Antagonistic changes of gastric and colonic motility during selective thermal stimulation of thoracic and lumbosacral cords in anesthetized dogs.

Changes in gastric and distal colonic motility evoked by thermal stimulation of the thoracic and lumbosacral cords, either individually or simultaneously, were investigated in spinal-intact dogs and in dogs spinalized at the cervical level. Simultaneous cooling of the thoracic and lumbosacral cords increased both gastric and colonic motility before and after spinalization. The direction of the responses evoked by simultaneous heating was the opposite, but only the decrease in gastric activity in the spinal-intact dog was significant. Selective cooling of the thoracic cord increased gastric motility, but decreased colonic motility before and after spinalization. Selective heating decreased gastric motility before and after spinalization, and increased colonic motility before spinalization. Selective cooling of the lumbosacral cord decreased gastric motility and increased colonic motility in spinal-intact dogs. No significant responses could be observed during selective heating in spinal-intact dogs. However, in spinalized dogs, the selective cooling and heating increased and decreased colonic motility respectively, while no significant change was observed in gastric motility during the cooling and the heating. It is concluded from the results that thermal stimulation of the spinal cord directly affects spinal functions which control gastrointestinal motility, and that there exists a mutual inhibitory interaction between the thoracic and lumbosacral innervation of the gastrointestinal tract.