Restraint stress stimulates colonic motility via central corticotropin-releasing factor and peripheral 5-HT₃ receptors in conscious rats

Abstract

Although restraint stress accelerates colonic transit via a central corticotropin-releasing factor (CRF), the precise mechanism still remains unclear. We tested the hypothesis that restraint stress and central CRF stimulate colonic motility and transit via a vagal pathway and 5-HT3 receptors of the proximal colon in rats. 51Cr was injected via the catheter positioned in the proximal colon to measure colonic transit. The rats were subjected to a restraint stress for 90 min or received intracisternal injection of CRF. Ninety minutes after the administration of 51Cr, the entire colon was removed, and the geometric center (GC) was calculated. Four force transducers were sutured on the proximal, mid, and distal colon to record colonic motility. Restraint stress accelerated colonic transit (GC of 6.7 ± 0.4, n = 6) compared with nonrestraint controls (GC of 5.1 ± 0.2, n = 6). Intracisternal injection of CRF (1.0 μg) also accelerated colonic transit (GC of 7.0 ± 0.2, n = 6) compared with saline-injected group (GC of 4.6 ± 0.5, n = 6). Restraint stress-induced acceleration of colonic transit was reduced by perivagal capsaicin treatment. Intracisternal injection of CRF antagonists (10 μg astressin) abolished restraint stress-induced acceleration of colonic transit. Stimulated colonic transit and motility induced by restraint stress and CRF were significantly reduced by the intraluminal administration of 5-HT3 antagonist ondansetron (5 × 10−6 M; 1 ml) into the proximal colon. Restraint stress and intracisternal injection of CRF significantly increased the luminal content of 5-HT of the proximal colon. It is suggested that restraint stress stimulates colonic motility via central CRF and peripheral 5-HT3 receptors in conscious rats.

Luminally released serotonin stimulates colonic motility and accelerates colonic transit in rats

“…We have recently shown that intraluminal administration of ondansetron had no effects on basal activity and that restraint stress significantly augmented colonic motility in conscious rats (40). Current study also showed that restraint stress significantly increased the motor activity of the distal colon.…”

“…Stress-induced simulation of colonic motility is antagonized by a systemic treatment with 5-HT 3 receptor antagonists (36). We have recently showed that restraint stress augmented colonic motility and increased the luminal release of 5-HT of the proximal colon in rats (40). Thus, luminally released 5-HT has an important role in stress-induced stimulation of colonic motility.…”

Anti-stress Effect of Hypothalamic Oxytocin, Importance of Somatosensory Stimulation and Social Buffering

“…Gastric emptying of solid and liquid meals is delayed by acute restraint stress in rodents [5] . In contrast, acute restraint stress accelerates colonic transit in rats [6] and mice [7] . There are two distinct CRF receptors, subtype 1 (CRF type1) and subtype 2 (CRF type2).…”

“…Delayed gastric emptying induced by acute restraint stress is mediated via central CRF2 receptors [5] . In contrast, accelerated colonic transit induced by acute restraint stress is mediated via central CRF1 receptors in rats [6] . Acute restraint stress stimulates central CRF2 receptors and sympathetic pathway, resulting in delayed gastric emptying [5] ( Figure 1), while acute restraint stress stimulates central CRF1 receptors and parasympathetic pathways (vagal nerve and pelvic nerve), resulting in acceleration of colonic transit in rats [6] ( Figure 1).…”

Impact of stressor exposure on the interplay between commensal microbiota and host inflammation

“…14,15 Unlike the slower motility in the stomach and small intestine, stressor exposure tends to enhance motility in the colon. 16 In addition to affecting these secretory and motor responses, the physiological stress response can also affect protective barriers in the intestines. Stress exposure can significantly alter mucous levels in the colon, as well as the levels of secretory immunoglobulin A.…”