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Previous issue date: 2015-03-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / O Sistema de Temporiza??o Circadiana (STC), em roedores, ? composto por estruturas
neurais interligadas como o n?cleo supraquiasm?tico (NSQ) do hipot?lamo, o folheto
intergeniculado (FIG) do t?lamo, vias sincronizadoras e efetores comportamentais. O NSQ
tem sido descrito como o principal marca-passo circadiano em diversas esp?cies de
mam?feros enquanto que o FIG parece estar envolvido na integra??o de informa??es
f?ticas e n?o-f?ticas retransmitindo-as ao NSQ. O STC, como um todo, permite que o
organismo tenha uma organiza??o temporal interna ordenada, o que propicia a execu??o
adequada dos mecanismos fisiol?gicos e comportamentais trazendo homeostasia para o
organismo. No entanto, essa estabilidade ? alterada com o avan?o da idade ocorrendo
desde perda de fun??es fisiol?gicas simples ? diminui??o no desempenho cognitivo. Tendo
isso em vista, ? proposto nesse estudo verificar se h? mudan?as neuroqu?micas,
citoarquitet?nicas e de afer?ncias retinianas no FIG com o envelhecimento e suas poss?veis
implica??es morfofuncionais. Para isso, ratos Wistar foram divididos em 3 grupos: Jovem
(3 meses); Meia Idade (13 meses); Idoso (23 meses). Esses animais foram submetidos a
perfus?o transcard?aca de paraformalde?do (4%) para fixar seus tecidos. Posteriormente seu
enc?falo foi removido e submetido ? microtomia (30 ?m) onde as sec??es foram coletadas
em intervalos de 6. Essas sec??es foram processadas por colora??o de Nissl e
imunoistoqu?micas para GFAP, GAD, ENK, NPY e CTb a fim de verificar as
caracter?sticas do FIG. Observamos uma perda celular em animais de meia-idade e idosos
na marca??o de Nissl, NPY e nas proje??es de CTb. Al?m disso, vimos um aumento de
GFAP em animais de meia-idade quando comparados a jovens e idosos. N?o houve
diferen?as na an?lise dos outros marcadores. Esses achados indicam que essa estrutura
perde afer?ncias retinianas e neur?nios, em especial os produtores de NPY, existindo uma
prov?vel gliog?nese compensat?ria. Isso aponta para uma correla??o entre os d?ficits de
funcionamento do STC e deteriora??o anat?mica de seus componentes com o
envelhecimento. / The circadian timing system (CTS), in rodents, consists of interconnected neural structures
such as the suprachiasmatic nucleus (SCN) of the hypothalamus, Intergeniculate Leaflet
(IGL) of the thalamus, synchronous pathways and behavioral effectors. The SCN has been
described as the major circadian pacemaker in several species of mammals, while the IGL
appears to be involved in integration of photic and non-photic clues relaying them to SCN.
The CTS allows an ordered internal temporal organization to the organism, providing the
proper execution of physiological and behavioral mechanisms, which brings homeostasis.
However, this stability is disrupted with aging process causing numerous pathological
disorders, ranging from simple loss of physiological functions to decreases in cognitive
performance. Therefore, is fundamental understanding the effects of senescence in this
system. In this context, is proposed in this study to check if there are changes in IGL
cytoarchitecture, neurochemical and retinal afferent markers with aging and their possible
morpho-functional implications. To achieve this goal wistar rats were divided into 3 groups:
young (3 months); Middle Age (13 months); Old (23 months). They were submitted to
paraformaldhyde (4%) transcardiac perfusion to tissue fixation. Then, they had their brain
removed and sectioned in 30 ?m slices, which every sixth section were collected. This
sections were processed by nissl method and immunostaining for GFAP, GAD, ENK, NPY
and CTb in order to analyze the IGL features. It was observed a cell loss in middle age and
old animals at Nissl, NPY and CTb stains. In addition, it was shown a increase in GFAP in
middle aged animals compared to young and old ones. No differences were found in other
neurochemichal stains. These data suggests IGL loss retinal afferents and neurons, in special
the NPY-IR ones, likely having a compensatory gliogenesis. This supports the correlations
between the CTS functional deficits and an anatomical deterioration of its components with
the aging process.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19847 |
| Date | 27 March 2015 |
| Creators | Fiuza, Felipe Porto |
| Contributors | 70317232487, http://lattes.cnpq.br/2378505945149958, Santos, Jos? Ronaldo dos, 01874441537, http://lattes.cnpq.br/3626754379892089, Lima, Ruthnaldo Rodrigues Melo de, 01183598432, http://lattes.cnpq.br/7840908268607919, Engelberth, Rovena Clara Galv?o Janu?rio, Cavalcante, Jeferson de Souza |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM PSICOBIOLOGIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| 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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