Effects of Morphine

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Morphine is an opioid that attacks the opioid receptors at the spinal cord, medulla oblongata, the spinal trigeminal nucleus and the grey region. The receptors, which are of µ, α, β types, enhance the interaction of the drug and eventual effects in the human body. Of these receptor types, the µ is the most important for analgesia effects to be realized. There are two µ subtypes: the µ1 and the µ2 (Stoelting 1999). The µ1 subtype is involved in analgesia more than the µ2 since, the second subtype, which is involved more in the respiratory depression. In addition, the µ2 subtype is also involved in mediating bradycardia and physical dependence (Hasslesstrom & Sawe 2001). The presence of Morphine makes the G-protein active and this is important for it to bind to the receptor. Upon being activated, the G protein alters the permeability at the neural receptors (Chay, Duff, & Walker 2002). When the permeability is affected, neuronal activity is altered through hyperpolarization of the membrane. When neuronal activities stop, analgesia is initiated (Dolin 2000). The opiate receptors at the Central Nervous System are the main areas where morphine attacks. At the brainstem centers, morphine directly affects the respiratory activities, causing respiratory depression that eventually leads to analgesia (Bhandari, Bergqvist, & Kronsberg 2005). Respiratory depression involves reducing the receptiveness of the respiratory centers, and this inhibits reaction to carbon dioxide increase and electrical stimulation (National Center for Biotechnology Information 2011). Other than analgesia, morphine also affects the cough center, causing depression in the cough reflex. The cough center is at the medulla and morphine penetrates and causes the depr... ... middle of paper ... ...amedic.com/paramedic-analgesia> Hasslesstrom, J & Sawe, J 2001, ‘Morphine pharmacokinetics and metabolism in humans. Enterohepatic cycling and relative contribution of metabolites to active opioid concentrations’, Clinical Pharmacokinetics, vol. 40, pp. 344-354. Health Grades 2011, Morphine, viewed 9 August 2011, Meldrum, ML 2003, ‘A capsule history of pain management’, JAMA, vol. 290, pp. 2470-2475 National Center for Biotechnology Information 2011, Morphine dependence, National Center for Biotechnology Information, Bethesda, MD. Stoelting, RK & Miller, RD 2000, Intravenous anesthetics, in basics of anesthesia, Churchill-Livingstone, Oxford, UK. Stoelting, RK 1999, ‘Pharmacokinetics and Pharmacodynamics of Injected and Inhaled Drugs’, Pharmacology and Physiology in Anesthetic Practice, vol. 3, pp. 1-17.

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