TABLE 2

Affinity constants (Ki) for other 5-HT2B receptor agonist ligands at wild-type and V2.53 mutant 5-HT2B receptors

Average Bmax values, fit directly and adjusted for radioligand specific activity and protein content, were as follows: WT, 3.7 ± 0.7 pmol/mg; V2.53L, 9 ± 2 pmol/mg; V2.53A, 7 ± 1 pmol/mg; V2.53I, 2.4 ± 0.2 pmol/mg. Where applicable, values are presented as mean ± S.E.

Drug pKi (Ki)
WT V2.53L V2.53A V2.53I
nM
5-HT 7.3 ± 0.1 (50) 7.17 ± 0.08 (68) 6.5 ± 0.2* (300) 6.2 ± 0.4* (600)
α-Methyl-5-HT 7.8 ± 0.1 (20) 7.3 ± 0.1*(50) 6.4 ± 0.2* (400) 6.7 ± 0.1* (200)
DHE 7.63 ± 0.08 (23) 6.9 ± 0.2* (120) 7.3 ± 0.2 (50) 7.2 ± 0.1* (60)
Pergolide 7.68 ± 0.09 (21) 7.5 ± 0.1 (30) 6.6 ± 0.1* (200) 7.3 ± 0.1* (50)
LSD 8.59 ± 0.05 (2.6) 8.34 ± 0.04* (4.6) 8.41 ± 0.05 (3.9) 8.61 ± 0.05 (2.4)
  • * P < 0.05 from F tests comparing curve fits of competition binding isotherms for wild-type and mutant 5-HT2BR.