Conserved cellular distribution of the glutamate receptors GluA2/3, mGlu1a and mGlu2/3 in isolated cultures of rat cerebellum

Abstract

To what extent the intrinsic glutamatergic system of the cerebellum is able to keep normal features in the absence of mossy and climbing fibres, is at present not known. To answer this question, immunocytochemistry for light and high resolution electron microscopy was used to reveal the cellular and subcellular distribution of glutamate receptors in isolated cerebellar cultures. The localization of the ionotropic glutamate receptor subunits GluA2/3 and the metabotropic glutamate (mGlu) 1a and mGlu2/3 receptor subtypes was carried out in 0 to 9-day-old rat parasagittal slices developed in vitro for 20–40 days.The typical localization of GluA2/3, mGlu1a and mGlu2/3 observed in Purkinje cells, granule cells, Golgi cells and unipolar brush cells was maintained in the organotypic cultures. Furthermore, the subcellular distribution of mGlu1a showed the characteristic in vivo perisynaptic position in Purkinje cell dendritic spines receiving parallel fibre synapses.We conclude that the cellular and subcellular localization of the studied ionotropic and metabotropic glutamate receptors is not affected by the removal of the two extrinsic cerebellar glutamatergic inputs, the mossy and climbing fibres.