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Previous issue date: 2013-06-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The circadian timing system (CTS) is responsible for the generation and
synchronization and the suprachiasmatic nucleus (SCN) of the hypothalamus has
been described as the major circadian pacemaker in many mammalian species.
The internal temporal organization managed by SCN is disturbed with aging
bringing many pathological disorders that range from loss of complex cognitive
performance to simple physiological functions. Therefore, our aim was perform a
comparative study of the morphological aspects and neurochemical composition in
the SCN of marmosets (Callithrix jacchus) adults and older using
immunohistochemical techniques. We found morphometric and neurochemical
changes in th SCN o folder animals in comparison to adults, among these a
possible decreased in retinal projection to the SCN of older animals, found through
a decline in CTB immunostaining, which can occur due atrophy and/or decreasing
of fibers from the retinohypothalamic tract (RHT). The Kl?ver-Barrera histological
technique strongly suggests a decrease in those fibers from RHT. Also, by means
of a morphometric study, it is found a atrophy and numerical decline of neurons in
SCN of aged animals, investigated by Nissl technique, and immunostaining with
NeuN and calbindin. Relative optical density (ROD) analysis were used to
evaluate the expression of some neurochemical components in SCN, such as
GFAP expression, which was increased in older, result that indirectly reinforces
that morphological changes occurs due the aging; the vasoactive intestinal
polipeptide (VIP) showed no expression alteration in SCN of older animals; the
serotonin (5-HT) was descreased in the dorsomedial portion of the SCN, and
neurpeptide Y (NPY) apparently also decrease due to the increase of age. Many of
these modifications were seen in other animals, such as rodents, human primates
and non-human primates. These data about marmoset comes to add new
information of the effect of aging on structures responsibles for the circadian
rhytmicity, and that some behavioral changes controlled by th SCN, and founded in
aged animals, may be caused by these morphological and neurochemical
changes. Although some results have been quantitatively negative, qualitatively all
analysis show significant change comparing adult and older animals, perhaps due
to a low sampling number. In conclusion, the marmoset presents several
morphological and neurochemical changes in the SCN of aged animals compared
to adults, which may result in behavioral changes that favor pathology aging
related / O sistema de temporiza??o circadiana (STC) ? respons?vel pela gera??o e
sincroniza??o dos ritmos circadianos e o n?cleo supraquiasm?tico (NSQ) do
hipot?lamo tem sido descrito como o principal marca-passo circadiano em
diversas esp?cies de mam?feros. A organiza??o temporal interna comandada
pelo NSQ ? perturbada com o avan?o da idade trazendo in?meros transtornos
patol?gicos que v?o desde a perda do desempenho cognitivo complexo a
fun??es fisiol?gicas simples. Portanto, nosso objetivo foi fazer um estudo
comparativo dos aspectos morfol?gicos e da composi??o neuroqu?mica no
NSQ de saguis (Callithrix jacchus) adultos e idosos atrav?s de t?cnicas
imunoistoqu?mica. Encontramos modifica??es morfom?tricas e neuroqu?micas
no NSQ de animais idosos quando comparado aos adultos, dentre essas uma
poss?vel diminui??o da proje??o da retina ao NSQ de animais idosos,
encontrada atrav?s da diminui??o na imunomarca??o a CTB, que pode ocorrer
devido uma atrofia e/ou diminui??o nas fibras provenientes do tracto
retinohipotal?mico (TRH). A t?cnica histol?gica de Kl?ver-Barrera sugere
realmente haver uma diminui??o dessas fibras que do TRH. Tamb?m ? visto,
atrav?s de um estudo morfom?trico, diminui??o e atrofia no n?mero de
neur?nios do NSQ de animais idosos, investigados por meio da t?cnica de
Nissl, imunomarca??o a NeUN e a calbindina. An?lises por densidade ?ptica
relativa (DOR) auxiliaram na avalia??o da express?o de alguns componentes
neuroqu?micos do NSQ, como a express?o de GFAP, que foi aumentada em
idosos, dado que indiretamente refor?a estar ocorrendo altera??es
morfol?gicas decorrentes do envelhecimento; o polipet?deo intestinal vasoativo
(VIP) que n?o mostrou altera??o na sua express?o no NSQ de aniamis idosos,
a serotonina (5-HT) que se mostrou diminu?da na por??o dorsomedial do NSQ,
e o neuropept?deo Y que aparentemente tamb?m diminuiu sua express?o em
decorr?ncia do aumento da idade. V?rias dessas modifica??es foram vistas em
outros animais roedores, primatas humanos e n?o humanos, o sagui vem
adicionar novas informa??es sobre o efeito do envelhecimento nas estruturas
respons?veis pela ritmicidade circadiana e que algumas altera??es
comportamentais comandadas pelo STC e vistas em animais idosos podem ser
provocadas por essas mudan?as morfol?gicas e neuroqu?micas. Embora
alguns resultados tenham sido quantitativamente negativos, qualitativamente
todas as an?lises mostram subst?ncial mudan?a ao se comparar animais
adultos e idosos, talvez em decorr?ncia de um baixo n?mero de amostragem.
Em conclus?o, o sagui mostra in?meras altera??es morfol?gicas e
neuroqu?micas no NSQ de animais idosos quando comparado aos adultos, o
que podem resultar em altera??es comportamentais que favorecem patologias
relacionadas ao envelhecimento
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17235 |
| Date | 21 June 2013 |
| Creators | Engelberth, Rovena Clara Galv?o Janu?rio |
| Contributors | CPF:70317232487, http://lattes.cnpq.br/2378505945149958, Gavioli, Elaine Cristina, CPF:97013390968, Santos, Jos? Ronaldo dos, CPF:01874441537, http://lattes.cnpq.br/3626754379892089, Costa, Miriam Stela Maris de Oliveira, CPF:05014077404, http://lattes.cnpq.br/8424747565185682, Cruz-rizzolo, Roelf Justino, CPF:00754607852, http://lattes.cnpq.br/1493560562521489, 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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