OBJECTIVE Astrocytic gap junctions formed by connexin 43(Cx43) are crucial for intercellular communication between spinal cord astrocytes. Various neurological disorders include chronic pain are associated with dysfunctional Cx43-gap junctions. A previous study showed that treatment of spinal astrocytes in culture with pro-inflammatory cytokines tumor necrosis factor-α(TNF-α) and interferon-γ(IFN-γ) decreased both Cx43 expression and gap junction intercellular communication(GJIC)via a c-jun terminal kinase-dependent pathway. However,the exact mechanism that Cx43 does this in the context of spinal astrocytic dysfunction is unclear. The current study investigated the downstream signaling of Cx43-gap junction in rat primary cultured spinal astrocytes stimulated with cytokines.METHODS Wefocused on the glutamate transporters,examined the alteration of GLT-1 and glutamate-aspartate transporter(GLAST)expression and function in rat primary cultured spinal astrocytes stimulated with cytokines by real-time PCR and Western blotting. The function of GLT-1 was analyzed using the carbon 14. To elucidate the effect of Cx43 on glutamate transporters in spinal astrocytes,changes in glutamate transporters expression and function were quantified after Cx43 siRNA treatment.RESULTS The transcriptional and translational levels of Cx43 were reduced after 12 hr co-treatment with TNF-α(10 ng·mL~(-1)) or IFN-γ(5 ng·mL~(-1)). Furthermore,transcriptional and translational levels of GLT-1 and GLAST were also significantly reduced 24 and 48 h co-treatment with TNF-α or IFN-γ.Moreover,functional GLT-1 and GLAST uptake were inhibited by the mixture of TNF-α and IFN-γ. In addition,Both the decrease of GLT-1 expression and the reduction in functional GLT-1 uptake induced by the Cx43 si RNA,but both the expression and functional GLAST were no changes. CONCLUSION These results indicate that a Cx43 downregulation is induced under inflammatory condition that disrupts spinal astrocytic GLT-1 expression and function,leading to astrocytic dysfunction and the maintenance of the neuroinflammatory state. OBJECTIVE Astrocytic gap junctions formed by connexin 43 (Cx43) are crucial for intercellular communication between spinal cord astrocytes. Various neurological disorders include chronic pain are associated with dysfunctional Cx43-gap junctions. A previous study showed that treatment of spinal astrocytes in culture with pro- However, the exact mechanism that inflammatory cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) decreased both Cx43 expression and gap junction intercellular communication (GJIC) Cx43 does this in the context of spinal astrocytic dysfunction is unclear. The current study investigated the downstream signaling of Cx43-gap junction in rat primary cultured spinal astrocytes stimulated with cytokines. METHODS Wefocused on the glutamate transporters, examined the alteration of GLT-1 and glutamate-aspartate transporter (GLAST) expression and function in rat primary cultured spinal astrocytes stimulated with cytokin es by real-time PCR and Western blotting. The function of GLT-1 was analyzed using the carbon 14. To elucidate the effect of Cx43 on glutamate transporters in spinal astrocytes, changes in glutamate transporters expression and function were quantified after Cx43 siRNA treatment. RESULTS The transcriptional and translational levels of Cx43 were reduced after 12 hr co-treatment with TNF-α (10 ng · mL -1) or IFN-γ (5 ng · mL -1). and translational levels of GLT-1 and GLAST were also significantly reduced 24 and 48 h co-treatment with TNF- [alpha] or IFN- [gamma]. Moreover, functional GLT-1 and GLAST uptake were inhibited by the mixture of TNF- [alpha] and IFN- γ. In addition, Both the decrease of GLT-1 expression and the reduction in functional GLT-1 uptake induced by the Cx43 si RNA, but both the expression and functional GLAST were no changes. CONCLUSION These results indicate that a Cx43 downregulation is induced under inflammatory condition that disrupts spinal astrocytic GLT-1 expression and function, leading to astrocytic dysfunction and the maintenance of the neuroinflammatory state.