Cholera toxin-induced small intestinal secretion has a secretory effect on the colon of the rat.
OBJECTIVE
Little information is available on the role of colon during small intestinal secretion. The aim of this study was to examine the effects of secretory changes in the small intestine on the colonic transport of electrolytes and water in vivo.


METHODS
The jejunum and colon of the rat were perfused in vivo simultaneously but separately, and jejunal secretion was induced by exposing the jejunum to cholera toxin, 8-bromo-cyclic guanosine monophosphate, or hyperosmolarity.


RESULTS
Jejunal perfusion with a hyperosmolar mannitol solution (600 mOsm/L) or with 8-bromo-cyclic guanosine monophosphate (0.5 mmol/L) resulted in net secretion of water in the jejunum but did not affect the baseline rate of water transport in the colon. On the contrary, addition of cholera toxin (1 microgram/loop) to the jejunal segment not only induced a significant local secretory change but also resulted in a similar change in the colon, which was not exposed to cholera toxin. The intestine was transected immediately below the jejunum, thus interrupting the anatomical continuity of the enteric nervous system. This procedure eliminated the distant secretory effect of cholera toxin, thus allowing the conclusion that the enteric nervous system is involved in the distant propagation of the local secretion induced by cholera toxin.


CONCLUSIONS
Cholera toxin, but not other secretagogues, triggers a secretory response that is not only local but also extends to distal segments via the enteric nervous system.
Nocerino
A
A
Department of Pediatrics, University of Naples Federico II, Italy.
Iafusco
M
M
Guandalini
S
S
D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002772:Cholera Toxin / Q000494:pharmacology*; D003106:Colon / Q000187:drug effects* / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003714:Denervation; D004573:Electrolytes / Q000378:metabolism; D007422:Intestines / Q000294:innervation; D007583:Jejunum / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D009424:Nervous System Physiological Phenomena; D009994:Osmolar Concentration; D051381:Rats; D017208:Rats, Wistar; D014867:Water / Q000378:metabolism
D004573:Electrolytes; D014867:Water; C016276:8-bromocyclic GMP; D002772:Cholera Toxin; D006152:Cyclic GMP; D001241:Aspirin