GIRK channels are G-protein coupled inwardly rectifying K⁺ channel (also known as K_ir3 channels) causing membrane hyperpolarization and plays a very important role in reducing neuronal excitability in most brain regions and in the heart. Four subunits have been identified in mammals, and neuronal GIRK channels are predominantly heteromultimers of GIRK1 and GIRK2. The channels are activated through the G-protein βγ dimer, derived mainly from G_i/o heterotrimers.

 G-Protein-Coupled Inwardly Rectifying Potassium Channels