Evaluation of a method to experimentally induce colic in horses and the effects of acupuncture applied at the Guan-yuan-shu (similar to BL-21) acupoint

To evaluate the reliability of a method for inducing colic via small intestinal distention in horses and to examine the analgesic potential of bilateral electroacupuncture (EAP) at the Guan-yuan-shu (similar to BL21) acupoint. 5 healthy adult horses, each with a gastric cannula. A polyester balloon connected to an electronic barostat was introduced into the duodenum via the gastric cannula. At 2 specified intervals (before and after commencement of EAP), the balloon was inflated to a barostat-controlled pressure that induced signs of moderate colic. Each inflation was maintained for 10 minutes. Heart and respiratory rates were continuously recorded. Frequency of various clinical signs of colic was recorded by 2 trained observers during various combinations of balloon inflation and EAP. Each horse received each of 5 treatment protocols (EAP at 20 Hz, sham EAP at 20 Hz, EAP at 80: 120 Hz dense:disperse, sham EAP at 80: 120 Hz dense:disperse, no treatment). Sham EAP was at a point located 2 cm lateral to the Guan-yuan-shu acupoint. Duodenal distention consistently induced a significant increase in frequency of signs of colic. None of the EAP protocols caused a significant reduction in frequency of these clinical signs during distention. The method described is reproducible and highly controllable method for inducing colic that involved duodenal distention that should be useful in evaluating the efficacy of various analgesic strategies. Bilateral EAP at the Guan-yuan-shu acupoint was ineffective in reducing signs of discomfort induced by this method.