Assay Method Information

Assay Name:  Effects of the Compounds of the Invention Against Activity of Dopamine D2 Receptor
Description:  Objective: positive symptoms (hallucination, delusion, etc.) in patients with schizophrenia may be associated with dopamine (DA) hyperfunction in subcortical limbic system, and antipsychotic drugs, which block Dopamine D2 Receptor (DRD2), can effectively control positive symptoms of schizophrenia. By establishing a cell line co-transfected with DRD2 and Gα16, the activated DRD2 can activate Gα16 protein, thereby activating phospholipase C (PLC) to produce inositol 1,4,5-triphosphate (IP3) and diacylglycerol (DAG), wherein IP3 can bind to the IP3 receptor on endoplasmic reticulum and mitochondria, resulting in intracellular calcium release. Therefore, the determination of a change in intracellular calcium can be used as a method for detecting the activated state of DRD2.Fluo-4/AM was a calcium fluorescent probe indicator for determining calcium ions. In this experiment, a Fluo-4 fluorescence method was used to determine the level of activated Gα protein by measuring the fluorescence intensity excited by intracellular calcium ions. If a compound could activate DRD2, the calcium influx was enhanced; on the contrary, if a compound could antagonize DRD2, the calcium influx was reduced.Methods: HEK293 cells stably expressing DRD2/Gα16 (a human embryonic kidney cell line, derived from Shanghai Institute of Materia Medica, Chinese Academy of Sciences) were seeded in a 96-well plate (the culture solution was 90% DMEM+10% fetal bovine serum), and incubated overnight. The culture solution was pipetted off, and a freshly prepared dye Fluo-4/AM was added. The cells were incubated in a 37° C. incubator for 40 min. The dye was completely pipetted off. After the cells were washed with a freshly prepared calcium buffer, a calcium buffer (50 μl) dissolved with a test drug was added. FlexStation II instrument was used in the determination. A calcium buffer (25 μl) dissolved with a known agonist was added automatically by the instrument at the fifteenth second, and the fluorescence value at 525 nm (an excitation wavelength of 485 nm) was finally read. Dopamine was used as agonist, Eticlopride (D2 receptor antagonist) was used as antagonist, and the cell response (% Response) of each sample at each concentration was calculated by the following formula: % Response=(LSample−LBlank)/(LDopamine−LBlank), wherein LSample represents the detected signal value of a test sample, LBlank represents the detected signal value as completely inhibited by Eticlopride, and LDopamine represents the detected signal value after the stimulation of the DMSO group with 50 nM Dopamine (agonist). IC50 value was calculated by GraphPad Prism.
Affinity data for this assay
 

If you find an error in this entry please send us an E-mail