SOMATOSTATIN ENHANCES NERVE GROWTH FACTOR-INDUCED NEURITE OUTGROWTH IN PC12 CELLS

The neuropeptide somatostatin has been found to be abundant in numerou s developing regions within the central nervous system. In order to un derstand the role of somatostatin in development, effects of exposure to the neuropeptide were studied in PC12 cells, a well characterized m odel of neuronal differentiation. Somatostatin increased neurite outgr owth after 2 days in culture and enhanced neurite outgrowth after nerv e growth factor (NGF) exposure. This effect was inhibited by somatosta tin antibody and pertussis toxin. Somatostatin had no effect on NGF bi nding or internalization but did cause a decrease in cAMP levels durin g the time of maximal stimulation of neurite outgrowth. In a protein k inase A-deficient cell line (A126-1B2), somatostatin had no effect on neurite outgrowth. These results indicate that somatostatin may functi on as a differentiation factor in developing systems through inhibitio n of cAMP synthesis.