the vagus in gastrointestinal motility through myoelectromechanical coordination in cats

This study was undertaken to investigate the effect of stimulation of the dorsal motor nucleus of the vagus (DMV) on myoelectric activity and motility of the gastric antrum and duodenum in normal and in vagotomized cats. 37 cats were starved for 24 h and then anesthetized with cu-chloralose (70-80 mg/kg, iv). Electrical stimulation (0.1 mA, 0.2 ms, 50 Hz) of the left DMV was performed through a stereotaxically inserted electrode in 19 of the cats. The remaining 18 cats were injected in the left DMV with a glutamate solution (1 M, 200 nl) through an inserted 3-barreled micropipette. The myoelectric activity (slow wave) and the motility of the gastric antrum (2 cm proximal to the pylorus) and duodenum (3 cm distal to the pylorus) were measured using serosal bipolar electrodes and intraluminal balloons. Both the electrical and the glutamate stimulations of the DMV markedly increased the occurrence of spike potentials on the antral and duodenal myoelectric activity; however, the stimulations significantly decreased the frequency of the antral slow wave. The stimulations also produced increases in the motility of the antrum and duodenum which corresponded to the changes in the myoelectric activity. All the changes in the myoelectric activity and the motility were not observed after the ipsilateral vagotomy. Thus, these results strongly suggest that the dorsal motor nucleus of the vagus has a stimulatory influence on antral and duodenal motility through myoelectromechanical coordination via the vagus nerve in cats.