1988 Fiscal Year Final Research Report Summary
Effect of dark rearing from birth until 30 days of age on the rat visual system
| Project/Area Number |
62570797
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Ophthalmology
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
HOSHINO Kiyoshi The Research Institute of Environmental Medicine, 環境医学研究所, 助教授 (70023653)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
ODA Sen-ichi The Research Institute of Environmental Medicine, 環境医学研究所, 助手 (60023660)
FUKUI Yoshihiro The Research Institute of Environmental Medicine, 環境医学研究所, 助手 (50144168)
|
|---|
| Project Period (FY) |
1987 – 1988
|
| Keywords | Stereology / Disector method / Synapse-to-neuron ratio / Dark-rearing / Rat / Superior colliculus / Visual cortex |
|---|
| Research Abstract |
Rearing animals in dark conditions during early postnatal life has been shown to affect both the morphology and the normal functioning of the visual system. We have investigated the effects of rearing male rats in complete darkness from birth until 30-days of age, followed in some cases by a 35-day period of rehabilitation in "Control" lighting conditions, on the synapse-to-neuron ratios in the superior colliculi and visual cortex. "control" lighting conditions consisted of a room on a 12-hour red/12-hour light cycle.
Synapse-to-neuron ratios were calculated from estimates of the numerical densities of neurons and synapses. These estimates were made using the "disector" method (Sterio, 1984) at the light and electron microscopical levels respectively. Neuronal nuclei were used as the counting unit for neurons and paramembranous densities for synapses.
There were no significant differences in the numerical densities of neurons, synapses or synapse-to-neuron ratios between dark-reared and control rats at 30-days of age. A two-way analysis of variance (two-way ANOVA) techniques showed the significant effects of age on the estimates of the numerical denstities of neurons and synapses. However, there were no significant major effects attributed directly to the lighting conditions, nor was there any significant interaction among the different measures taken.
|
