Glutamate activated spinal astrocyte are involved in the thermal hyperalgesia by the release of IL-6

• 1、Department of Physiology/Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan city, 030001

Abstract：Objective: Activated glia plays an important role in chronic pain. But how did each stimulus activates glia still has no mechanisms. Glutamate is a significant excitatory transmitter and involved in the spinal pain signal transmission. Whether glutamate could activate astrocytes and participated in chronic pain is still not clear. This study explored whether glutamate can activate astrocytes and activated astrocytes are involved in the thermal hyperalgesia. Methods: Primary cultured spinal astrocytes were incubated with glutamate. The morphologic changes of astrocytes were analyzed by immunocytochemistry. The mRNA expression and release of IL-6 were determined by RT-PCR and ELISA assay respectively to observe the functional changes of astrocyte. The glutamate activated spinal astrocytes were injected intrathecally into the lumber subarachnoid space of rats, paw withdrawal latency (PWL) in response to thermal stimuli was tested. Results: Glutamate stimulation could induce astrocyte reaction. 6 hours after glutamate incubation, the IL-6 release started to increase and reached the peak 24 hours after glutamate stimulation. The mRNA expression of IL-6 had the same tendency. The intrathecally injection of glutamate-stimulated astrocytes induced a dramatic reduction in PWL. The PWL reduction started 2 h after astrocyte injection and lasted for 6 hours. Conclusions: Glutamate can activate astrcytes in vitro. Glutamate activated astrocytes are involved in the thermal hyperalgesia. IL-6 released from glutamate activated astrocytes may play an important role in the thermal hyperalgesia..

Keywords： neurobioloby glutamate hyperalgesia spinal astrocyte IL-6