In vitro, radioligand competition binding of lorcaserin, DOI, 5-HT, and ketanserin or mesulergine at human (h) and mouse (m) 5-HT2ARs (A and B) and 5-HT2CRs (C and D). Data are concentration–response curves showing means and SEMs, compiled from at least three independent experiments, wherein each concentration was tested at least in duplicate. The 1 mM data points were interpolated, so curves reached asymptote (no specific binding). At 5-HT2ARs, DOI and 5-HT data best fit to a “two-site, fit Ki” model, which is shown, whereas lorcaserin and ketanserin data best fit to a “one-site, fit Ki model,” which is shown. At 5-HT2CRs, 5-HT data best fit to a “two-site, fit Ki” model, which is shown, whereas lorcaserin, DOI and mesulergine data best fit to a “one-site, fit Ki model,” which is shown. NC is an abbreviation for “no compound,” and the associated data points represent total, specific binding.