Molecular diversity in T-type Ca2+ channels is produced by expression of three genes, and alternative splicing of those genes. Prompted by differences noted between rat and human Cav3.3 sequences, we searched for splice variants. We cloned six variants, which are produced by splicing at exon 33 and exon 34. Expression of the variants differed between brain regions. The electrophysiological properties of the variants displayed similar voltage-dependent gating, but differed in their kinetic properties. The functional impact of splicing was inter-related, suggesting an interaction. We conclude that alternative splicing of the Cav3.3 gene produces channels with distinct properties.
