Fig. 4: A_2AR–D₂R heteromer assessment in mouse striatum and human caudate using an AlphaLISA approach.

a Illustration of the specific AlphaLISA protein–protein interaction assay designed for A_2AR–D₂R heteromer identification and quantification in native tissue; anti-guinea pig-coated acceptor beads (red sphere) were generated to capture a guinea pig anti-A_2AR antibodies bound to the receptors within the membrane extract; anti-rabbit coated donor beads (blue sphere) capture the immune complexes between the rabbit anti-D₂R antibodies and the receptors within the membrane extract; A_2AR–D₂R heteromerization brings donor beads into close proximity (<200 nm) to the acceptor beads. The excitation of the donor beads at 680 nm generates singlet oxygen (¹O₂) molecules triggering a chemical reaction within the acceptor beads, which results in a sharp peak of fluorescent emission at 615 nm (figure designed using image templates from Servier Medical Art https://smart.servier.com/image-set-download/). b The A_2AR–D₂R interaction capacity in membranes from saline- (n = 10) and PCP- (n = 10) treated mouse striatum (left panel) or from postmortem control (n = 10) and schizophrenic (n = 10; SCZ) caudate (right panel) was determined by AlphaLISA method (see ‘Methods’); the specific AlphaLISA signal (i.e., ∆AlphaLISA) was calculated as described in the ‘Methods’ section and expressed as percentage (mean ± SEM) of either the saline-treated mice or control subjects. **P < 0.01 and ***P < 0.001, Student’s t-test.