Activity at the 5-HT2A Receptor

Activity at the 5-HT_2A receptor was assessed as previously described in detail (Luethi et al., 2018a). Briefly, NIH-3T3 cells expressing the human 5-HT_2A receptor were incubated in buffer for 1 hour at 37°C before 100 μL of dye solution (fluorescence imaging plate reader [FLIPR] calcium 5 assay kit; Molecular Devices) was added to each well, and the plates were again incubated for 1 hour at 37°C. The plates were then placed in a FLIPR, and 25 μL of the test drugs that were diluted in buffer was added online. The increase in fluorescence was measured for 51 s. EC₅₀ values were derived from the concentration-response curves using nonlinear regression.