GPR88 and Anxiety: In sum, data from marble burying and social interaction tests reveal a D2R cell-specific function of GPR88 in anxiety-related and social behavior (De Boer and Koolhaas, 2003), as modifications are detected in CMV-Gpr88 and A2AR-Gpr88 KO, but not D1R-Gpr88 KO, mice.