Mechanism of Colonic Slow Wave Rhythm Regulated by Electro-acupuncture Determined using Calcium-Sensitive Receptor

Abstract

The calcium-sensitive receptor (CaSR) plays a role in several biological processes. However, its role in intestinal motility remains unclear. In this study, we aimed to determine the effect of electro-acupuncture (EA) at Shangjuxu (ST37) on CaSR in colonic dysplasia mice, and to explore the possible mechanism of EA regulating colonic movement. The mice were injected with nicardipine or hexamethonium bromide to induce colonic dysplasia. Intestinal transit function was assessed by twelve hours fecal granules and fecal water content percentage, while colonic slow wave was assessed by multi-channel physiological signal acquisition system, immunofluorescence and laser confocal microscopy were used to examine CaSR expression in the gastrointestinal (GI) tract of the mice. We found that the number of fecal particles, the frequency and amplitude of colonic slow wave were disrupted after nicardipine or hexamethonium bromide injection. In addition, CaSR expression in control group was mainly distributed in intestinal epithelial cells, and the morphological structure of mucosal layer was regular. Compared with control group, the structure of mucosal layer in nicardipine group and hexamethonium bromide group were all disorderly, the expression and fluorescence intensity of CaSR in nicardipine group were visible, but in hexamethonium bromide group were weakened. After EA intervention, these disorders were ameliorated, which suggested that EA at ST37 could therefore regulate colonic motility disorders via the involvement of CaSR.