Galanin--a neuroendocrine peptide.

Galanin is a widely distributed 29/30 amino acid long neuropeptide with multiple biological effects. It inhibits glucose-induced insulin release, hippocampal acetylcholine release, hippocampal glutamate but not GABA release, and it lowers spinal excitability and firing of locus coeruleus neurons. It stimulates food (fat) intake and growth hormone release upon hypothalamic or i.c.v. injection. Galanin actions are mediated via high affinity Gi/G0 protein-coupled receptors--involving effector systems such as K(+)-, Ca(2+)-channels and adenylate cyclase. Galanin receptor agonists are thought to have therapeutic application in treatment of chronic pain and prevention of ischemic damage; galanin receptor antagonists have therapeutic potential in the treatment of Alzheimer's disease, depression, and feeding disorders.