[Microinjection of L-NAME into dorsal raphe nucleus inhibits nociceptive response in sigmoid pain model of rats].
By means of Fos immunocytochemistry, nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and microinjection methods, the role of nitric oxide synthase (NOS) of dorsal raphe (DR) neurons in the modulation of rats sigmoid pain was studied. The results showed: (1) Rats exhibited aversive behavioral responses related to visceral pain after injecting formalin into the sigmoid wall. NOS neurons in DR were up-regulated, in addition, about 8% of NOS-labeled neurons were Fos positive. By contrast, there were no Fos/NOS double-labeled neurons in the control group. (2) Formalin-induced sigmoid pain scores and the expression of Fos in the spinal cord at S1 segment were decreased after microinjecting L-NAME into the DR. These findings suggest that NOS neurons are involved in the modulation of formalin-induced sigmoid pain and that NO may play an important role in the transmission of visceral nociceptive message in the midbrain.
Yang
Bin
B
Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou 221002. amyangbin@163.com
Zhang
Li-Cai
LC
Zeng
Yin-Ming
YM
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D016762:Genes, fos; D008845:Microinjections; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009474:Neurons / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D010147:Pain Measurement; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012810:Sigmoid Diseases / Q000139:chemically induced / Q000503:physiopathology
D000700:Analgesics; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester