[Neuropeptides and the skin: morphological, functional and physiopathological aspects]

Several non-opioid regulatory peptides have been described in normal human skin localized both in neural fibres and in cellular elements. These include substance P, neurokinin A, neurotensin, calcitonin gene-related peptide, vasoactive intestinal polypeptide, peptide histidine methionine, neuropeptide Y, somatostatin, galanin and atrial natriuretic peptide. In the present review the morphological aspects and distribution of peptidergic nerves in normal human skin are presented. The main functional roles on nociception, pruritus, cutaneous blood flow and sweat production are discussed in regard to neuropeptides. The relationships between neuropeptides, mast-cells and neurogenic inflammation are discussed in detail. Pathological conditions are reported in which an alteration in the peptidergic control might be of importance in their pathogenesis. Some working hypothesis are discussed.