The Kappa Opioid Receptor (KOR) is a type of protein found in the brain and other parts of the body. It belongs to the opioid receptor family, which also includes Mu Opioid Receptors and Delta Opioid Receptors. KOR is primarily involved in regulating pain, mood, and stress responses. When activated by specific substances, it can produce effects such as analgesia and sedation. Kappa Opioid Receptors are also linked to various mental health conditions, including depression and anxiety. Research into KOR has led to the development of potential treatments that target this receptor, aiming to provide pain relief with fewer side effects compared to traditional opioids.