title: The structure of the caudal wall of the zebrafish (Danio rerio) swim bladder: evidence of localized lamellar body secretion and a proximate neural plexus.
abstract: In this study, we present a morphological description of the fine structure of the tissues composing the caudal tip of the adult zebrafish swim bladder and an immunochemical survey of the innervation at this site. The internal aspect of the caudal tip is lined by an epithelium specialized to secrete surfactant into the lumen as evinced by the exocytosis of lamellar bodies. The sole innervation to this region consists of a neural plexus, present on the external surface, of nitric oxide synthase-positive (nNOS) neuronal cell bodies that are contacted by axon terminals, some containing neuropeptide Y and vasoactive intestinal polypeptide. As the specialized epithelium and neural plexus are coincident and of common extent, we suggest that the morphological relationship between the two elements allows the nervous system to affect surfactant processing, possibly through a paracrine mechanism.
authors.affiliation: Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2; Department of Biology, Saint Francis Xavier University, Antigonish, Nova Scotia, Canada, B2G 2W5.
authors.forename: George N
authors.initials: GN
authors.lastname: Robertson
authors.forename: Roger P
authors.initials: RP
authors.lastname: Croll
authors.forename: Frank M
authors.initials: FM
authors.lastname: Smith
mesh_terms: D000400:Air Sacs / Q000201:enzymology / Q000294:innervation* / Q000378:metabolism; D000818:Animals; D004848:Epithelium / Q000378:metabolism; D005109:Extracellular Matrix / Q000648:ultrastructure; D005260:Female; D005347:Fibroblasts / Q000648:ultrastructure; D008297:Male; D057146:Multivesicular Bodies / Q000648:ultrastructure; D009130:Muscle, Smooth / Q000648:ultrastructure; D009415:Nerve Net / Q000648:ultrastructure; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D022142:Secretory Vesicles / Q000648:ultrastructure; D015027:Zebrafish / Q000033:anatomy & histology*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D029961:Zebrafish Proteins; D052248:Nitric Oxide Synthase Type I
keywords: autonomic nervous system; cyprinid; surfactant; ultrastructure