Evidence for thoracolumbar spinal cord processing of inflammatory, but notacute colonic pain

The lower bowel is innervated by visceral afferents projecting to the lumbo sacral and thoracolumbar spinal segments. The present study tested the hypo thesis that sensory processing from the normal colon occurs in the lumbosac ral spinal cord with little or no activity in the thoracolumbar segments. F ollowing colonic inflammation, viscerosensory processing in the thoracolumb ar spinal cord is recruited, contributing to visceral hyperalgesia. A basel ine visceromotor reflex to colorectal distention recorded in intact rats wa s eliminated following bilateral L6-S3 dorsal rhizotomies. The visceromotor reflex recovered to 29% of baseline following colonic inflammation. These results suggest that visceral hyperalgesia and referred pain in patients wi th lower bower disorders partly result from novel viscerosensory processing in the thoracolumbar spinal cord. NeuroReport 11:2113-2116 (C) 2000 Lippin cott Williams & Wilkins.