01-09-2009
Phospholipase Cβ4 Expression Identifies a Novel Subset of Unipolar Brush Cells in the Adult Mouse Cerebellum
Published in: The Cerebellum | Issue 3/2009
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Unipolar brush cells (UBCs) are glutamatergic cerebellar interneurons of the granular layer. Previous studies have shown that there are two distinct subsets of UBCs present in the mice cerebellar cortex: calcium-binding protein calretinin (CR) positive and metabotropic glutamate receptor (mGluR)1α positive. In this study, we identify phospholipase C (PLC) β4 as an antigenic marker of a novel subset of UBCs. Double immunolabeling reveals that none of the CR+ subset expresses PLCβ4. In contrast, most members of the mGluR1α subset also express PLCβ4. In addition, 65% of the PLCβ4+ subset does not express mGluR1α. Thus, there are three distinct UBC subsets in the mouse cerebellum: CR+/PLCβ4−/mGluR1α−, PLCβ4+/mGluR1α−/CR−, and mGluR1α+/PLCβ4+/CR−. Each has a different topographical distribution, both between lobules and mediolaterally within the vermis. The development of PLCβ4 expression in UBCs is exclusively postnatal—first seen only at P12 and mature at about 3 weeks. A distinct subset of PLCβ4+ UBCs is also present in primary cerebellar cultures.