Effect of prolonged hypoxia on Na+ channel mRNA subtypes in the developing rat cortex.
Voltage-gated Na+ channels are regulated in response to oxygen deprivation in the mammalian cortex. Past investigations have demonstrated that Na+ channel protein expression is up-regulated in the immature brain exposed to prolonged hypoxia. Since it is unknown as to which Na+ channel subtype(s) is involved in this regulation, we used RT-PCR to assess the effect of hypoxia on Na+ channel I, II and III alpha-subunit mRNA expression in the developing rat cortex. Na+ channel II mRNA tended to increase during early development, whereas Na+ channel I and III did not change or slightly decreased with age. Hypoxic exposure for 1-day had no effect on Na+ channel expression, while 5-day hypoxia significantly increased Na+ channel III density, with a slight increase in Na+ channel I and no appreciable change in Na+ channel II. These results suggest that Na+ channel subtype expression in the developing cortex is differentially regulated in response to prolonged hypoxic exposure.
Zhang
J H
JH
Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, LMP 3107, New Haven CT 06520, USA.
Gibney
G T
GT
Xia
Y
Y
D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000254:growth & development / Q000503:physiopathology*; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental; D002534:Hypoxia, Brain / Q000503:physiopathology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015222:Sodium Channels / Q000235:genetics*
D017931:DNA Primers; D012333:RNA, Messenger; D015222:Sodium Channels