Gpr176 modulates the firing pattern of parvalbumin-positive interneurons in the orbitofrontal cortex of mouse.

Parvalbumin-positive (PV+) interneurons are the most abundant type of interneurons in the cortex. Its characteristic high-frequency non-accommodating firing pattern is critical for cortical inhibition, network activity, and mouse behavior. In the brain, neuromodulation via G protein-coupled receptors (GPCRs) regulates neuronal activities, including the output of neurons. GPCRs are the largest receptor superfamily, and there are GPCRs called "orphan GPCRs" whose endogenous ligands are still not clear. Meanwhile, studies have shown that some of them are constitutively active, but the modulation of these GPCRs on neuronal activity is far from clear. Among orphan GPCRs, Gpr176 is a constitutively active GPCR known for its role in the circadian rhythm in the central nervous system. In the present study, we found that the expression of Gpr176 was mainly expressed in PV + interneurons in the prefrontal cortex, and the knockdown of Gpr176 increased the output of PV + interneurons by increasing the membrane potential change in the repolarizing phase of action potentials in a train. We also found that the synaptic activities of these neurons were not affected. Furthermore, we observed changes in behaviors of mice with the knockdown of Gpr176 in the PV + interneurons of the prefrontal cortex. These data suggest an important role of Gpr176 in the regulation of intrinsic membrane properties of PV + interneurons in the prefrontal cortex.