Objective: To investigate the effect of acupuncture on visceral sensitivity in patients with functional dyspepsia(FD) who were undergoing mechanical gastric distention.Methods: Thirty volunteer FD patients were randomly divided into control group(n=11) and acupuncture group(n=19) according to the designed random table.For patients of acupuncture group

Zusanli(ST 36) and Neiguan(PC 6) were punctured and stimulated with an electric pulse generator by setting the parameters being(10 mA) in strength

(500 μs) in the duration of pulses

(40 Hz) in frequency

12 cpm of pulse trains

and(15 min) in the duration of stimulation.Tianshu(ST 25) was punctured with the needle retained.Isovolumetric gastric distention was performed in all the subjects through a balloon which was swallowed before hand and filled with(300 mL) of air and then connected to SVS/Barostat(Synectice Visceral Stimulator).Heart rate variability(HRV) was recorded and analyzed by using HS9616 Dynamic Electrocardiography Recorder.The maximal tolerable volume and pressure of the stomach were recorded

the epigastric pain

fullness and nausea were scored simultaneously.The automatic nervous function was assessed by the power spectral analysis of HRV.Results: Self-comparison showed that in acupuncture group

the scores of gastralgia

fullness and nausea

and low frequency/high frequency(LF/HF) and ultimate LF of HRV decreased remarkably(P<0.05)

and the maximal tolerable volume and pressure

LF and HF of HRV increased significantly after acupuncture stimulation(P<0.05

0.01)

suggesting that acupuncture stimulation could lower gastric distension induced increase of the visceral sensitivity(noxious reactions)

lower the activity of the sympathetic nerve and potentiate vagal tension in FD patients.No significant changes were found in control group(P>0.05).Conclusion: Acupuncture can reduce the increased visceral sensitivity in FD patients

which may be realized by favorable regulation of activities of the automatic nerve.