VIP AS A CELL-GROWTH AND DIFFERENTIATION NEUROMODULATOR ROLE IN NEURODEVELOPMENT

In addition to its commonly recognized status as a neuromodulator of v irtually all vital functions, including neurobiological, the neuropept ide VIP plays a role in the control of cell growth and differentiation and of neuronal survival. Through these actions, VIP, whose impact ap pears early in ontogeny, may possess developmental functions. VIP can be stimulatory or inhibitory on cell growth in function of the model c onsidered. The growth regulatory actions of VIP, which are often indep endent of cAMP, are most likely significant when mitogenic or trophic factors, eventually released by nontarget cells, are simultaneously pr esent in the extracellular medium. The intracellular mechanisms that m ediate these actions of VIP may involve different transduction cascade s triggered by subsets of VIP binding sites that may coexist in the sa me tissue.