一氧化氮通过巯基亚硝化途径抑制培养海马神经元的大电导钙激活钾电流（BK）

发布时间：2019-03-07 23:31

【摘要】：NO参与了大脑的许多生理(如LTP)和病理过程如脑缺血缺氧、炎性退行性疾病、Alzheimer’s病和Parkinson’s病。在非神经组织中,NO对BK通道的调控已得到广泛研究,而NO对神经细胞上BK通道的调控未见报道。海马神经元富含BK通道,我们实验室以往的工作表明脑缺血缺氧可调节海马神经元BK通道的活性,而缺血缺氧时海马组织可产生大量的NO。因此,我们研究了NO对BK通道的调节作用及其机制。 1 NO抑制培养海马神经元上的BK电流在我们的实验中,我们运用全细胞膜片钳模式在培养的海马神经元上记录到去极化激活的外向电流(从-70mV逐步去极化到+50mV)。该电流对TEA、Cd~(2+)、paxilline(BK通道特异性阻断剂)敏感,并呈电压依赖性激活,因而我们确定这部分敏感电流即为BK电流。当去极化电压为+30mV时,NO的底物L-ARG(2mM/L)抑制37.5%的外向钾电流,其中BK电流成分被抑制了约20%。而在相同去极化电压条件下,L-ARG的一种同分异构体D-ARG(2mM/L)对外向钾电流并没有作用,这说明L-ARG的抑制作用并非由精氨酸本身引起。为进一步确定它的抑制作用是通过释放NO而产生的,我们观察了阻断NO生成过
[Abstract]:NO is involved in many physiological and pathological processes of the brain, such as cerebral ischemia and hypoxia, inflammatory degenerative disease, Alzheimer' s disease and Parkinson's disease. In non-neural tissues, the regulation of BK channel by NO has been extensively studied, but the regulation of BK channel by NO has not been reported. Hippocampal neurons are rich in BK channels. Previous work in our laboratory has shown that cerebral ischemia and hypoxia can regulate the activity of BK channels in hippocampal neurons, and a large amount of NO. can be produced in hippocampal tissues during ischemia and hypoxia. Therefore, we studied the regulatory effect of NO on BK channel and its mechanism. 1 in our experiment, NO inhibits the BK current in cultured hippocampal neurons. We recorded depolarization-activated outward currents (from-70mV to 50mV) in cultured hippocampal neurons using whole-cell patch-clamp mode. The current is sensitive to TEA,Cd~ (2 -), paxilline (BK channel-specific blocker) and activated in a voltage-dependent manner, so we determined that this part of the sensitive current is BK current. When the depolarization voltage was 30mV, the substrate of NO, L-ARG (2mM/L), inhibited 37.5% of the outward potassium current, in which the component of BK current was inhibited by about 20%. However, under the same depolarization voltage, D-ARG (2mM/L), an isomer of L-ARG, has no effect on outward potassium current, which indicates that the inhibition of L-ARG is not caused by arginine itself. To further determine that its inhibition is due to the release of NO, we observed the blocking of NO production.
【学位授予单位】：第一军医大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R363

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