title: Ultrastructural characteristics of circadian pacemaker neurones, immunoreactive to an antibody against a pigment-dispersing hormone in the fly's brain.
abstract: Neurones immunoreactive to an antibody against a pigment-dispersing hormone (PDH-ir) are considered to be pacemaker cells in the neuronal circadian system of flies. We investigated the ultrastructure of PDH-ir varicosities, possible releasing sites of the PDH-like peptide, in the distal medulla of the optic lobe and in the dorsal protocerebrum of the two fly species Drosophila melanogaster and Musca domestica. In both species PDH-ir varicosities show accumulation of dense core vesicles (DCVs). PDH-like peptide is localized in the DCVs as shown by post-embedding immuno-electron microscopy. Localization of PDH-like peptide in DCVs and normally lacking synaptic specializations at PDH-ir varicosities in the medulla are interpreted as a non-synaptic paracrine release of peptide.
authors.affiliation: Department of Cell Biology, Institute of Zoology and Developmental Biology, George-August University, Goettingen, Germany. kmiskie@gwdg.de
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Miskiewicz
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Pyza
authors.forename: Friedrich-Wilhelm
authors.initials: FW
authors.lastname: Schürmann
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D004331:Drosophila melanogaster; D006793:Houseflies; D007150:Immunohistochemistry / Q000379:methods; D007301:Insect Hormones / Q000378:metabolism; D016253:Microscopy, Immunoelectron / Q000379:methods; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology*; D010455:Peptides / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D013687:Telencephalon / Q000166:cytology*
chemical_list: D007301:Insect Hormones; D010455:Peptides; C027714:melanophore-dispersing hormone