[Role of calcium ions in the process of synaptic transmission]

On the basis of literary data possible mechanisms of calcium ions transport into cell through the potential-dependent channel, Ca/Na exchange mechanism, channel opening due to receptor activation are being discussed. Electrochemical characteristics of potential-dependent Ca-channel in nervous tissue and values of calcium ions content of isolated nervous ends are presented. Discussing the mechanism of agonist-dependent channel action a hypothesis of coupling of phosphoinositol cycle and calcium ions current into a cell has been considered and the results concerning ionoforic properties of phosphatidic acid--the intermediate product of this cycle--are given. The influence of changes in phospholipid content of synaptosomal membranes and synaptosomal vesicules on different stages of synaptic transmission is analysed. These stages regulated by calcium ions include protein phosphorylation, fusion of synaptosomal vesicules with synaptosomal membrane and mediator release into synaptic slit. It has been concluded that phospholipids and products of their metabolism play active part in the process of transmembrane signal transmission by increasing intercellular calcium ions concentration.