Table 3.

Effects of an activator and of an inhibitor of PKC in the presence or absence of CNTF on the maximal peak amplitude, kinetic parameters and voltage dependence of activation and steady-state fast inactivation parameters of sodium currents in FDB muscle fibres

	Peak INa amplitude (nA)	τm (ms)	τh (ms)	Va,1/2 (mV)	Vh,1/2 (mV)	n
Control	−0.449 ± 0.062	0.101 ± 0.008	0.281 ± 0.015	−30.1 ± 3.4	−75.9 ± 7.6	6
OAG (40 μm)	−0.289 ± 0.083*	0.100 ± 0.003	0.283 ± 0.019	−31.9 ± 4.5	−85.4 ± 9.0*	6
Control	−0.346 ± 0.167	0.105 ± 0.009	0.215 ± 0.030	−38.5 ± 4.4	−88.7 ± 3.1	5
Chelerythine (1 μm)	−0.316 ± 0.156	0.103 ± 0.013	0.213 ± 0.012	−40.5 ± 2.3	n.d.	5
Chelerythine (1 μm) +
CNTF (2 ng ml−1)	−0.342 ± 0.174	0.115 ± 0.027	0.223 ± 0.029	−39.4 ± 4.3	−86.9 ± 2.8	5

All parameters are obtained in individual patches and are expressed as mean ± s.e.m. n is the number of patches. Peak I_Na amplitude, τ_m and τ_h of sodium current were determined as described in Table 1. V_a,1/2: the half-maximal activation potential, as derived from the fit with the Boltzmann equation of normalized current–voltage curves between −60 and 0 mV. V_h,1/2: the half-maximal steady-state fast inactivation potential, as derived from the fit with the Boltzmann equation of normalized steady-state fast inactivation curves. OAG (1-oleoyl-2-acetyl-sn-glycerol) was applied for 10 min. Chelerythrine was applied for 10 min before the 10 min application of CNTF (2 ng ml⁻¹).

^**Significant difference from control value with P < 0.05. n.d., not determined.