Peptides
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Neural development is controlled by region-specific factors that regulate cell proliferation, migration and differentiation. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that exerts a wide range of effects on different cell types in the brain as early as the fetal stage. Here we review current knowledge concerning several aspects of PACAP expression in embryonic and neonatal neural tissue: (i) the distribution of PACAP and PACAP receptors mRNA in the developing brain; (ii) the characteristic generation of neurons, astrocytes and oligodendrocytes in brain areas where the PACAP receptor is expressed and (iii) the role of PACAP as a regulator of neural development, inducing differentiation and proliferation in association with other trophic factors or signal transduction molecules.
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Mice lacking the PACAP gene (PACAP(-/-)) display psychomotor abnormalities such as novelty-induced hyperactivity and jumping behavior, and they show different responses to amphetamine, a typical psychostimulant. The present study examined the possible role of endogenous PACAP in methamphetamine (METH)-induced hyperactivity and behavioral sensitization. The locomotor activity of hyperactive PACAP(-/-) mice was measured using the infrared photocell beam detection system, Acti-Track, after a habituation period. ⋯ There was no difference in the degree of development and expression of METH-induced behavioral sensitization between wild-type and PACAP(-/-) mice. In addition, there was no difference in METH-induced increases in extracellular serotonin and dopamine levels in the prefrontal cortex of the normal and sensitized mice between the two groups. These results suggest that endogenous PACAP is not involved in the locomotor stimulant activity of acute METH and repeated METH-induced behavioral and neurochemical sensitization.