Fig. 4. Analysis of Na⁺ conductance (g_Na) and K⁺ conductance (g_K) from voltage-clamped axons. All analyses are derived from experiments at 10°C. , L. pealei; , L. plei; , Sepioteuthis sepioidea. Values are means ± S.E.M. (A) g_Na, normalized to membrane surface area, versus voltage. L. pealei, N=5; L. plei, N=5; S. sepioidea, N=9. Values for S. sepioidea are significantly different (P0.05) from those for either species of Loligo between O mV and +30 mV (at +40 mV, P=0.06). (B) g_K, normalized to membrane surface area, versus voltage. L. pealei, N=5; L. plei, N=7; S. sepioidea, N=8. Values are significantly different between L. plei and L. pealei at all voltages +20 mV and between L. plei and S. sepioidea at all voltages 0 mV. (C) g_Na, normalized to maximum values of g_Na, versus voltage. (D) g_K, normalized to maximum values of g_K, versus voltage. (E) Half-time (t_1/2) for I_Na versus voltage. (F) t_1/2 for I_K versus voltage. t_1/2 was defined as the time after the voltage step when half the maximum current was activated. V_m, membrane potential.