Submitted on December 16, 2004
Accepted on January 26, 2005
Cross-talk along gastrointestinal tract during electrical stimulation: effects and mechanisms of gastric/colonic stimulation on rectal tone in dogs
Shi Liu1, Lijie Wang1, and JDZ Chen2*
1 Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, USA
2 Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, USA; Transneuronix, Mt Arlington, NJ, USA
* To whom correspondence should be addressed. E-mail: jianchen{at}utmb.edu.
Gastric electrical stimulation (GES) has been shown to alter motor and sensory
functions of the stomach. However, its effects on other organs of the gut have rarely
been investigated. The study was performed in 12 dogs implanted with two pairs of
electrodes, one on the serosa of the stomach, and the other, on the colon. The study
was composed of two experiments. Experiment 1 was designed to study the effects of
GES on rectal tone and compliance in 9 dogs, compared with colonic electrical
stimulation (CES). Rectal tone and compliance were assessed before and after GES or
CES. Experiment 2 was performed to study the involvement of sympathetic pathway
in 8 of the 12 dogs. The rectal tone was recorded for 30-40 min at baseline and 20
minutes after IV guanethidine. GES or CES was given for 20 minutes 20 min after the
initiation of the infusion. It was found that both GES and CES reduced rectal tone
with comparable potency. Rectal compliance was altered neither with GES, nor with
CES. The inhibitory effect of GES but not CES on rectal tone was abolished by an
adrenergic blockade, guanethidine. Conclusions: GES inhibits rectal tone with a
comparable potency with CES but did not alter rectal compliance. The inhibitory
effect of GES on rectal tone is mediated by the sympathetic pathway. It should be
noted that electrical stimulation of one organ of the gut may have a beneficial or
adverse effect on another organ of the gut.
