Electroacupuncture alleviates stress-induced visceral hypersensitivity through an opioid system in rats

Figure 1 Heterotypic intermittent stress protocol and pellets count. A: Nine-day heterotypic intermittent stress (HIS) protocol comprising three different randomly arranged stressors; B: Stress accelerated colonic transit (n = 10 for control, n = 8 for HIS), which was accompanied by an increase in visceral hypersensitivity (^aP < 0.05). C: A schematic representation of the various treatments: stressors, colorectal distention (CRD) and drug treatment with time sequence. CON: Control; AVE: The mean number of pellets for all 9-d stress protocol or from respective control rats; CRS: Cold restrained stressor; FSS: Forced swimming stressor; WAS: Water avoidance stressor.