The involvement of the spinal release of glutamate and nitric oxide in peripheral noxious stimulation-induced pain-related behaviors—Study in mouse spinal microdialysis

► Spinal release of glutamate and NO were measured using the mouse microdialysis. ► Formalin or capsaicin produced a licking/biting responses toward the injected hindpaw. ► Formalin or capsaicin increased in spinal release of glutamate during the first 5min. ► Formalin produced the increase of NO release in spinal cord at late phase. The quantification of neurotransmitters in the dorsal horn of the spinal cord under pain conditions is important to investigate the mechanism of pain transmission. Microdialysis is widely used for the quantification of the release of endogenous substances in various tissues; however, most of the experiments have been conducted in rats. In the present study, we measured the spinal release of glutamate and NO2/NO3 under pain conditions induced by formalin or capsaicin using mouse spinal microdialysis. We found an association between formalin- or capsaicin-induced nociceptive behaviors and the release of glutamate and NO2/NO3 in the spinal cord.