Fig. 5: Voltage-gated Na+ channel inactivation anomalies due to trisomy 21.
From: Synaptic and intrinsic membrane defects disrupt early neural network dynamics in Down syndrome
A TTX-sensitive Na+ current density of D21 and T21 cells evoked by a single depolarising step. B TTX-sensitive Na+ currents across a range of voltages along with the voltage-step protocol and I-V curve of current density. C Step protocol for fast (100 ms) inactivation and example traces of Na+ channel recovery from fast inactivation immediately following test pre-pulse (blue arrow in step protocol). The trace with −40 mV pre-pulse is shown in red. Graph shows the voltage dependence of fast inactivation of D21 and T21 cells. Inset, Half-maximal fast inactivation potential. D Step protocol for slow (5 s) inactivation and example traces of Na+ channel recovery from slow inactivation following pre-pulse (blue arrow in step protocol). The trace with −40 mV pre-pulse is shown in red. Graph shows voltage dependence of slow inactivation of D21 and T21 cells. Inset, Half-maximal slow inactivation potential. n = 14–52 cells. ***P < 0.001, two-tailed unpaired t-test or Mann-Whitney test. The plot in A shows median, 25–75% interquartile range and 2–95% whiskers; bar charts and error bars in B-D depict means +/- SEM.
