Figure 2.

Long-term incubation with agonists or inverse agonists modifies 5-HT₇ receptor density. Receptor density (B_max) in the membranes of HEK293 cells stably expressing the human 5-HT₇ receptor splice variants after 24 h of pre-incubation with either 10 μM 5-HT or 1 μM mesulergine, clozapine or SB269970. Radioligand binding was performed with increasing concentrations of [³H]-5-CT in the absence (total binding) and presence (non-specific binding) of 10 μM 5-HT for 1 h at 24°C. B_max and K_d were determined as described in the Methods section. Data are presented as a % of control (sister plates of cells pre-incubated without drug or vehicle). The data shown are mean ± SEM of 5–14 experiments from two to three different clonal cell lines of each splice variant. ^*P < 0.01 versus control (one-way anova with Dunnett’s multiple comparison test), ^†P < 0.05 versus the other two 5-HT₇ splice variants pre-incubated with the same ligand (two-way anova with Bonferroni adjustment).