Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, United States.
Department of Psychology, University of Houston, Houston, TX 77204, United States.
Neuroscience. 2022 Apr 1;487:166-183. doi: 10.1016/j.neuroscience.2022.02.008. Epub 2022 Feb 12.
The Munc13 family of proteins is critically involved in synaptic vesicle priming and release in glutamatergic neurons in the brain. Munc13-1 binds to alcohol and, in Drosophila, modulates sedation sensitivity and self-administration. We examined the effect of alcohol consumption on the expression of Munc13-1 and Munc13-2, NMDA receptor subunits GluN1, GluN2A and GluN2B in the hippocampus-derived HT22 cells, hippocampal primary neuron culture, and wild-type and Munc13-1 male mouse hippocampus after ethanol consumption (Drinking in the Dark (DID) paradigm). In HT22 cells, Munc13-1 was upregulated following 25 mM ethanol treatment for 24 h. In the primary neuronal culture, however, the expression of both Munc13-1 and Munc13-2 increased after ethanol exposure. While Munc13-1 was upregulated in the hippocampus, Munc13-2 was downregulated following DID. This differential effect was found in the CA1 subfield of the hippocampus. Although Munc13-1 mice had approximately 50% Munc13-1 expression compared to wild-type, it was nonetheless significantly increased following DID. Munc13-1 and Munc13-2 were expressed in vesicular glutamate transporter1 (VGLUT1) immunoreactive neurons in the hippocampus, but ethanol did not alter the expression of VGLUT1. The NMDA receptor subunits, GluN1, GluN2A and GluN2B were upregulated in the hippocampal primary culture and in the CA1. Ethanol exerts a differential effect on the expression of Munc13-1 and Munc13-2 in the CA1 in male mice. Our study also found that ethanol's effect on Munc13 expression is dependent on the experimental paradigm, and both Munc13-1 and Munc13-2 could contribute to the ethanol-induced augmentation of glutamatergic neurotransmission.
Munc13 蛋白家族在大脑中谷氨酸能神经元的突触囊泡引发和释放中起着至关重要的作用。Munc13-1 与酒精结合，并在果蝇中调节镇静敏感性和自我给药。我们研究了酒精消耗对 HT22 细胞、海马原代神经元培养物以及雄性 Munc13-1 小鼠海马中 Munc13-1 和 Munc13-2、NMDA 受体亚基 GluN1、GluN2A 和 GluN2B 表达的影响，这些细胞和组织是在乙醇消耗后（暗饮（DID）范式）获得的。在 HT22 细胞中，25 mM 乙醇处理 24 小时后，Munc13-1 上调。然而，在原代神经元培养物中，乙醇暴露后，Munc13-1 和 Munc13-2 的表达均增加。虽然 DID 后海马中 Munc13-1 上调，但 Munc13-2 下调。这种差异效应发生在海马 CA1 亚区。尽管 Munc13-1 小鼠的 Munc13-1 表达量比野生型小鼠低约 50%，但 DID 后其表达量仍显著增加。Munc13-1 和 Munc13-2 在海马中囊泡谷氨酸转运体 1（VGLUT1）免疫反应性神经元中表达，但乙醇并未改变 VGLUT1 的表达。在海马原代培养物和 CA1 中，NMDA 受体亚基 GluN1、GluN2A 和 GluN2B 上调。乙醇对雄性小鼠 CA1 中 Munc13-1 和 Munc13-2 的表达有不同的影响。我们的研究还发现，乙醇对 Munc13 表达的影响取决于实验方案，Munc13-1 和 Munc13-2 都可能有助于增强谷氨酸能神经传递。
