Kv2.1 Potassium Channel Expression Transiently Increases in Ischemic Cerebral Cortical Neurons

[Objective]: Potassium channels play an essential role in neuronal potassium homeostasis. Kv2.1 is widely expressed in the mammalian brain and it undergoes dramatic functional modulation during brain ischemia. This study characterized the serial changes in brain Kv2.1 expression after transient focal cerebral ischemia in mice. [Methods]: C57BL/6 mice (n=45) were subjected to 60 min of middle cerebral artery occlusion followed by 1, 1.5, 2, and 3 h reperfusion. Hypoxic area was determined by hypoxyprobe-1 and Kv2.1 expression was measured by real-time PCR, immunofluorescence imaging, and western blotting. [Results]: Kv2.1 mRNA increased 1 h after cerebral ischemia-reperfusion injury, and then decreased. In western blotting, expression of Kv2.1 protein decreased at 1 h and decreased Kv2.1 protein level turned to peak level of Kv2.1 expression at 1.5 h. In immunohistochemistry revealed a gradual increase in Kv2.1 at 1.5 h after reperfusion. [Conclusions]: Kv2.1 expression transiently increased after cerebral ischemia. Our results suggest Kv2.1 may play an important role in potassium transport during the early period of focal cerebral ischemia.