CB1, or cannabinoid receptor type 1, is a protein found primarily in the brain and central nervous system. It plays a crucial role in the endocannabinoid system, which helps regulate various physiological processes, including mood, appetite, and pain sensation. CB1 receptors interact with naturally occurring compounds in the body, known as endocannabinoids, as well as with cannabinoids found in the cannabis plant. When activated, CB1 receptors can influence neurotransmitter release, affecting communication between nerve cells. This interaction is why cannabinoids, such as THC (tetrahydrocannabinol), can produce psychoactive effects, altering perception and mood. Understanding CB1 is essential for exploring potential therapeutic applications of cannabinoids in medicine.