Galanin - A neuropeptide with inhibitory actions

1. Galanin is a 29 (in humans 30) amino acids long neuropeptide with mostly inhibitory, hyperpolarizing actions. 2. Differential structural requirements of truncated forms of galanin and differential agonist/antagonist behaviour of chimeric peptides, high affinity galanin receptor ligands suggest the presence of pharmacologically distinct galanin receptor subtypes. 3. The galanin receptor from human Bowes melanoma cell line-a member of G-protein coupled receptor superfamily-has been cloned. 4. Galanin acts via G(i)/G(o) proteins inhibiting cAMP production, inositol phosphate turnover, opening K+ channels or closing Ca2+ channels.