title: Functional regulation of neuronal nitric oxide synthase expression and activity in the rat retina.
abstract: In the nervous system within physiological conditions, nitric oxide (NO) production depends on the activity of nitric oxide synthases (NOSs), and particularly on the expression of the neuronal isoform (nNOS). In the sensory systems, the role of NO is poorly understood. In this study, we identified nNOS-positive cells in the inner nuclear layer (INL) of the rat retina, with distinct characteristics such as somata size, immunolabeling level and location. Employing mathematical cluster analysis, we determined that nNOS amacrine cells are formed by two distinct populations. We next investigated the molecular identity of these cells, which did not show colocalization with calbindin (CB), choline acetyltransferase (ChAT), parvalbumin (PV) or protein kinase C (PKC), and only partial colocalization with calretinin (CR), revealing the accumulation of nNOS in specific amacrine cell populations. To access the functional, circuitry-related roles of these cells, we performed experiments after adaptation to different ambient light conditions. After 24h of dark-adaptation, we detected a subtle, yet statistically significant decrease in nNOS transcript levels, which returned to steady-state levels after 24h of normal light-dark cycle, revealing that nNOS expression is governed by ambient light conditions. Employing electron paramagnetic resonance (EPR), we demonstrated that dark-adaptation decreases NO production in the retina. Furthermore, nNOS accumulation changed in the dark-adapted retinas, with a general reduction in the inner plexiform layer. Finally, computational analysis based on clustering techniques revealed that dark-adaptation differently affected both types of nNOS-positive amacrine cells. Taken together, our data disclosed functional regulation of nNOS expression and activity, disclosing new circuitry-related roles of nNOS-positive cells. More importantly, this study indicated unsuspected roles for NO in the sensory systems, particularly related to adaptation to ambient demands.
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Brazil.
authors.forename: Lais Takata
authors.initials: LT
authors.lastname: Walter
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Brazil; Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
authors.forename: Guilherme Shigueto Vilar
authors.initials: GS
authors.lastname: Higa
authors.affiliation: Institute of Physics, Humboldt University at Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schmeltzer
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Brazil.
authors.forename: Erica
authors.initials: E
authors.lastname: Sousa
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Brazil.
authors.forename: Erika Reime
authors.initials: ER
authors.lastname: Kinjo
authors.affiliation: Institute of Physics, Humboldt University at Berlin, Germany.
authors.forename: Sten
authors.initials: S
authors.lastname: Rüdiger
authors.affiliation: Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
authors.forename: Dânia Emi
authors.initials: DE
authors.lastname: Hamassaki
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Brazil.
authors.forename: Giselle
authors.initials: G
authors.lastname: Cerchiaro
authors.affiliation: Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Brazil; Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil. Electronic address: alexandrekihara@gmail.com.
authors.forename: Alexandre Hiroaki
authors.initials: AH
authors.lastname: Kihara
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D000818:Animals; D064032:Calbindin 2 / Q000378:metabolism; D064026:Calbindins / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D016000:Cluster Analysis; D015536:Down-Regulation / Q000502:physiology*; D004578:Electron Spin Resonance Spectroscopy; D009474:Neurons / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000166:cytology / Q000201:enzymology* / Q000502:physiology*
chemical_list: D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D019001:Nitric Oxide Synthase; D002795:Choline O-Acetyltransferase; D011493:Protein Kinase C
keywords: CNS; Dark-adaptation; Development; Perception; ROS; Synapse; Synaptic plasticity; Vision; Visual system