Pharmacological and functional properties of voltage-independent Ca2+ channels.

During the last few years, considerable progress has taken place in our knowledge of the molecular and functional properties of the various voltage-independent Ca2+ channels. In addition to the ionotropic receptor-channels (ROCs), that are not discussed in the present review, these channels include the SMOCs, activated via second messengers or other transducing processes directly triggered by receptor activation; and the SOCCs, activated as a consequence of depletion of the rapidly exchanging Ca2+ stores in the cytoplasm. In parallel, a pharmacological approach to the study of these channels has been developed, based primarily on heterogeneous drugs already known for different biological effects, and subsequently recognized as voltage-independent Ca(2+)-channel blockers. From the systematic analysis of the effects of these drugs new information has emerged about SMOCs and SOCCs function. In addition, pharmacological blockade of these channels appears to have beneficial therapeutic effects in pathological conditions such as tumoral cell growth, inflammation and immunity. At the moment the field is rapidly evolving, with major developments expected in the years ahead.