How Opioids Affect the Brain
Opioids work by binding to specific molecules called opioid receptors, which are found on cells in the brain, spinal cord, gut, and other parts of the body. These receptors are part of the body’s endogenous opioid system, which controls pain, reward, and addictive behaviors. When opioids attach to these receptors, they block pain signals sent from the body through the spinal cord to the brain. This is how they effectively reduce the sensation of pain.
Beyond their pain-relieving effects, opioids also affect the brain’s reward system. When opioids bind to receptors in the limbic system, which controls emotions, they can induce feelings of pleasure and euphoria. This rewarding sensation can lead to increased opioid use and, over time, addiction.
The repeated use of opioids can lead to changes in the brain’s structure and function, specifically in areas critical to judgment, decision making, behavior control, and response to stress. Chronic opioid use can result in tolerance, where higher doses of the drug are needed to achieve the same effect, and dependence, where the body adapts to the drug’s presence and experiences withdrawal symptoms without it. Addiction, or opioid use disorder, is characterized by the compulsive use of opioids despite harmful consequences, changes in the brain’s reward system, and behavior patterns focused on drug seeking and use.
Understanding how opioids work in the brain is crucial for developing effective treatments for pain, as well as for preventing and treating opioid addiction.