Concentration–response curves of six antagonists for the reactivation of risperidone-inactivated h5-HT7 receptors. Cells were exposed to 10 nM risperidone, and reactivation was determined as described in Fig. 3. Clozapine, SB269970, mianserin, cyproheptadine, mesulergine, and ICI169369 produced potent, concentration-dependent reactivation of the h5-HT7 receptor. The partial effect of 1 μM ICI169369 observed in Fig. 3 is due to its lower potency. The results are the mean±SEM of three experiments performed in triplicate