Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France.
The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.
Elife. 2020 May 13;9:e56839. doi: 10.7554/eLife.56839.
Type 1 metabotropic glutamate receptors (mGluR1s) are key elements in neuronal signaling. While their function is well documented in slices, requirements for their activation in vivo are poorly understood. We examine this question in adult mice in vivo using 2-photon imaging of cerebellar molecular layer interneurons (MLIs) expressing GCaMP. In anesthetized mice, parallel fiber activation evokes beam-like Ca rises in postsynaptic MLIs which depend on co-activation of mGluR1s and ionotropic glutamate receptors (iGluRs). In awake mice, blocking mGluR1 decreases Ca rises associated with locomotion. In vitro studies and freeze-fracture electron microscopy show that the iGluR-mGluR1 interaction is synergistic and favored by close association of the two classes of receptors. Altogether our results suggest that mGluR1s, acting in synergy with iGluRs, potently contribute to processing cerebellar neuronal signaling under physiological conditions.
1 型代谢型谷氨酸受体（mGluR1s）是神经元信号传递的关键要素。虽然它们在切片中的功能已有充分记录，但它们在体内激活的要求却知之甚少。我们在成年小鼠体内使用表达 GCaMP 的小脑分子层中间神经元（MLIs）的双光子成像来研究这个问题。在麻醉小鼠中，平行纤维的激活会在突触后 MLIs 中引发束状 Ca 上升，这依赖于 mGluR1s 和离子型谷氨酸受体（iGluRs）的共同激活。在清醒小鼠中，阻断 mGluR1 会降低与运动相关的 Ca 上升。体外研究和冷冻断裂电子显微镜显示，iGluR-mGluR1 相互作用具有协同作用，并且两种受体的密切关联有利于这种相互作用。总的来说，我们的研究结果表明，mGluR1s 与 iGluRs 协同作用，在生理条件下强烈促进小脑神经元信号处理。
