NEUROPEPTIDE-Y STIMULATES DNA-SYNTHESIS IN VASCULAR SMOOTH-MUSCLE CELLS

Neuropeptide Y (NPY) stimulated DNA synthesis in porcine aortic smooth muscle cells in a concentration-dependent manner. [Leu31, Pro34]NPY, a Y1-specific agonist, was several hundred times more potent than NPY(13-36), which preferentially bound to Y2 receptors, for stimulating DNA synthesis. On the other hand, human pancreatic polypeptide had no effect. The potency of NPY and related peptides for stimulating DNA synthesis paralleled their potency for increasing the cytosolic free Ca2+ concentration in the cells. Pertussis toxin treatment completely blocked both effects of the peptides. Thus, NPY may induce Ca2+ mobilization and stimulation of DNA synthesis in vascular smooth muscle cells via Y1 receptors whose signal transduction system involves pertussis toxin-sensitive GTP-binding protein(s).