title: Regional distribution of methionine-enkephalin-Arg6-Phe7 in the rat brain: comparative study with the distribution of other opioid peptides.
abstract: The distribution of the opioid peptide methionine-enkephalin-arginine6-phenylalanine7 (M-Enk-Arg6-Phe7) has been investigated in various structures of the rat brain by using a highly specific radioimmunoassay (RIA). Immunoreactive M-Enk-Arg6-Phe7 has been further characterized by high performance liquid chromatography. The levels of M-Enk-Arg6-Phe7 in various structures of the rat brain were compared with the levels of several other opioid peptides, including methionine-enkephalin (M-Enk), leucine-enkephalin (L-Enk), dynorphin 1-13, and alpha-neoendorphin, which were also measured by RIA. There was a close relationship between the distribution of M-Enk-Arg6-Phe7 immunoreactive material (ir), M-Enk ir, and L-Enk ir. The distribution of dynorphin 1-13 ir and alpha-neoendorphin ir appeared to be distinct from that of the enkephalin group. These results are in agreement with recent reports on the cloning and sequencing of the c-DNA coding for the prohormones, in which it has been hypothesized that M-Enk-Arg6-Phe7 and M-Enk are synthesized by the same precursor, called proenkephalin, and that dynorphin-related peptides and alpha-neoendorphin arise from a separate precursor, prodynorphin.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000032:analysis*; D004743:Enkephalin, Leucine / Q000032:analysis; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000032:analysis; D004745:Enkephalins / Q000032:analysis; D008297:Male; D010908:Pituitary Hormones, Anterior / Q000032:analysis; D011333:Pro-Opiomelanocortin; D011498:Protein Precursors / Q000032:analysis; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
chemical_list: D004723:Endorphins; D004745:Enkephalins; D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; C029992:proenkephalin; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D011333:Pro-Opiomelanocortin; C027511:enkephalin-Met, Arg(6)-Phe(7)-; C033660:preproenkephalin