Opioids are a class of drugs that act on the nervous system to relieve pain. They include both natural and synthetic substances, and work by binding to opioid receptors in the brain and spinal cord. Opioids can be taken orally, injected, or inhaled.
Common opioids include morphine, codeine, oxycodone, hydrocodone, and fentanyl. These drugs are typically prescribed for moderate to severe pain relief. However, they can also be used recreationally for their euphoric effects. Opioids carry a high risk for addiction and overdose; in 2017 alone, over 47,000 people died from an opioid overdose in the United States.
There are several different types of opioid receptors, which are classified according to their structure and location in the body. The three major types are mu (µ), kappa (κ), and delta (δ) receptors. Mu receptors are found mainly in the central nervous system (CNS), while kappa and delta receptors are found primarily in the periphery. Each type of receptor has a different affinity for different opioids; for example, mu receptors have a higher affinity for morphine than for other opioids.
The activation of opioid receptors leads to inhibition of neurotransmitter release from neurons. This results in decreased excitability of neurons and reduced pain signalling from the periphery to the CNS. In addition, opioids produce feelings of pleasure by activating reward pathways in the brain; this is one reason why they are often abused recreationally despite their risks.
Opioid addiction is a serious problem with potentially devastating consequences. Individuals who develop an addiction may suffer from financial ruin, job loss, relationship problems, legal troubles, mental health issues such as depression or anxiety disorders – all while struggling with intense cravings and withdrawal symptoms if they attempt to quit without professional help . If you or someone you know is struggling with an opioid addiction , please seek help from a qualified healthcare provider or treatment center as soon as possible .