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Ayoub LJ, Honigman L, Barnett AJ, McAndrews MP, Moayedi M. Mechanical pain sensitivity is associated with hippocampal structural integrity. Pain 2024; 165:2079-2086. [PMID: 39159941 PMCID: PMC11331818 DOI: 10.1097/j.pain.0000000000003221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 01/22/2024] [Accepted: 02/06/2024] [Indexed: 08/21/2024]
Abstract
ABSTRACT Rodents and human studies indicate that the hippocampus, a brain region necessary for memory processing, responds to noxious stimuli. However, the hippocampus has yet to be considered a key brain region directly involved in the human pain experience. One approach to answer this question is to perform quantitative sensory testing on patients with hippocampal damage-ie, medial temporal lobe epilepsy. Some case studies and case series have performed such tests in a handful of patients with various types of epilepsy and have reported mixed results. Here, we aimed to determine whether mechanical pain sensitivity was altered in patients diagnosed with temporal lobe epilepsy. We first investigated whether mechanical pain sensitivity in patients with temporal lobe epilepsy differs from that of healthy individuals. Next, in patients with temporal lobe epilepsy, we evaluated whether the degree of pain sensitivity is associated with the degree of hippocampal integrity. Structural integrity was based on hippocampal volume, and functional integrity was based on verbal and visuospatial memory scores. Our findings show that patients with temporal lobe epilepsy have lower mechanical pain sensitivity than healthy individuals. Only left hippocampal volume was positively associated with mechanical pain sensitivity-the greater the hippocampal damage, the lower the sensitivity to mechanical pain. Hippocampal measures of functional integrity were not significantly associated with mechanical pain sensitivity, suggesting that the mechanisms of hippocampal pain processing may be different than its memory functions. Future studies are necessary to determine the mechanisms of pain processing in the hippocampus.
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Affiliation(s)
- Lizbeth J. Ayoub
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
| | - Liat Honigman
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Alexander J. Barnett
- Department of Psychology, Faculty of Arts and Science, University of Toronto, Toronto, ON, Canada
| | - Mary Pat McAndrews
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- Department of Psychology, Faculty of Arts and Science, University of Toronto, Toronto, ON, Canada
| | - Massieh Moayedi
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
- Department of Dentistry, Mount Sinai Hospital, Toronto, ON, Canada
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Soleimanii A, Fallah F, Ghorbanzadeh B, Oroojan AA, Amirgholami N, Alboghobeish S. Simultaneous use of venlafaxine and calcium channel blockers on tolerance to morphine: The role of mitochondrial damage and oxidative stress in the brain. Pharmacol Biochem Behav 2024:173864. [PMID: 39216833 DOI: 10.1016/j.pbb.2024.173864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 08/20/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND One of the reasons for tolerance to morphine is increased oxidative stress and dysfunction of cell mitochondria in the hippocampus. Venlafaxine and calcium channel blockers can protect mitochondrial function. The investigation of the role of mitochondrial damage and oxidative stress in the simultaneous use of venlafaxine and calcium channel blockers on the acute analgesic effects of morphine and the induction of tolerance to its effects in mice was assessed. METHOD In this experimental study, to induce tolerance to morphine, NMRI mice were treated with 50 mg/kg morphine for three consecutive days and 5 mg/kg morphine on the fourth day. Venlafaxine (20 mg/kg) alone or in combination with calcium channel blockers, nimodipine (10 mg/kg), and diltiazem (40 mg/kg) was administered 30 min before morphine, and the hot plate test was used. Then, hippocampal mitochondria were isolated by differential centrifugation method, and the levels of mitochondrial dehydrogenase activity, mitochondrial membrane potential, mitochondrial ROS production rate, as well as the content of glutathione and malondialdehyde in hippocampal mitochondria, were measured. RESULTS The administration of venlafaxine-nimodipine and venlafaxine-diltiazem increased morphine's acute analgesic effects (P < 0.05) and reduced the induction and expression of tolerance to the analgesic effects of morphine (P < 0.05). Morphine significantly decreased MTT and GSH and increased MDA, mitochondrial membrane damage, and ROS compared to the control group (P < 0.01). Injection of venlafaxine-nimodipine and also venlafaxine-diltiazem 30 min before morphine can improve these alterations (P < 0.05). DISCUSSION AND CONCLUSION Our data showed that the simultaneous use of venlafaxine with calcium channel blockers could increase the acute analgesic effects of morphine and reduce the induction and expression of tolerance to it. Also, the preventive and protective roles of simultaneous administration of venlafaxine and calcium channel blockers on morphine-induced mitochondrial oxidative stress and damage during the tolerance test were achieved.
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Affiliation(s)
- Asma Soleimanii
- School of medicine, Student Research Committee, Dezful University of Medical Sciences, Dezful, Iran
| | - Faezeh Fallah
- School of medicine, Student Research Committee, Dezful University of Medical Sciences, Dezful, Iran
| | - Behnam Ghorbanzadeh
- Department of Pharmacology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
| | - Ali Akbar Oroojan
- Department of Physiology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
| | - Neda Amirgholami
- Department of Pharmacology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
| | - Soheila Alboghobeish
- Department of Pharmacology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran.
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Caliskan EB, Bingel U, Kunkel A. Translating knowledge on placebo and nocebo effects into clinical practice. Pain Rep 2024; 9:e1142. [PMID: 38533458 PMCID: PMC10965200 DOI: 10.1097/pr9.0000000000001142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 12/18/2023] [Indexed: 03/28/2024] Open
Abstract
Introduction Positive and negative treatment expectations are powerful modulators of health and treatment outcomes. A substantial part of treatment success is due to contextual factors modulating patient's expectations towards a treatment. Consequently, treatment expectations should be a target of therapeutic interventions themselves. Objectives This article highlights the neurobiological underpinnings of treatment expectations as well as strategies to modulate contextual factors to optimize treatment outcomes in daily clinical settings. Methods This clinical update aligns with the 2022 IASP Global Year Translating Pain Knowledge into Practice and selectively reviews the best available evidence and practice. Results The effects of treatment expectations, also known as placebo and nocebo effects, are observed in various clinical conditions and physiological systems. However, most of our knowledge comes from the field of pain, where expectation effects substantially contribute to overall analgesic treatment outcomes. Experimental placebo analgesia paradigms provide the best illustration of how analgesic effects can be attributed not only to a pharmacological or specific treatment, but instead are the result of the expectation towards the treatment. The impact of expectations on treatment outcome is highly variable between individuals, and the identification of factors predicting an individual's response has proven to be challenging. Further research is required to provide personalized treatment strategies for the daily clinical practice. Conclusion Patient's previous experiences and expectations are powerful modulators of treatment efficacy, tolerability, and adherence. By providing a comprehensive overview of recent advances in this field, this review offers valuable insights for clinicians and researchers seeking to improve patient-clinician interaction.
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Affiliation(s)
- Elif Buse Caliskan
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ulrike Bingel
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Angelika Kunkel
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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Zhang Y, Huang W, Shan Z, Zhou Y, Qiu T, Hu L, Yang L, Wang Y, Xiao Z. A new experimental rat model of nocebo-related nausea involving double mechanisms of observational learning and conditioning. CNS Neurosci Ther 2024; 30:e14389. [PMID: 37545429 PMCID: PMC10848046 DOI: 10.1111/cns.14389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/12/2023] [Accepted: 07/23/2023] [Indexed: 08/08/2023] Open
Abstract
AIM The nocebo effect, such as nausea and vomiting, is one of the major reasons patients discontinue therapy. The underlying mechanisms remain unknown due to a lack of reliable experimental models. The goal of this study was to develop a new animal model of nocebo-related nausea by combining observational learning and Pavlovian conditioning paradigms. METHODS Male Sprague-Dawley rats with nitroglycerin-induced migraine were given 0.9% saline (a placebo) or LiCl (a nausea inducer) following headache relief, according to different paradigms. RESULTS Both strategies provoked nocebo nausea responses, with the conditioning paradigm having a greater induction impact. The superposition of two mechanisms led to a further increase in nausea responses. A preliminary investigation of the underlying mechanism revealed clearly raised peripheral and central cholecystokinin (CCK) levels, as well as specific changes in the 5-hydroxytryptamine and cannabinoid systems. Brain networks related to emotion, cognition, and visceral sense expressed higher c-Fos-positive neurons, including the anterior cingulate cortex (ACC), insula, basolateral amygdala (BLA), thalamic paraventricular nucleus (PVT), hypothalamic paraventricular nucleus (PVN), nucleus tractus solitarius (NTS), periaqueductal gray (PAG), and dorsal raphe nucleus-dorsal part (DRD). We also found that nausea expectances in the model could last for at least 12 days. CONCLUSION The present study provides a useful experimental model of nocebo nausea that might be used to develop potential molecular pathways and therapeutic strategies for nocebo.
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Affiliation(s)
- Yu Zhang
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
- Central LaboratoryRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Wanbin Huang
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
- Central LaboratoryRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Zhengming Shan
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
- Central LaboratoryRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Yanjie Zhou
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
- Central LaboratoryRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Tao Qiu
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Luyu Hu
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Liu Yang
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Yue Wang
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Zheman Xiao
- Department of NeurologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
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Abstract
Adverse nocebo responses can cause harm to patients and interfere with treatment adherence and effects in both clinic practice and clinical trials. Nocebo responses refer to negative outcomes to active medical treatments in clinical trials or practice that cannot be explained by the treatment's pharmacologic effects. Negative expectancies and nocebo effects are less known than placebo responses. Nocebo effects can be triggered by verbal suggestions, prior negative experiences, observation of others experiencing negative outcomes, and other contextual and environmental factors. As research advances over the years, mechanistic knowledge is accumulating on the neurobiological mechanisms of nocebo effects. This review summarizes studies on different facets of nocebo effects and responses and discusses clinical implications, ethical considerations, and future directions.
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Affiliation(s)
- Luana Colloca
- Department of Pain and Translational Symptom Science and Placebo Beyond Opinions Center, School of Nursing, University of Maryland, Baltimore, Maryland, USA;
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Rossettini G, Campaci F, Bialosky J, Huysmans E, Vase L, Carlino E. The Biology of Placebo and Nocebo Effects on Experimental and Chronic Pain: State of the Art. J Clin Med 2023; 12:4113. [PMID: 37373806 DOI: 10.3390/jcm12124113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
(1) Background: In recent years, placebo and nocebo effects have been extensively documented in different medical conditions, including pain. The scientific literature has provided strong evidence of how the psychosocial context accompanying the treatment administration can influence the therapeutic outcome positively (placebo effects) or negatively (nocebo effects). (2) Methods: This state-of-the-art paper aims to provide an updated overview of placebo and nocebo effects on pain. (3) Results: The most common study designs, the psychological mechanisms, and neurobiological/genetic determinants of these phenomena are discussed, focusing on the differences between positive and negative context effects on pain in experimental settings on healthy volunteers and in clinical settings on chronic pain patients. Finally, the last section describes the implications for clinical and research practice to maximize the medical and scientific routine and correctly interpret the results of research studies on placebo and nocebo effects. (4) Conclusions: While studies on healthy participants seem consistent and provide a clear picture of how the brain reacts to the context, there are no unique results of the occurrence and magnitude of placebo and nocebo effects in chronic pain patients, mainly due to the heterogeneity of pain. This opens up the need for future studies on the topic.
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Affiliation(s)
| | - Francesco Campaci
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, 10124 Turin, Italy
| | - Joel Bialosky
- Department of Physical Therapy, University of Florida, Gainesville, FL 32611, USA
- Clinical Research Center, Brooks Rehabilitation, Jacksonville, FL 32211, USA
| | - Eva Huysmans
- Pain in Motion Research Group (PAIN), Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
- Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Lene Vase
- Department of Psychology and Behavioural Sciences, School of Business and Social Sciences, Aarhus University, 8000 Aarhus, Denmark
| | - Elisa Carlino
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, 10124 Turin, Italy
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Schaefer M, Kühnel A, Schweitzer F, Enge S, Gärtner M. Neural underpinnings of open-label placebo effects in emotional distress. Neuropsychopharmacology 2023; 48:560-566. [PMID: 36456814 PMCID: PMC9852452 DOI: 10.1038/s41386-022-01501-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/12/2022] [Accepted: 11/01/2022] [Indexed: 12/05/2022]
Abstract
While placebo effects are well-known, research in the last decade revealed intriguing effects that placebos may have beneficial effects even when given without deception. At first glance, this seems paradoxical, but several studies have reported improvements in pain, depression, or anxiety. However, it still remains unclear whether these results represent objective biological effects or simply a bias in response and what neural underpinnings are associated with the open-label placebo effects. In two studies, we address this gap by demonstrating that open-label placebos reduce self-reported emotional distress when viewing highly arousing negative pictures. This reduced emotional distress was associated with an activation of brain areas known to modulate affective states such as the periaqueductal gray, the bilateral anterior hippocampi, and the anterior cingulate cortex. We did not find any prefrontal brain activation. Furthermore, brain activation was not associated with expectation of effects. In contrast, we found that brain responses were linked to general belief in placebos. The results demonstrate that the neural mechanisms of open-label placebo effects are partly identical to the neurobiological underpinnings of conventional placebos, but our study also highlights important differences with respect to a missing engagement of prefrontal brain regions, suggesting that expectation of effects may play a less prominent role in open-label placebos.
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Affiliation(s)
| | - Anja Kühnel
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Felix Schweitzer
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Sören Enge
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Matti Gärtner
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
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Avoiding nocebo and other undesirable effects in chiropractic, osteopathy and physiotherapy: An invitation to reflect. Musculoskelet Sci Pract 2022; 62:102677. [PMID: 36368170 DOI: 10.1016/j.msksp.2022.102677] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/12/2022] [Accepted: 10/16/2022] [Indexed: 11/05/2022]
Abstract
INTRODUCTION While the placebo effect is increasingly recognised as a contributor to treatment effects in clinical practice, the nocebo and other undesirable effects are less well explored and likely underestimated. In the chiropractic, osteopathy and physiotherapy professions, some aspects of historical models of care may arguably increase the risk of nocebo effects. PURPOSE In this masterclass article, clinicians, researchers, and educators are invited to reflect on such possibilities, in an attempt to stimulate research and raise awareness for the mitigation of such undesirable effects. IMPLICATIONS This masterclass briefly introduces the nocebo effect and its underlying mechanisms. It then traces the historical development of chiropractic, osteopathy, and physiotherapy, arguing that there was and continues to be an excessive focus on the patient's body. Next, aspects of clinical practice, including communication, the therapeutic relationship, clinical rituals, and the wider social and economic context of practice are examined for their potential to generate nocebo and other undesirable effects. To aid reflection, a model to reflect on clinical practice and individual professions through the 'prism' of nocebo and other undesirable effects is introduced and illustrated. Finally, steps are proposed for how researchers, educators, and practitioners can maximise positive and minimise negative clinical context.
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Holzer P. Gut Signals and Gut Feelings: Science at the Interface of Data and Beliefs. Front Behav Neurosci 2022; 16:929332. [PMID: 35874652 PMCID: PMC9296981 DOI: 10.3389/fnbeh.2022.929332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/01/2022] [Indexed: 11/29/2022] Open
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