Identification of pituitary adenylate cyclase activating polypeptide (PACAP) and PACAP type 1 receptor in human skin: expression of PACAP-38 is increased in patients with psoriasis

Morphological and biochemical evidence is presented for the presence of pit uitary adenylate cyclase activating peptide (PACAP) and the high-affinity P ACAP-1 receptor subtype in human skin. Immunohistochemical analysis reveale d PACAP-immunoreactivity (IR) to be present predominantly in dermal nerve f ibers close to the dermal-epidermal border, hair follicles, blood vessels a nd sweat glands. Radioimmunoassay, chromatographic analysis and Western blo tting revealed this PACAP-IR to be PACAP-38 whereas the second molecular fo rm, PACAP-27, is absent. In tissue of psoriasis patients significantly more PACAP-38 protein was detected as compared to normal skin. Using RT-PCR, th e expression of a high-affinity PACAP-1 receptor in human skin was observed . These results indicate a possible role for PACAP-38 in inflammatory proce sses of psoriasis. (C) 1999 Elsevier Science B.V. All rights reserved.