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Pain
Published in Michele Barletta, Jane Quandt, Rachel Reed, Equine Anesthesia and Pain Management, 2023
Jarred Williams, Katie Seabaugh, Molly Shepard, Dana Peroni
Transduction: Initiation of a nerve impulse. A noxious stimuli (chemical, electrical, mechanical, or thermal) occurs.Peripheral afferent nerve endings (nociceptors) detect the stimuli and convert (transduce) the signal to electrical energy.Types of nociceptors include mechanoreceptors, thermoreceptors, chemoreceptors, and visceral nociceptors (for visceral pain).
Assessment of fetal behavior
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Asim Kurjak, Milan Stanojevic, Badreldeen Ahmed, Guillermo Azumendi, Lara Spalldi-Barisic
The next study by this team showed the ability of 4D sonography to depict different facial expressions and grimacing (Fig. 16), which might represent fetal awareness (36). This was based on the consideration that “the face predicts the brain” because of the same embryologic origin for many facial and encephalic structures (37). Very early in pregnancy fetuses are reactive to stimuli, but the reaction does not provide any evidence that the fetus actually experienced the stimulus. It has been shown that noxious stimuli can initiate physiologic, hormonal, and metabolic responses, but these neither imply nor preclude suffering, pain, or awareness. Is it the facial expressions of the fetus that can help to understand what the fetus would like to communicate? We can see on the fetal face whether it is satisfied or unhappy, smiling or worried, self-confident or uncertain, but it is questionable whether the expression of the fetal face predicts its normal neurologic development. Whether the fetal face is an “organ that expresses awareness” with very complex functions is still questionable, because we need more scientific confirmation of what constitutes fetal awareness.
Pain Sensitization
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Many forms of pain arise from direct activation or sensitization of primary afferent neurons, especially C-fibre polymodal nociceptors. However, the process of nociceptor activation sets in train other processes that contribute to and modify responses to further stimuli. For example, a relatively benign noxious stimulus such as a scratch to the skin initiates an inflammatory process in the periphery, which then changes the response properties to subsequent sensory stimuli. Under normal conditions, thermal, mechanical and chemical stimuli activate high-threshold nociceptors, which signal this information to the first relay in the spinal cord. However, under clinical conditions, the application of a noxious stimulus is usually prolonged, traumatic and associated with tissue damage. Tissue damage results in inflammation, which directly affects the response of the nociceptor to further stimulation.
Antinociceptive activity of doliroside B
Published in Pharmaceutical Biology, 2023
Xishan Bai, Yanhong Li, Yuxiao Li, Min Li, Ming Luo, Kai Tian, Mengyuan Jiang, Yong Xiong, Ya Lu, Yukui Li, Haibo Yu, Xiangzhong Huang
Pain causes a negative consequence on health status and influences the quality of life (Williams and Craig 2016). As pain is a complex medical concern, multiple pathways involved in the process from the transduction of noxious stimuli to cognitive and emotional processing in the brain (Ossipov et al. 2014). To date, many drugs are used in clinic management of pain symptoms, such as non-steroidal anti-inflammatory drugs (NSAIDs), opioid drugs, and anti-depressive drugs. Among these drugs, opioid analgesics are the most effective pharmacological agents for moderate to severe pain. Unfortunately, their therapeutic benefit is often limited by analgesic tolerance and hyperalgesia (Benyamin et al. 2008). Unwanted side effects also occur very often. In this sense, natural products could serve as a better choice for pain management drug discovery.
Differentiating primary dry eye disease from ocular neuropathic pain: implications for symptom management
Published in Clinical and Experimental Optometry, 2023
Mark T Forristal, Kirk A J Stephenson
1. Nociceptive pain (pain in response to a noxious stimulus, such as heat, cold, mechanical force or chemical irritants), 2. Inflammatory pain (pain caused by activation of immune cells, such as macrophages, neutrophils, mast cells, and granulocytes in response to tissue injury or infection) and 3. Pathological pain (pain due to abnormal functioning of peripheral pain nerves leading to abnormal central processing).12 Pathological pain can be further divided into neuropathic pain and dysfunctional pain. Neuropathic pain is the abnormal function of the peripheral or central nervous system which occurs due to damage to the nervous system, while dysfunctional pain is the abnormal function of the nervous system which occurs in the absence of damage or inflammation (See Figure 1).13 DED can lead to nerve damage via sensitisation of nociceptors, leading to altered gene expression in ion channels of corneal nerve endings and trigeminal ganglion cells. This causes the formation of corneal neuromas leading to dysaesthesia and neuropathic pain.14 Ocular pain can therefore be simply classified as helpful (physiological) pain, which stimulates a response to physical insult, or pathological where pain results from sensitisation of nociceptors (Figure 1).
Pro-nociceptive pain modulation profile in patients with acute and chronic shoulder pain: a hypothesis-generating topical review
Published in Physical Therapy Reviews, 2021
Rani Othman, Nicola Swain, Steve Tumilty, Prasath Jayakaran, Ramakrishnan Mani
Pain experienced following the application of a noxious stimulus might differ significantly between individuals. The variability in the amount of pain experienced can be better explained by the efficiency of balance in the ascending and descending nociceptive facilitation and inhibition processes within the central nervous system. Ascending and descending nociceptive facilitatory and inhibitory systems function in concert, thus maintaining a baseline state of sensory processing [62, 102, 103]. When experiencing a significant nociceptive event, disruption of the balance of descending nociceptive to favour facilitation and/or enhance the activity of dorsal horn nociceptive neurons may promote and maintain pain [62, 104]. The imbalance between ascending and descending nociceptive facilitation and inhibition processes is termed the pro-nociception and anti-nociception [79].