The dynarnic changes of ACh activity in the spinal dorsal horn of rats were recorded by ACh ion selective microelectrodes. The influences of applying capsaicin to the spinal surface

adm1nistering anti - SP surum to the interior of dorsal horn

cutting of f dorsal roots and electroacupuncturing at "points" on the ACh activity were studied. The results showed that electroacupuncture at "points" and capsaicin could facilitate ACh release of the spinaI dorsal horn

it was fully inhibited by cutting off dorsal roots or obviously inhibited by administering anti-SP surum

The above results indicated that ACh rnight participate in the prirnary afferent of painsensation and acupuncture sensation as a neurotransmitter and SP might adjust the relese of ACh in spinal dorsal horn