Intrathecal SB366791 Prevents Spinal EphrinB1/EphB1 Signaling Activation-induced Acute Thermal Hyperalgesia

Recent studies reported that activation of spinal ephrinB1/EphB1 signaling induced pain-like behaviors, although the underlying mechanisms remain largely unknown. The present study investigated the functional role of transient receptor potential vanilloid receptor 1 (TRPV1) in intrathecal ephrinB1-Fc-induced acute thermal hyperalgesia. Intrathecal ephrinB1-Fc provoked significant decrease in thermal paw withdrawal latency (PWL) behavioral response, while intrathecal pretreatment with SB366791, a selective TRPV1 antagonist, markedly reversed this decrease in a dose-dependent manner. Immunohistochemical staining of spinal c-Fos activation, a widely-used neuronal marker in the central nervous system, further confirmed the behavioral finding. Taken together, these findings, for the first time, indicate that TRPV1 may be a potential downstream effector in spinal ephrinB/EphB system activation-induced thermal pain behavior in the mature nervous system.