ABSTRACT
BACKGROUND/AIMS: Stress has a role in the pathogenesis of functional dyspepsia (FD) and influences food intake in humans and animals. Prokinetic drugs have been used in FD, and some of these drugs reverse the feeding inhibition (FI) induced by acute restraint stress in rats. We aimed to evaluate the effect of DA-9701 on FI induced by acute restraint in rats. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into 6 groups: Control (no stress), Stress+vehicle, and Stress+DA-9701 at doses of 1, 3, 10, and 30 mg/kg (n=6~7). DA-9701 or vehicle was administered through gastric gavage 45 minutes before stress. After 60 minutes of stress, pre-weighed chow was given and the weight of remaining food was measured 30 and 60 minutes later. The effect of DA-9701 on FI was compared after pretreatment with WAY100635, a 5HT1A antagonist. RESULTS: The restraint stress group had significantly less food intake than the control group. After feeding, rats given 1 and 3 mg/kg of DA-9701 showed increased food intake at 60 minutes, but this was not statistically significant. Rats given 10 mg/kg of DA-9701 showed significantly increased food intake at 30 minutes and 60 minutes (P < 0.05). Interestingly, rats given 30 mg/kg of DA-9701 showed a significant decrease in food intake, similar to that of the vehicle group. The beneficial effect of 10 mg/kg of DA-9701 on FI was abolished by the pretreatment with WAY100635. CONCLUSIONS: Acute restraint stress reduced food intake in rats and pretreatment with DA-9701 improved stress-induced FI.
Subject(s)
Animals , Humans , Male , Rats , Dyspepsia , Eating , Rats, Sprague-Dawley , Stress, PhysiologicalABSTRACT
BACKGROUND/AIMS: There have been no reports on the effect of chronic psychological stress on colonic immune cells or the regional differences. We aimed to investigate the effect of chronic psychological stress on the number of mast cells and protease-activated receptor (PAR)-2-positive cells in the rat colonic mucosa. METHODS: Six-week-old and 14-week-old Ws/Ws rats, which lack mast cells after 10 weeks, were used as control and mast cell-deficient groups, respectively. The rats were divided into stress and sham-treated groups. Rats in the stressed group were exposed to water avoidance stress (WAS, 1 hour/day) for 13 days. Fecal pellet output and the number of mast cells and PAR-2-positive cells in colonic mucosa were compared between the WAS and sham groups. RESULTS: In 6-week-old rats, the WAS group showed a significantly higher number of mast cells compared to the sham group. In 14-week-old rats, mast cells were nearly absent in the colonic mucosa. WAS significantly increased PAR-2-positive cells in 14-week-old rats, but not in 6-week-old rats. Indirect estimation of PAR-2-positive mast cells in 6-week-old rats suggested that the majority of increased mast cells following WAS did not express PAR-2. WAS increased mast cells and PAR-2-positive cells mainly in the proximal colon. Fecal pellet output was continuously higher in the WAS group than in the sham group, and the difference was significant for both 6-week-old and 14-week-old rats. CONCLUSIONS: Chronic psychological stress increased the number of mast cells and PAR-2-positive cells in rat colonic mucosa, and these increases were more prominent in the proximal colon.