Immunohistochemical study on the distribution of neuronal voltage-gated calcium channels in the rat cerebellum

Abstract

Many neuronal processes are regulated by calcium influx through voltage-gated calcium channels (VGCCs), including protein phosphorylation, gene expression, neurotransmitter release, and firing patterns of action potential. In the present study, we have used anti-peptide antibodies directed against a unique sequence in rat alpha(1A), alpha(1B), alpha(1C) and alpha(1D) subunits of VGCCs to determine their cellular distribution in normal rat cerebellum. Throughout the molecular layer, immunoreactivity for alpha(1B) and alpha(1D) subunits were found in the cell bodies of basket and stellate cells as well as in the neuropil. In the Purkinje cells, only alpha(1C)-IR was observed in the dendritic branches of Purkinje cells, whereas immunoreactivity for alpha(1B) and alpha(1D) subunits were rarely found in the cell bodies of Purkinje cells. Immunoreactivity for the alpha(1A), alpha(1B,) and alpha(1D) subunits were strong in the granule cell bodies, whereas alpha(1C)-IR was not prominent in the cell bodies. In the cerebellar nuclei, a distinct band of punctate immunoreactivity for the alpha(1A), alpha(1B), alpha(1C), and alpha(1D) subunits were observed. The overall results of the above localization study showed clearly that the alpha(1A), alpha(1B,) alpha(1C) and alpha(1D) pore forming subunits of VGCCs have differential distribution in the rat cerebellum. The present studies may provide useful data for such future investigations to understand the role of calcium channels in neurological pathways.