Transcortical alterations in Na(+)-K+ ATPase and microtubule-associated proteins immunoreactivity in the rat cortical atrophy model induced by hypoxic ischemia.
To identify the chronological transcortical change in the contralateral hemisphere following ischemic insults, we investigated the changes in microtubule associated protein (MAP) and Na(+)-K+ ATPase expressions in the peri-infarct zone and contralateral hemisphere, including the hippocampus. Two days after hypoxic ischemia, Na(+)-K+ ATPase immunoreactivity was significantly enhanced in the contralateral cortex and was maintained up to 7 days after ischemia, whereas Na(+)-K+ ATPase immunoreactivity in the peri- and infarct zones was unaffected by hypoxic ischemia. In contrast, 2 to 7 days after ischemia, MAP1A and MAP2 immunoreactivity in the ipsi- and contralateral cortex significantly decreased, whereas in layer V, MAP1 immunoreactivity obviously accumulated in the neurons and their processes. In the hippocampus, 2 days after insults both MAP1A and MAP2 immunoreactivity was significantly reduced within the ipsi- and contralateral hippocampus. In the contralateral hippocampus, however, the distribution of MAP2 immunoreactivity recovered to the sham level 7 days after ischemia, whereas MAP1A immunoreactive axons remained 2 months after ischemia. The results suggest that the unilateral elevation of Na(+)-K+ ATPase immunoreactivity reflects elevated neuronal activity. In addition, this asymmetric hyperexcitability might play an important role in the recovery or the reorganization of the brain, accompanied by transcortical changes in MAPs expression.
Suh
Jun-Gyo
JG
Department of Medical Genetics & Experimental Animal Center, College of Medicine, Hallym University, Chunchon 200-702, South Korea.
An
Sung-Jin
SJ
Park
Jae-Bong
JB
Ryoo
Zae-Young
ZY
Lee
Jeong Woong
JW
Oh
Yang-Seok
YS
Won
Moo Ho
MH
Kang
Tae-Cheon
TC
D000818:Animals; D001284:Atrophy; D001921:Brain / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D004195:Disease Models, Animal; D007839:Functional Laterality; D006624:Hippocampus / Q000378:metabolism; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
C490546:Map1a protein, rat; D008869:Microtubule-Associated Proteins; D000254:Sodium-Potassium-Exchanging ATPase