GABAB2受体亚基调控双孔钾通道TREK亚家族在抑郁症发病机制的作用

The up-regulation of GABA-B2 receptor subtype correlated closely with pathogenesis of Depression, which may involve with inward rectified potassium current. The recently identified TREK subfamily of two-pore-domain potassium channels possesses the character of inward rectified current. Down-regulation of TREK function or TREK gene knockout showed anti-depression effects in mice. We recently found that activation of GABA-B receptor lead to activation of TREK two-pore-domain potassium channels via cAMP/PKA pathway. Therefore we hypothesize that GABA-B2 receptor subtype - cAMP dependent protein phosphorylation - TREK potassium channels play an important roles on pathogenesis of Depression. This project will down regulate the expression of GABA-B2 receptor subtype or up regulate the function of GABA-B2 receptor subtype, and then examine and compare animal behaviors, relevant target molecules in involved brain regions and differential responses on the pharmacological intervention in chronic stress-induced depression model between two-pore-domain potassium channels TREK subfamily gene knock-out mice and mild type ones. Patch clamp will be employed to validate the in vivo data, and further test the hypothesis that the GABA-B2 receptor subtypes-TREK pathway is important in pathogenesis of Depression. The proposed project will provide novel molecular targets for designing more effective prevention and treatment strategies against Depression

GABA-B2受体亚基上调表达与抑郁症发生密切相关，其作用机制可能涉及调控内向整流钾通道。人们新近发现双孔钾通道TREK亚家族具有内向整合电流特征而且抑制其功能表现出抗抑郁效应。我们前期研究发现在内嗅皮质GABA-B受体通过cAMP/PKA途径可进一步开放TREK亚家族双孔钾通道。因此推测"GABA-B2受体亚基 - cAMP依赖蛋白磷酸化-TREK亚家族双孔钾通道开放"通路可能在抑郁症的发生与发展中发挥重要作用。因此本研究拟通过上调或下调GABA-B2受体亚基功能与表达，比较TREK基因敲除小鼠及其野生型小鼠在慢性应激诱导抑郁症中行为学、受累脑区内相关靶分子表达及相应药理学干预效应的差异；并以膜片钳记录方法进一步检验体内实验的主要结论，进而明确在抑郁症发病中存在"GABA-B2--TREK"通路，为有效防治抑郁症提供新的靶点与策略。

本研究通过比较TREK-2基因敲除小鼠及其野生型小鼠在红藻氨酸诱导癫痫发作中行为学、脑电图、受累脑区内相关靶分子表达及相应药理学干预效应的差异；并以膜片钳记录方法进一步检验体内实验的主要结论，进而明确在癫痫发生与发展中可能存在“腺苷-腺苷受体-cAMP依赖蛋白磷酸化-TREK-2通道开放”机制。本课题进一步应用锂盐-匹罗卡品建立癫痫模型，以TREK-2双孔钾通道为研究中心，采用Western-blot、免疫荧光技术观察在匹罗卡品癫痫模型中不同时期TREK-2于癫痫主要好发部位的表达特点，并且通过siRNA干扰技术下调TREK-2的表达，证实TREK-2双孔钾通道参与了癫痫的发生发展，为抗癫痫药物的研制提供新的靶点和癫痫治疗提供新的指导策略