Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan.
Department of Anatomy and Neurobiology, Faculty of Medicine, Kagawa University, Miki, Kagawa, Japan.
Neurotox Res. 2020 Mar;37(3):702-713. doi: 10.1007/s12640-020-00180-6. Epub 2020 Feb 15.
We aimed to investigate whether ethanol (EtOH) and acetaldehyde (AcH) can affect glutamate and its receptors GluN1 and GluA1 in the hippocampus of Aldh2-knockout (Aldh2-KO) and C57BL/6N (wild-type (WT)) mice. To do this, we first examined the effect of local administration of EtOH (100 mM, 200 mM, and 500 mM) and AcH (100 μM, 200 μM, and 500 μM) on extracellular glutamate levels in freely moving mice. Retrodialysis of 200 mM and 500 mM EtOH into the hippocampus of WT and Aldh2-KO mice produced significant decreases in extracellular glutamate levels (p < 0.05). A dose of 500 mM EtOH induced a greater decrease in Aldh2-KO mice (p < 0.05) than in WT mice, indicating the action of AcH. Similarly, perfusion of 200 μM and 500 μM AcH decreased glutamate in Aldh2-KO mice (p < 0.05), but this decrease was not seen in WT mice at any AcH dose. Second, we tested whether the EtOH- and AcH-induced decrease in glutamate was associated with decreases in GluN1 and GluA1 expression, as measured by real-time PCR and Western blot. We found a significant decrease in GluN1 (p < 0.05) and GluA1 (p < 0.05) subunits after a high dose of EtOH (4.0 g/kg) and AcH (200 mg/kg) in WT mice. However, a 2.0 g/kg dose of EtOH did not produce a consistent decrease in GluN1 or GluA1 between messenger RNA and protein. In Aldh2-KO mice, all three doses of EtOH (1.0 g/kg, 2.0 g/kg, and 4.0 g/kg) and AcH (50 mg/kg, 100 mg/kg, and 200 mg/kg) decreased GluN1 expression (p < 0.05), while moderate-to-high doses of EtOH (2.0 g/kg and 4.0 g/kg) and AcH (100 mg/kg and 200 mg/kg) decreased GluA1 expression (p < 0.05). Together, these in vivo and ex vivo data suggest that EtOH and AcH decrease extracellular glutamate in the hippocampus of mice with a concomitant decrease in GluN1 and GluA1 subunits, but these effects require relatively high concentrations and may, therefore, explain the consequences of EtOH intoxication.
我们旨在探究乙醇（EtOH）和乙醛（AcH）是否会影响 Aldh2 敲除（Aldh2-KO）和 C57BL/6N（野生型（WT））小鼠海马中的谷氨酸及其受体 GluN1 和 GluA1。为此，我们首先检测了 EtOH（100mM、200mM 和 500mM）和 AcH（100μM、200μM 和 500μM）局部给药对自由活动小鼠中海马外谷氨酸水平的影响。200mM 和 500mM EtOH 透入 WT 和 Aldh2-KO 小鼠的海马中会显著降低细胞外谷氨酸水平（p<0.05）。500mM EtOH 诱导的降低在 Aldh2-KO 小鼠中比在 WT 小鼠中更为显著（p<0.05），表明 AcH 的作用。同样，200μM 和 500μM AcH 的灌注会降低 Aldh2-KO 小鼠的谷氨酸（p<0.05），但在任何 AcH 剂量下均未观察到 WT 小鼠的这种降低。其次，我们通过实时 PCR 和 Western blot 检测了 EtOH 和 AcH 诱导的谷氨酸降低是否与 GluN1 和 GluA1 表达的降低有关。我们发现 WT 小鼠中高剂量 EtOH（4.0g/kg）和 AcH（200mg/kg）后 GluN1（p<0.05）和 GluA1（p<0.05）亚基的表达显著降低。然而，2.0g/kg 剂量的 EtOH 并未在信使 RNA 和蛋白质之间产生一致的 GluN1 或 GluA1 降低。在 Aldh2-KO 小鼠中，所有三种剂量的 EtOH（1.0g/kg、2.0g/kg 和 4.0g/kg）和 AcH（50mg/kg、100mg/kg 和 200mg/kg）均降低了 GluN1 表达（p<0.05），而中高剂量的 EtOH（2.0g/kg 和 4.0g/kg）和 AcH（100mg/kg 和 200mg/kg）降低了 GluA1 表达（p<0.05）。总的来说，这些体内和体外数据表明，EtOH 和 AcH 降低了小鼠海马中的细胞外谷氨酸，同时 GluN1 和 GluA1 亚基减少，但这些作用需要相对较高的浓度，因此可能解释了 EtOH 中毒的后果。
