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目的 探索AT1受体介导AngII调节SHR和WKY鼠脑神经元电活动的信号转导机制。 方法 原代培养SHR和WKY新生鼠脑干和下丘脑神经元 ,用全细胞膜片钳以电流箝方式记录神经元的放电活动 ,观察AngII及各种信号分子抑制剂对脑神经元放电频率的影响。结果 AngⅡ (10 0nmol·L-1)可使WKY新生鼠脑神经元的放电频率从 (0 .4 4± 0 .0 8)Hz增加到 (1.39± 0 .16 )Hz。这种效应在SHR鼠更加显著。由AngⅡ引起的这两种鼠脑神经元放电频率的增加均可被AT1受体拮抗剂Losartan完全消除。使用PKC抑制剂calphostinC和钙调蛋白激酶II抑制剂KN 93能完全阻断AngⅡ对WKY鼠脑神经元的作用 ,但对SHR鼠脑神经元的放电频率仅阻抑约 5 0 %。磷脂酰肌醇 3(PI3 )激酶抑制剂LY2 94 0 0 2 (10 μmol·L-1)对SHR鼠脑神经元的放电频率可产生部分阻断作用 ,但对WKY鼠脑神经元无明显影响。结论 AngII增加SHR和WKY鼠脑神经元放电频率的作用均由AT1受体介导。PI3 激酶在AngⅡ调节SHR鼠脑神经元电活动的信号转导机制中发挥重要作用
Objective To explore the signal transduction mechanism of AT1 receptor-mediated AngII in the electrical activity of neurons in SHR and WKY mice. Methods Primary cultured rat brain stem and hypothalamic neurons of SHR and WKY neonatal rats were harvested. Whole-cell patch clamp was used to record the firing activity of neurons. The effects of AngII and various inhibitors on the neuronal firing rate were observed . Results AngⅡ (100 nmol·L-1) increased the firing rate of neurons in WKY neonatal rats from (0.444 ± 0.08) Hz to (1.39 ± 0.16) Hz. This effect is even more pronounced in SHR mice. The increase in the discharge frequency of both neurons induced by Ang II was completely abolished by Losartan, an AT1 receptor antagonist. The use of PKC inhibitor calphostinC and calmodulin kinase II inhibitor KN 93 completely blocked the effect of AngⅡon WKY mouse brain neurons, but only inhibited about 50% of the firing rate in SHR mouse brain neurons. The PI3K inhibitor LY294002 (10 μmol·L-1) could partially block the firing rate of SHR neurons but had no effect on the neurons of WKY mouse . Conclusions The effect of AngII on firing rate of neurons in SHR and WKY mice is mediated by AT1 receptor. PI3 kinase plays an important role in the signal transduction mechanism of Ang Ⅱ in regulating the electrical activity of brain neurons in SHR mice