Differential association of GABAB receptors with their effector ion channels in Purkinje cells
| Autor: | David Kleindienst, Luis de la Ossa, Masahiko Watanabe, Kevin Wickman, Javier Cózar, Rafael Luján, Carolina Aguado, Bernhard Bettler, Francisco Ciruela, Ryuichi Shigemoto, Yugo Fukazawa |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Male Dendritic spine GABAB receptors Canals de calci Parallel fibre Freeze-fracture replica immunolabelling Mice Purkinje Cells 0302 clinical medicine Calcium Channels N-Type Postsynaptic potential Cerebellum 571 Physiology GABAA receptor Chemistry General Neuroscience Cerebel Cell biology Purkinje cells Original Article Female Anatomy Histology Dendritic Spines Mice Transgenic GABAB receptor Inhibitory postsynaptic potential Statistics Nonparametric Potassium channels 03 medical and health sciences Canals de potassi Microscopy Electron Transmission Quantification Electron microscopy Animals Immunoprecipitation G protein-coupled inwardly-rectifying potassium channel Active zone Cryoelectron Microscopy Dendrites Mice Inbred C57BL Calcium channels 030104 developmental biology Metabotropic receptor G Protein-Coupled Inwardly-Rectifying Potassium Channels Receptors GABA-B nervous system Sinapsi Synapses 030217 neurology & neurosurgery |
| Zdroj: | RUIdeRA. Repositorio Institucional de la UCLM instname Brain Structure & Function Dipòsit Digital de la UB Universidad de Barcelona |
| Popis: | Metabotropic GABAB receptors mediate slow inhibitory effects presynaptically and postsynaptically through the modulation of different effector signalling pathways. Here, we analysed the distribution of GABAB receptors using highly sensitive SDS-digested freeze-fracture replica labelling in mouse cerebellar Purkinje cells. Immunoreactivity for GABAB1 was observed on presynaptic and, more abundantly, on postsynaptic compartments, showing both scattered and clustered distribution patterns. Quantitative analysis of immunoparticles revealed a somato-dendritic gradient, with the density of mmunoparticles increasing 26-fold from somata to dendritic spines. To understand the spatial relationship of GABAB receptors with two key effector ion channels, the G protein-gated inwardly rectifying K? (GIRK/Kir3) channel and the voltage-dependent Ca2? channel, biochemical and immunohistochemical approaches were performed. Co-immunoprecipitation analysis demonstrated that GABAB receptors co-assembled with GIRK and CaV2.1 channels in the cerebellum. Using double-labelling immunoelectron microscopic techniques, co-clustering between GABAB1 and GIRK2 was detected in dendritic spines, whereas they were mainly segregated in the dendritic shafts. In contrast, co-clustering of GABAB1 and CaV2.1 was detected in dendritic shafts but not spines. Presynaptically, although no significant co-clustering of GABAB1 and GIRK2 or CaV2.1 channels was detected, inter-cluster distance for GABAB1 and GIRK2 was significantly smaller in the active zone than in the dendritic shafts, and that for GABAB1 and CaV2.1 was significantly smaller in the active zone than in the dendritic shafts and spines. Thus, GABAB receptors are associated with GIRK and CaV2.1 channels in different subcellular compartments. These data provide a better framework for understanding the different roles played by GABAB receptors and their effector ion channels in the cerebellar network. |
| Databáze: | OpenAIRE |
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