Neuroprotective effects of inhalation anesthetics based on the analysis of the signal transduction related to ubiquitous protein kinases.

本研究采用小鼠断头模型，探讨异氟醚和七氟醚的神经保护机制。C57/黑鼠暴露1.5MAC异氟醚或七氟醚，检查右侧反射消失后断头，冷冻保存。将脑匀浆和离心法分离成P2(突触体组分)、P3(颗粒组分)和S3组分(胞质组分)。用免疫印迹法检测CaMKII-α、PKC-Y、磷酸化CaMKII和磷酸化酪氨酸水平。异氟醚组和七氟醚吸入组可明显抑制CaMKII-_α由S3向P2的转位。此外，与七氟醚相比，异氟醚对CaMKII易位的抑制作用更明显。这些结果提示，异氟烷和七氟烷通过抑制CaMKII信号通路而具有神经保护作用。另一方面，我们发现在缺血小鼠脑内，磷酸化的CaMKII不存在于胞浆中，只有在突触膜中。这一结果提示，CaMKII磷酸化的抑制可能参与了异氟烷和七氟烷的神经保护作用。静脉麻醉药咪达唑仑和异丙酚也与吸入麻醉药相同。给予咪达唑仑或异丙酚10 mg/kg对缺血小鼠脑内PKC和CaMKII的易位无明显影响。虽然这些静脉麻醉药被认为具有神经保护作用，但PKC或CaMKII信号级联可能不起作用。

We aimed to clarify the neuroprotective mechanism of Isoflurane and Sevoflurane using mice decapitation model. C57/black mice were exposed 1.5 MAC Isoflurane or Sevoflurane and decapitated after checking their loss of right reflex, and they were frozen and stored. The brains were homogenized and centrifuged into the elude P2 (synaptosomal ), P3 ( particulate ), and S3 ( cytosolic ) fractions. SDS-PAGE was performed with each sample and CaMKII-_α, PKC-_Y, phospho-CaMKII, and phospho-tyrosine levels were analyzed by immnoblotting. The significant inhibition of CaMKII-_α translocation to P2 from S3 were seen in the Isoflurane and Sevoflurane inhalation groups. In addition, Isoflurane inhibites the CaMKII translocation more significantly compared to that of Sevoflurane. These results suggest that Isoflurane and Sevoflurane have the neuroprotective effects due to the inhibition of CaMKII signalling cascade.On the other hand, we found that in the ischemic mice brain, phospho-CaMKII does not exists in the cytosol, nothing but in the synaptic membranes. This result indicates that the inhibition of CaMKII phosphorylation may contribute for the neuroprotective action of Isoflurane and Sevoflurane.Intravenous anesthetics Midazoram and Propofol were also investigated same as inhalation anesthetics. No significant change was seen on the PKC nor CaMKII translocation in the ischeunic mice brain administrated 10 mg/kg Midazoram or Propofol. Although these intravenous anesthetics supposed to have the neuroprotective action, PKC or CaMKII signaling cascade may not contribute their actions.