Changes in Lipid-Sensitive Two-Pore Domain Potassium Channel TREK-1 Expression and Its Involvement in Astrogliosis Following Cerebral Ischemia in Rats

Astrocytes play an active and important role in the pathophysiology of cerebral ischemia. We have previously shown that mature hipppocampal astrocytes functionally express two-pore domain K+ channel TREK-1, which significantly contributes to the passive conductance and help to set the negative resting membrane potential essential for the optimal operation of some astrocytic homeostatic functions. However, its expression under ischemic conditions remains to be determined. In this study, we examined the expression of TREK-1 in rat brain under physiological and focal ischemia conditions. The results show that TREK-1 was broadly expressed on astrocytes and neurons in the cortex, CA1 region of hippocampus. After middle cerebral artery occlusion induced focal ischemia, the TREK-1 expression was significantly increased at days 3, 7 and 30 following reperfusion, which correlated with reactive astrogliosis in the cortex and hippocampus. Cultured cortical astrocytes also express TREK-1. TREK-1 inhibitor quinine inhibited the proliferation of astrocytes exposed to hypoxia condition. These data provide evidence showing the astrocytic TREK-1 involvement in ischemia pathology.