CHEMBL5735495

Dopamine D1 Receptor Agonism: Dopamine D1 receptor agonism was measured using a HTRF cAMP from CisBio using the protocol developed by HD Biosciences (China). Briefly, the assay is a homogeneous time resolved-fluorescence resonance energy transfer (HTRF) assay that measures production of cAMP by cells in a competitive immunoassay between native cAMP produced by cells and cAMP-labeled with XL-665. A cryptate-labeled anti-cAMP antibody visualizes the tracer. The assay was performed in accordance with instructions from manufacturer.Test compounds were added to wells of microplates (384 format). HEK-293 cells expressing the human D1 receptor were plated at 1000 cells/well and incubated 30 min at room temperature. cAMP-d2 tracer was added to wells and followed by addition of Anti-cAMP antibody-cryptate preparation and incubated for 1 h at room temperature in dark. HTRF cAMP was measured by excitation of the donor with 337 nm laser (the “TRF light unit”) and subsequent (delay time 100 microseconds) measurement of cryptate and d2 emission at 615 nm and 665 nm over a time window of 200 microseconds with a 2000 microseconds time window between repeats/100 flashes). HRTF measurements were performed on an Envision microplate reader (PerkinElmer). The HTRF signal was calculated as the emission-ratio at 665 nm over 615 nm. The HTRF ratio readout for test compounds was normalized to 0% and 100% stimulation using control wells with DMSO-solvent or 30 uM dopamine. Test compound potency (EC50) was estimated by nonlinear regression using the sigmoidal dose-response (variable slope) using Xlfit 4 (IDBS, Guildford, Surrey, UK, model 205).y=(A+((B−A)/(1+((C/x){circumflex over ( )}D))))where y is the normalized HTRF ratio measurement for a given concentration of test compound, x is the concentration of test compound, A is the estimated efficacy at infinite compound dilution, and B is the maximal efficacy. C is the EC50 value and D is the Hill slope coefficient. EC50 estimates were obtained from an independent experiment and the logarithmic average was calculated.