Low voltage-activated calcium channels discovered 15 year ago are unique molecular structures which play a specific role in the functioning of different types of excitable cells. This conclusion is supported by recent identification of special channel-forming 1- subunits which after expression in artificial cellular systems generate transmembrane currents characteristic for low-voltage-activated calcium channels. At the same time, analysis of recent experimental data indicate the existence of several subtypes of low voltage-activated channels which differ in the characteristics of their permeability, kinetics and pharmacological sensitivity. The expression of different subtypes of low-voltage activated channels is found to be highly coordinated, on one hand, with different phases of the ontogenetic development of excitable cells and, on the other, with their fulfillment of specific functions. Therefore the search for selective modulators of the activity of these channels is an extremely important goal for modern investigations.