<p style="text-align: center;">CHEN Hong, YANG Jinsheng, XU Dongsheng, BAI Wanzhu, WANG Yingying △(1 Shanxi University of Chinese Medicine, Xi&#39;an 712046, China; 2 Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China)</p><p style="text-align: justify;"><strong>Abstract:</strong> <strong>Objective</strong>: To observe the effect of electroacupuncture&nbsp; on the expression of substance P, calcitonin gene-related peptide, 5-hydroxytryptamine and histamine in &quot;YangLingQuan&quot; (GB 34)&nbsp; local&nbsp; tissue&nbsp; by&nbsp; using immunohistochemistry&nbsp; combined&nbsp; with&nbsp; confocal&nbsp; technique,&nbsp; so&nbsp; as&nbsp; to explore&nbsp; its&nbsp; signal&nbsp; transduction&nbsp; pathway.&nbsp; Methods:&nbsp; 6&nbsp; male&nbsp; Wistar&nbsp; rats,&nbsp; the&nbsp; left&nbsp; hind&nbsp; limb &quot;YangLingQuan&quot; (GB 34)skin&nbsp; electroacupuncture, corresponding to the right as control. The ·skin tissue on hind limbs&nbsp; &quot;YangLingQuan&quot; (GB 34)&nbsp; was exposed by shearing wool. Subsequently,electroacupuncture was carried out on the left side of&nbsp; &quot;YangLingQuan&quot; (GB 34)&nbsp; Then the local tissue about 1 ㎝ width&nbsp; and 1.5 ㎝ length on hibateral&quot;YangLingQuan&quot;&nbsp; (GB&nbsp; 34)&nbsp; of&nbsp; rats&nbsp; were dissected out following perfusion with 4% paraformaldehyde, and put into 25 % sucrose solution. Serial tissue sections were cut at a thickness of 20 mm on a cryostat. The chemicalexpression of tissue&nbsp; was demonstrated by using fluorescent immunohistochemical staining for Substance (SP), Calcitonin&nbsp; gene-related&nbsp; peptide&nbsp; (CGRP),&nbsp; 5-Hydroxytryptamine&nbsp; (5-HT)&nbsp; and&nbsp; histamine&nbsp; (HA).Results:&nbsp; Compared&nbsp; with&nbsp; the&nbsp; control&nbsp; group,&nbsp; the&nbsp; positive&nbsp; labeling&nbsp; of&nbsp; SP,&nbsp; CGRP,&nbsp; 5-HT,&nbsp; HAincreased in the&nbsp; electroacupuncture&nbsp; tissue,&nbsp; in which SP and CGRP mainly around blood vessels and&nbsp; hair&nbsp; follicle;&nbsp; 5-HT-labeling&nbsp; between&nbsp; the&nbsp; epidermis&nbsp; and&nbsp; dermissubcutaneous&nbsp; tissue&nbsp; layer formed a continuous band of enhancement; HA-labeling concentrated the blood vessels of deep dermis and subcutaneous tissue. The length of SP and CGRP positive fibers and the number of 5-HT and HA in electroacupuncture and control tissues were countedrespectively. we found that significant&nbsp; differences&nbsp; existed&nbsp; in&nbsp; the&nbsp; electroacupuncture&nbsp; group&nbsp; and&nbsp; control&nbsp; group(＊P＜0.05). <strong>Conclusion</strong>:&nbsp; Nociceptive&nbsp; neuropeptide&nbsp; SP,&nbsp; CGRP&nbsp; and&nbsp; active&nbsp; substances&nbsp; 5-HT,&nbsp; HA&nbsp; may&nbsp; be involved in the transduction pathway of electroacupuncture information.</p><p><strong>Key words</strong>: electroacupuncture, Calcitonin gene-related peptide, SubstanceP, 5-Hydroxytryptamine, Histamine, Immunohistochemistry</p><p><br/></p>