Table 2.

Affinity (K_d), receptor density B_max and potency to activate AC (EC₅₀) were determined in membranes of HEK293 cells transiently transfected with either wild-type (WT), N-terminally FLAG-tagged or C-terminally YFP-tagged 5-HT_7(b) receptors incubated with either vehicle or 1 μM clozapine for 24 h

Receptor	Kd (nM)	Bmax after clozapine pre-incubation (% of control)	pEC50	Efficacy (% of WT)
5-HT7(b) WT	0.17 ± 0.02	72 ± 4*	7.38 ± 0.04	100
FLAG-5-HT7(b)	0.18 ± 0.02	76 ± 3*	7.46 ± 0.20	70 ± 12
5-HT7(b)-YFP	0.14 ± 0.05	105 ± 5	7.32 ± 0.04	122 ± 7

Membranes were incubated with increasing concentration of [³H]-5-CT in the absence (total binding) or presence (non-specific binding) of 10 μM 5-HT. B_max and K_d were determined as described in the Methods section. B_max of WT, FLAG- and YFP-labelled 5-HT_7(b) receptors were 2.4 ± 0.7, 0.9 ± 0.2 and 2.6 ± 1.2 pmol·mg protein⁻¹. To determine pEC₅₀ and efficacy, vehicle-treated membranes were incubated with increasing concentrations of 5-HT (95 pM–100 μM) and AC activity was measured. The data shown are mean ± SEM from two to five experiments.

^*P < 0.01 versus 5-HT_7(b)-YFP, one-way anova with Bonferroni’s adjustment for multiple comparisons.