CB1 receptors are a type of protein found primarily in the brain and central nervous system. They are part of the endocannabinoid system, which helps regulate various physiological processes, including mood, appetite, and pain sensation. These receptors interact with naturally occurring compounds in the body, known as endocannabinoids, as well as with cannabinoids found in cannabis. When CB1 receptors are activated, they can influence neurotransmitter release, affecting communication between nerve cells. This interaction plays a crucial role in the effects of cannabis, such as euphoria or relaxation, and is also being studied for potential therapeutic applications in conditions like chronic pain and anxiety.