Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel

Abstract

Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie nonselective cation currents and are downstream effectors of G protein-coupled receptors. Ca 2+ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel.

Stress decreases contraction of the colon, and the effects of stress are different among the regions of the colon

“…Diarrhea and constipation are two of the most typical symptoms that appear with stress, and the colon is involved in these [ 10 ]. In a previous report, we reported that water immersion restraint stress affected small intestinal motility in mice [ 3 ], however we did not analyse colon motility. Based on this background, the purpose of this study is to measure the changes in colon motility due to stress.…”

“…Water immersion restraint stress was performed as described previously [ 3 ] with some modifications. Male C57BL/6 mice (8–10 weeks old) were purchased from CLEA Japan, Inc. (Tokyo, Japan).…”

“…Quantitative real-time PCR was performed using a previously described method [ 11 ]. The primers were used from a previously described method [ 3 ]. The results were expressed as the mean ± standard error of the mean (SEM).…”

“…This difference in the reactivity in the regions of the colon must be due to something. We focused on TRPC3, which we investigated in our previous report [ 3 ]. We examined the expression levels of TRPC3 in the colon of the control mouse and stressed mouse.…”

“…However, the difference was not significant. In a previous report, we found that TRPC3 expression was decreased in the ileum of stressed mice, resulting in a reduced contractile mechanism [ 3 ]. TRP channels underlie non-selective cation currents [ 14 ].…”