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Previous issue date: 2014-08-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The pregeniculate nucleus (PGN) of the primate s thalamus is an agglomerate
neuronal having a cap shaped located dorsomedially to the main relay visual
information to the cerebral cortex, the dorsal lateral geniculate nucleus (GLD). Several
cytoarchitectonic, neurochemical and retinal projections studies have pointed PGN as
a structure homologous to intergeniculate leaflet (IGL) of rodents. The IGL receives
retinal terminals and appears to be involved in the integration of photic and non-photic
information relaying them, through geniculo-hypothalamic tract (TGH), to the main
circadian oscillator in mammals, the suprachiasmatic nucleus (SCN) of the
hypothalamus. Thus, the IGL participates in the control of the biological rhythm by
modulating the activity of the SCN. Pharmacological and IGL injury studies conclude
that it is critical in the processing of non-photic information which is transmitted to the
SCN. Other studies have found that especially neurons immunoreactive to
neuropeptide Y (NPY) respond to this type of stimulation, determined by its colocation
with the FOS protein.
Has not been determined if the PGN responds, expressing the FOS protein, to
the non-photic stimulus nor the neurochemical nature of these cells. Thus, we apply a
dark pulse in the specifics circadian phases and analyze the pattern of expression of
FOS protein in PGN of the marmoset (Callithrix jacchus). We found that in all
animals analyzed the FOS expression was higher in the experimental than in the
control group. There was a higher expression of FOS when the dark pulse was applied
during the subjective day between the groups. Still, a subregion of the PGN, known by
immunoreactive to NPY, had a greater number of FOS-positive cells in relation to his
other just close dorsal region.
Our data corroborate the theory that the PGN and IGL are homologous
structures that were anatomically modified during the evolutionary process, but kept
its main neurochemical and functional characteristics. However, injury and
hodological studies are still needed for a more accurate conclusion / O n?cleo pr?-geniculado (NPG) do t?lamo de primatas ? um aglomerado
neuronal, em forma de capuz, localizado dorsomedialmente ao principal retransmissor
de informa??es visuais para o c?rtex cerebral, o n?cleo geniculado lateral dorsal
(GLD). Diversos estudos citoarquitet?nicos, neuroqu?micos e de proje??es retinianas
t?m apontado o NPG como estrutura hom?loga ao folheto intergeniculado (FIG) de
roedores. O FIG recebe terminais retinianos e parece estar envolvido na integra??o de
informa??es f?ticas e n?o-f?ticas retransmitindo-as, atrav?s do trato geniculohipotal?mico
(TGH), ao principal oscilador circadiano em mam?feros, o n?cleo
supraquiasm?tico (NSQ) do hipot?lamo. Desse modo, o FIG participa no controle da
ritmicidade biol?gica modulando a atividade do NSQ. Estudos farmacol?gicos e de
les?o concluem que o FIG ? fundamental no processamento de informa??es n?of?ticas
as quais s?o transmitidas ao NSQ. Outros trabalhos verificaram que,
especialmente, neur?nios imunorreativos ao neuropept?deo Y (NPY) respondem a esse
tipo de est?mulo, determinados por sua co-localiza??o com a prote?na FOS.
Ainda n?o foi determinado se o NPG responde, expressando a prote?na FOS, a
est?mulos n?o-f?ticos nem tampouco a natureza neuroqu?mica dessas c?lulas. Assim,
aplicamos um pulso de escuro em fases circadianas espec?ficas e analisamos o padr?o
de express?o da prote?na FOS no NPG do sagui (Callithrix jacchus). Verificamos que
em todos os animais analisados a express?o de FOS foi maior em rela??o ao grupo
controle. Houve uma maior express?o de FOS quando o pulso de escuro foi aplicado
durante o dia subjetivo entre os grupos estudados. Ainda, uma sub-regi?o do NPG,
sabidamente imunorreativa a NPY, apresentou um maior n?mero de c?lulas FOSpositivas
em rela??o ? sua outra regi?o imediatamente mais dorsal.
Os nossos dados corroboram com a teoria de que o NPG e o FIG s?o estruturas
hom?logas que se modificaram anatomicamente durante o processo evolutivo, mas
mantiveram suas principais caracter?sticas neuroqu?micas e funcionais. No entanto,
estudos de les?o e hodol?gicos ainda s?o necess?rios para uma conclus?o mais precisa
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17233 |
| Date | 30 August 2014 |
| Creators | Lima, Ruthnaldo Rodrigues Melo de |
| Contributors | CPF:70317232487, http://lattes.cnpq.br/2378505945149958, Ara?jo, John Fontenele, CPF:22800662387, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792718J4, Cavalcante, Judney Cley, CPF:00932163432, Pinato, Luciana, CPF:06964593888, http://lattes.cnpq.br/8372363591179624, Cavalcante, Jeferson de Souza |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Psicobiologia, UFRN, BR, Estudos de Comportamento; Psicologia Fisiol?gica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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