Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan.
Proc Natl Acad Sci U S A. 2022 Mar 29;119(13):e2119636119. doi: 10.1073/pnas.2119636119. Epub 2022 Mar 25.
SignificanceIt is now established that many neurons can release multiple transmitters. Recent studies revealed that fast-acting neurotransmitters, glutamate and GABA, are coreleased from the same presynaptic terminals in some adult brain regions. The dentate gyrus (DG) granule cells (GCs) are innervated by the hypothalamic supramammillary nucleus (SuM) afferents that corelease glutamate and GABA. However, how these functionally opposing neurotransmitters contribute to DG information processing remains unclear. We show that glutamatergic, but not GABAergic, cotransmission exhibits long-term potentiation (LTP) at SuM-GC synapses. By the excitatory selective LTP, the excitation/inhibition balance of SuM inputs increases, and GC firing is enhanced. This study provides evidence that glutamatergic/GABAergic cotransmission balance is rapidly changed in an activity-dependent manner, and such plasticity may modulate DG activity.
意义
现在已经确定，许多神经元可以释放多种递质。最近的研究表明，在一些成年大脑区域中，快速作用的神经递质谷氨酸和 GABA 从相同的突触前末端共同释放。齿状回（DG）颗粒细胞（GCs）由下丘脑乳头上核（SuM）传入神经支配，这些传入神经共同释放谷氨酸和 GABA。然而，这些功能相反的神经递质如何有助于 DG 的信息处理仍不清楚。我们发现，谷氨酸能，但不是 GABA 能，共传递在 SuM-GC 突触处表现出长时程增强（LTP）。通过兴奋性选择性 LTP，SuM 输入的兴奋/抑制平衡增加，GC 放电增强。这项研究提供了证据表明，谷氨酸能/GABA 能共传递平衡以活动依赖的方式迅速改变，这种可塑性可能调节 DG 的活动。
