Structural requirements for galanin interaction with receptors from pancreatic beta cells and from brain tissue of the rat

Abstract

The binding activity of several galanin fragments and analogs was measured on specific receptors present in rat brain and the rat pancreatic beta cell line Rin m 5F. In both tissues it was observed that: 1) galanin(3-29), galanin(10-29) and [Ile2]-galanin were ineffective for inhibiting [125I] galanin binding and 2) active peptides had the following rank order of potency: galanin(1-29) greater than [Ac-Trp2]-galanin(2-29) greater than galanin(2-29) greater than galanin(1-15) greater than [Phe2]-galanin greater than [Tyr2]-galanin. It was concluded that the N-terminal portion of galanin is very important for interaction with central or peripheral receptors. The aromatic amino acid in position 2 (Trp in native galanin) plays a crucial role.