KOR-1 also known as OPRK1 is an opioid receptor, which is a member of the 7 transmembrane-spanning G protein-coupled receptor family. KOR-1 plays a crucial role in mediating the effects of endogenous opioid peptides and exogenous opiates, such as morphine. Located primarily in the central nervous system, KOR-1 is involved in modulating pain perception, stress response, and emotional regulation. KOR-1 activation leads to a cascade of intracellular signaling events that can inhibit neurotransmitter release, thereby influencing various brain functions. KOR-1 receptor is part of the G-protein-coupled receptor superfamily, which is characterized by seven transmembrane domains and ability to interact with G-proteins.