Receptors for Bombesin/Gastrin-Releasing Peptide and Epidermal Growth Factor on Central Nervous System Cells

Abstract

Publisher Summary This chapter describes receptors for bombesin/gastrin-releasing peptide (BN/GRP) and epidermal growth factor (EGF) on central nervous system cells. Growth factors, including EGF and BN/GRP may play a role in brain plasticity. EGF is a 53-amino acid polypeptide, which stimulates the growth of neuronal and nonneuronal cells. These actions may be mediated by the endogenous EGF, which has been detected in the neonatal and adult rat brain. EGF receptors have been detected in the neonatal rat cortex, and EGF induces enzymatic activity of glial cells. Also, EGF enhances tyrosine monooxygenase activity in rat sympathetic superior cervical ganglia. It has been demonstrated that neuropeptides such as BN/GRP stimulate the growth of the neuroendocrine tumor small cell lung cancer (SCLC). BN is a 14-amino acid peptide initially isolated from frog skin; its mammalian equivalent is the 27-amino acid peptide GRP. The peptide is made in and secreted from SCLC cells, where it binds to cell-surface receptors and stimulates tumor growth. As both peptides and receptors for BN/GRP are present in discrete regions of the rat brain, this neuropeptide may be biologically active in brain cells. In this regard, BN or GRP stimulates phosphatidylinositol turnover in rat cortical slices and causes depolarization of rat hippocampal neurons.