抄録
It has been reported that peripheral glutamate is involved in the peripheral hyperalgia induced by an inflammation or a nerve injury. The interaction between capsaicin and glutamate receptors is thought to be somehow involved in the nerve injury- or inflammation-induced hyperalgesia. However, how the glutamates contributes to modulate the peripheral neuronal excitability is not known.The aim of the present study was to evaluate the interaction between glutamate and capsaicin receptors in the modulation of Vc neuronal excitability in rats. We divided rats into 5 groups depend on the subcutaneous injections of drugs, vehicle injection (Veh), capsaicin injection (Cap), glutamate injection (Glu), glutamate following capsaicin injection (Cap/Glu) and capsaicin following glutamate injection (Glu/Cap). The pERK immunohistochemistry was carried out in these five groups of rats. 1)The number of pERK-LI cells in all groups was significantly increased as compared to those of Veh group.2)The number of pERK-LI cells in Cap group was significantly decreased compared to Glu/Cap group, but not after Cap/Glu injection.3)The number of pERK-LI cells in Glu group was significantly increased compared to Cap/Glu group, but not after Glu/Cap injection.These findings indicate that glutamate is involved in an enhancement of the excitability of the capsaicin receptors as well as activation of glutamate receptors. [J Physiol Sci. 2008;58 Suppl:S132]
