To explore the neural connection pathway between the kidney and its back shu and front mu points. Methods: 18 Wistar rats anesthetized with pentobarbital (40 mg/kg) were randomly and equally divided into "Shenshu" (BL 23)

"Jingmen" (GB 25) and "Shenshu" "Jingmen" groups. Propidium Iodide (PI

5%

15 μL) was separately injected into the left "Shenshu" (BL 23) and "Jingmen" (GB 25) areas and 10% Bisbenzimide (Bb

20 μL) was injected into the left kidney following laparotomy in each group. After surviving for 14 hours

these rats were anesthetized again and infused with normal saline

4% paraformaldehyde phosphate buffer solution through the aorta. Then the spinal dorsal root ganglions (DRG) of T 9～L 6 segments were collected to be cut into sections (40 μm thick) for detecting the labeled neurons under light microscope. Results: In "Shenshu" group

the mono labeled cells from the acupoint and the kidney were found in DRG of T 11 ～L 5 (being densest in L 1～L 3) and T 12 ～L 4 (being densest in L 1～L 3) respectively; while the doubly labeled neurons founded in T 13 ～L 3 (peaking between L 1～L 2). In "Jingmen" group

the mono labeled cells from GB 25 were found in DRG of T 10 ～L 3 (being densest in T 12 ～L 1)

while the doubly labeled neurons founded in T 12 ～L 2 (peaking in T 12 and T 13 ). In "Shenshu" "Jingmen" group

the doubly labeled neurons founded in T 13 ～L 1. Conclusion: T 12 ～L 2 DRGs are the important connective links between "Shenshu"

"Jingmen" and the kidney

which also reveals the biological essence of "Qijie" doctrine in TCM.