Abstract EN:

GABAergic and glycinergic inhibitory transmissions are ubiquitous in the vertebrate brain and ensure its proper function by controlling the activity of neural networks. In brain areas such as the thalamus, brainstem, cerebellum and spinal cord, some inhibitory neurons synthesize GABA and glycine with cytosolic concentrations compatible neurotransmission. The relative affinity of VIAAT, the vesicular transporter for these two neurotransmitters, can then lead to their co-release. Therefore, the inhibitory effects vary greatly according to the synaptic configurations. Faced with this diversity of GABA-glycine co-transmission action, the functional utility of those neurochemical profile diversity (GABAergic, glycinergic and mixed) in the spinal cord, the brainstem or the cerebellum remains poorly understood. To address this question, we took advantage of inhibitory transmission organization in the cerebellar cortex granular layer. In this layer, the activity of granular cells is controlled primarily by a single type of inhibitory neuron organized into different neurochemical subpopulations, Golgi cells. The granule cell-Golgi cell synapse is therefore particularly suited to study how the neurochemical diversity of inhibitory neurons is used by neural networks. We have established in this synaptic context, that the uptake of extracellular glycine by its GlyT2 neuronal transporter may modulate GABAergic transmission by disrupting vesicular filling of GABA. This graduation of the vesicular content of GABA would have the consequence of modulating the inhibitory power of the Golgi cells according to their neurochemical profile: GlyT2+ or GlyT2-.