title: [Segmental and regional distribution of neurons and their axonal projection associated with acupoint "yongquan" (KI 1) in the rat: cholera toxin subunit B method].
abstract: OBJECTIVE
  To observe the distribution of neurons and their axonal projection associated with "Yongquan" (KI 1) area by neural tracing technique with cholera toxin subunit B (CTB).
  
  
  METHODS
  A total of 5 microL of 1% CTB solution was injected into the front central part of hind foot plantar (corresponding to the KI 1 region in the human body) using a Hamilton microsyringe. After 3 survival days, the rats were deeply anesthetized and transcardically perfused for collecting the dorsal root ganglia (DRGs), spinal cord and brain tissues. Following fixing in 4% paraforldehyde containing phosphate buffer solution (PBS) and incubation in PBS containing 25% glucose solution, the aforementioned tissues were sectioned to be stained with immunofluorescence or immunohistochemistry for revealing the labeled sensory neurons and their tansganglionic projection and motor neurons.
  
  
  RESULTS
  All the labeled neurons (sensory and motor neurons) and transganglionic axonal projection appeared ipsilaterally to the injection side. The labeled sensory neurons were located in the DRGs of lumbar 3-5 segments (L 3-L 5) with a higher concentration at L 4, while motor neurons distributed in the dorsolateral portion of spinal ventral horn from L 3 to L 6 with a higher concentration at L 5. In addition, transganglionic axonal projections were found to situate in the medial part of laminae III - IV from L 3 to L 5, as far as in the gracile nucleus.
  
  
  CONCLUSIONS
  Acupoint KI 1 area is innervated by sensory neurons in L 3-L 5 DRGs and motor neurons from the dorsolateral ventral horns of L 3-L 6. The axonal projection of the primary sensory neurons distributes in the medial part of laminae III - IV of L 3-L 5 and gracile nucleus, respectively.
authors.affiliation: Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China. hali420@yahoo.cn
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Ha
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Cui
authors.forename: Xin-Long
authors.initials: XL
authors.lastname: Zhu
authors.forename: Fu-Chun
authors.initials: FC
authors.lastname: Wang
authors.forename: Xiang-Hong
authors.initials: XH
authors.lastname: Jing
authors.forename: Wan-Zhu
authors.initials: WZ
authors.lastname: Bai
mesh_terms: D015669:Acupuncture Points; D000818:Animals; D001369:Axons / Q000737:chemistry*; D058948:Cell Tracking / Q000379:methods*; D002772:Cholera Toxin / Q000032:analysis*; D006801:Humans; D008297:Male; D009474:Neurons / Q000737:chemistry* / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000737:chemistry / Q000166:cytology; D013194:Staining and Labeling
chemical_list: D002772:Cholera Toxin