Layer-specific expression of Cl- transporters and differential [Cl-]i in newborn rat cortex.
GABA is the main inhibitory neurotransmitter in the adult brain. However, GABAergic transmission is depolarizing during early postnatal development, suggesting that changes in the expression of cation-Cl- co-transporters regulating neuronal Cl- homeostasis underlie the ontogeny of GABAergic functions. The developmental changes in the expressions of Cl- co-transporter mRNAs in the neocortex were in opposite directions for NKCC1 (Cl- uptake) and KCC2 (Cl- extrusion). In the newborn, NKCC1 mRNA expression was highest in ventricular zone followed by cortical plate, and then by Layer V/VI, while the reverse was true for KCC2 mRNA. The [Cl-]i levels were in the same rank order as for NKCC1 mRNA. Thus, the ontogeny of Cl- homeostasis in neocortical neurons could be regulated via the differential expression of NKCC1 and KCC2.
Shimizu-Okabe
Chigusa
C
Department of Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, Shizuoka 431-3192, Japan.
Yokokura
Masamichi
M
Okabe
Akihito
A
Ikeda
Masahiko
M
Sato
Kohji
K
Kilb
Werner
W
Luhmann
Heiko J
HJ
Fukuda
Atsuo
A
D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D028021:Sodium-Potassium-Chloride Symporters / Q000235:genetics* / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2; D027981:Symporters / Q000235:genetics / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000502:physiology; D000096922:K Cl- Cotransporters
D002712:Chlorides; D012333:RNA, Messenger; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; D027981:Symporters; D005680:gamma-Aminobutyric Acid; D000096922:K Cl- Cotransporters; C578879:Slc12a2 protein, rat