Evidence for ascending visceral nociceptive information in the dorsal midline and lateral spinal cord.
The effect of acute, mid-cervical spinal cord lesions on neuronal and reflex activity evoked by the noxious visceral stimulus, colorectal distension (CRD; 80 mmHg, 20 s), was determined in halothane-anesthetized rats. Extracellular recordings were performed of neurons stereotaxically located within the ventrobasal group of the thalamus and in the region of the medullary lateral reticular nucleus. CRD-evoked activity of thalamic neurons was attenuated by lesions of the dorsal midline, but minimally affected by lateral lesions of the spinal cord. In contrast, CRD-evoked activity of medullary neurons was attenuated by lateral lesions ipsilateral to the recording site, but minimally affected by contralateral lateral lesions or dorsal midline lesions. Pseudo-affective visceromotor/cardiovascular responses were vigorous in rats with dorsal midline lesions and absent/attenuated in rats with bilateral lateral spinal lesions. This study presents evidence that visceral nociceptive information ascends in the spinal cord by both dorsal midline and lateral spinal pathways.
Ness
T J
TJ
Department of Anesthesiology, ZRB 940, University of Alabama at Birmingham, 1530 Third Avenue, South, Birmingham, AL 35294, USA.
D000818:Animals; D002404:Catheterization; D003106:Colon / Q000503:physiopathology; D004594:Electrophysiology; D008297:Male; D008526:Medulla Oblongata / Q000503:physiopathology*; D009475:Neurons, Afferent; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley; D012007:Rectum / Q000503:physiopathology; D013116:Spinal Cord / Q000503:physiopathology*; D020651:Ventral Thalamic Nuclei / Q000503:physiopathology*; D014781:Viscera / Q000294:innervation*; D017833:Visceral Afferents / Q000503:physiopathology*