Banca de DEFESA: FELIPE PORTO FIUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : FELIPE PORTO FIUZA
DATA : 09/11/2018
HORA: 14:30
LOCAL: Sala de Reuniões do Centro de Biociências
TÍTULO:

Aging of the rat lateral geniculate nucleus: morphological changes and daily rhythm of calretinin.

PALAVRAS-CHAVES:

Aging, Lateral geniculate nucleus, Stereology, Zeitgeber Time, Calretinin.

PÁGINAS: 100
GRANDE ÁREA: Ciências Humanas
ÁREA: Psicologia
RESUMO:

Normal aging is accompanied by declines in visual system even in the absence of pathological processes. Among the components of this system, the lateral geniculate nucleus (LGN) comprises the dorsal lateral geniculate nucleus (dLGN), intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus (vLGN). A characteristic of these nuclei is the immunoreactivity of calcium binding proteins (CaBPs), which regulates the intracellular concentration of this ion and presents a daily and regional expression. In parallel, modern theories of aging correlates functional deficits of neurons to dysregulation of calcium homeostatic mechanisms. In this context, the present study aims to describe quantitative morphological parameters of LGN and immunoreactivity of the CaBP calretinin (CR) in distinct phases of day across different age groups. Male wistar rats were divided into three age groups: young, middle-age and aged (3, 13 and 23 months old) and perfused with formalin (10%) in Zeitgeber times (ZTs) corresponding to distinct photic conditions, namely ZT 0 (dark/light transition), ZT 6 (light), ZT 12 (light/dark transition), ZT 14( beginning of dark) and ZT 18 (dark) . Then, the brains were sectioned and submitted to immunohistochemistry for Neuronal Nuclei protein (NeuN) with Nissl counterstain or immunohistochemistry for CR. Through the stereological methodologies of optical fractionator and Cavalieri estimator we estimated the regional volume, neuronal and glial number, glia/neuron ratio and CR+ neuronal number in the CGL nuclei. We observed LGN neuronal numbers remained stable during aging. However, glial numbers, glia/neuron ratio and volume increased in a region-specific manner. In addition, we observed a peak of CR-immunorreactive cells in the light phase that was diminished in the beginning of the dark in all LGN subnuclei of young animals. Furthermore, we show na age-related reduction of CR+ cells in all subnuclei at ZT 12, as well as in ZT 6 of IGL and the external portion of vLGN. These reductions seem to be due to the neuron capacity in express CR rather than neuronal loss, since no alterations were observed in total cell numbers. The daily rhythm of CR observed in young is lost in middle-aged and aged animals and were detected only in the light phase.

MEMBROS DA BANCA:
Externo ao Programa - 1076490 - FERNANDO VAGNER LOBO LADD
Externo à Instituição - FRANCISCO GILBERTO OLIVEIRA - URCA
Presidente - 2351800 - JEFERSON DE SOUZA CAVALCANTE
Externo à Instituição - MANUELA SALES LIMA NASCIMENTO - IINN
Externo ao Programa - 3492786 - RUTHNALDO RODRIGUES MELO DE LIMA