Immunohistochemical study on the distribution of the voltage-gated calciumchannel alpha(1B) subunit in the mature rat brain

Many neuronal processes are regulated by calcium influx through voltage-gat ed calcium channels. Among these calcium channels, the N-type channel has b een shown to play a significant role in the regulation of neurotransmitter release. This present report has demonstrated the distribution of the alpha (1B) subunit of the N-type calcium channel in the mature rat brain. The mos t striking findings were the highest immunoreactivity in the CA1 region of the hippocampus and the clear demarcation in the thalamus. Characteristic p atterns of distribution were noted in the cerebral cortex, hippocampus, cau date-putamen, thalamus, and cerebellum. In the cerebral cortex, strong stai ning was seen in layers II-III and V. In the basal ganglia, the staining in tensity was high in the caudate-putamen, whereas there was no immunoreactiv ity in the globus pallidus. Although the staining intensity was relatively low compared to that of the forebrain, moderate alpha(1B)-IR was found in t he dorsal cochlear nucleus and mesencephalic trigeminal nucleus. The detail ed features of this study will extend our current knowledge of alpha(1B) su bunit distribution in terms of the number of neuroanatomical areas examined , by investigating alpha(1B) subunit protein expression, for the first time . (C) 2000 Elsevier Science B.V. All rights reserved.