Brain and gut peptides.

Abstract

The first evidence that the same peptides could be present in both the brain and the gut was given in 1931 with the discovery of substance P (Von Euler and Gaddum, 1931). In spite of this early start, the important revelation that there were a large number of peptides with this dual localisation and also with powerful and extensive pharmacological actions took more than 40 years to materialise. After the finding of large quantities of the hypothalamic peptide somatostatin (Arimura et al., 1975) in the gastrointestinal tract, increasing numbers of peptides have been found to be common to the gut and brain. To date the list includes somatostatin, substance P, cholecystokinin (CCK), enkephalin, neurotensin, vasoactive intestinal polypeptide (VIP), and bombesin. A number of these peptides, such as somatostatin, neurotensin, and enkephalin, were originally found in the brain and later in the gut, whereas others, such as VIP, bombesin, and gastrin, were found first in the gut. There is increasing evidence that outside the brain these peptides are localised in typical endocrine cells, or in fine efferent nerve fibres, or both, as part of the autonomic innervation. Although some peptides