A–B. Representative traces of spontaneous firing at resting membrane
potential recorded from shControl (A) and shGSK3β (B) neurons in
whole-cell patch clamp. C. Summary bar graph of action potential firing
frequency recorded in whole cell, control n=13 cells
and shGSK3β n=15 cells (mean±SEM).
Control n=6 rats, shGSK3β
n=8 rats. D–E. Passive properties of same
neurons as A–B showing hyperpolarizing sag and action potential rebound
in control (D) and shGSK3β knockdown (E) with injected current (500
msec, 20 pA/step). F. Summary graph of sag amplitude (mV) at different injected
current (pA) showing reduced sag amplitude in GSK3β knockdown
(n=18 cells) versus control
(n=13 cells) (mean±SEM). Control
n=6 rats, shGSK3β
n=8 rats. G. and H. Representative traces from control
vector (G) and shGSK3β vector (H) transduced TANs showing trains of
evoked action potentials at 800 msec and 150 pA current step injection. I.
Input-output curve of evoked AP trains in response to repetitive current steps
of constant increment. J. Action potential waveforms evoked at the current
threshold are illustrated for control (black line) or shGSK3β vector
(red line) transduced TANs. K. Bar graph showing reduced maximum rise (dV/dt,
mV/msec) in GSK3β knockdown (n=17 cells) versus
control (n=16 cells) (mean±SEM); control
n=6 rats, shGSK3β
n=8 rats. L. Bar graph showing no significant
difference in action potential maximum decay (dV/dt, mV/msec) in GSK3β
knockdown (n=17 cells) versus control
(n=16 cells) (mean±SEM); control
n=6 rats, shGSK3β
n=8 rats. M. Bar graph showing no difference in the
action potential voltage threshold (Vtrh, mV) in GSK3β
knockdown (n=17 cells) versus control
(n=16 cells) (mean±SEM); control
n=6 rats, shGSK3β
n=8 rats. N. Bar graph showing increased current
threshold (Itrh, pA) in GSK3β knockdown
(n=17 cells) versus control
(n=16 cells) (mean±SEM); control
n=6 rats, shGSK3β
n=8 rats. *p<0.05.