Table 1.

Structures and in vitro pharmacological profiles of E‐162 and TR‐7 in binding and functional assays (cAMP) at human H₃ receptors, H₄ receptors, and H₁ receptors

In vitro assays		Compounds
		E‐162	TR‐7
H3R	Binding assay	K i = 55 ± 15 nMa	K i = 13 200 ± 800 nMa
	Functional cAMP assay	IC50 = 165 nMb	nt
H4R	Binding assay	K i = 58 500 ± 6600 nMc	K i = 203 ± 65 nMe
	Functional cAMP assay	nt	IC50 = 512 nMf
H1R	Binding assay	K i = 1824 ± 203 nMd	nt
	Functional assay in guinea pig ileum	nt	pA2 = 6.3g

nt, not tested.

^a[³H]N ^α‐Methylhistamine binding assay performed with cell membrane preparation of HEK293 cells stably expressing the human histamine H₃ receptor. Data are means ± SD of three independent experiments.

^bcAMP accumulation assay in HEK293 cells expressing human histamine H₃ receptors, co‐treated with forskolin, (R)‐(−)‐α‐methylhistamine and the tested compound.

^c[³H]Histamine binding assay in membrane preparations of CHO cells stably expressing the human histamine H₄ receptor. Data are means ± SD of three independent experiments.

^d[³H]Pyrilamine binding assay performed with CHO‐K1 cells stably transfected with the human H₁ receptor. Data are means ± SD of three independent experiments.

^e[³H]Histamine binding assay performed with membrane preparation of Sf9 cells expressing the human H₄ receptor, co‐expressed with G‐protein G_αi2 and G_β1γ2 subunits (data from Łażewska et al., 2014).

^fcAMP accumulation assay in CHO cells expressing the human H₄ receptor, co‐treated with forskolin, histamine and the tested compound (Łażewska et al., 2014).

^gData from Mogilski et al. (2017).