NOS1 and Constipation: After EA at ST 37, the expression of nNOS was significantly decreased compared to constipation models in jejunum (Fig. 4a, b, c), ileum (Fig. 4e, f, g) and proximal colon (Fig. 4i, j, k), almost returned to normal levels and there was no difference compared with the control group, respectively (Fig. 4d, h, l).