Activation of axonal Kv7 channels in human peripheral nerve by flupirtine but not placebo - therapeutic potential for peripheral neuropathies: results of a randomised controlled trial

Table 2 Electrical excitability parameters for motoneurones to APB in vivo (n = 20)

	Baseline			Flupirtine 200 mg			Placebo			Control			Paired t-test p, baseline vs. flupirtine
Strength-duration time constant (ms)	0.48	±	0.01	0.47	±	0.01	0.47	±	0.01	0.47	±	0.01	0.18
Rheobase (mA)	2.87	±	0.14	3.04	±	0.18	2.67	±	0.15	2.82	±	0.14	0.20
Relative Refractory Period (RRP ms)	3.40	±	0.10	3.23	±	0.09	3.45	±	0.12	3.54	±	0.13	< 0.01
Refractoriness at 2 ms (%)	165.00	±	13.96	105.83	±	10.12	169.77	±	33.36	138.68	±	9.49	0.01
Refractoriness at 2.5 ms (%)	66.27	±	8.86	40.09	±	6.20	60.28	±	8.88	60.21	±	5.84	0.02
Superexcitability at 5 ms (%)	−24.57	±	1.49	−24.73	±	1.55	−24.11	±	1.99	−23.28	±	1.54	0.89
Superexcitability at 7 ms (%)	−27.12	±	1.42	−25.69	±	1.67	−27.05	±	1.57	−26.71	±	1.32	0.09
Depolarisation TEd (90–100 ms)	40.04	±	0.78	40.37	±	4.25	40.23	±	1.11	39.74	±	0.96	0.69
Hyperpolarisation TEh (90–100 ms)	−107.61	±	3.01	−106.31	±	2.82	−107.07	±	4.63	−106.30	±	2.92	0.50
Skin Temperature (°C)	31.89	±	0.22	32.20	±	0.29	31.95	±	0.32	31.74	±	0.24	0.13

Electrical excitability parameters determined for motor axons to abductor pollicus brevis in healthy subjects. Values are indicated for recordings made before (Baseline), 2 hours after oral flupirtine (200 mg p.o.) or placebo and 48 hours subsequent to this (post-Control). Skin temperature was determined with a thermocouple placed on the skin at the site of stimulation above the median nerve at the end of each recording session. Data were analysed with Student’s paired t-tests; * and ** indicate levels of significance for p < 0.05 and p < 0.01 respectively. Oral flupirtine reduced the RRP and the refractoriness at 2 ms and 2.5 ms., but had neither effect on the magnitude of superexcitability at both 5 and 7 ms nor the de- and hyperpolarizing threshold electrotonus. There were no changes in peoples skin temperature throughout the experiment.

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