Characterisation of orthosteric and allosteric activators of mouse GPR84. Flp-In T-REx 293 cells harbouring a mouse GPR84-Gαi2 fusion protein were either untreated (−) or treated with doxycycline (100 ng.ml−1, 24 h) (+) to induce expression of the fusion construct. Membranes from these cells were then used to measure binding of [35S]GTPγS in response to varying concentrations of 2-HTP (a) and either PSB-16671 or DIM (b). Equivalent studies measured the effects of various concentrations of PSB-16671 on the potency and efficacy of 2-HTP (c) or vice versa (d). Data represent means ± S.E.M. of combined data from experiments performed on 4 (a) or 5 (b) individual membrane preparations. See Table 2 for quantitative outcomes.