Immunohistochemical localization of dynorphin (1-8) in hypothalamic magnocellular neurons: evidence for absence of proenkephalin.
Dynorphin(1-8) immunoreactivity was visualized by immunohistofluorescence in hypothalamic magnocellular neurons of the rat. No immunoreactive met-enkephalin-Arg6-Gly7-Leu8, a fragment of the adrenal medulla pro-enkephalin molecule, was detected in magnocellular neurons. However, a strong met-enkephalin-Arg6-Gly7-Leu8-like immunostaining was seen in other regions of the brain. These results suggest that in magnocellular neurons dynorphin(1-8) exists independently from pro-enkephalin and therefore the magnocellular neurons represent a third opioid peptide neuronal system in brain. These observations, however, do not rule out a coexistence of proenkephalin and dynorphin-related peptides in other regions of the brain.
D000818:Animals; D004399:Dynorphins; D004723:Endorphins / Q000032:analysis*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D007031:Hypothalamus / Q000032:analysis* / Q000166:cytology; D009474:Neurons / Q000032:analysis*; D051381:Rats
D004723:Endorphins; D004744:Enkephalin, Methionine; D004399:Dynorphins; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-