Effects of extrinsic autonomic denervation and myenteric plexus transection on colonic motility in conscious dogs.
BACKGROUND
The role of extrinsic autonomic nerves in regulation of colonic contractile activity is not well understood.


METHODS
Twelve dogs had 6 strain gauge force transducers implanted in the colon and were divided into 3 experimental groups: (1) a control group, (2) an extrinsic denervation group (denervation group), and (3) an extrinsic denervation with proximal intrinsic myenteric plexus transection group (denervation + transection group). After recovery, colonic contractile activity during fasting and effects of feeding on gastrocolonic response were recorded.


RESULTS
Colonic contractile activity occurred not only in the denervation group but also in the denervation + transection group. Both mean duration and propagation time of the colonic contractile activity were shorter in the denervation + transection group than in the control group. In the denervation group, propagation time was shorter than in the controls but the other parameters were not different. Feeding failed to immediately induce the gastrocolonic response in both experimental groups.


CONCLUSIONS
We conclude that extrinsic nerves are not required for the appearance of colonic contractile activity. However, colonic contractile activity and its propagation are modulated by extrinsic innervation or proximal intrinsic neural continuity. Gastrocolonic response may be predominantly under extrinsic neural control.
D000818:Animals; D017763:Autonomic Denervation; D001341:Autonomic Nervous System / Q000502:physiology*; D003106:Colon / Q000294:innervation* / Q000502:physiology; D004285:Dogs; D005215:Fasting; D005260:Female; D005769:Gastrointestinal Motility; D008297:Male; D009197:Myenteric Plexus / Q000502:physiology*; D016065:Myoelectric Complex, Migrating