ON THE RESPONSES OF COLON MOTILITY TO STIMULATION OF DOG'S LUMBAR CORD

The responses of the movements of distal colon to stimulating dog's lumbar cord were examined. The stimulated areas in the lumbar cord which were responsible for the changes of colon motility were investigated histologically.1. The inhibitory and excitatory responses of movements of the distal colon were observed by the stimulation of lumbar cord. The inhibitory response was obtained through the ventral roots of the hypogastric and lumbar colonic nerves. The excitatory response was obtained through the dorsal roots of the hypogastric and lumbar colonic nerves. The excitatory response was abolished after application of atropine.2. The inhibitory areas were almost located in the ventral column, i.e. Cellulae mediales ventrales, Cellulae latero-ventrales, Cellulae latero-dorsales externae. The inhibitory areas were also found in the lateral and median regions of intermediate substance.The excitatory areas were located in the intermediate substance and dorsal column, i.e. Cellulae cornu-commissurales posteriores, Cellulae dorsomedialis, Cervix cornu dorsalis spinalis, and Cellulae intercornuales laterales.