The Involvement Of Psychological Status And Stress In The Pathomechanism Of IBS

Aims:irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder in the west. Information on the prevalence of IBS in the university students is relatively scanty, especially in Asia country. Therefore, the aims of the present study were to investigate the prevalence and the pattern of symptoms of IBS and its relationship with psychological stress status in university students in China.Method:Basic demographic data and symptoms of IBS using the Rome II criteria were sought using a validated bowel symptom questionnaire administered. Another questionnaire asked related to psychosomatic symptoms of depression and anxiety.Result:A response of 92.6% yielded 491 questionnaires for analysis,241(49.1%) were men and 250(50.9%) were women. Medical college students (313/491) and non-medical college students (178/491) comprised the subjects. The apparent prevalence of IBS was 15.7% with a prevalence of 14.5% in men and 16.8% in women. The most common symptom was abdominal pain associated with change in consistency of stool (36.9%), followed by Altered stool frequency (16.3%), and Abdominal pain relieved by defecation (12.4%), predominantly women. The self-reported psychological and psychosomatic symptoms of anxiety (P＜0.001), depression (P＜0.001) were encountered more frequently in the subjects with IBS. Depression measure (P=0.03) and Anxiety measure (P=0.02) significantly predicted IBS status.Conclusion:The prevalence of IBS in Chinese university is greater compared with general population previously appreciated. Depression and anxiety might be the potential induce factors of IBS. Medical education should be considered when aiming to reduce stress of university students who are susceptible to IBS. Aims:This study was designed to investigate the possibility that the enhanced nociceptive responsiveness associated with CB1 receptors and identify its role in mediating in rats with sustained visceral hypersensitivity induced by chronic restraint stress.Methods:Male Sprague-Dawley rats were exposed to daily 2-hour partial restraint stress (PR) or sham PR for 4 consecutive days. We tested the visceromotor reflex to colorectal distention (CRD) at day 5 after intraperitoneal injection of the CB1 receptor agonist or antagonist. Reverse-transcription (R-T) polymerase chain reaction and Western blot were used to assess the expression of CB1 receptors in samples of distal colon, proximal colon and distal small intestinal.Results:Intraperitoneal CB1 agonist injection significant diminished (P<0.05) the enhanced visceromotor reflex to colorectal distention at day 5 in stressed rats. Change in EMG response after ACE A over baseline, at press of 40 mmHg (+13.3±2.2),60 mmHg (+15.3±2.8) and 80 mmHg (+17.0±4.0) were much lower than in the control animals, which were +35.9±5.1,+41.1±6.3 and +54.1±9.6, separately. Whereas, CB1 antagonist had an opposite effect, compared with control group, the change in EMG response after SR141716A over baseline was significantly enhanced (P<0.05) for the distending pressure of 40mmHg (+56.0±10.3),60mmHg (+74.6±12.3) and 80mmHg (+82.9±11.0), separately. R-T polymerase chain reaction and Western blotting demonstrated the stress-induced up-regulation of colon CB1Rs (P<0.05).Conclusions:Our results suggest there is a key contribution of peripheral CB1 receptors involved in the maintenance of visceral hyperalgesia after repeated restraint stress, providing a novel mechanism for development of peripheral visceral sensitization. Aim To investigate the response of cannabinoid 1 receptor to restraint stress in rat intestinal tract. Methods Divided 30 Sprague-Dawley rats into fowllowing groups:①Control group,②Acute Stress group,③Acute Stress and Agonist group. Rats of all groups were received colorectal distension (CRD). The frequencies of discharges of EMG of the rats were recorded to evaluate the visceral sensitivity. The expression of the cannabinoid 1 receptor in intestinal tract of the rats was examined by means of RT-PCR techniques. Results (1) Acute restraint stress can increase the visceral senstitivity:the frequencies of discharges of EMG responding to CRD of the rats of Acute Stress group at 40,60 and 80mmHg immediately after restraint stress significant higher than those of Vehicle group. (2) The visceral sensitivity was up-regulated after restraint stress, but i.p. with agonist before the'stress had a significant effect on the hyperalgesia:before stress, the frequencies of discharges of EMG responding to CRD at 40,60 and 80mmHg of the rats deal with agonist significant lower than the rats deal with vehicle, after stress and 3 days after, no significant change was observed between the two groups. (3) Restraint stress increased the expression of cannabinoid 1 receptor:in Acute Stress group the expression of cannabinoid 1 receptor in ileocecal junction, proximal colonic and distal colonic was up-regulated in Acute Stress group (p<0.05). Conclusion The visceral sensitivity in rats induced by stress can trigger the accommodation of endogenous cannabinoid system, which can modulate visceral sensitivity. Aim To investigate the response of NMD A receptor NR1 subunit to restraint stress in rat intestinal tract. Methods Divided 30 Sprague-Dawley rats into fowllowing 3 groups: Control group, Acute Stress group and Acute Stress+MK-801 group. Rats of all groups were received colorectal distension (CRD). The frequencies of discharges of EMG of the rats were recorded to evaluate the visceral sensitivity. The expression of the NMDA receptor in intestinal tract of the rats was examined by means of RT-PCR techniques and Western-blot. Results (1) Acute restraint stress can increase the visceral sensitivity:the frequencies of discharges of EMG responding to CRD of the rats of Acute Stress group at 40,60 and 80mmHg immediately after restraint stress significant higher than those of Vehicle group (P<0.05). However, I.p. with antagonist before the stress had a significant effect on the hyperalgesia:the frequencies of discharges of EMG responding to CRD at 40, 60 and 80mmHg of the stressed rats deal with MK-801 significant lower than the stressed rats deal with vehicle (P＜0.05). (2) Compared with Control group, the expression of NR1 in ileocecal junction, proximal colonic and distal colonic was up-regulated in Acute Stress group (p<0.05), but no significant change in Acute Stress+MK-801 group. Compared with Acute Stress group, the expression of NR1 in ileocecal junction, proximal colonic and distal colonic was much lower in Acute Stress+MK-801 group. Conclusion NMDA receptor plays an important role on the visceral sensitivity in rats induced by acute restraint stress.