Monocular deprivation enhances the nuclear signalling of extracellular signal-regulated kinase in the developing visual cortex.
Monocular deprivation (MD) of vision leads to a loss of cortical response to the deprived eye in the early postnatal period (ocular dominance plasticity). The activity of several signal molecules, including extracellular signal-regulated kinase (ERK), has been reported as playing a crucial role in the ocular dominance plasticity. Although pharmacological inhibition of ERK disturbed the ocular dominance plasticity, it remains to be elucidated how the ERK activity is modulated by MD. We herein report the effects of MD on ERK activation in the visual cortex of young and adult rats. Phosphorylated ERK (pERK)-immunopositive cells are mainly distributed in layers II/III of the visual cortex. Following MD, we found a significant decrease in the density of pERK-immunopositive cells in the cortex receiving deprived-eye inputs in both young and adult animals. The amount of pERK protein also decreased in the input-deprived cortex as revealed by Western blotting. Regarding the subcellular localization of pERK, we found a significant increase in the pERK-immunopositive nucleus following MD in young animals. In these animals, the amount of pERK protein in the nuclear fraction of cortical tissue was significantly increased. No up-regulation of the nuclear pERK was observed in adults or following binocular deprivation. These findings suggest that ERK activation may therefore be regulated by different mechanisms between young and adult animals, and MD during the developing period may thus specifically up-regulate the nuclear signalling of ERK.
Takamura
Hironori
H
Division of Integrative Bioscience, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, 86 Nishicho, Yonago 683-8503, Japan.
Ichisaka
Satoshi
S
Hayashi
Chihiro
C
Maki
Hirotoshi
H
Hata
Yoshio
Y
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D007839:Functional Laterality / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D008297:Male; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012683:Sensory Deprivation / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D015349:Vision, Monocular; D014793:Visual Cortex / Q000201:enzymology* / Q000254:growth & development; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005680:gamma-Aminobutyric Acid; D048049:Extracellular Signal-Regulated MAP Kinases; D010751:Phosphopyruvate Hydratase