title: Expression of functional dopaminergic phenotype in purified cultured Müller cells from vertebrate retina.
abstract: Purified retina glial Müller cells can express the machinery for dopamine synthesis and release when maintained in culture. Dopamine is detected in cell extracts of cultures exposed to its precursor, L-DOPA. A large portion of synthesized dopamine is recovered in the superfusing medium showing the tendency of the accumulated dopamine to be released. Müller cells purified from developing chick and mouse retinas express L-DOPA decarboxylase (DDC; aromatic-L-amino-acid decarboxylase; EC 4.1.1.28) and the dopamine transporter DAT. The synthesis of dopamine from L-DOPA supplied to Müller cultures is inhibited by m-hydroxybenzylhydrazine, a DDC inhibitor. Dopamine release occurs via a transporter-mediated process and can activate dopaminergic D(1) receptors expressed by the glia population. The synthesis and release of dopamine were also observed in Müller cell cultures from mouse retina. Finally, cultured avian Müller cells display increased expression of tyrosine hydroxylase, under the influence of agents that increase cAMP levels, which results in higher levels of dopamine synthesized from tyrosine. A large proportion of glial cells in culture do express Nurr1 transcription factor, consistent with the dopaminergic characteristics displayed by these cells in culture. The results show that Müller cells, deprived of neuron influence, differentiate dopaminergic properties thought to be exclusive to neurons.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, UFRJ, Brazil.
authors.forename: Regina C C
authors.initials: RC
authors.lastname: Kubrusly
authors.forename: Rogerio
authors.initials: R
authors.lastname: Panizzutti
authors.forename: Patricia F
authors.initials: PF
authors.lastname: Gardino
authors.forename: Bernardo
authors.initials: B
authors.lastname: Stutz
authors.forename: Ricardo A M
authors.initials: RA
authors.lastname: Reis
authors.forename: Ana Lucia M
authors.initials: AL
authors.lastname: Ventura
authors.forename: Maria Christina F
authors.initials: MC
authors.lastname: de Mello
authors.forename: Fernando G
authors.initials: FG
authors.lastname: de Mello
mesh_terms: D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D002642:Chick Embryo; D000242:Cyclic AMP / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004296:Dopa Decarboxylase / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes; D051379:Mice; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D010641:Phenotype; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D015415:Biomarkers; D004268:DNA-Binding Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; C539883:Nr4a2 protein, mouse; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D017447:Receptors, Dopamine D1; D014157:Transcription Factors; D014443:Tyrosine; D000242:Cyclic AMP; D014446:Tyrosine 3-Monooxygenase; D004296:Dopa Decarboxylase; D004298:Dopamine