Introductory remarks

Abstract

It was in 1895 that Oliver & Schafer discovered the pressor activity of glycerol extracts of the pituitary. By 1928 it was clear that this activity, called vasopressin, was due to a peptide derived from the neural lobes of the pituitary and, in the early fifties, its structure and that of its ‘twin’, oxytocin, were determined by du Vigneaud and his colleagues, who were also able to prepare them synthetically. For a long time these two peptides, which were clearly of neural origin, were thought to have only peripheral physiological actions. However, evidence has gradually accumulated that these as well as some hormonal peptides not of neural origin, such as angiotensin and corticotrophin, could have actions on the central nervous system. The discovery of the enkephalins by Hughes & Kosterlitz in 1975 revealed the presence of an oligopeptide in the forebrain that could influence brain function and for which a specific receptor could be delineated which provided an immediate connection with the well documented non-peptide analgesic drugs of the morphine group. Within a short time discrete localization both of enkaphalin stores and of enkephalin receptors within the nervous system was demonstrated. In the ensuing period a growing number of peptides have either been isolated from the brain or have been inferred, from immunological evidence, to be present. Some of these peptides, such as insulin and gastrin, have well established peripheral biological actions, and their presence in the brain has engendered considerable surprise.