Table 2. Kinetic Binding Parameters of Radioligands and Unlabeled FPT at 5-HT_1ARs, 5-HT_2CRs, and 5-HT₇Rs^a.

receptor	compound	residence time	koff	kon	Kd
5-HT1A	[3H]5-CT	3	0.32 ± 0.06	1.3 × 108 ± 3.3 × 107	2.5
	FPT	2	0.50 ± 0.04	2.8 × 107 ± 8.6 × 106	18
5-HT2C	[3H]mesulergine	143	0.007 ± 0.001	4.1 × 106 ± 2.2 × 105	1.7
	FPT	5	0.186 ± 0.018	2.5 × 105 ± 1.9 × 104	732
5-HT7	[3H]5-CT	143	0.007 ± 0.002	2.3 × 107 ± 2.9 × 106	0.3
	FPT	4	0.26 ± 0.12	4.3 × 107 ± 1.8 × 107	6.2

^ak_off (min^–1) and k_on (M^–1·min^–1) were derived from 3–4 independent experiments. Residence time was calculated as 1/k_off and was rounded to the nearest minute, while the kinetically determined K_d was calculated using mean kinetic parameters and the equation K_d = k_off/k_on, presented in nM.