KCNJ3 (Potassium Voltage-Gated Channel Subfamily J Member 3): KCNJ3, also known as GIRK1 (G protein-activated inwardly rectifying potassium channel 1), is a gene that encodes a protein involved in regulating neuronal excitability and heart rate. By controlling potassium ion flow, KCNJ3 helps stabilise the resting membrane potential and modulate action potentials in neurones and cardiac muscle cells. Dysregulation of KCNJ3 may contribute to neurological disorders, such as epilepsy and mood disorders, as well as cardiovascular diseases.