title: Pro-enkephalin intermediates in bovine brain and adrenal medulla: characterization of immunoreactive peptides related to BAM-22P and peptide F.
abstract: Using antibodies against the synthetic opioid peptides BAM-22P and peptide F, immunoreactive (ir-) peptides were measured in bovine brain and adrenal medulla. In addition to the high levels in the adrenal medulla, both ir- peptides were measurable in various areas of the brain with highest concentrations in the anterior hypothalamus. Analysis of the ir- components by gel filtration revealed molecular heterogeneity. Besides peptides with the size of BAM-22P or peptide F, various higher molecular weight species were found. These forms were found in the adrenal medulla in much higher concentrations than in the brain indicating a different processing mechanism for proenkephalin. Synthetic BAM-22P injected intracerebroventricularly into mice produces a substantial analgesia (ED50 6.4 nmole) which is almost as high as that of morphine (ED50 2.8 nmole). This finding and the presence of BAM-22P-like compounds in the brain suggests a role of the enkephalinergic system in pain transmission.
mesh_terms: D000313:Adrenal Medulla / Q000276:immunology*; D000698:Analgesia; D000818:Animals; D001921:Brain / Q000276:immunology*; D002417:Cattle; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000276:immunology / Q000494:pharmacology; D004745:Enkephalins / Q000276:immunology*; D008968:Molecular Conformation; D011498:Protein Precursors / Q000276:immunology* / Q000494:pharmacology; D014018:Tissue Distribution
chemical_list: D004745:Enkephalins; D011498:Protein Precursors; C029992:proenkephalin; D004744:Enkephalin, Methionine; C036452:peptide F; C028837:BAM 22P