Fig. 8

Sketch map of the mechanism of acupoint sensitization due to GMI. 1) Nociceptive information from the gastric mucosa activate neurons in the DRG, and then the impulses travel antidromically toward the periphery via axon reflexes (ARs). 2) Nociceptive information is transmitted orthodromically to the dichotomized neurons in the spinal cord leading to antidromic activation of the somatic branch, or to the neighboring primary afferent fiber through an interneuron via dorsal root reflexes (DRRs). 3) The antidromic activity induced by ARs or DRRs results in the release of inflammatory mediators such as SP and CGRP in skin nerve fibers, resulting in mast cells activation. 4) Activated mast cells release some algogenic substances HA and 5-HT and cause hyperalgesia in local acupoints. 5) In local acupoints, increased SP and CGRP cause plasma extravasation and vasodilatation. SP can also induce aggregation and degranulation of mast cells to release allergic substances HA and 5-HT. All aggravate the neurogenic inflammation further in the local point. This is possible the pathway of acupoint sensitization