Neuroendocrine regulation of galanin gene expression

Over the past several decades, we have come to appreciate the central role of intercellular communication in the regulation of normal homeostasis. Effective communication requires a dynamic web of pathways that carry precise, and informative, messages. Several classes of molecules have been shown to carry these messages, including nucleosides, amino acids, complex amines, carbohydrates, steroids, and peptides. Our understanding of the importance of small peptides in this communications network has been expanded by the physiological and pharmacological studies of numerous investigators over the past sixty years. This understanding has led to a search for additional peptide mediators to account for the exquisite subtleties of intercellular communication. Dr. Victor Mutt, whom we honor by this volume, has led the efforts to identify and characterize such peptides and is responsible for the discovery of several of the most important of them. As described elsewhere in this volume, one of the more recent products of these investigations is galanin, an amidated peptide isolated and purified from copious quantities of porcine intestinal extracts (Tatemoto et al., 1983). Amino acid sequence and structural analysis suggest that galanin is unrelated to any of the other known families of regulatory peptides, and to date it remains the only known member of its own family.