Although total KCC2 expression is increased in the cortex during
postnatal development, KCC2a levels remain constant. A, equal
amounts (20 μg) of total protein lysates obtained from brainstems,
cortices, and spinal cords of P2 or adult (48-week-old) mice were analyzed by
standard SDS-PAGE and detected sequentially with the KCC2a (upper
panel) and KCC2pan (middle panel) antibodies. A protein of 140
kDa, close to the predicted molecular mass for KCC2a, was observed in all
samples analyzed. IB, immunoblot. B, shown is the result of
quantification of four independent experiments, one of which is presented in
A. Expression of KCC2a in the mouse brainstem and spinal cord was
about 2-fold higher in P2 than in adult mice. By contrast, KCC2a expression in
the cortex was about 2-fold lower in P2 than in adult mice. Values are mean
± S.E. (error bars) of four independent experiments.
C, total KCC2 expression (detected with KCC2pan antibody) was
dramatically up-regulated in the cortex between P2 and adulthood but increased
only moderately in the brainstem. In the spinal cord, total KCC2 expression
did not change significantly between the P2 and adult time points. Values are
mean ± S.E. (error bars) of four independent experiments.