<p style="text-align: center;">ZHANG Zhiyun, WANG Hui, XU Dongsheng, BAI Wanzhu*</p><p style="text-align: center;">(Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China)</p><p style="text-align: justify;"><strong>Abstract</strong>:&nbsp; <strong>Objective:</strong>&nbsp; To&nbsp; research&nbsp; the&nbsp; distribution&nbsp; of&nbsp; the&nbsp; neurons&nbsp; associated&nbsp; with&nbsp; kidney&nbsp; and&nbsp; acupoint “Shenshu” (BL&nbsp; 23) area in the rat&nbsp; and&nbsp; explore&nbsp; the&nbsp; neuroanatomical basis of acupoint-visceral correlation.&nbsp;</p><p style="text-align: justify;"><strong>Methods&nbsp; </strong>Normal&nbsp; male&nbsp; SD&nbsp; rats&nbsp; were&nbsp; used&nbsp; as&nbsp; present&nbsp; experimental&nbsp; subjects.&nbsp; Under&nbsp; the&nbsp; respiratory anesthesia, AF488-CTB&nbsp; (green)&nbsp; was injected subcutaneously into the left side of BL&nbsp; 23 area, at the same time,&nbsp; AF594-CTB&nbsp; (red)&nbsp; was injected into the same side of kidney&nbsp; that was exposed by local surgery. Both injections were performed in the same rat. Three days after injection, the rats were transcardially perfused with 4% paraformaldehyde in 0.1 M phosphate buffer (PB), and dorsal root ganglions (DRG), spinal cord, and sympathetic chain were dissected out and stored in 25% sucrose PB at 4°C for sample making.The neuronal labeling with AF488/594-CTB can be directly observed under a fluorescent microscope or a laser scanning&nbsp; confocal&nbsp; microscope.&nbsp; <strong>Results</strong>&nbsp; The&nbsp; sensory&nbsp; neurons&nbsp; associated&nbsp; with&nbsp; kidney&nbsp; and&nbsp; acupoint&nbsp; BL&nbsp; 23 distributed from thoracic (T) 10 to lumbar (L)&nbsp; 2&nbsp; and T11 to L3&nbsp; DRG respectively,&nbsp; and some of them were labeled&nbsp; with&nbsp; both&nbsp; AF488/594-CTB&nbsp; and&nbsp; coexisted&nbsp; in&nbsp; T13&nbsp; DRG.&nbsp; For&nbsp; the&nbsp; sympathetic&nbsp; innervation,&nbsp; the postganglionic sympathetic neurons&nbsp; associated with both&nbsp; kidney&nbsp; and acupoint&nbsp; BL&nbsp; 23 were found in&nbsp; the sympathetic chain at the same lumbar segments and&nbsp; labeled with&nbsp; AF488/594-CTB separately .&nbsp; In addition, the motor neurons associated with acupoint BL 23 area were mainly detected in the spinal ventral horn of cord at thoracic segments and also a few at cervical segments. Conclusions&nbsp; These results reveal that sensory neurons associated with both kidney and acupoint BL 23 area can be the basis of correlation between them in the sensory nervous system. In addition, the postganglionic sympathetic neurons associated with kidneyand&nbsp; acupoint&nbsp; BL&nbsp; 23&nbsp; area&nbsp; locate&nbsp; adjacently&nbsp; in&nbsp; the&nbsp; same&nbsp; sympathetic&nbsp; ganglion,&nbsp; further&nbsp; demonstrating sympathetic connection between them.&nbsp; Present study&nbsp; suggests that stimulating signals from&nbsp; acupoint BL23 area can be transported to the kidney through both sensory and sympathetic pathway simultaneously.&nbsp;</p><p style="text-align: justify;"><strong>Keywords</strong>: acupuncture, shenshu (BL 23), kidney, neural tracing technique, neuron&nbsp; &nbsp;</p><p><br/></p>