THE RAT DERMORPHIN-LIKE IMMUNOREACTIVITY IS SUPPORTED BY AN AMINOPEPTIDASE RESISTANT PEPTIDE

Site-directed antibodies against synthetic related dermorphin peptides were previously produced and characterized. One of them, which specif ically recognizes the crucial `opioid message' (the N-terminal part of the dermorphin molecule (i.e. Tyr-D-Ala-Phe-Gly) was selected in orde r to detect and locate endogenous dermorphin-like molecules in rat, mo use and guinea pig tissues. Dermorphin-like peptides were found to be present in tissues known to contain peptides such as neurons in the ce ntral nervous system, nerve fibers in the gut and B and T immune cells . With all the tissues assayed, the HPLC profile obtained on the immun oreactive material showed the same main peak eluted al a retention tim e of 32 +/- 1 min. The results of biochemical experiments in which enz ymatic treatments were performed on the dermorphin-like immunoreactivi ty indicate the immunoreactivity is a peptide resistant to aminopeptid ase hydrolysis. This finding suggests the presence of a residue confer ring resistance to proteolytic processes of this kind, which is likely to be a D-amino acid residue. (C) 1998 Elsevier Science B.V.