Galanin is a neuropeptide found both in the central and peripheral
nervous system. The 29-amino acid peptide (named after its N-terminal
glycine and C-terminal alanine) was identified in 1983 by its C-terminal
amidation. This 'reverse' approach, that is to discover a substance
through a distinct chemical feature, and only subsequently to
characterize its biological activity, was novel and has been successful
in the identification of several other peptides. After the structure of
galanin was determined in 1983, functional studies were performed with
material purified from natural sources until the synthetic form of the
peptide became available. Galanin can act as transmitter, modulator and
trophic factor, and is involved in a number of physiological processes
such as hormone secretion, cardiovascular mechanisms, feeding and
cognition. This peptide may also be of significance for a number of
pathological processes/disorders including pain, depression, Alzheimer's
disease, epilepsy, addiction and cancer. This wide diversity of actions
is mediated by three galanin receptor subtypes. The studies reviewed in
this volume give a fairly complete overview of the spectrum of the
biological actions and functions of galanin and its receptors and on
possible therapeutic applications in a number of pathological
conditions. Finally, a closely related molecule, galanin-like peptide,
is discussed.