title: Evidence for the occurrence of an enkephalin-like peptide in adrenaline and noradrenaline neurons of the rat medulla oblongata.
abstract: The indirect immunofluorescence technique was used to analyze the catecholaminergic neurons in the medulla oblongata of the rat for the presence of enkephalin (ENK)- and neuropeptide Y (NPY)-like immunoreactivity (LI). In colchicine pretreated animals, using a double staining technique with mouse and rabbit antibodies against ENK and tyrosine hydroxylase (TH) or phenylethanolamine N-methyltransferase (PNMT), it was demonstrated that both TH- and ENK-LI occurred in the same neurons, particularly in many neurons of the A1 noradrenaline cell group. In the transition zone to the C1 adrenaline cell group, a proportion of PNMT-positive cells also contained ENK-LI. In the rostral and mid portion of the C1 group only few TH/PNMT-positive cells were found to be ENK-positive. In the noradrenergic A2 region, a moderate number of cell bodies also contained TH- plus ENK-LI, whereas only a few of the adrenaline cells of the C2 and C3 groups showed ENK-LI. In addition, with an elution restaining technique it was possible to demonstrate that several of the cells containing TH- and ENK-LI were also positive for NPY-LI. The present findings demonstrate that a subpopulation of the catecholaminergic neurons in the medulla oblongata of the rat is ENK-positive, thereby indicating a possible co-release of the two compounds in their projection areas, for example the paraventricular nucleus and the spinal cord.
authors.affiliation: Department of Histology and Neurobiology, Karolinska Institute, Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Ceccatelli
authors.forename: D E
authors.initials: DE
authors.lastname: Millhorn
authors.forename: T
authors.initials: T
authors.lastname: Hökfelt
authors.forename: M
authors.initials: M
authors.lastname: Goldstein
mesh_terms: D000320:Adrenergic Fibers / Q000378:metabolism*; D000818:Animals; D004745:Enkephalins / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D004745:Enkephalins; D009478:Neuropeptide Y; D014446:Tyrosine 3-Monooxygenase; D010625:Phenylethanolamine N-Methyltransferase