[Effect of chlorpromazine on the Ca2+-transport system of secretory cell membrane in Chironomus plumosus L. larval salivary glands].

Effect of chlorpromasine (specific blocking agent of calmoduline) on Na(+)-Ca(2+)-exchanger functioning, Ca(2+)-pump and potential dependent Ca(2+)-channels in plasmatic membrane of isolated salivary glands in Chironomus plumosus L. larvae was investigated. Addition of chlorpromasine in different concentrations to the incubation medium with physiological Na+ and K+ concentration increased Ca2+ content in the gland tissue and secretion of general protein by gland cells. Chlorpromasine addition to the hyposodium and hyperpotassium mediums decreased Ca2+ content in the gland tissue and protein secretion. We made a conclusion that chlorpromasine, as an inhibitor of calmoduline, blocks Na(+)-Ca(2+)-exchanger and Ca(2+)-pump of plasmatic membrane of secretory cells. Potentialdependent Ca(2+)-channels are also effectively blocked by chlorpromasine but mechanism of this process is unknown. We suppose that Ca(2+)-calmoduline complex forming leads to increase of calcium oscillations amplitude in the cells of the investigated glands and stimulation of secretion.