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。将C57/black小鼠暴露于1.5MAC异氟烷或七氟烷，并在检查其右反射丧失后将其断头，将其冷冻并储存。将脑匀浆并离心分离成洗脱液P2（突触体）、P3（颗粒）和S3（细胞溶质）组分。对每个样品进行SDS-PAGE，并通过免疫印迹法分析CaMKII-α、PKC-γ、磷酸化CaMKII和磷酸化酪氨酸水平。异氟醚和七氟醚吸入组CaMKII-α从S3向P2的转位受到明显抑制。此外，与七氟烷相比，异氟烷对CaMKII易位的抑制作用更显著。这些结果表明异氟烷和七氟烷具有神经保护作用，其机制可能与抑制CaMK Ⅱ信号级联有关。另一方面，我们发现在缺血小鼠脑中，磷酸化CaMK Ⅱ不存在于胞浆中，只存在于突触膜中。这一结果表明，抑制CaMK Ⅱ磷酸化可能有助于异氟烷和七氟烷的神经保护作用。静脉麻醉药咪达唑仑和丙泊酚也进行了研究，与吸入麻醉药相同。10 mg/kg咪达唑仑或丙泊酚对缺血小鼠脑内PKC和CaMK Ⅱ的转位无明显影响。虽然这些静脉麻醉药被认为具有神经保护作用，但PKC或CaMK II信号级联可能对其作用无贡献。

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.