The Experience Of Acute Pain

999 WordsMay 14, 20174 Pages
Introduction The experience of acute pain is a primal way of understanding and responding to potentially hazardous environmental cues. The fundamental process underlying the conscious experience of pain is nociception (Boron and Boulpaep, 2017; Silverthorn and Johnson, 2016). This involves the transduction of chemical or physical stimuli into electrical signals which travel to the pain centres of the brain; namely the somatosensory cortex for perceiving the location and severity of pain, and the cingulate and insular cortex, which associate emotional unpleasantness to pain. Nociceptors are primary afferent sensory neurons located in peripheral tissues that can detect changes in their local environment. They are responsible for the initial…show more content…
Once threshold is reached an action potential is generated and propagated, causing the release of glutamate and substance P in the spinal cord and the activation of the ascending analgesic pathway (AAP) to the brain, which is ultimately responsible for the perception of pain. In response to the activation of the AAP, the endogenous inhibitory descending analgesic pathway (DAP) from the brain is activated. This system aims to reduce the noxious pain signals sent to the brain through nociception, releasing endogenous opioids such as endorphins to activate the µ-opioid receptors in the periaqueductal grey of the central nervous system (CNS) (Behbehani, Jiang, Chandler and Ennis, 1990). This leads to the release of noradrenaline, 5-HT and other opioids into the spinal cord, inhibiting peripheral nociceptors from releasing their excitatory neurotransmitters. Thus reducing the noxious pain signals received in the brain (Silverthorn and Johnson, 2016), causing analgesia. Many commonly available drugs have been designed to further enhance the activation of the DAP, namely Codeine and Paracetamol. It is widely accepted that Codeine is one of the most effective analgesics for treating pain, ranging from mild to severe (Ram, Eisenberg, Haddad and Pud, 2008; Australian Medicines Handbook, 2017). Codeine is a prodrug that gets converted by the body to morphine, an opioid which mimics the actions of
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