Neurobiology of Acute and Chronic Pain

Author(s):  
Adrian Pichurko ◽  
Richard E. Harris

Pain is a complex phenomenon that may involve both peripheral and central neurobiological processes. Nociception is the unconscious registration of a noxious stimulus by the nervous system, while pain is a conscious experience. Neurobiological correlates of pain perception have been characterized from the initial point of tissue damage to its realization in the brain. Importantly, various pharmacological and psychological interventions exist that can target various points along this pathway. Evidence shows the nervous system remodels in response to chronic pain. More evidence-based treatments showing efficacy for chronic pain conditions are needed. Finally, an individualized and multidisciplinary approach in concordance with the biopsychosocial model of illness is often advocated. The neuroanaesthetist requires a nuanced understanding of pain, since many patients presenting for neurosurgical procedures suffer chronic pain.

Cephalalgia ◽  
2001 ◽  
Vol 21 (7) ◽  
pp. 765-769 ◽  
Author(s):  
TS Jensen

Within the last 2 decades there has been an explosion in new information on mechanisms underlying pain. Unfortunately this information has not resulted in a similar improvement of our handling of patients with chronic pain including chronic musculoskeletal pain. Neuronal hyperexcitability, which apparently is a key phenomenon in many (if not all) types of chronic pain results in changes in the nervous system from the level of the peripheral nociceptor to the highest cortical centers in the brain. The neuronal plastic changes in chronic pain conditions makes the nociceptive system amenable for treatment with several traditional as well as untraditional types of interventions. Two treatment areas that seem worth exploring within chronic pain including headache concerns preventive measures and endogenous pain modulation.


2021 ◽  
Author(s):  
Esther Benedetti ◽  
James Burnett ◽  
Meredith Degnan ◽  
Danielle Horne ◽  
Andres Missair ◽  
...  

The neuronal, chemical, and electrical transmission of pain is a complex and intricate subject that continues to be studied and expounded. This review discusses the relevant physiology and influential factors contributing to the experience and subjective variation in a variety of acute and chronic pain presentations. This review contains 4 figures, 4 tables, and 30 references Keywords: acute pain, chronic pain, somatic pain, neuropathic pain, visceral pain, nociception, pain perception, gender-related pain, cancer pain, spine pain


2021 ◽  
Vol 8 (29) ◽  
pp. 2639-2643
Author(s):  
Sruthy Unni ◽  
Ranju Sebastian ◽  
Elizabeth Joseph ◽  
Remani Kelan Kamalakshi ◽  
Jamsheena Muthira Parambath

BACKGROUND Anaesthesia for neurosurgery requires special considerations. The brain is enclosed in a rigid cranium, so the rise in intracranial pressure (ICP) which impairs cerebral perfusion pressure (CPP), results in irrepairable damage to various vital areas in the brain. Stable head position is required in long neurosurgical procedures. This is obtained with the use of clamps which fix the head rigidly. This is done usually under general anaesthesia because it produces intense painful stimuli leading to stimulation of sympathetic nervous system which in turn causes release of vasoconstrictive agents. This can impair perfusion in all organ systems. The increase in blood pressure due to sympathetic nervous system causes increase in blood flow. This causes increases in intracranial pressure which result in reduction in cerebral perfusion pressure once the auto regulatory limits are exceeded. We compared the effects of dexmedetomidine 1 µgm/kg and propofol 100 µgm/kg given as infusion over a period of 10 minutes before the induction of anaesthesia and continued till 5 minutes after pinning to attenuate the stress response while cranial pinning. In this study, we wanted to compare the effects of dexmedetomidine and propofol as infusion to attenuate the stress response while cranial pinning in patients undergoing neurosurgical procedures. METHODS This is a randomized interventional trial. Patients were divided into 2 groups of 20 each. Group 1 receiving dexmedetomidine and group 2 receiving propofol, both drugs given as infusion. Haemodynamic variables were monitored before and after cranial pinning. Data was analysed using IBM statistical package for social sciences (SPSS) statistics. The parameters recorded were analysed with the help of a statistician. RESULTS The two groups were comparable in demographic data. Incidence of tachycardia between group 1 and 2 showed that tachycardia to pinning was better controlled with propofol than dexmedetomidine (P < 0.05) which is statistically significant. There is no statistically significant difference in blood pressure values between group 1 and 2 after pinning. CONCLUSIONS From our study, we came to a conclusion that propofol was superior to dexmedetomidine in attenuating the heart rate response to cranial pinning. The effect of propofol and dexmedetomidine was comparable in attenuating the blood pressure response to cranial pinning. KEYWORDS Cranial Pinning, Dexmedetomidine, Propofol


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Myeounghoon Cha ◽  
Songyeon Choi ◽  
Kyeongmin Kim ◽  
Bae Hwan Lee

AbstractNeuropathic pain induced by a nerve injury can lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in chronic pain models are difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed cerebrocortical excitability changes and compared regional Mn2+ enhancement after mTOR inhibition. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1, and XL388) effects were compared within groups using MEMRI. Therein, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region, motor cortex 1/2, and anterior cingulate cortex regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, rostral-caudal analysis of the IC indicated that the rostral region of the IC was more strongly associated with pain perception than the caudal region. Our data suggest that MEMRI can depict pain-related signal changes in the brain and that mTOR inhibition is closely correlated with pain modulation in chronic pain rats.


2022 ◽  
Vol 12 ◽  
Author(s):  
Zhengwu Zhang ◽  
Jennifer S. Gewandter ◽  
Paul Geha

The prevalence of chronic pain has reached epidemic levels. In addition to personal suffering chronic pain is associated with psychiatric and medical co-morbidities, notably substance misuse, and a huge a societal cost amounting to hundreds of billions of dollars annually in medical cost, lost wages, and productivity. Chronic pain does not have a cure or quantitative diagnostic or prognostic tools. In this manuscript we provide evidence that this situation is about to change. We first start by summarizing our current understanding of the role of the brain in the pathogenesis of chronic pain. We particularly focus on the concept of learning in the emergence of chronic pain, and the implication of the limbic brain circuitry and dopaminergic signaling, which underly emotional learning and decision making, in this process. Next, we summarize data from our labs and from other groups on the latest brain imaging findings in different chronic pain conditions focusing on results with significant potential for translation into clinical applications. The gaps in the study of chronic pain and brain imaging are highlighted in throughout the overview. Finally, we conclude by discussing the costs and benefits of using brain biomarkers of chronic pain and compare to other potential markers.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Timothy R. Deer ◽  
Ramana Naidu ◽  
Natalie Strand ◽  
Dawn Sparks ◽  
Alaa Abd-Elsayed ◽  
...  

2020 ◽  
Author(s):  
Myeounghoon Cha ◽  
Songyeon Choi ◽  
Kyeongmin Kim ◽  
Bae Hwan Lee

Abstract Neuropathic pain induced by a nerve injury can lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in chronic pain models are difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed cerebrocortical excitability changes and compared regional Mn 2+ enhancement after mTOR inhibition. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1, and XL388) effects were compared within groups using MEMRI. Therein, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region, motor cortex 1/2, and anterior cingulate cortex regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, rostral-caudal analysis of the IC indicated that the rostral region of the IC was more strongly associated with pain perception than the caudal region. Our data suggest that MEMRI can depict pain-related signal changes in the brain and that mTOR inhibition is closely correlated with pain modulation in chronic pain rats.


2020 ◽  
Author(s):  
Myeounghoon Cha ◽  
Songyeon Choi ◽  
Kyeongmin Kim ◽  
Bae Hwan Lee

Abstract Neuropathic pain induced by a nerve injury could lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in the chronic pain model were difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed the cerebrocortical excitability changes and compared the regional Mn 2+ enhancement after mTOR inhibitions. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1 and XL388) effects were compared within groups using MEMRI. In the results, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region (S1HL), motor cortex 1/2 (M1/2), and anterior cingulate cortex (ACC) regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, the rostral-caudal analysis of the IC indicated that the rostral region of the IC was more associated with pain perception than caudal region. Our data suggest that MEMRI could present the pain-related signal changes in the brain, and mTOR inhibition is closely correlated with pain modulation in chronic pain rats.


2021 ◽  
Vol 14 (1) ◽  
pp. 106-113
Author(s):  
Zakir Uddin ◽  
Joy C. MacDermid ◽  
Fatma A. Hegazy ◽  
Tara L. Packham

Introduction: Chronic pain has multiple aetiological factors and complexity. Pain theory helps us to guide and organize our thinking to deal with this complexity. The objective of this paper is to critically review the most influential theory in pain science history (the gate control theory of pain) and focus on its implications in chronic pain rehabilitation to minimize disability. Methods: In this narrative review, all the published studies that focused upon pain theory were retrieved from Ovoid Medline (from 1946 till present), EMBAS, AMED and PsycINFO data bases. Results: Chronic pain is considered a disease or dysfunction of the nervous system. In chronic pain conditions, hypersensitivity is thought to develop from changes to the physiological top-down control (inhibitory) mechanism of pain modulation according to the pain theory. Pain hypersensitivity manifestation is considered as abnormal central inhibitory control at the gate controlling mechanism. On the other hand, pain hypersensitivity is a prognostic factor in pain rehabilitation. It is clinically important to detect and manage hypersensitivity responses and their mechanisms. Conclusion: Since somatosensory perception and integration are recognized as a contributor to the pain perception under the theory, then we can use the model to direct interventions aimed at pain relief. The pain theory should be leveraged to develop and refine measurement tools with clinical utility for detecting and monitoring hypersensitivity linked to chronic pain mechanisms.


2018 ◽  
Vol 18 (4) ◽  
pp. 711-717 ◽  
Author(s):  
Raphaëlle Chrétien ◽  
Sarah Lavoie ◽  
Philippe Chalaye ◽  
Emmanuelle de Vette ◽  
François-Pierre Counil ◽  
...  

Abstract Background and aims Chronic pain is affecting a growing number of individuals including adolescents. Different endogenous pain inhibitory systems could confer protection against development of chronic pain. Decreased pain perception can be observed following intense pain (i.e. conditioned pain modulation – CPM) or after physical exercise (i.e. exercise-induced analgesia – EIA). Reduced effectiveness of pain inhibitory mechanisms have been reported in several chronic pain conditions. However, the extent of these dysfunctions has not been thoroughly investigated in adolescents suffering from chronic pain. Our hypothesis was that adolescents suffering from chronic pain have less effective CPM and EIA than pain-free teenagers. Methods Twenty-five healthy adolescent girls and 16 teenage girls with chronic pain participated in this study. Only girls were included in this investigation, since chronic pain is more prevalent in females. The effectiveness of CPM was assessed by comparing heat pain stimulations (individually adapted to induce mild pain intensity) performed with a thermode before and after a cold pressor test (CPT; 2 min, 10 °C). EIA was evaluated by comparing pain intensity produced by an ice cube placed on the forearm before and after a graded exercise test on a cycle ergometer. Results Pain intensity produced by heat pain stimulations decreased following CPT in healthy (p<0.05), but not in chronic pain adolescent girls (p=0.4). Pain intensity induced by the ice cube was reduced after exercise in healthy (p<0.05), but not in chronic pain adolescents (p=0.9). The effectiveness of CPM and EIA was inferior in teenage girls suffering from chronic pain compared to healthy participants (p<0.05). Conclusions Endogenous pain inhibitory mechanisms triggered by intense pain or by physical exercise are effective in healthy adolescent girls. Teenage girls living with chronic pain do not show diminished pain perception after a CPT or a graded exercise test. These results suggest that pain inhibitory mechanisms such as CPM and EIA are ineffective in adolescent girls suffering from chronic pain. Implications In a wider context, the findings of the present research could help understand better the mechanisms involved in the development of chronic pain. Improved comprehension of this subject might help prevent chronic pain conditions and thus, reduce the negative impacts of this burden.


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