Objective:To investigate the therapeutic efficacy and mechanisms of transcutaneous electrical acupoint stimulation (TEAS) in the treatment of postprandial distress syndrome (PDS) in functional dyspepsia (FD).Methods:A double-blinded, randomized, controlled study was conducted. At Sir Run Run Shaw Hospital, Medical School Zhejiang University 40 patients aged 18-70 years old who met the Rome Ⅳ diagnostic criteria of PDS were prospectively enrolled. After informed consent, the patients were randomly assigned to TEAS group or sham-TEAS group. The patients in the TEAS group received transcutaneous electrical acupoint stimulation at acupoints Zusanli and Neiguan, and those in the sham-TEAS group underwent stimulation at other mimic acupoints for four weeks. The symptoms, gastric accommodation (initial satiety volume (ISV) and maximum tolerable volume (MTV), time of half gastric emptying of solid food ( T1/2) and heart rate variability (high frequency, low frequency and ratio of low frequency to high frequency) were compared between the two groups before and after treatment. The expression levels of inflammatory cytokines in duodenal mucosa were also evaluated by polymerase chain reaction in PDS patients and 24 healthy volunteers. Independent sample t test, Mann-Whitney U test and chi square test were used for statistical analysis. Results:A total of 26 PDS patients were enrolled in the study, 13 cases each in the TEAS group and sham-TEAS group. Between the patients of the two groups, there were no statistically significant differences in gender, age, or score of 36-item short form health survey (SF-36), score of self-rating anxiety scale (SAS), score of self-rating depression scale (SDS), score of dyspeptic symptom severity index (DSSI), ISV, MTV, T1/2 or heart rate variability indexes (high frequency, low frequency and ratio of low frequency to high frequency) before treatment (all P>0.05). After treatment, the DSSI score of TEAS group was lower than that of sham-TEAS group (13.5±5.3 vs. 19.9±9.3), the values of ISV and MTV were both higher than those of sham-TEAS group ((180.0±44.6) mL vs. (121.9±61.0) mL, (480.4±200.7) mL vs. (338.5±108.8) mL), and the differences were all statistically significant ( t=2.18, 2.77 and 2.24, all P<0.05). After treatment there was no statistically significant difference in T1/2 between TEAS group and sham-TEAS group ( P>0.05). There was no statistically significant difference in T1/2 between before and after treatment in patients of TEAS group ( P>0.05). After treatment, the high frequency increased (5.3±1.2 vs. 4.0±0.9) and the ratio of low frequency to high frequency decreased (1.0±0.2 vs. 1.3±0.2), and the differences were statistically significant ( t=-3.31 and 3.73, both P<0.01). The expression levels of interleukin 6 (IL-6) mRNA in mucosa of duodenal bulb and descending duodenum of PDS patients were both higher than that of healthy control group (0.68, 0.11 to 6.74 vs. 0.03, 0.02 to 0.25; 6.46, 1.35 to 12.62 vs. 0.86, 0.32 to 2.90), and the differences were statistically significant ( Z=-2.24 and -2.03, P=0.02 and 0.04). After TEAS treatment for four weeks, the expression of IL-6 mRNA in duodenal bulb mucosa decreased compared with that before treatment in TEAS group (0.04, 0.01 to 0.06 vs. 0.23, 0.09 to 3.66) and the difference was statistically significant ( Z=-2.07, P=0.04). Conclusions:TEAS can improve the gastric accommodation and dyspeptic symptoms in PDS patients. The mechanism may be related with the vagal pathway mediating and regnlating the expression of inflammatory cytokine IL-6 in duodenal bulb mucosa.