2.2. GloSensor cAMP accumulation assay

CHO cells transfected with pGloSensor were suspended in OptiMEM (Invitrogen, UK), seeded onto 96‐half well plates at a density of 1.5 × 10⁴ cells per well and left to settle overnight. The medium was subsequently replaced with assay buffer containing: HBSS supplemented with 20 mM HEPES, 3 mM luciferin, 30 μM forskolin at pH 7.4. Cells were left to incubate in assay buffer for 2 h at room temperature. Luminescence as a result of forskolin‐stimulated accumulation of cAMP (maximum luminescence) was recorded on a GloMAX Navigator (Promega, UK) at 1 s integration. Agonists were diluted into assay buffer and added to the cells and incubated for 30 min at room temperature. Luminescence was read again at the end of the 30 min incubation with agonists.