OBJECTIVETo probe into the relationship of different needle-retained time with therapeutic effects.

METHODSForty experimental rats were evenly randomized into 5 groups, electroacupuncture (EA) at "Zusanli" (ST 36) for 5 min, 15 min, 30 min and 60 min groups, who received EA for 5, 15, 30 and 60 min respectively, and a control group who did not receive EA. Nicotinamide adenosine dinucleotide phosphate diaphorase (NADPH-d) method and computer image analysis system were used to detect the meangray of nitric oxide synthase (NOS) positive neurons in the septum.

RESULTSNOS positive neurons in the septum did not change as the EA for 5 min group compared with the control group (P > 0.05); the number of heavily staining NOS positive neurons increased significantly (P < 0.05) and the meangray of the NOS positive neurons significantly decreased (P < 0.01) in some septal subnuclei (lateral septum, and medial septum, vertical diagnonal band) after EA for 15, 30, 60 min as compared with the control group, and the numbers and the meangray of the NOS positive neurons in the septum were not significantly difference among the 3 EA groups.

CONCLUSIONNOS expression in the septum increases and keeps a same level from EA for 15 min to 60 min.