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Current Molecular Pharmacology 2021Pain is often flammable, sharp and sometimes described as an electrical shock. It can be categorized in three different ways as nociceptive, neuropathic and... (Review)
Review
BACKGROUND
Pain is often flammable, sharp and sometimes described as an electrical shock. It can be categorized in three different ways as nociceptive, neuropathic and inflammatory. Nociceptive pain always originates in specific situations such as in trauma. Neuropathic pain results in nerve damage. In inflammatory pain, inflammatory mediators are involved in the sensitization of nociceptors. It is important to control the pain as it affects the individual physically, mentally, and socially.
OBJECTIVE
Recognizing pain physiopathology and pain pathways, defining the relationship between receptor and transmitter is critical in developing new treatment strategies. In this review, current information on the definitions, classifications, and physiological and chemical mechanisms involved in pain are reviewed.
METHODS
Various search engines were used to gather related articles/information. Only peer-reviewed journals were considered. Additional, books/chapters of standard publishers were also included in the article.
RESULTS
With a better understanding of the physiological and chemical mechanisms that play a role in pain, significant improvements have been made in pain treatment. Various oral or intravenous drugs, local injection treatments, physical and occupational therapy, electrical stimulation, alternative medicine applications, psychological support, and surgical applications are routinely performed in the treatment, dependent upon the type, severity and cause of the pain.
CONCLUSION
Improved understanding of pain physiopathology will serve as the basis for future improvements in the delivery of efficacious and reliable treatments, and is likely to rely on novel technological innovations.
Topics: Humans; Nociceptors; Pain; Pain Perception
PubMed: 32525788
DOI: 10.2174/1874467213666200611142438 -
Neuroscience and Biobehavioral Reviews Nov 2021Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause... (Review)
Review
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause of human suffering worldwide, because effective, specific and safe therapies have yet to be developed. It is unevenly distributed among sexes, with women experiencing more pain and suffering. Chronic pain can be anatomically and phenomenologically dissected into three separable but interacting pathways, a lateral 'painfulness' pathway, a medial 'suffering' pathway and a descending pain inhibitory pathway. One may have pain(fullness) without suffering and suffering without pain(fullness). Pain sensation leads to suffering via a cognitive, emotional and autonomic processing, and is expressed as anger, fear, frustration, anxiety and depression. The medial pathway overlaps with the salience and stress networks, explaining that behavioural relevance or meaning determines the suffering associated with painfulness. Genetic and epigenetic influences trigger chronic neuroinflammatory changes which are involved in transitioning from acute to chronic pain. Based on the concept of the Bayesian brain, pain (and suffering) can be regarded as the consequence of an imbalance between the two ascending and the descending pain inhibitory pathways under control of the reward system. The therapeutic clinical implications of this simple pain model are obvious. After categorizing the working mechanisms of each of the available treatments (pain killers, psychopharmacology, psychotherapy, neuromodulation, psychosurgery, spinal cord stimulation) to 1 or more of the 3 pathways, a rational combination can be proposed of activating the descending pain inhibitory pathway in combination with inhibition of the medial and lateral pathway, so as to rebalance the pain (and suffering) pathways.
Topics: Anxiety; Bayes Theorem; Brain; Chronic Pain; Female; Humans; Pain Perception
PubMed: 34411559
DOI: 10.1016/j.neubiorev.2021.08.013 -
The Journal of Pain Nov 2019Exercise is considered an important component of effective chronic pain management and it is well-established that long-term exercise training provides pain relief. In... (Review)
Review
Exercise is considered an important component of effective chronic pain management and it is well-established that long-term exercise training provides pain relief. In healthy, pain-free populations, a single bout of aerobic or resistance exercise typically leads to exercise-induced hypoalgesia (EIH), a generalized reduction in pain and pain sensitivity that occurs during exercise and for some time afterward. In contrast, EIH is more variable in chronic pain populations and is more frequently impaired; with pain and pain sensitivity decreasing, remaining unchanged or, in some cases, even increasing in response to exercise. Pain exacerbation with exercise may be a major barrier to adherence, precipitating a cycle of physical inactivity that can lead to long-term worsening of both pain and disability. To optimize the therapeutic benefits of exercise, it is important to understand how EIH works, why it may be impaired in some people with chronic pain, and how this should be addressed in clinical practice. In this article, we provide an overview of EIH across different chronic pain conditions. We discuss possible biological mechanisms of EIH and the potential influence of sex and psychosocial factors, both in pain-free adults and, where possible, in individuals with chronic pain. The clinical implications of impaired EIH are discussed and recommendations are made for future research, including further exploration of individual differences in EIH, the relationship between exercise dose and EIH, the efficacy of combined treatments and the use of alternative measures to quantify EIH. PERSPECTIVE: This article provides a contemporary review of the acute effects of exercise on pain and pain sensitivity, including in people with chronic pain conditions. Existing findings are critically reviewed, clinical implications are discussed, and recommendations are offered for future research.
Topics: Chronic Pain; Exercise; Humans; Hyperalgesia; Hypesthesia; Pain Perception; Pain Threshold
PubMed: 30904519
DOI: 10.1016/j.jpain.2019.03.005 -
Best Practice & Research. Clinical... Sep 2019Opioid-free anesthesia (OFA) is emerging as a new stimulating research perspective. The rationale to propose OFA is based on the aim to avoid the negative impact of... (Review)
Review
Opioid-free anesthesia (OFA) is emerging as a new stimulating research perspective. The rationale to propose OFA is based on the aim to avoid the negative impact of intraoperative opioid on a patient's postoperative outcomes and also on the physiology of pathways involved in intraoperative nociception. It is based on the concept of multimodal anesthesia. OFA has been shown to be feasible but the literature is still scarce on the clinically meaningful benefits for patients as well as on the side effects and/or complications that might be associated with it. This review focused first on the physiology of nociception, the reasons for using or not using opioids during anesthesia, and then on the literature reporting evidence-based proofs of benefits/risks associated with OFA.
Topics: Analgesics, Opioid; Anesthesia; Humans; Nociception; Pain, Postoperative
PubMed: 31785720
DOI: 10.1016/j.bpa.2019.09.002 -
Archivos Argentinos de Pediatria Oct 2019The recognition of the existence of pain in infants hospitalized in the Neonatal Intensive Care Units makes it necessary to reach consensus on prevention, assessment and...
The recognition of the existence of pain in infants hospitalized in the Neonatal Intensive Care Units makes it necessary to reach consensus on prevention, assessment and treatment strategies. Acute pain produces adverse changes in the short term and chronic pain alters the response systems to stress and impacts on neurodevelopment. The objective of this pain management agreement is to unify criteria of attention of these patients in different situations that generate pain and stress that they face during their hospitalization. There are validated scales to assess pain and guide appropriate strategies for its approach that include measures of comprehensive or nonpharmacological care and pharmacological care that we will review.
Topics: Acute Pain; Chronic Pain; Humans; Infant, Newborn; Intensive Care Units, Neonatal; Neonatology; Pain Management; Pain Measurement; Pain Perception
PubMed: 31833337
DOI: 10.5546/aap.2019.S180 -
Science (New York, N.Y.) Jul 2022Sound-including music and noise-can relieve pain in humans, but the underlying neural mechanisms remain unknown. We discovered that analgesic effects of sound depended...
Sound-including music and noise-can relieve pain in humans, but the underlying neural mechanisms remain unknown. We discovered that analgesic effects of sound depended on a low (5-decibel) signal-to-noise ratio (SNR) relative to ambient noise in mice. Viral tracing, microendoscopic calcium imaging, and multitetrode recordings in freely moving mice showed that low-SNR sounds inhibited glutamatergic inputs from the auditory cortex (ACx) to the thalamic posterior (PO) and ventral posterior (VP) nuclei. Optogenetic or chemogenetic inhibition of the ACx→PO and ACx→VP circuits mimicked the low-SNR sound-induced analgesia in inflamed hindpaws and forepaws, respectively. Artificial activation of these two circuits abolished the sound-induced analgesia. Our study reveals the corticothalamic circuits underlying sound-promoted analgesia by deciphering the role of the auditory system in pain processing.
Topics: Acoustic Stimulation; Animals; Audioanalgesia; Auditory Cortex; Mice; Music Therapy; Pain; Pain Management; Pain Perception; Sound; Thalamus
PubMed: 35857536
DOI: 10.1126/science.abn4663 -
Anesthesiology Oct 2023Chronic pain is a public health concern that affects approximately 1.5 billion people globally. Conventional therapeutic agents including opioid and non-opioid... (Review)
Review
Chronic pain is a public health concern that affects approximately 1.5 billion people globally. Conventional therapeutic agents including opioid and non-opioid analgesics have been associated with adverse side effects, issues with addiction, and ineffective analgesia. Novel agents repurposed to treat pain via different mechanisms are needed to fill the therapeutic gap in chronic pain management. Psychedelics such as lysergic acid diethylamide and psilocybin (the active ingredient in psychedelic mushrooms) are thought to alter pain perception through direct serotonin receptor agonism, anti-inflammatory effects, and synaptic remodeling. This scoping review was conducted to identify human studies in which psychedelic agents were used for the treatment of pain. Twenty-one articles that assessed the effects of psychedelics in treating various pain states were included. The present scarcity of clinical trials and small sample sizes limit their application for clinical use. Overall, psychedelics appear to show promise for analgesia in patients with certain headache disorders and cancer pain diagnoses. Future studies must aim to examine the combined effects of psychotherapy and psychedelics on chronic pain.
Topics: Humans; Hallucinogens; Chronic Pain; Pain Management; Pain Perception; Analgesia; Drug-Related Side Effects and Adverse Reactions
PubMed: 37698433
DOI: 10.1097/ALN.0000000000004673 -
Nature Neuroscience May 2023A painful episode can lead to a life-long increase in an individual's experience of pain. Fearful anticipation of imminent pain could play a role in this phenomenon, but...
A painful episode can lead to a life-long increase in an individual's experience of pain. Fearful anticipation of imminent pain could play a role in this phenomenon, but the neurobiological underpinnings are unclear because fear can both suppress and enhance pain. Here, we show in mice that long-term associative fear memory stored in neuronal engrams in the prefrontal cortex determines whether a painful episode shapes pain experience later in life. Furthermore, under conditions of inflammatory and neuropathic pain, prefrontal fear engrams expand to encompass neurons representing nociception and tactile sensation, leading to pronounced changes in prefrontal connectivity to fear-relevant brain areas. Conversely, silencing prefrontal fear engrams reverses chronically established hyperalgesia and allodynia. These results reveal that a discrete subset of prefrontal cortex neurons can account for the debilitating comorbidity of fear and chronic pain and show that attenuating the fear memory of pain can alleviate chronic pain itself.
Topics: Mice; Animals; Chronic Pain; Memory, Long-Term; Fear; Brain; Prefrontal Cortex; Hyperalgesia; Pain Perception
PubMed: 37024573
DOI: 10.1038/s41593-023-01291-x -
Brazilian Journal of Physical Therapy 2023
Topics: Humans; Nociception; Neuralgia; Chronic Pain
PubMed: 37639943
DOI: 10.1016/j.bjpt.2023.100537 -
Neuropharmacology Aug 2020The opioid epidemic has led to a serious examination of the use of opioids for the treatment of pain. Opioid drugs are effective due to the expression of opioid... (Review)
Review
The opioid epidemic has led to a serious examination of the use of opioids for the treatment of pain. Opioid drugs are effective due to the expression of opioid receptors throughout the body. These receptors respond to endogenous opioid peptides that are expressed as polypeptide hormones that are processed by proteolytic cleavage. Endogenous opioids are expressed throughout the peripheral and central nervous system and regulate many different neuronal circuits and functions. One of the key functions of endogenous opioid peptides is to modulate our responses to pain. This review will focus on the descending pain modulatory circuit which consists of the ventrolateral periaqueductal gray (PAG) projections to the rostral ventromedial medulla (RVM). RVM projections modulate incoming nociceptive afferents at the level of the spinal cord. Stimulation within either the PAG or RVM results in analgesia and this circuit has been studied in detail in terms of the actions of exogenous opioids, such as morphine and fentanyl. Further emphasis on understanding the complex regulation of endogenous opioids will help to make rational decisions with regard to the use of opioids for pain. We also include a discussion of the actions of endogenous opioids in the amygdala, an upstream brain structure that has reciprocal connections to the PAG that contribute to the brain's response to pain.
Topics: Amygdala; Animals; Humans; Opioid Peptides; Pain; Pain Management; Pain Perception; Periaqueductal Gray; Receptors, Opioid
PubMed: 32422213
DOI: 10.1016/j.neuropharm.2020.108131