Figure 7. Efavirenz is an antagonist of the cloned 5-HT_2C receptor.

G_q-signaling was measured as a change in intracellular calcium. All data are presented as averaged values from multiple experiments ± SEM. A, Efavirenz dose-dependently antagonizes agonist responses produced by an EC₅₀ concentration of 5-HT (EC₅₀ data normalized to 100%). For these experiments cells were maintained in serum free media for at least 12 hours, pretreated with efavirenz, then stimulated with 0.03 nM serotonin, which is the EC₅₀ for 5-HT for this receptor under serum free conditions (see Figure 3B). Values significantly different from 0.03 nM 5-HT, (Dunnett’s multiple comparison test set to high stringency, P < 0.001) are denoted by asterisks. B, Efavirenz did not have any agonist activity at the 5-HT_2C receptor under similar conditions.