GasGasGas - The FRCA Primary Exam Podcast Gas Gas Gas - Morphine
Nov 22, 2024
Dive into the fascinating world of morphine as experts dissect its role in pain management. Learn about opiate receptors and how they work through G-protein mechanisms. Discover the various opioid agonists, from morphine to fentanyl, used in anesthesia. The discussion delves into morphine’s absorption, metabolism, and systemic side effects, including cardiovascular and respiratory impacts. Clinical cautions around dosage and renal clearance are also highlighted, making this a must-listen for anyone interested in pharmacology.
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The Discovery Of Morphine
- Friedrich Sertürner isolated morphine from opium in 1803 and named it after Morpheus.
- He tested morphine on himself during his experiments.
How Morphine Reduces Neuronal Excitability
- Morphine agonises G-protein coupled opioid receptors to hyperpolarize neurons and reduce excitability.
- It opens K+ channels, closes voltage-gated Ca2+ channels and inhibits adenylate cyclase to blunt pain transmission.
Dual CNS Sites Explain Analgesic Potency
- Opioids act presynaptically in the dorsal horn and in the periaqueductal grey to inhibit ascending pain and engage descending inhibition.
- These dual sites explain strong spinal and central analgesic effects of morphine.