The long-term goal of this project is to study the structure and function of brain voltage-sensitive calcium channels (VSCC) using biochemical and molecular genetics techniques. Multiple types of VSCC, T,N,L, and P-type, are present in both excitable and nonexcitable cells and are important for excitation-contraction coupling and secretion of neurotransmitter and hormone release. Mammalian brain expresses a heterogeneous family of VSCC. We have cloned and sequenced full-length cDNAs corresponding to alphal and alpha2 subunits of the brain L-type dihydropyridine (DHP)-sensitive calcium channels. In addition, we have also isolated a number of related cDNA clones encoding alphal subunits of other types of brain calcium channels. With these cDNA clones, the following areas of the study are actively being pursued: 1) functional expression of VSCC by introducing full-length cDNAs for alphal and alpha2 subunits into neuronal cells; 2) hybridization histochemistry technique is being utilized to determine regional distribution of different types of VSCC mRNA in brain; and 3) genomic clones for human calcium channel alphal subunits gene have been isolated and their locus mapped on human chromosomes. The human genomic clone will be used to identify and characterize regulatory elements in the promoter region.
