Table 1.

EC50 values (μm) and Hill coefficients for 5-HT activation of 141-Tyr mutant receptors (n = 3-6) (A) and [3H]granisetron binding affinities of Tyr mutants (B)

A
141- EC50 ± SE nH ± SE
Ala 2.73 ± 0.15 2.68 ± 0.40
Ser 4.70 ± 0.38 2.02 ± 0.31
Cha 3.14 ± 0.40 1.92 ± 0.21
Phe 0.92 ± 0.06 2.80 ± 0.44
4-F-Phe 1.32 ± 0.05 2.47 ± 0.17
F5-Phe 1.38 ± 0.08 1.89 ± 0.17
Tyr (WT) 1.16 ± 0.04 2.76 ± 0.20
mTyr 1.69 ± 0.06 3.24 ± 0.29
4-Me0-Phe 3.36 ± 0.14 2.17 ± 0.16
B
141- Kd (nm) n
Ala 8.97 ± 2.44* 4
Ser NB 8
Phe 0.98 ± 0.15 4
Tyr (WT) 0.32 ± 0.035 7
  • The asterisk indicates a significant difference (p<0.05) to Tyr. Substitutions have been approximately ordered by increasing size. NB, No binding; WT, wild type. The asterisk data in B are from Price and Lummis (2004).