GALANIN RECEPTORS - INVOLVEMENT IN FEEDING, PAIN, DEPRESSION AND ALZHEIMERS-DISEASE

Galanin, a neuroendocrine peptide with a multitude of functions, binds to and acts on specific G-protein coupled receptors. Only one galanin receptor subtype, GalR1, has been cloned so far, although pharmacolog ical evidence suggests the presence of more than one galanin receptor subtype. These receptors mediate via different G(i)/G(o)-proteins the inhibition of adenylyl cyclase, opening of K+-channels and closure of Ca2+-channels. Galanin inhibits secretion of insulin, acetylcholine, s erotonin and noradrenaline, while it stimulates prolactin and growth h ormone release. Determination of structural components of galanin rece ptors required for binding of the peptide ligand as carried out recent ly will facilitate the screening and design of molecules specifically acting on galaninergic systems with therapeutic potential in Alzheimer 's disease, feeding disorders, pain and depression.