Table 2.

Passive and active membrane properties of control and Kcnq2-null DRG neurons.

	control	Kcnq2-null
Passive properties
Cm (pF)	39 ± 3.3	45 ± 4.1
Initial RMP (mV)	−58 ± 2.5	−56 ± 1.6
Pre-drug firing properties
Fast AHP peak (mV)	−83 ± 1.3	−86 ± 0.97*
AP rheobase (nA)	0.77 ± 0.23	0.81 ± 0.16
1 times rheobase (#APs)	2.1 ± 0.38	2.9 ± 0.75
2 times rheobase (#APs)	5.8 ± 1.3	11 ± 2.8
3 times rheobase (#APs)	8.0 ± 1.3	17. ± 4.4*
Absolute stimulus (#APs)	16 ± 1.6	25 ± 5.2*
Slow AHP peak (mV)	−74 ± 1.9	−68 ± 1.2**
Post-drug firing properties
Fast AHP peak (mV)	−82 ± 0.97	−84 ± 1.21
AP rheobase (nA)	0.39 ± 0.07	0.88 ± 0.19*
1 times rheobase (#APs)	4.0 ± 1.1	2.5 ± 0.66
2 times rheobase (#APs)	11 ± 2.0	9.2 ± 2.2
3 times rheobase (#APs)	13 ± 2.2	16 ± 2.9
Absolute stimulus (#APs)	21 ± 2.2	23 ± 3.9
Slow AHP peak (mV)	−66 ± 1.2	−67 ± 1.6

Twenty-five DRG neurons from five animals were recorded in the control and Kcnq2-null groups. Values are means ± SEM. C_m = membrane capacitance; RMP = resting membrane potential; AHP = afterhyperpolarization potential; fast AHP peak = AHP undershoot peak magnitude after single 3-ms stimulus; AP rheobase = either the minimum amount of current required to evoke a single AP, or 0.1 nA (whichever one was smallest); 1, 2, and 3 times rheobase = the number of APs fired by a DRG neuron during a 500-ms depolarizing current step of a magnitude 1, 2, or 3 times its rheobase, respectively; absolute = the maximum number of APs fired in response to a single 500-ms depolarizing current step of 0.1–0.9 nA magnitude (in 0.1-nA increments); slow AHP peak = AHP undershoot magnitude after 500-ms stimulus at 0.4nA. Values of C_m of the control DRG neurons were compared to mutant neurons using unpaired 2-sample Student’s t-test with equal variance; AHP and AP rheobase were compared with 2-way ANOVA with Tukey test; numbers of APs were compared with two-way repeated measures ANOVA.

^*p<0.05;

^**p<0.01.