title: Somatic and neuritic spines on tyrosine hydroxylase-immunopositive cells of rat retina.
abstract: Dopamine- and tyrosine hydroxylase-immunopositive cells (TH cells) modulate visually driven signals as they flow through retinal photoreceptor, bipolar, and ganglion cells. Previous studies suggested that TH cells release dopamine from varicose axons arborizing in the inner and outer plexiform layers after glutamatergic synapses depolarize TH cell dendrites in the inner plexiform layer and these depolarizations propagate to the varicosities. Although it has been proposed that these excitatory synapses are formed onto appendages resembling dendritic spines, spines have not been found on TH cells of most species examined to date or on TH cell somata that release dopamine when exposed to glutamate receptor agonists. By use of protocols that preserve proximal retinal neuron morphology, we have examined the shape, distribution, and synapse-related immunoreactivity of adult rat TH cells. We report here that TH cell somata, tapering and varicose inner plexiform layer neurites, and varicose outer plexiform layer neurites all bear spines, that some of these spines are immunopositive for glutamate receptor and postsynaptic density proteins (viz., GluR1, GluR4, NR1, PSD-95, and PSD-93), that TH cell somata and tapering neurites are also immunopositive for a γ-aminobutyric acid (GABA) receptor subunit (GABAARα1), and that a synaptic ribbon-specific protein (RIBEYE) is found adjacent to some colocalizations of GluR1 and TH in the inner plexiform layer. These results identify previously undescribed sites at which glutamatergic and GABAergic inputs may stimulate and inhibit dopamine release, especially at somata and along varicose neurites that emerge from these somata and arborize in various levels of the retina. J. Comp. Neurol. 525:1707-1730, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.
authors.forename: Anna
authors.initials: A
authors.lastname: Fasoli
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.
authors.forename: James
authors.initials: J
authors.lastname: Dang
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Johnson
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.
authors.forename: Aaron H
authors.initials: AH
authors.lastname: Gouw
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.
authors.forename: Alex
authors.initials: A
authors.lastname: Fogli Iseppe
authors.affiliation: Department of Neurobiology, Physiology and Behavior, University of California, Davis, California.|Department of Ophthalmology and Vision Science, University of California, Sacramento, California.
authors.forename: Andrew T
authors.identifier: http://orcid.org/0000-0003-3771-3357
authors.initials: AT
authors.lastname: Ishida
mesh_terms: D000818:Animals; D049229:Dendritic Spines / Q000648:ultrastructure*; D005260:Female; D007150:Immunohistochemistry; D007395:Interneurons / Q000648:ultrastructure*; D008297:Male; D018613:Microscopy, Confocal; D051381:Rats; D011917:Rats, Inbred Lew; D020318:Rats, Long-Evans; D012160:Retina / Q000166:cytology*; D014446:Tyrosine 3-Monooxygenase
chemical_list: D014446:Tyrosine 3-Monooxygenase
keywords: RRID: AB_11001825 (antibody_PSD-93); RRID: AB_2201528 (antibody_TH MS); RRID: AB_2213602 (antibody_GluR1); RRID: AB_2307331 (antibody_PSD-95); RRID: AB_2314955 (antibody_NMDAR1); RRID: AB_2315778 (antibody_DKαSHcy3); RRID: AB_2338694 (antibody_GTαIgG1MSCy3); RRID: AB_2338854 (antibody_GTαIgG1MSaf488); RRID: AB_2338917 (antibody_GTαIgG2aMSaf647); RRID: AB_2340863 (antibody_DKαMSaf647); RRID: AB_2576217 (antibody_GTαRBaf488); RRID: AB_310272 (antibody_GABAA_α1); RRID: AB_399431 (antibody_RIBEYE); RRID: AB_90711 (antibody_GluR4); RRID: AB_90755 (antibody_TH_SH); RRID: NLX_143660 (database_JCNantibody); RRID: RGD_1566443 (organism_Lrat); RRID: RGD_60991 (organism_LErat); RRID: SCR_001622 (MatLab); RRID: SCR_001905 (R Project for Statistical Computing); RRID: SCR_002285 (Fiji); RRID: SCR_007370 (Imaris); RRID: SCR_014237 (Huygens); axons; dendrites; dopamine; interplexiform cells; retina; spines