TABLE 1

Effect of Rg3 on wild-type and various mutant Na+ channels expressed in X. laevis oocytes Data represent mean ± S.E.M. (n = 10–11/group). Currents were elicited by single-step voltage pulses from -100 to -10 mV at 0.2 Hz. The IC50, Hill coefficient, and Vmax values were determined as described under Materials and Methods.

Type IC50nHVmax
Wild 32 ± 6 1.1 ± 0.4 75 ± 6
Pore entrance
   Y401C 43 ± 2* 1.5 ± 0.5 72 ± 2
   Y401T 22 ± 5 1.3 ± 0.3 61 ± 5
Channel pore
   D927N 33 ± 4 1.1 ± 0.1 74 ± 3
   E942Q 40 ± 9 1.3 ± 0.3 58 ± 6
   E945Q 35 ± 5 1.2 ± 0.1 72 ± 4
Lidocaine binding site
   F1764A 23 ± 4 1.3 ± 0.4 71 ± 3
   Y1771A 36 ± 6 1.1 ± 0.5 67 ± 5
   F1764A-Y1771A 33 ± 5 1.2 ± 0.1 70 ± 3
TTX binding site
   F385C 26 ± 6 1.4 ± 0.4 52 ± 5
   F385S 27 ± 3 1.4 ± 0.2 73 ± 3
   F385Y 29 ± 9 1.2 ± 0.5 60 ± 9
   F385T 26 ± 8 1.0 ± 0.5 67 ± 9
   F385M 60 ± 6* 0.9 ± 0.4 84 ± 3
   E387G 36 ± 4 1.2 ± 0.1 85 ± 3
   E387T 29 ± 2 1.3 ± 0.4 60 ± 2
   E387Q 44 ± 9* 1.1 ± 0.2 75 ± 6
Voltage sensor
Domain I K226Q 30 ± 3 1.4 ± 0.2 65 ± 3
Domain II K859Q 47 ± 9* 1.1 ± 0.1 88 ± 7
Domain III R1312Q 30 ± 2 1.2 ± 0.7 73 ± 2
Domain IV R1638Q 33 ± 6 1.0 ± 0.7 62 ± 3
Inactivation site
   IFMQ3
      Peak 38 ± 3 1.1 ± 0.1 70 ± 5
      Plateau 14 ± 4 1.3 ± 0.4 98 ± 1
   IFMQ3-K859Q
      Peak 56 ± 6** 1.1 ± 0.3 76 ± 6
      Plateau 20 ± 1 1.4 ± 0.3 97 ± 2

  • ↵* P < 0.01 compared with wild-type Na+ channel

  • ↵** P < 0.01 compared with IFMQ3 mutant