TABLE 2

EC50 values for current and fluorescence responses to 5-HT and mCPBG at unlabeled and labeled WT and mutant h5-HT3A receptors

MutantEC50 Value
5-HTamCPGBa
TEVC∆FTEVC∆F
µMµMµMµM
WT2.6 [2.2; 3.0]N.D.0.45 [0.35; 0.60]N.D.
WT + TAMRA3.5 [3.1; 4.7]*N.D.0.95 [0.70; 1.3]N.D.
Y89C0.24 [0.20; 0.28]*N.D.0.48 [0.34; 0.68]N.D.
Y89C + TAMRA0.70 [0.56; 0.86]*4.0 [3.2; 4.9]#0.26 [0.20; 0.34]1.0 [0.67; 1.5]
Q146C1.2 [0.9; 1.7]*N.D.1.5 [1.4; 2.0]N.D.
Q146C + TAMRA4.8 [3.0; 7.9]61 [48; 79]#1.1 [0.90; 1.45]49 [36; 65]#
F221C85 [76; 94]*N.D.N.D.N.D.
F221C + TAMRA>300*>300N.D.N.D.
M223C7.2 [5.2; 10]*N.D.3.7 [ 3.0; 4.5]*N.D.
M223C + TAMRA22 [19; 26]*18 [14; 23]8.9 [6.1; 13]*24 [15; 38]
  • TEVC, two-electrode voltage clamp. N.D., not determined.

  • a The EC50 values were determined as described in Materials and Methods by nonlinear fitting of concentration-inhibition data collected at 5–10 oocytes. Numbers in brackets denote the 95% confidence interval for EC50.

  • * P < 0.01 vs. WT. #P < 0.01 vs. two-electrode voltage-clamp EC50 (ANOVA with Dunnet’s correction for multiple comparisons).