[Structural-membrane regulation of intercellular contacts of low-molecular weight peptides]

It has been shown by microelectrode techniques and microcytofluorometry that fragments of the substance P and L-vasopressin--low molecular physiologically active peptides of wide regulatory action--bind to the receptors on the surface of plasma membranes outside the region of high permeable gap contact in unimolar concentrations and cause an increase in the rate of intracellular diffusion exchange of inorganic ions and fluorescein molecules in the salivary gland cells of Drosophila larva. The growth of intracellular contact permeability induced by low peptide concentrations is blocked by carbodiimide--a reagent cross-linking the membrane proteins. On the basis of the previous data it is suggested that the functions of intracellular contacts are regulated by the distant action mechanism involving the generalized structural rearrangements of plasma membranes.