Influence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cells

dc.creatorSAMPAIO, Lucia de Fatima Sobral
dc.creatorHAMASSAKI, Dânia Emi
dc.creatorMARKUS, Regina Pekelmann
dc.date.accessioned2014-06-24T13:21:20Z
dc.date.available2014-06-24T13:21:20Z
dc.date.issued2005-04
dc.description.abstractThe influence of melatonin on the developmental pattern of functional nicotinic acetylcholine receptors was investigated in embryonic 8-day-old chick retinal cells in culture. The functional response to acetylcholine was measured in cultured retina cells by microphysiometry. The maximal functional response to acetylcholine increased 2.7 times between the 4th and 5th day in vitro (DIV4, DIV5), while the Bmax value for 125I-a-bungarotoxin was reduced. Despite the presence of a8-like immunoreactivity at DIV4, functional responses mediated by a-bungarotoxin-sensitive nicotinic acetylcholine receptors were observed only at DIV5. Mecamylamine (100 µM) was essentially without effect at DIV4 and DIV5, while dihydro-ß-erythroidine (10-100 µM) blocked the response to acetylcholine (3.0 nM-2.0 µM) only at DIV4, with no effect at DIV5. Inhibition of melatonin receptors with the antagonist luzindole, or melatonin synthesis by stimulation of D4 dopamine receptors blocked the appearance of the a-bungarotoxin-sensitive response at DIV5. Therefore, a-bungarotoxin-sensitive receptors were expressed in retinal cells as early as at DIV4, but they reacted to acetylcholine only after DIV5. The development of an a-bungarotoxin-sensitive response is dependent on the production of melatonin by the retinal culture. Melatonin, which is produced in a tonic manner by this culture, and is a key hormone in the temporal organization of vertebrates, also potentiates responses mediated by a-bungarotoxin-sensitive receptors in rat vas deferens and cerebellum. This common pattern of action on different cell models that express a-bungarotoxin-sensitive receptors probably reflects a more general mechanism of regulation of these receptors.pt_BR
dc.identifier.citationSAMPAIO, L. F. S.; HAMASSAKI-BRITTO, D. E.; MARKUS, R. P. Influence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cells. Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v. 38, n. 4, p. 603-613, abr. 2005. Disponível em: <http://www.scielo.br/pdf/bjmbr/v38n4/5594.pdf>. Acesso em: 04 fev. 2014. <http://dx.doi.org/10.1590/S0100-879X2005000400015>.pt_BR
dc.identifier.issn1414-431X
dc.identifier.urihttps://repositorio.ufpa.br/handle/2011/5121
dc.language.isoengpt_BR
dc.rightsAcesso Aberto
dc.subjectMelatoninapt_BR
dc.subjectReceptores nicotínicos de acetilcolinapt_BR
dc.subjectNicotinapt_BR
dc.subjectMicrofisiometriapt_BR
dc.subjectAlpha-bungarotoxinpt_BR
dc.titleInfluence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cellspt_BR
dc.typeArtigo de Periódicopt_BR

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