Biochemical and Physiological Effects of Galanin in Health and Disease.

Galanin is a biologically active peptide discovered in 1983 from the intestines of pigs. Discovered by Doctors Tatemoto, Rökaeus, Jörnvall, McDonald, and Mutt, it was found to contract smooth muscle tissue in rat intestine and produce hyperglycemia in dogs. Since its discovery, research into galanin has revealed a wide array of effects in numerous organ systems. As these effects have been uncovered, there has been growing interest in the galanin system as a therapeutic target. Targeting galanin has proven difficult as it influences much of the body, leading to challenges in identifying the source of observed changes and, moreover, selecting those sources as targets. A critical tool in overcoming these challenges is a cohesive understanding of galanin's broad effects in various organ systems. Galanin and galanin receptor expression, receptor and ligand affinity, biochemical signaling paths, and physiological effects of galanin remain under investigation. As research into this field continues, greater appreciation of the complexity of galanergic signaling is critical to elucidate galanin's role in health. This review seeks to provide insight into these aspects and provide researchers with the knowledge needed to continue to expand investigations in the galanergic system.