Orofacial movements in phospholipase C-related catalytically inactive protein-1/2 double knockout mice: Effect of the GABAergic agent diazepam and the D₁ dopamine receptor agonist SKF 83959

Orofacial movements are regulated by D₁-like dopamine receptors interacting with additional mechanisms. Phospholipase C-related catalytically inactive protein (PRIP) regulates cell surface expression of GABA_A receptors containing a γ2 subunit. Mutant mice with double knockout of PRIP-1 and PRIP-2 were used to investigate aspects of GABAergic regulation of orofacial movements and interactions with D₁ mechanisms. Vertical jaw movements, tongue protrusions and movements of the head and vibrissae were reduced in PRIP-1/2 double knockouts. The GABA_Aergic agent diazepam reduced movements of the head and vibrissae; these effects were unaltered in PRIP-1/2 double knockouts. The D₁-like agonist SKF 83959 induced vertical jaw movements, incisor chattering, and movements of the head and vibrissae that were unaltered in PRIP-1/2 double knockouts. However, SKF 83959-induced tongue protrusions were reduced in PRIP-1/2 double knockouts. PRIP-mediated regulation of GABA_Aergic receptor mechanisms influences topographically distinct aspects of orofacial movement and interacts with D₁ receptor systems.