[Study on the mechanism of antinociception of intrathecal neostigmine in the formalin test in rats].
OBJECTIVE
To assess the effect of intrathecal neostigmine and its possible mechanism in formalin test.


METHODS
Forty healthy male SD rats were randomly divided into control groups (NS, F) and test groups (NeF, LaNeF, LnNeF). Group NS served as normal control. Group F was treated with 5% formalin 100 microliters, s.c. Group NeF, LaNeF, LnNeF were treated respectively with Neo 10 micrograms, L-Arg 4.7 mumol ith, L-NAME 370 nmol ith before receiving 5% formalin 100 microliters, s.c. like group F. 0-1 h and 2 h after formalin treatment, behavior responses were observed and spinal cord segments were removed for expression of Fos.


RESULTS
The flinching and licking time of group NeF was shorter than that of group F, and the Fos expression of group NeF was weaker than that of group F. Pretreatment of L-Arg or L-NAME potentiated or reduced neostigmine induced responses respectively.


CONCLUSIONS
Intrathecal neostigmine could induce nitric oxide release in the spinal cord, the suppression of Fos expression might be one of the antinociception mechanisms of intrathecal neostigmine in the formalin test.
Lin
Xuemei
X
Department of Anesthesiology, West China Second Hospital, Sichuan University, Chengdu 610041, China.
Wang
Quanyun
Q
Huang
Wei
W
Zhu
Lin
L
Yang
Bangxiang
B
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D005557:Formaldehyde; D007278:Injections, Spinal; D008297:Male; D009388:Neostigmine / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D009619:Nociceptors / Q000187:drug effects*; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism
D000700:Analgesics; D016760:Proto-Oncogene Proteins c-fos; D005557:Formaldehyde; D009569:Nitric Oxide; D009388:Neostigmine