RESUMEN
Human skin sections of the Goukoku (LI·4)-corresponding area and its surroudings were collected and they were stained with H. E. dyes. Abundant nerve fibers and blood vessels were observed in the Goukoku (LI·4)-corresponding area, while their numbers were slightly decreased in the non-acupoint area on the meridian. Their numbers in the extra-meridian non-acupoint area were the lowest.<br>Substance P-containing nerve fibers were examined by histochemistry in the same areas, and many of them were observed in the Goukoku (LI·4)-corresponding area. And further more, they were closely associated with lymphatic vessels. These findings suggest the mechanism that Substance-P secreted by the stimulation of acupoint, is transported to the lymph node via lymphatic vessels, thus leading the stimulation of the lymphatic system.<br>Lymphatic vessels with abundant smooth muscles were predominantly noted in the Goukoku (LI·4)-corresponding area and scarcely in the non-acupoint area by fluorescent stain. This finding suggests that hypersensitive one may feel the contraction of lymphatic smooth muscle induced by the Substance-P as a phenomenon of propagated sensations along the meridians (PSM).