Human skeletal muscle calcium channel alpha 1S is expressed in the basal ganglia: distinctive expression pattern among L-type Ca2+ channels

Voltage-gated calcium channels (VGCCs) are essential molecules for neuronal function. VGCCs consist of five subunits, alpha1, alpha2,, gamma, and delta. Among the ten subtypes of the alpha1 subunit (alpha1A-1 and S), expression of alpha1S was previously believed to be restricted to the skeletal muscle. We report here, however, that alpha1S is also expressed in human and rat central nervous system. First, we performed PCR screening for VGCC alpha1 subunits in human nervous system using degenerate primers, and identified alpha1S as well as all the eight alpha1 subunits with previously described expression. Intriguingly, alpha1S was selectively localized to the basal ganglia, particularly the caudate nucleus. In situ hybridization showed that alpha1S was expressed in medium-sized caudate neurons. Quantitative analysis using real time RT-PCR revealed a distinct pattern of alpha1S expression among L-type calcium channels. Furthermore, RT-PCR using laser-mediated manipulation of single cells suggested that human alpha1S was coexpressed with ryanodine receptors (RYRs) in GABAergic neurons. Our results suggest the potential relevance of alpha1S to dopaminergic signal transduction and calcium-induced calcium release in caudate neurons. (C) 2002 Elsevier Science Ireland Ltd and the Japan Neuroscience Society. All rights reserved.