Ca2+ channels: diversity of form and function.

The past year has seen some significant advances in our understanding of the structural and functional properties of neuronal voltage-gated Ca2+ channels. Molecular cloning and protein purification studies have identified structural components, and expression studies are beginning to define the biophysical and pharmacological properties of the cloned channels. A number of studies of native Ca2+ channels show that the concept of channel modulation includes gating by both voltage and ligands.