Longnecker's Anesthesiology > Part 4. Managing Anesthesia Care > Section C. Anesthesia Drugs and Drug Delivery Systems > Chapter 41. Pharmacology of Opioid Analgesics Carl Rosow, MD, PhD, and Mark Dershwitz, MD, PhD

Key Points

"1. An opioid is any natural or synthetic compound that has effects similar to those of morphine or that acts as an antagonist at the same receptors to which morphine binds.

2. Because opioid agonists relieve pain, they are classified as analgesics. In contrast to the local anesthetics (which interrupt the transmission of all nerve impulses, including pain), and the antiinflammatory analgesics such as aspirin (which decrease some of the pathologic processes leading to pain), the opioid analgesics act primarily to alter the perception of pain as a noxious entity.

3. The "classical" pharmacologic effects of morphine, like analgesia and ventilatory depression, are mediated by receptors. The receptor shares a number of effects with the receptor, including analgesia, sedation, and ventilatory depression. The receptor is responsible for mediating some of the analgesic effects of the endogenous opioid peptides, especially in the spinal cord.

4. All opioid receptors are G-protein-coupled receptors. The actions of both and agonists result in overall neuronal depression, and they share several signal transduction..."