title: Enkephalin: radioimmunoassay and radioreceptor assay in morphine dependent rats.
abstract: A sensitive and specific radioimmunoassay for enkephalins is described which discriminates between leucineenkephalin and methionine-enkephalin. Total opioid peptide activity was assayed by the ability of brain extracts to compete for opiate receptor binding. In rats treated with morphine and/or naloxone, opiates were separated from opioid peptides by Dowex AG-50W column chromatography prior to radioreceptor assay. Chronic administration of morphine failed to alter immunoreactive enkephalin levels or total opioid activity in radioreceptor assays.
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D003342:Corpus Striatum / Q000032:analysis; D004723:Endorphins / Q000032:analysis*; D004745:Enkephalins / Q000032:analysis*; D006801:Humans; D007031:Hypothalamus / Q000032:analysis; D009021:Morphine Dependence / Q000378:metabolism*; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats
chemical_list: D004723:Endorphins; D004745:Enkephalins