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Edwards SA, Martin SL, Rainey T, Whitaker G, Greenwood DC, Jones A, Sivan M. Influence of acute fasting on pain tolerance in healthy subjects: a randomised crossover study. FRONTIERS IN PAIN RESEARCH 2023; 4:1153107. [PMID: 37753146 PMCID: PMC10518402 DOI: 10.3389/fpain.2023.1153107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 08/28/2023] [Indexed: 09/28/2023] Open
Abstract
Background Although chronic pain and obesity are global health crises with substantial healthcare costs, little is known about the relationship between pain perception and eating behaviours. Food consumption has been reported to provide an analgesic effect by the release of neurotransmitters modulating the pain network. However, whether short-term (acute) fasting affects pain perception remains unclear. Purpose This study aimed to investigate the effect of acute fasting on pain perception and whether attention and mood changes drove the observed changes. Patients and methods The cold pressor test (CPT) was used to investigate the pain tolerance of 25 healthy participants in both non-fasting and 12-h fasting sessions. They were randomised to either session with a crossover to the other after at least 24 h, with the experimenter blinded to the sessions. The pain tolerance was measured using a Stroop task in both attentive and distracted states. The Profile of Mood States (POMS) questionnaire was used to capture the mood, and a 10-point hunger scale was used to measure hunger. Mixed-effects models were used to investigate the influence of fasting and distraction on pain perception, accounting for the repeated measures. Results Fasting reduced CPT pain tolerance, with fasting participants twice as likely to withdraw their hands early (hazard ratio = 2.4, 95% CI: 1.3-4.5). Though men tolerated CPT pain longer than women, there was no evidence that men responded to fasting differently than women (p = 0.9). In addition, no evidence supporting that fasting affected attention or mood was found. Nonetheless, it increased hunger scores by 2.7 points on a 10-point scale (95% CI: 1.2-4.2) and decreased blood glucose concentration levels by 0.51 mmol/L (95% CI: 0.19-0.84). Conclusion Acute fasting reduces pain tolerance in the healthy participants, and this effect is independent of gender and attention or mood changes.
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Affiliation(s)
- Sophie A. Edwards
- The Human Pain Research Group, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
| | - Sarah L. Martin
- The Human Pain Research Group, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Timothy Rainey
- The Human Pain Research Group, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
| | - Grace Whitaker
- Centro de Investigación y Desarrollo en Ingeniería en Salud, Universidad de Valparaiso, Valparaiso, Chile
| | - Darren C. Greenwood
- Leeds Institute for Data Analytics, University of Leeds, Leeds, United Kingdom
| | - Anthony Jones
- The Human Pain Research Group, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
| | - Manoj Sivan
- The Human Pain Research Group, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Leeds Institute of Rheumatology and Musculoskeletal Medicine, University of Leeds, Leeds, United Kingdom
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Durgin CJ, Huhn AS, Bergeria CL, Finan PH, Campbell CM, Antoine DG, Dunn KE. Within subject, double blind, examination of opioid sensitivity in participant-reported, observed, physiologic, and analgesic outcomes. DRUG AND ALCOHOL DEPENDENCE REPORTS 2023; 8:100188. [PMID: 37731966 PMCID: PMC10507188 DOI: 10.1016/j.dadr.2023.100188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/22/2023] [Accepted: 08/29/2023] [Indexed: 09/22/2023]
Abstract
Background Inter-individual differences in opioid sensitivity may underlie different opioid risk profiles but have often been researched in persons who have current or past opioid use disorder or physical dependence. This study examined how opioid sensitivity manifests across various assessments of opioid effects in a primarily opioid-naïve population. Procedures Data were harmonized from two within-subject, double-blind trials wherein healthy participants (N = 123) received placebo and 4 mg oral hydromorphone. Demographics, self-report ratings, observer ratings, physiological, and cold pressor measures were collected. Participants were categorized as being responsive or nonresponsive to the opioid dose tested and compared using mixed-models, Pearson product correlations, and paired t-tests. Findings Participants were 49.6% female, mean 33.0 (SD=9.3) years old, and 44.7% Black/African American and 41.5% White, with 89.4% reporting no prior exposure to opioids. Within-subject sensitivity to opioids varied depending on the measure. One in five participants did not respond subjectively to the 4 mg hydromorphone dose based on their "Drug Effects" rating. Persons who were responsive showed more evidence of drug-dependent effects than did persons who were not responsive on ratings of Bad Effects (p= .03), feeling High (p= .01), Nausea (p= .03), pupil diameter (p< 0.01), and on the circular lights task (p< 0.001). Conclusions This study provides initial evidence that the experience of opioids may be domain specific. Data suggest potentially clinically meaningful differences exist regarding opioid response patterns, evident following one dose among opioid inexperienced individuals.
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Affiliation(s)
- Caitlyn J. Durgin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
| | - Andrew S. Huhn
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
| | - Cecilia L. Bergeria
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
| | - Patrick H. Finan
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA
| | - Claudia M. Campbell
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
| | - Denis G. Antoine
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
| | - Kelly E. Dunn
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr, Baltimore MD 21224, USA
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Ramos KA, James IE, Skobieranda F, Soergel DG, Ruff D, Fossler MJ. Two-Part Phase 1 Multiple-Ascending-Dose Study to Evaluate the Safety, Tolerability, Pharmacodynamics, and Pharmacokinetics of TRV734 in Healthy Adults. Clin Pharmacol Drug Dev 2021; 11:51-62. [PMID: 34480428 DOI: 10.1002/cpdd.1016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/27/2021] [Indexed: 11/06/2022]
Abstract
TRV734, an oral G-protein biased ligand at the μ-opioid receptor has demonstrated differentiated pharmacology in preclinical studies compared to unbiased ligands. First-time-in-human data suggested that TRV734 was safe and well tolerated and caused effective pain relief after single doses of 150 to 250 mg. In this study, safety and tolerability of multiple ascending doses of TRV734, and single doses of TRV734 125 mg following various administration paradigms, in healthy subjects were evaluated. In both parts of the study, TRV734 was generally well tolerated with no serious adverse events. Pharmacokinetics of TRV734 were similar when TRV734 125 mg was administered following a high-fat or standard meal. Compared to either of the fed conditions, maximum concentration and area under the plasma concentration-time curve did not change, and time to maximum concentration was 1.5 hours later when TRV734 125 mg was administered as 3 split portions over 120 minutes under fasted conditions. Split doses of TRV734 delayed time to peak decrease in pupil diameter. Following multiple-dose administration of TRV734 60 to 175 mg every 6 hours, there was a trend of slightly less-than-dose proportional increase of maximum concentration, and area under the plasma concentration-time curve and accumulation was modest. Time to maximum concentration was ≈1 to 2 hours and elimination half-life ≈1.9 to 2.5 hours. The analgesic effect of TRV734 on the cold pain test was generally dose proportional and similar to that of oxycodone 10 mg immediate release, after both the first and last doses. There was a dose-related decrease in pupil diameter following administration of TRV734 up to TRV734 125 mg every 6 hours. A favorable trend in bowel function index for TRV734 warrants continued study.
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Affiliation(s)
| | - Ian E James
- Trevena, Inc., Chesterbrook, Pennsylvania, USA
| | | | | | - Dennis Ruff
- ICON Early Phase Services, San Antonio, Texas, USA
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Normalized skin conductance level could differentiate physical pain stimuli from other sympathetic stimuli. Sci Rep 2020; 10:10950. [PMID: 32616939 PMCID: PMC7331661 DOI: 10.1038/s41598-020-67936-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 06/17/2020] [Indexed: 12/31/2022] Open
Abstract
Skin conductance monitoring is one of the promising methods for objectively evaluating pain. However, skin conductance might possibly increase in response to sympathetic stimulation other than pain. In this study, we aimed to test whether skin conductance monitoring can distinguish physical pain stimulation (heat, mechanical and cold stimulation) from other sympathetic stimuli (stimulation by noise and painful images). Twenty-three healthy volunteers participated in this prospective observational study. The number of fluctuations in skin conductance (NFSC) and normalized skin conductance level (nSCL) were measured and compared with pain scores on a self-reported pain scale (numerical pain scale [NPS]). Both NFSC and nSCL increased during mechanical stimulation. Further, nSCL, but not NFSC, well reflected heat stimulus intensity, suggesting its ability to quantitatively evaluate pain. nSCLs during physical pain stimulation were greater than those during other sympathetic stimulations. However, NFSC was not able to completely distinguish between the stimuli. These results suggest that nSCL could better differentiate physical pain stimuli from other sympathetic stimuli than NFSC. In comparisons between subjective and objective pain assessment in the same individual, nSCL correlated better with NPS score, indicating the possibility of being able to monitor the transition of pain. Monitoring changes in skin conductance using nSCL might be useful for objectively detecting physical pain.
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James IE, Skobieranda F, Soergel DG, Ramos KA, Ruff D, Fossler MJ. A First-in-Human Clinical Study With TRV734, an Orally Bioavailable G-Protein-Biased Ligand at the μ-Opioid Receptor. Clin Pharmacol Drug Dev 2019; 9:256-266. [PMID: 31286645 DOI: 10.1002/cpdd.721] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 06/03/2019] [Indexed: 11/08/2022]
Abstract
TRV734 is an orally bioavailable G-protein-biased ligand at the μ-opioid receptor. In nonclinical studies it was potently analgesic while causing less gastrointestinal dysfunction than morphine, suggesting unique benefits in acute pain management. A 2-part, first-in-human study was conducted with ascending doses of TRV734 to explore its tolerability, pharmacokinetics, and pharmacodynamics in healthy volunteers. TRV734 was well tolerated over the dose range 2 to 250 mg when administered orally. Plasma TRV734 maximum concentration and area under the plasma concentration-time curve generally increased with dose, while time to maximum concentration was similar across doses (0.5-1.3 h). The half-life increased with dose from 10 mg through 150 mg (0.75-2.28 h) but was similar from 150 mg through 250 mg. Pupil constriction, confirming central nervous system μ-opioid receptor engagement, correlated with higher plasma TRV734 concentrations; the greatest reductions in pupil diameter occurring between 0 and 4 hours after dosing (-2.9 mm/h, with reduction peaking at 1 hour, and returning to baseline by 8 hours). Following administration of TRV734 125 mg under fasted or fed conditions, there was no significant difference in bioavailability when given as a solution or drug in capsule to fasted subjects. When drug in capsule was given to subjects following a high-fat meal, absorption was slowed, resulting in decreased peak concentrations, but area under the plasma concentration-time curve was not affected.
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Affiliation(s)
| | | | - David G Soergel
- Trevena, Inc, Chesterbrook, PA, USA.,Novartis, East Hanover, NJ, USA
| | - Kimberly A Ramos
- Trevena, Inc, Chesterbrook, PA, USA.,Intact Vascular, Wayne, PA, USA
| | - Dennis Ruff
- ICON Early Phase Services, San Antonio, TX, USA
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Ogino Y, Kakeda T, Nakamura K, Saito S. Dehydration Enhances Pain-Evoked Activation in the Human Brain Compared with Rehydration. Anesth Analg 2014; 118:1317-25. [DOI: 10.1213/ane.0b013e3182a9b028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Soergel DG, Subach RA, Sadler B, Connell J, Marion AS, Cowan CL, Violin JD, Lark MW. First clinical experience with TRV130: pharmacokinetics and pharmacodynamics in healthy volunteers. J Clin Pharmacol 2014; 54:351-7. [PMID: 24122908 DOI: 10.1002/jcph.207] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/09/2013] [Indexed: 11/10/2022]
Abstract
TRV130 is a G protein-biased ligand at the µ-opioid receptor. In preclinical studies it was potently analgesic while causing less respiratory depression and gastrointestinal dysfunction than morphine, suggesting unique benefits in acute pain management. A first-in-human study was conducted with ascending doses of TRV130 to explore its tolerability, pharmacokinetics, and pharmacodynamics in healthy volunteers. TRV130 was well-tolerated over the dose range 0.15 to 7 mg administered intravenously over 1 hour. TRV130 geometric mean exposure and Cmax were dose-linear, with AUC0-inf of 2.52 to 205.97 ng h/mL and Cmax of 1.04 to 102.36 ng/mL across the dose range tested, with half-life of 1.6-2.7 hours. A 1.5 mg dose of TRV130 was also well-tolerated when administered as 30, 15, 5, and 1 minute infusions. TRV130 pharmacokinetics were modestly affected by CYP2D6 phenotype: clearance was reduced by 53% in CYP2D6 poor metabolizers.TRV130 caused dose- and exposure-related pupil constriction, confirming central compartment µ-opioid receptor engagement. Marked pupil constriction was noted at 2.2, 4, and 7 mg doses. Nausea and vomiting observed at the 7 mg dose limited further dose escalation. These findings suggest that TRV130 may have a broad margin between doses causing µ-opioid receptor-mediated pharmacology and doses causing µ-opioid receptor-mediated intolerance.
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Yuan CS, Mehendale SR, Wang CZ, Aung HH, Jiang T, Guan X, Shoyama Y. Effects of Corydalis yanhusuo and Angelicae dahuricae on Cold Pressor-Induced Pain in Humans: A Controlled Trial. J Clin Pharmacol 2013; 44:1323-7. [PMID: 15496650 DOI: 10.1177/0091270004267809] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Pain is considered the most common complaint worldwide for which patients seek treatment. Conventional analgesic agents play an important role in modern pain therapy, but they cause several adverse effects. Therefore, newer and better analgesics continue to be investigated. In this controlled clinical trial, the authors evaluated the analgesic effects of 2 herbal medicines, Corydalis yanhusuo and Angelicae dahuricae. They used the cold-pressor test-a simple, reliable, and widely used model in humans-for induction of tonic pain. They demonstrated that after a single, oral administration of the extracts of C. yanhusuo and A. dahuricae, the pain intensity and pain bothersomeness scores significantly decreased (both P < .01). Dose-related analgesic effect was also observed. Results from this study suggest that C. yanhusuo and A. dahuricae may have a potential clinical value for treating mild to moderate pain.
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Affiliation(s)
- Chun-Su Yuan
- Tang Center for Herbal Medicine Research, Committee on Clinical Pharmacology, and Department of Anesthesia & Critical Care, Pritzker School of Medicine, University of Chicago, Illinois 60637, USA
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Khambam SKR, Naidu M, Rani PU, Rao TRK. A simple thermal pain model for the evaluation of analgesic activity in healthy subjects. J Anaesthesiol Clin Pharmacol 2012; 28:214-20. [PMID: 22557746 PMCID: PMC3339728 DOI: 10.4103/0970-9185.94887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objective: Assessment of the analgesic effect of an agent in an experimental pain model permits a level of control not possible in a clinical pain setting and is an ideal approach for evaluation of analgesic drugs. The aim of the present study was to establish a simple and reliable method of producing experimental pain, which can be used for screening of various analgesic agents. Materials and Methods: The standardized method was followed in all cases, by recording thermal pain threshold in seconds in 24 healthy volunteers using hot air source at two different speeds, which is equipped in an acrylic-made chamber adjustable to three different levels. Reproducibility of the test procedure was evaluated by recording the thermal threshold parameter by a single observer on two sessions (interday reproducibility) and second observer on one session (interobserver reproducibility) separately. Validity of model was further tested by evaluating the analgesic effect of tramadol on 12 healthy volunteers. Results: Thermal pain model was found to produce low variability with coefficient of variation (CV) less than 10%. Interobserver and interday reproducibility were very good, as shown by Bland–Altman plot, with most of the values within ± 2SD. There was a significant increase in pain threshold time with use of tramadol as compared to placebo which was statistically significant (P < 0.05). Conclusion: The newly developed pain model offers a stable and sensitive method for the early assessment of analgesic activity.
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Affiliation(s)
- Sunil Kumar Reddy Khambam
- Department of Clinical Pharmacology and Therapeutics, ICMR Advance Centre for Clinical Pharmacodynamic, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
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Gormsen L, Bach FW, Rosenberg R, Jensen TS. Differential pain modulation in patients with peripheral neuropathic pain and fibromyalgia. Scand J Pain 2012; 3:116-123. [DOI: 10.1016/j.sjpain.2012.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/30/2012] [Indexed: 10/28/2022]
Abstract
Abstract
Background
The definition of neuropathic pain has recently been changed by the International Association for the Study of Pain. This means that conditions such as fibromyalgia cannot, as sometimes discussed, be included in the neuropathic pain conditions. However, fibromyalgia and peripheral neuropathic pain share common clinical features such as spontaneous pain and hypersensitivity to external stimuli. Therefore, it is of interest to directly compare the conditions.
Material and methods
In this study we directly compared the pain modulation in neuropathic pain versus fibromyalgia by recording responses to a cold pressor test in 30 patients with peripheral neuropathic pain, 28 patients with fibromyalgia, and 26 pain-free age-and gender-matched healthy controls. Patients were asked to rate their spontaneous pain on a visual analog scale (VAS (0–100 mm) immediately before and immediately after the cold pressor test. Furthermore the duration (s) of extremity immersion in cold water was used as a measure of the pain tolerance threshold, and the perceived pain intensity at pain tolerance on the VAS was recorded on the extremity in the water after the cold pressor test. In addition, thermal (thermo tester) and mechanical stimuli (pressure algometer) were used to determine sensory detection, pain detection, and pain tolerance thresholds in different body parts. All sensory tests were done by the same examiner, in the same room, and with each subject in a supine position. The sequence of examinations was the following: (1) reaction time, (2) pressure thresholds, (3) thermal thresholds, and (4) cold pressor test. Reaction time was measured to ensure that psychomotoric inhibitions did not influence pain thresholds.
Results
Pain modulation induced by a cold pressor test reduced spontaneous pain by 40% on average in neuropathic pain patients, but increased spontaneous pain by 2.6% in fibromyalgia patients. This difference between fibromyalgia and neuropathic pain patients was significant (P < 0.002). Fibromyalgia patients withdrew their extremity from the cold water significantly earlier than neuropathic pain patients and healthy controls; however, they had a higher perceived pain intensity on the VAS than neuropathic pain patients and control subjects. Furthermore, neuropathic pain patients had a localized hypersensitivity to mechanical and thermal stimuli in the affected area of the body. In contrast, fibromyalgia patients displayed a general hypersensitivity to mechanical and thermal stimuli when the stimuli were rated by the VAS, and hypersensitivity to some of the sensory stimuli.
Conclusions
These findings are the first to suggest that a conditioning stimulus evoked by a cold pressor test reduced spontaneous ongoing pain in patients with peripheral neuropathic pain, but not in fibromyalgia patients when directly compared. The current study supports the notion that fibromyalgia and neuropathic pain are distinct pain conditions with separate sensory patterns and dysfunctions in pain-modulating networks. Fibromyalgia should therefore not, as sometimes discussed, be included in NP conditions.
Implications
On the basis of the findings, it is of interest to speculate on the underlying mechanisms. The results are consistent with the idea that peripheral neuropathic pain is primarily driven from damaged nerve endings in the periphery, while chronic fibromyalgia pain may be a central disorder with increased activity in pain-facilitating systems.
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Affiliation(s)
- Lise Gormsen
- Danish Pain Research Center , Aarhus University Hospital , Aarhus , Denmark
| | | | - Raben Rosenberg
- Center for Psychiatric Research , Aarhus University Hospital Risskov , Risskov , Denmark
| | - Troels S. Jensen
- Danish Pain Research Center , Aarhus University Hospital , Aarhus , Denmark
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Streff A, Kuehl LK, Michaux G, Anton F. Differential physiological effects during tonic painful hand immersion tests using hot and ice water. Eur J Pain 2012; 14:266-72. [DOI: 10.1016/j.ejpain.2009.05.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 05/19/2009] [Accepted: 05/20/2009] [Indexed: 11/29/2022]
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Morin C, Duncan GH, Lavigne G, Boily JG, Bushnell MC. Differential effects of morphine on pain and temperature perception in human volunteers. Eur J Pain 2012. [DOI: 10.1016/s1090-3801(99)90046-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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A simple contact heat experimental pain model for evaluation of analgesic agents in healthy volunteers. Curr Ther Res Clin Exp 2011; 72:233-42. [PMID: 24648591 DOI: 10.1016/j.curtheres.2011.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2011] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Human experimental pain models help to understand the mechanism of the underlying clinical pain conditions and can be adopted to test analgesic efficacy of drugs used in the management of pain. In early phases, the clinical development of new analgesic agents is severely hindered due to lack of reliable sensitive tests for the experimental pain models. OBJECTIVE The aim of the present study was to standardize and validate a simple contact heat pain model that can be used for future screening of various analgesic agents. METHODS The method was standardized by recording heat detection and heat pain detection threshold in degrees centigrade in 24 healthy volunteers. Reproducibility of the test procedure was evaluated by recording the thermal threshold parameters by a single observer on 2 sessions (inter-day reproducibility) and a second observer on 1 session (inter-observer reproducibility) separately. Validity of model was further tested by evaluating the analgesic effect of tramadol on 12 healthy volunteers. RESULTS Thermal pain model using contact heat method was found to produce low variability with coefficient of variation <5%. Inter-observer and inter-day reproducibility was very good, as shown by Bland-Altman Plot; with most of the values within 2 SD. There was a significant difference in both heat detection threshold and heat pain detection threshold produced by tramadol, as compared with placebo (P < 0.05). CONCLUSIONS The newly developed pain model produces a type of experimental pain that is responsive to analgesic effects of tramadol at clinically relevant doses. The model might be useful in early screening of new therapeutic agents before proceeding to expensive clinical trials in acute and chronic pain sufferers.
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Abstract
We investigated the brain activation associated with sweet taste-induced analgesia by 3-T functional magnetic resonance imaging, the mechanism of which is considered to involve the central nervous system. After 12 healthy individuals ingested tasteless gelatin (nonsweet condition) or sweet glucose (sweet condition) in a magnetic resonance imaging scanning gantry, the cold pressor test was applied to their medial forearm. Under both conditions, the cold pressor test robustly activated the pain-related neural network, notably the anterior cingulate cortex, insula, posterior parietal cortex, and thalamus, although such activations under the sweet condition weakened with pain threshold increase, compared with those under the nonsweet condition. Together with emotional changes in pain appraisal, our findings provide objective representation of sweet taste-induced analgesia in the human brain.
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Johnson MI, Penny P, Sajawal MA. An examination of the analgesic effects of microcurrent electrical stimulation (MES) on cold-induced pain in healthy subjects. Physiother Theory Pract 2009. [DOI: 10.3109/09593989709036476] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
OBJECTIVE To examine the extent to which nicotine dependence alters endogenous opioid regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis functions. Endogenous opiates play an important role in regulating mood, pain, and drug reward. They also regulate the HPA functions. Previous work has demonstrated an abnormal HPA response to psychological stress among dependent smokers. METHODS Smokers and nonsmokers (total n = 48 participants) completed two sessions during which a placebo or 50 mg of naltrexone was administered, using a double-blind design. Blood and saliva samples, cardiovascular and mood measures were obtained during a resting absorption period, after exposure to two noxious stimuli, and during an extended recovery period. Thermal pain threshold and tolerance were assessed in both sessions. Participants also rated pain during a 90-second cold pressor test. RESULTS Opioid blockade increased adrenocorticotropin, plasma cortisol, and salivary cortisol levels; these increases were enhanced by exposure to the noxious stimuli. These responses were blunted in smokers relative to nonsmokers. Smokers tended to report less pain than nonsmokers, and women reported more pain during both pain procedures, although sex differences in pain were significant only among nonsmokers. CONCLUSIONS We conclude that nicotine dependence is associated with attenuated opioid modulation of the HPA. This dysregulation may play a role in the previously observed blunted responses to stress among dependent smokers.
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La Vincente SF, White JM, Somogyi AA, Bochner F, Chapleo CB. Enhanced Buprenorphine Analgesia with the Addition of Ultra-low-dose Naloxone in Healthy Subjects. Clin Pharmacol Ther 2007; 83:144-52. [PMID: 17568402 DOI: 10.1038/sj.clpt.6100262] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Animal studies have demonstrated that co-administration of an ultra-low-dose opioid antagonist with an opioid agonist may result in enhanced analgesia. Investigation of this effect in humans has been limited and produced inconsistent findings, with previous reports suggesting that dose ratio may be critical to analgesic potentiation. The aim of the current investigation was to determine whether buprenorphine analgesia could be enhanced with the addition of ultra-low-dose naloxone among healthy volunteers, using a range of dose ratios. Tolerance to cold pressor pain was significantly greater with the combination of buprenorphine and naloxone compared to buprenorphine alone, and this effect was dose ratio dependent. Importantly, this enhanced analgesia occurred without an increase in adverse effects; indeed at some ratios, respiratory depression was attenuated. These findings demonstrate that the addition of ultra-low-dose naloxone can enhance the analgesic effect of buprenorphine in humans without a concurrent increase in side effects.
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Affiliation(s)
- S F La Vincente
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia.
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Gormsen L, Ribe AR, Raun P, Rosenberg R, Videbech P, Vestergaard P, Bach FW, Jensen TS. Pain thresholds during and after treatment of severe depression with electroconvulsive therapy. Eur J Pain 2004; 8:487-93. [PMID: 15324780 DOI: 10.1016/j.ejpain.2003.11.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2003] [Accepted: 11/19/2003] [Indexed: 12/17/2022]
Abstract
Pain and depression are often associated suggesting that both conditions share a common neurobiological mechanism, which modulate emotional function and processing of noxious information. Pain thresholds are hypothesized to be altered in depressed patients and normalized with the amelioration of depression. The purpose of this study was therefore to determine pain thresholds in patients during and after treatment with electroconvulsive therapy (ECT) of severe depression and in healthy controls. Seventeen depressed patients (Hamilton depression score > 18) and an age and gender matched control group of same size participated in the study. Pain detection and tolerance thresholds to pressure and pain tolerance thresholds to the Cold Pressor Test by exposure to ice-water was measured twice in depressed patients during and after ECT and twice in controls with a similar time interval. While ECT significantly improved Hamilton depression score (from mean 23.9 (SD:5) to mean 12.5 (SD:5.7)) there was no significant change in pain thresholds during and after ECT in the patient group. However, depressed patients had significantly lower pain tolerance in the Cold Pressor Test on both examinations and on pressure pain tolerance on the second examination day than their corresponding control subjects. The differential effect of ECT on depression score and pain processing indicate that mood and noxious processing are not medicated directly by the same systems but that a complex relationship between pain and depression exists.
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Affiliation(s)
- Lise Gormsen
- Department of Neurology, Danish Pain Research Centre, Aarhus Kommune Hospital, University of Aarhus, Noerrebrogade 44, Building 1, 8000 Aarhus, Denmark.
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Hutchinson MR, La Vincente SF, Somogyi AA. In vitro opioid induced proliferation of peripheral blood immune cells correlates with in vivo cold pressor pain tolerance in humans: a biological marker of pain tolerance. Pain 2004; 110:751-755. [PMID: 15288416 DOI: 10.1016/j.pain.2004.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Revised: 05/13/2004] [Accepted: 05/20/2004] [Indexed: 11/24/2022]
Abstract
There is substantial evidence for bidirectional communication between the immune system and the central nervous system, as the cells and signalling molecules of the immune system influence many central nervous system functions, for instance nociception. Opioids, such as morphine, produce analgesia and numerous other central and peripheral effects including sedation and euphoria, while their effects on the immune system are wide-ranging. There is considerable interindividual variability in basal nociception and response to opioids, however, the physiological and biological mechanisms underlying this are unclear. Therefore, we investigated the relationship between the immune system and basal nociceptive thresholds, using the proliferative response of isolated peripheral blood mononuclear cells and cold pressor pain tolerance. Here we show that the percent increase in proliferation of peripheral immune cells from 13 healthy subjects incubated with morphine ex vivo is highly correlated with the subjects' tolerance to noxious cold stimuli (Pearson r = 0.92, P < 0.0001). These pilot data provide evidence of a novel objective biological marker of pain tolerance in humans, which also links the immune and opioid systems with basal pain tolerance.
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Affiliation(s)
- Mark R Hutchinson
- Department of Clinical and Experimental Pharmacology, Level 5, Medical School North, University of Adelaide, Frome Rd, Adelaide, SA 5005, Australia
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20
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Compton P, Charuvastra VC, Ling W. Effect of oral ketorolac and gender on human cold pressor pain tolerance. Clin Exp Pharmacol Physiol 2004; 30:759-63. [PMID: 14516415 DOI: 10.1046/j.1440-1681.2003.03907.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. Although the analgesic effect of opioids on experimental cold pressor (CP) pain has been well demonstrated, the analgesic effect of non-steroidal anti-inflammatory drugs (NSAIDs) on experimental CP pain has been less reliable, a finding complicated by inconsistencies in how CP analgesic effect is measured. 2. In the present study, a clinically relevant CP response of pain tolerance was used to assess the previously undescribed analgesic efficacy of the potent NSAID ketorolac (10 mg, p.o.), on CP pain across gender in a sample of normal subjects (n = 50). 3. Using a placebo-controlled crossover design, neither a main nor interaction effect for ketorolac on CP pain tolerance was detected. When examined by gender, male subjects exhibited a large placebo response to CP pain under study conditions, whereas women (albeit less pain tolerant at baseline) evidenced no placebo effect but a modest-to-good NSAID analgesic response. 4. Findings on the gender-specific placebo and analgesic NSAID response, integrated with the current literature, indicate that the lack of NSAID analgesic efficacy in the CP pain model may be related to unexamined and differential effects of how gender affects NSAID analgesic effect.
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Affiliation(s)
- Peggy Compton
- School of Nursing, University of California at Los Angeles, Los Angeles, California, USA.
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al'Absi M, Wittmers LE, Ellestad D, Nordehn G, Kim SW, Kirschbaum C, Grant JE. Sex differences in pain and hypothalamic-pituitary-adrenocortical responses to opioid blockade. Psychosom Med 2004; 66:198-206. [PMID: 15039504 DOI: 10.1097/01.psy.0000116250.81254.5d] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Sex differences in pain sensitivity and stress reactivity have been well documented. Little is known about the role of the endogenous opioid system in these differences. This study was conducted to compare adrenocortical, pain sensitivity, and blood pressure responses to opioid blockade using naltrexone in men and women. METHODS Twenty-six participants completed 2 sessions during which placebo or 50 mg of naltrexone was administered, using a double-blind, counterbalanced design. Thermal pain threshold and heat tolerance were assessed. Participants also rated pain during a 90-second cold pressor test (CPT) and completed the McGill Pain Questionnaire (MPQ) after each pain challenge. Blood and saliva samples and cardiovascular and mood measures were obtained throughout the sessions. RESULTS Plasma cortisol, adrenocorticotropin, beta endorphin, prolactin, and salivary cortisol levels increased similarly in men and women after naltrexone administration compared with placebo. Women reported more pain during both pain procedures and had lower thermal pain tolerance. In response to naltrexone, women exhibited reduced blood pressure responses and reduced MPQ pain ratings after CPT. No effects of naltrexone on these measures were found in men. CONCLUSIONS Although men and women exhibited similar hormonal responses to opioid receptor blockade, women reported less pain and showed smaller blood pressure responses during CPT. Results suggest differential effects of the endogenous opioid system on pain perception and blood pressure in men and women.
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Affiliation(s)
- Mustafa al'Absi
- Department of Behavioral Sciences, University of Minnesota School of Medicine, Duluth, Minnesota 55812, USA.
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al'Absi M, Petersen KL. Blood pressure but not cortisol mediates stress effects on subsequent pain perception in healthy men and women. Pain 2004; 106:285-295. [PMID: 14659511 DOI: 10.1016/s0304-3959(03)00300-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Research has demonstrated that exposure to acute stress may attenuate pain perception. Mechanisms of this effect in humans have not been determined. This study was conducted to determine the extent to which psychophysiological and adrenocortical responses to acute stress predict subsequent pain perception. One hundred and fifty-two healthy participants (80 women) were assigned to one of two conditions: rest followed by the cold pressor test (CPT; N=76) or stress followed by CPT (N=76). The stress protocol consisted of a public-speaking challenge. Participants rated their pain every 15 s during a 90-s hand CPT (0-4 degrees C), and they completed the short form of the McGill Pain Questionnaire. Salivary cortisol, mood, blood pressure (BP), and impedance cardiography measures were collected in both conditions. Women had lower BP and reported greater pain than men in both conditions (ps<0.01). Participants in the stress condition reported less pain during CPT than those in the rest condition (p=0.02). Regression analyses demonstrated that the stress effect on pain ratings was mediated by systolic BP level during stress; however, cortisol responses did not affect this relationship. Mood changes were independent predictors of pain. The study demonstrates that BP changes in response to stress mediate the stress-induced attenuation of pain perception.
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Affiliation(s)
- Mustafa al'Absi
- Department of Behavioral Sciences, University of Minnesota School of Medicine, 1035 University Drive, Duluth, MN 55812, USA Department of Family Medicine, University of Minnesota School of Medicine, 1035 University Drive, Duluth, MN 55812, USA Department of Physiology, University of Minnesota School of Medicine, 1035 University Drive, Duluth, MN 55812, USA
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23
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Johnson MI, Tabasam G. An investigation into the analgesic effects of different frequencies of the amplitude-modulated wave of interferential current therapy on cold-induced pain in normal subjects 11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or any organization with which the authors are associated. Arch Phys Med Rehabil 2003; 84:1387-94. [PMID: 13680579 DOI: 10.1016/s0003-9993(03)00151-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate the analgesic effects of different amplitude-modulated frequencies of interferential current therapy (IFT) on cold-induced pain in healthy subjects. DESIGN Single-blind parallel group methodology was used. Subjects completed 6 cycles of the cold-induced pain test (2 pretreatment, 2 during treatment, 2 posttreatment). During each cycle, subjects plunged their hand into iced water and the time taken to reach pain threshold was recorded. The hand remained immersed in the iced water for a further 30 seconds, after which the self-reports of pain intensity and pain unpleasantness were recorded. SETTING Laboratory in the United Kingdom. PARTICIPANTS Sixty unpaid, pain-free volunteers without a known pathology that could cause pain. INTERVENTIONS IFT delivered on the nondominant arm at a "strong but comfortable" intensity without visible muscle twitches, using a quadripolar application technique at 1 of 6 possible amplitude modulated "beat" frequencies (20, 60, 100, 140, 180, 220Hz). MAIN OUTCOME MEASURES The percentage change in pain threshold, pain intensity, and pain unpleasantness from the pretreatment baseline. RESULTS Two-way repeated-measures analyses of variance found no effects for groups for pain threshold (P=.11) or pain ratings (P>.05). There were no effects for cycle for any of the outcome measures. Effects for group by cycle interaction were noted for pain intensity and unpleasantness ratings (P<.05), although post hoc analysis failed to determine the nature of this interaction. CONCLUSIONS Experimentally induced cold pain was not influenced by IFT frequencies.
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Affiliation(s)
- Mark I Johnson
- Scool of Health Sciences, Faculty of health and Environment, Leeds Metropolitan University, Leeds, UK
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24
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Gustorff B, Hoerauf KH, Lierz P, Kress HG. Comparison of different quantitative sensory testing methods during remifentanil infusion in volunteers. Br J Anaesth 2003; 91:203-8. [PMID: 12878618 DOI: 10.1093/bja/aeg161] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The aim of this study was to compare thermal and current sensory testing stimuli with respect to opioid responsiveness. METHODS Eighteen healthy volunteers were randomized in a placebo-controlled, double-blind crossover study to receive an infusion of remifentanil 0.08 micro g kg(-1) min(-1) or saline for 40 min. Test procedures included determination of pain perception thresholds (PPT) and pain tolerance thresholds (PTT) to heat, cold, and current at 5, 250 and 2000 Hz, at baseline and at the end of the infusion. RESULTS Both current at 5 Hz (PPT 3.69 (SD 2.48) mA vs 2.01 (1.52) mA; PTT 6.42 (2.79) mA vs 3.63 (2.31) mA; P<0.001) and 250 Hz (PPT 4.31 (2.42) mA vs 2.89 (1.57) mA; PTT 7.08 (2.68) mA vs 4.81 (2.42) mA; P<0.001) and heat (PPT 47.4 (2.7) degrees C vs 45.2 (3) degrees C; PTT 51.1 (1.8) degrees C vs 49.7 (1.8) degrees C; P<0.05) detected a significant analgesic effect of remifentanil compared with placebo. No analgesic effect was shown on cold or current at 2000 Hz. The magnitude of responsiveness of current stimuli at 5 Hz and 250 Hz was superior to heat stimuli. CONCLUSION Both current (5 and 250 Hz) and heat sensory testing detected a significant analgesic effect of a remifentanil infusion compared with saline. There was more response to current testing.
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Affiliation(s)
- B Gustorff
- Department of Anaesthesia and General Intensive Care Medicine (B), University of Vienna, Währinger-Gürtel 18-20, A-1090 Vienna, Austria.
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25
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Fillingim RB. Sex differences in analgesic responses: evidence from experimental pain models. EUROPEAN JOURNAL OF ANAESTHESIOLOGY. SUPPLEMENT 2003; 26:16-24. [PMID: 12512212 DOI: 10.1097/00003643-200219261-00004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE Sex-related influences on the experience of pain have received considerable empirical attention. Women are at greater risk for several forms of clinical pain and exhibit greater perceptual responses to experimental pain. In recent years, investigators have turned their attention to the influence of sex-related factors on analgesic responses. The purpose of this review is to examine the literature on sex differences in analgesic responses, emphasizing findings from experimental studies. METHODS First, important methodological issues in laboratory pain research are presented, and sex differences in responses to experimentally-induced pain are briefly addressed. Next, previous data from non-human animal research and human experimental and clinical research related to sex differences in analgesia are discussed. Also, preliminary results are presented from an ongoing study in our laboratory examining analgesic responses in women and men. RESULTS AND CONCLUSIONS Both previous research and preliminary findings from our laboratory suggests that opioids produce greater analgesic responses in women than men. Potential mechanisms underlying sex differences in analgesia are proposed, and important directions for future research are suggested.
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Affiliation(s)
- R B Fillingim
- University of Florida College of Dentistry, Public Health Services and Research, 1600 SW Archer Road, Room D8-44A, PO Box 100404, Gainesville, FL 32610-0404, USA.
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26
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Witting N, Svensson P, Jensen TS. Differential recruitment of endogenous pain inhibitory systems in neuropathic pain patients. Pain 2003; 103:75-81. [PMID: 12749961 DOI: 10.1016/s0304-3959(02)00421-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Neuronal hyperexcitability is a key finding in patients with neuropathic pain. Contributing to hyperexcitability may be decreased activity in the endogenous pain inhibitory systems. The present study aimed at recruiting descending inhibition, by the use of painful heterotopic stimulation (HTS), in 16 patients with peripheral chronic neuropathic pain and associated brush-evoked allodynia. Two experiments were performed: one examined the effect of HTS on ongoing pain and intensity of brush-evoked allodynia and the other tested the effect of HTS on ongoing pain and area of brush-evoked allodynia. Both experiments consisted of two sessions, one with painful cold HTS (1 degrees C water bath) another with non-painful neutral HTS (32 degrees C water bath). The area of brush-evoked allodynia was significantly reduced (P=0.003) during painful HTS, as compared to non-painful HTS. In contrast, neither the intensity of brush-evoked allodynia nor the ongoing pain was significantly changed. The results indicate that endogenous pain modulating systems can alter some aspects of chronic neuropathic brush-evoked allodynia. The differential effect of painful HTS on ongoing pain and area of brush-evoked allodynia suggest that separate mechanisms are involved.
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Affiliation(s)
- Nanna Witting
- Department of Neurology and Danish Pain Research Center, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
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27
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Yuan CS, Attele AS, Dey L, Lynch JP, Guan X. Transcutaneous electrical acupoint stimulation potentiates analgesic effect of morphine. J Clin Pharmacol 2002; 42:899-903. [PMID: 12162472 DOI: 10.1177/009127002401102812] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pain is the major complaint of patients who choose acupuncture treatment. Transcutaneous electrical acupoint stimulation (TEAS) provides a safe, standardized technique without needle insertion. TEAS can be tested with the cold-pressor test, a simple, reliable, and widely used model in humansfor the induction of tonic pain. In this controlled study, the effects of TEAS on cold-pressor-induced pain were evaluated in 20 healthy human subjects. Electrical stimulation electrodes were applied to He-Gu (LI 4) and Nui-Guan (P 6) acupoints. The effects of saline plus no TEAS, 15-minute TEAS alone, 0.05 mg/kg morphine alone, and 15-minute TEAS plus morphine were assessed. Pain score ratings were evaluated at four time points from 30 to 170 seconds during the cold-pressor test. The authors observed analgesic effects in both TEAS-alone and morphine-alone sessions, and pain score rating reductions were statistically significant compared to unstimulated control (both p < 0.01). The degree of TEAS analgesia combined with 0.05 mg/kg morphine was significantly higher than TEAS alone (p < 0.01). The results support the efficacy of TEAS analgesia and suggest that combination of TEAS with low-dose morphine can achieve better pain control in a variety of clinical settings.
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Affiliation(s)
- Chun-Su Yuan
- Tang Center for Herbal Medicine Research, Department of Anesthesia & Critical Care, University of Chicago, Illinois 60637, USA
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28
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Johnson MI, Tabasam G. A single-blind placebo-controlled investigation into the analgesic effects of interferential currents on experimentally induced ischaemic pain in healthy subjects. Clin Physiol Funct Imaging 2002; 22:187-96. [PMID: 12076344 DOI: 10.1046/j.1475-097x.2002.00416.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this single-blind placebo-controlled study was to examine the analgesic effects of interferential currents (IFC) on experimentally induced ischaemic pain. Ischaemic pain was induced using the submaximal effort tourniquet technique (SETT) and pain intensity was recorded using a visual analogue scale at 1-min intervals was used as the primary outcome measure. Following baseline recordings 30 healthy volunteers received either active IFC, sham IFC, or no treatment (10 subjects per group). Data were analysed by calculating the mean change in pain intensity at each 1-min interval by subtracting data during treatment from the baseline data. IFC was administered throughout the duration of the ischaemic pain test via four electrodes (quadripolar application) on the forearm. Active IFC delivered electrical currents at a 'strong but comfortable' intensity. A 'dummy' stimulator that delivered no current was used as sham IFC. Subjects in the no treatment control group were informed that the IFC device was not switched on. There were significant effects for Groups (P=0.04) which were attributed to a significant reduction in pain intensity for the IFC group when compared with sham and no-treatment control (P< or =0.05). There were no significant effects for Time (P=0.69) or Group-Time interaction (P=0.45). In conclusion, IFC produced significantly greater analgesia than sham and no-treatment control groups under the present experimental conditions.
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Affiliation(s)
- Mark I Johnson
- Principal Lecturer in Human Physiology, School of Health Sciences, Faculty of Health and Environment, Leeds Metropolitan University, Leeds, UK.
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29
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Gustorff B, Nahlik G, Hoerauf KH, Kress HG. The absence of acute tolerance during remifentanil infusion in volunteers. Anesth Analg 2002; 94:1223-8, table of contents. [PMID: 11973194 DOI: 10.1097/00000539-200205000-00032] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED The development of acute opioid tolerance in humans remains controversial. We tested the hypothesis that continuous remifentanil infusion leads to rapid development of opioid tolerance. Twenty healthy male volunteers were enrolled onto a randomized, placebo-controlled, double-blinded, cross-over design study to receive a 3 h continuous infusion of remifentanil (0.08 microg x kg(-1) x min(-1)) or saline. Test procedures included determination of pain perception thresholds and pain tolerance thresholds to heat and cold and neuroselective sine wave constant current at 5 Hz and 250 Hz. Test procedures were performed at baseline and then repeated at 25, 55, 85, 115, and 160 min (heat/cold) and at 35, 65, 95, 125, and 170 min (electrical current) during infusion. No significant decrease of the pain threshold devolutions between 55 and 180 min after the start of infusion of remifentanil could be detected. In conclusion, no development of acute opioid tolerance was observed during constant remifentanil infusion of 3 h in volunteers. IMPLICATIONS The opioid remifentanil was applied to 20 volunteers at a constant concentration for 3 h while pain thresholds to temperature and current were repeatedly assessed. Our aim was to study whether thresholds decrease over time because of the rapid development of opioid tolerance. No development of rapid opioid tolerance was observed.
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Affiliation(s)
- Burkhard Gustorff
- Department of Anesthesia, Vienna General Hospital, University of Vienna, Austria.
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30
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al'Absi M, Petersen KL, Wittmers LE. Adrenocortical and hemodynamic predictors of pain perception in men and women. Pain 2002; 96:197-204. [PMID: 11932075 DOI: 10.1016/s0304-3959(01)00447-x] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Research has demonstrated that women report more pain than men, and clinical observations suggest that attenuated adrenocortical activity is associated with high pain sensitivity. The extent to which cortisol concentrations and hemodynamics contribute to gender differences in pain sensitivity has not been investigated. Thirty-four women and 31 men performed the hand cold pressor test (CPT). Participants rated their pain every 15 s during a 90-s CPT and a 90-s post-CPT recovery period and reported pain using the McGill Pain Questionnaire (MPQ). Salivary cortisol samples and cardiovascular measures were collected prior to, during, and after the CPT. Women reported greater pain than men during and after the CPT and on the MPQ (Ps<0.01). CPT disrupted the expected diurnal decline in cortisol, as shown by a significant increase in cortisol concentration post-CPT (P<0.01) in men and women. Regression analyses revealed that pre-CPT cortisol concentrations predicted lower pain reports during and after CPT in men only (P<0.01). Systolic blood pressure (BP) and stroke volume correlated negatively with pain reports only in women (Ps<0.05). Controlling for potential confounding variables did not alter these relationships. The negative association between pre-CPT cortisol and pain perception in men and the association between BP and pain in women demonstrate different physiological predictors of pain perception in men and women.
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Affiliation(s)
- Mustafa al'Absi
- Department of Behavioral Sciences, School of Medicine, University of Minnesota, 10 University Avenue, Duluth, MN 55812-2487, USA.
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31
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Webb JA, Rostami-Hodjegan A, Abdul-Manap R, Hofmann U, Mikus G, Kamali F. Contribution of dihydrocodeine and dihydromorphine to analgesia following dihydrocodeine administration in man: a PK-PD modelling analysis. Br J Clin Pharmacol 2001; 52:35-43. [PMID: 11453888 PMCID: PMC2014498 DOI: 10.1046/j.0306-5251.2001.01414.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS It is not clear whether the analgesic effect following dihydrocodeine (DHC) administration is due to either DHC itself or its metabolite, dihydromorphine (DHM). We examined the relative contribution of DHC and DHM to analgesia following DHC administration in a group of healthy volunteers using a PK-PD link modelling approach. METHODS A single oral dose of DHC (90 mg) was administered to 10 healthy volunteers in a randomised, double-blind, placebo-controlled study. A computerized cold pressor test (CPT) was used to measure analgesia. On each study day, the volunteers performed the CPT before study medication and at 1.25, 2.75, 4.25 and 5.75 h postdose. Blood samples were taken at 0.25 h (predose) and then at half hourly intervals for 5.75 h postdose. PK-PD link modelling was used to describe the relationships between DHC, DHM and analgesic effect. RESULTS Mean pain AUCs following DHC administration were significantly different to those following placebo administration (P = 0.001). Mean pain AUC changes were 91 score x s(-1) for DHC and -17 score x s(-1) for placebo (95% CI = +/- 36.5 for both treatments). The assumption of a simple linear relationship between DHC concentration and effect provided a significantly better fit than the model containing DHM as the active moiety (AIC = 4.431 vs 4.668, respectively). The more complex models did not improve the likelihood of model fits significantly. CONCLUSIONS The findings suggest that the analgesic effect following DHC ingestion is mainly attributed to the parent drug rather than its DHM metabolite. It can thus be inferred that polymorphic differences in DHC metabolism to DHM have little or no effect on the analgesic affect.
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Affiliation(s)
- J A Webb
- Wolfson Unit of Clinical Pharmacology, University of Newcastle, Newcastle upon Tyne, UK
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32
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Compton P, Charuvastra VC, Ling W. Pain intolerance in opioid-maintained former opiate addicts: effect of long-acting maintenance agent. Drug Alcohol Depend 2001; 63:139-46. [PMID: 11376918 DOI: 10.1016/s0376-8716(00)00200-3] [Citation(s) in RCA: 209] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Patients on methadone maintenance therapy are relatively intolerant of pain, a finding hypothesized to reflect a hyperalgesic state induced by chronic opioid administration. To explore if the intrinsic activity of the opioid maintenance agent might affect expression of hyperalgesia in this population, withdrawal latency for cold-pressor (CP) pain was compared between small groups of methadone-maintained (n = 18), buprenorphine-maintained (n = 18), and matched control (n = 18) subjects. The opioid-maintained groups had equal and significantly shorter withdrawal latencies than controls, however it is possible that high rates of continued illicit opioid use precluded finding differences between methadone and buprenorphine groups. Differential effects of maintenance agent were found for the few subjects without illicit opioid use, such that withdrawal latencies for methadone-maintained (n = 5) were less than for buprenorphine-maintained (n = 7) which were less than controls (n = 18). Diminished pain tolerance in patients receiving opioid maintenance treatment has significant clinical implications. More research is needed to determine if buprenorphine offers advantages over methadone in this regard.
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Affiliation(s)
- P Compton
- School of Nursing, University of California at Los Angeles (UCLA), Factor Building 4-246, Box 956918, Los Angeles, CA 90095-6918, USA.
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33
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Tavernor SJ, Abduljawad KA, Langley RW, Bradshaw CM, Szabadi E. Effects of pentagastrin and the cold pressor test on the acoustic startle response and pupillary function in man. J Psychopharmacol 2001; 14:387-94. [PMID: 11198057 DOI: 10.1177/026988110001400407] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pentagastrin, a cholecystokinin2 (CCK2) receptor agonist, evokes autonomic and subjective features of anxiety in healthy volunteers. The present experiments examined the effects of pentagastrin on two responses with known sensitivity to another anxiogenic procedure (threat of electric shock): the acoustic startle response and the pupillary light reflex. The effects of pentagastrin were compared with those of the cold pressor test, a procedure known to elicit sympathetic activation. Twelve healthy males (18-35 years) participated in two experiments each consisting of two sessions in which they received (1) pentagastrin (0.3 microg/kg, i.v.) and a control infusion (saline), and (2) cold pressor test (90 s hand immersion at 4 degrees C) and a control immersion (37 degrees C), using a balanced single-blind protocol. Electromyographic responses of the orbicularis oculi to 40 ms, 1 kHz, 115 dB tones ('startle responses') [Experiment 1], and miotic responses to 200 ms, 0.43 mW/cm2 light pulses [Experiment 2] were recorded before, during and after the infusions and hand immersions. Heart rate, blood pressure and subjective feelings were also recorded. The amplitude of the startle response was not significantly affected by pentagastrin, but was reduced during the cold pressor test. Resting pupil diameter increased during both pentagastrin infusion and the cold pressor test, but neither procedure altered the amplitude of the light reflex. Tachycardia, increased blood pressure and subjective anxiety were induced by both pentagastrin and the cold pressor test. The cardiovascular and mydriatic effects of pentagastrin and the cold pressor test are consistent with the known ability of these treatments to induce sympathetic activation. The anxiety induced by these treatments, unlike anxiety induced by threat of electric shock, was not accompanied by potentiation of the startle response or reduction of the miotic response. The results indicate that different anxiogenic procedures do not have equivalent effects on these reflexes.
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Affiliation(s)
- S J Tavernor
- Division of Psychiatry, University of Nottingham, UK
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Gustorff B, Felleiter P, Nahlik G, Brannath W, Hoerauf KH, Spacek A, Kress HG. The Effect of Remifentanil on the Heat Pain Threshold in Volunteers. Anesth Analg 2001. [DOI: 10.1213/00000539-200102000-00017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Gustorff B, Felleiter P, Nahlik G, Brannath W, Hoerauf KH, Spacek A, Kress HG. The effect of remifentanil on the heat pain threshold in volunteers. Anesth Analg 2001; 92:369-74. [PMID: 11159234 DOI: 10.1097/00000539-200102000-00017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Remifentanil offers a wide range of clinical uses and has been successfully combined with general anesthetics. However, there are few human experimental studies demonstrating the analgesic property of remifentanil. It was our aim to determine the analgesic effect of remifentanil with regard to dose-dependent increments in a human model of heat pain threshold assessment. Twenty healthy volunteers were randomized in a double-blinded cross-over design to receive an infusion of remifentanil or saline. The stepped infusion was increased every 5 min by 0.01 microg. kg(-1). min(-1) up to 0.17 microg. kg(-1). min(-1)and terminated in case of defined safety limits. Thermal sensory testing of the heat pain threshold was performed every 5 min at the left forearm. The dose-response relationship and the effective dose for at least 50% of the subjects (ED(50)) were determined. Remifentanil led to a clear dose-dependent increase of the heat pain threshold differing significantly from placebo (P < 0.0007). The ED(50) of remifentanil equals 0.05 microg. kg(-1). min(-1) (first quartile 0.025 microg. kg(-1). min(-1) and third quartile 0.06 microg. kg(-1). min(-1)) in this experimental setting. In conclusion, an opioid-mediated analgesic effect of remifentanil was determined in a human heat pain threshold model. The dose of 0.05 microg. kg(-1). min(-1) is an effective and safe increment in healthy volunteers.
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Affiliation(s)
- B Gustorff
- Department of Anesthesia and General Intensive Care (B), University of Vienna, Vienna, Austria.
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al'Absi M, Petersen KL, Wittmers LE. Blood pressure but not parental history for hypertension predicts pain perception in women. Pain 2000; 88:61-68. [PMID: 11098100 DOI: 10.1016/s0304-3959(00)00306-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Previous work has suggested an attenuated sensitivity to painful stimulation in hypertensive men. We recently reported that, compared with persons with negative parental history, men, but not women, with a positive history for hypertension showed attenuated pain perception. This study specifically addressed factors that predict pain perception in women, including blood pressure, parental history and mood states. Fifty-four normotensive women with positive (PH+; n = 20) or negative parental history (PH-; n = 34) for hypertension and high or low casual systolic blood pressure (BP) performed the cold pressor (CP) test. Participants rated their pain every 15 s during a 90-s hand CP (0-4 degrees C) and a 90-s post-CP rest period. Detailed mood ratings were obtained immediately before the CP test. Data were evaluated using multivariate repeated measure analyses of variance and regression analyses. PH+ and PH- women did not differ in age, height, weight, education, resting BP, or heart rate. PH+ and PH- women did not differ in pain ratings during or after the CP, or pain ratings using the McGill Pain Questionnaire (MPQ), and they did not differ in their cardiovascular responses to the CP, confirming our earlier study in a separate sample. Women with high casual systolic BP reported significantly less pain, especially after the CP (P < 0.01). MPQ total scores confirmed this finding with high BP women reporting less pain than low BP women (P < 0.05). Regression analyses confirmed these effects. Controlling for potential confounding variables did not alter these relationships. These findings suggest that in women, phenotype systolic BP may be a better predictor of hypoalgesia than parental history of hypertension.
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Affiliation(s)
- Mustafa al'Absi
- Department of Behavioral Sciences, School of Medicine, University of Minnesota, Duluth, MN 55812-2487, USA Department of Family Medicine, School of Medicine, University of Minnesota, Duluth, MN 55812-2487, USA Department of Physiology, School of Medicine, University of Minnesota, Duluth, MN 55812-2487, USA
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Radzievsky AA, Rojavin MA, Cowan A, Ziskin MC. Suppression of Pain Sensation Caused by Millimeter Waves. Anesth Analg 1999. [DOI: 10.1213/00000539-199904000-00029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Radzievsky AA, Rojavin MA, Cowan A, Ziskin MC. Suppression of pain sensation caused by millimeter waves: a double-blinded, cross-over, prospective human volunteer study. Anesth Analg 1999; 88:836-40. [PMID: 10195534 DOI: 10.1097/00000539-199904000-00029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain relief effect of millimeter waves (MW) under experimental conditions. The cold pressor test was used as a model of tonic aching pain. Twelve healthy male volunteers were exposed to an active medical MW generator and to a disabled sham generator with at least 24 h between exposures. Characteristics of continuous-wave electromagnetic output from the active generator were: wavelength 7.1 mm, incident power density 25 +/- 5 mW/cm2, and duration of exposure 30 min. MW produced a significant (P < 0.05) suppression of pain sensation, with an average 37.7% gain in pain tolerance and a 49.3% increase in pain sensitivity range (the latter being the difference between pain tolerance and pain threshold values). Of the 12 volunteers, 7 (58.3%) reacted to the active MW generator with an increased pain tolerance, and the individual reactions varied from 120% to 315% comparison with their own preexposure levels. MW therapy can potentially be used as a supplementary or alternative treatment for pain relief. IMPLICATIONS Pain management is still a significant medical problem. In a double-blinded, experimental setting, we confirmed that low-intensity millimeter wave therapy can reduce pain sensitivity in healthy human volunteers and can potentially be used as a supplementary or alternative treatment for pain relief.
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Affiliation(s)
- A A Radzievsky
- Richard J. Fox Center for Biomedical Physics, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Tabasam G, Johnson M. Electrotherapy for painrelief: does it work? A laboratory-based study to examine the analgesic effects of electrotherapy on cold-induced pain in healthy individuals. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1361-9004(99)80004-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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40
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Abstract
The blood vessels of orofacial tissues are innervated by cranial parasympathetic, superior cervical sympathetic, and trigeminal nerves, a situation somewhat different from that seen in body skin. This review summarizes our current knowledge of the nervous control of blood flow in the orofacial region, and focuses on what we know of the respective roles of sympathetic, parasympathetic, and trigeminal sensory nerves in the regulation of blood flow in this region, with particular attention being paid to the mutual interaction between them.
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Affiliation(s)
- H Izumi
- Department of Physiology, Tohoku University School of Dentistry, Sendai, Japan
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41
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Zmarzty SA, Read NW. An examination of the effects of isoenergetic intragastric infusions of pure macronutrients on cold pain perception in healthy human volunteers. Physiol Behav 1999; 65:643-8. [PMID: 10073461 DOI: 10.1016/s0031-9384(98)00231-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Our previous study demonstrated that meals, particularly when rich in fat, significantly reduced the pain induced by the cold pressor stimulus in healthy human subjects. To determine the mechanisms involved, the aim of this study was to bypass the taste and cognitive component of food and to investigate the scope of these analgesic effects with direct intragastric infusion of pure macronutrients in a group of 16 healthy human volunteers (eight male and eight female) on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on three occasions in a counterbalanced order: before and after intragastric intubation and infusion of isoenergetic fat (10% intralipid), carbohydrate (CHO-maltodextrin), and a control infusion of isotonic saline. All solutions were of equal volume and administered at room temperature. The CPT was carried out four times on each test day, once before intubation, and 0.5, 1.5, and 2.5 h after intragastric infusion. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. There were no significant differences in pain scores between the three test conditions, suggesting that by bypassing the cognitive and taste component of eating, the trigger for any postingestive analgesic effects of food are lost.
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Affiliation(s)
- S A Zmarzty
- The Department of Gerontological & Continuing Care Nursing, University of Sheffield, Nurse Education Centre, Northern General Hospital Trust
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42
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Witting N, Svensson P, Arendt-Nielsen L, Jensen TS. Differential effect of painful heterotopic stimulation on capsaicin-induced pain and allodynia. Brain Res 1998; 801:206-10. [PMID: 9729389 DOI: 10.1016/s0006-8993(98)00440-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Painful heterotopic stimulation (HTS) may inhibit experimental and clinical pain, an effect known as diffuse noxious inhibitory control (DNIC). This study examined the effect of painful HTS on capsaicin-induced pain intensity, brush-evoked pain intensity and area of brush-evoked pain in humans. Immersion of the foot into painful cold water significantly reduced capsaicin-induced pain intensity and brush-evoked pain intensity in the contralateral forearm, but did not change area of brush-evoked pain. The observed differential effect on the magnitude of pain and hyperalgesia on the one hand and area of hyperalgesia on the other suggests that the DNIC effect on spinal activity is selective and not general.
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Affiliation(s)
- N Witting
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.
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Webb J, Kamali F. Analgesic effects of lamotrigine and phenytoin on cold-induced pain: a crossover placebo-controlled study in healthy volunteers. Pain 1998; 76:357-363. [PMID: 9718254 DOI: 10.1016/s0304-3959(98)00068-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The analgesic activity of a single dose of lamotrigine (300 mg p.o.) and phenytoin (300 mg p.o.) was evaluated in a randomised, double-blind, placebo-controlled study in 12 healthy volunteers. A computerised cold-pressor test (CPT) was used to measure analgesia. Dihydrocodeine (90 mg p.o.) was used to validate the effectiveness of the CPT in measuring analgesia in the volunteers. On each study day the volunteers performed the CPT before study medication and at 1.25, 2.75, 4.25 and 5.75 h post-dose. Psychomotor tests were carried out before each CPT to determine possible drug-induced sedation. These included digit symbol substitution, critical flicker fusion and choice reaction time. Subjective feelings of concentration, vigilance and relaxation were also measured using visual analogue scales. All three active drugs significantly reduced pain scores. Maximum pain relief was achieved at 1.25 h post-dose for both dihydrocodeine and lamotrigine, whereas for phenytoin it occurred at 4.25 h post-dose. There was a significant association between analgesia and plasma concentrations of lamotrigine (P = 0.013) and phenytoin (P = 0.028). There were no significant differences in the sedation produced by any of the active drugs, compared to placebo. The findings of this study suggest that lamotrigine and phenytoin could have a wider clinical use as analgesics.
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Affiliation(s)
- James Webb
- Wolfson Unit of Clinical Pharmacology, Universify of Newcastle-upon-Tyne, Newcastle upon Tyne, NE2 4HH, UK
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Yuan CS, Karrison T, Wu JA, Lowell TK, Lynch JP, Foss JF. Dose-related effects of oral acetaminophen on cold-induced pain: a double-blind, randomized, placebo-controlled trial. Clin Pharmacol Ther 1998; 63:379-83. [PMID: 9542481 DOI: 10.1016/s0009-9236(98)90169-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cold-pressor test is a widely used pain-induction model in humans. This method has been shown to be a sensitive measure for detecting opioid analgesia. However, nonsteroidal anti-inflammatory drugs have not produced consistent analgesic effects with use of this model. The analgesic effect of acetaminophen (INN, paracetamol) on cold pressor-induced pain has not been reported by other investigators. In this study, a double-blind, randomized, placebo-controlled design was used to evaluate the dose-related effects of oral acetaminophen on cold pressor-induced pain in 18 normal healthy human subjects. We observed dose-related analgesic activity of oral acetaminophen using the cold pressor-induced pain model in these subjects. There were statistically significant main effects of both dose and time (pain and bothersomeness ratings decreased with increasing drug dose and increased over time). In pairwise comparisons only the contrast between the highest dose of acetaminophen (1000 mg) and placebo reached statistical significance. Results from our study suggest that the cold-pressor method may have clinical value in evaluating nonopioid analgesic agents.
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Affiliation(s)
- C S Yuan
- Department of Anesthesia and Critical Care, Pritzker School of Medicine, University of Chicago, Illinois 60637, USA.
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45
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Johnson MI, Wilson H. The Analgesic Effects of Different Swing Patterns of Interferential Currents on Cold-induced Pain. Physiotherapy 1997. [DOI: 10.1016/s0031-9406(05)65631-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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Zmarzty SA, Wells AS, Read NW. The influence of food on pain perception in healthy human volunteers. Physiol Behav 1997; 62:185-91. [PMID: 9226361 DOI: 10.1016/s0031-9384(97)00038-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of this study was to investigate if food could reduce pain perception in a group of 16 healthy human volunteers (8 male and 8 female), and to explore the differential effects of macronutrient composition on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on 3 occasions in a counterbalanced order, before and after administration of isoenergetic high-fat low-carbohydrate (CHO) and high-CHO low-fat meals, and when no meal was given. The CPT was carried out 4 times on each test day, once before the meal, and 0.5, 1.5, and 2.5 h after the meal, and at the equivalent times on the day when no food was given. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. Mean pain scores were significantly reduced following both meals compared with the no-food condition. The maximum reduction in pain occurred 1.5 h after ingestion, and a significantly greater effect was exerted by the high-fat low-CHO meal compared with the high-CHO low-fat meal. These results demonstrate that food, particularly when rich in fat, significantly reduces the pain induced by the cold pressor stimulus in healthy human subjects.
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Affiliation(s)
- S A Zmarzty
- University of Sheffield, Northern General Hospital Trust, Centre for Human Nutrition, UK
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47
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Zacny JP, Coalson DW, Klafta JM, Klock PA, Alessi R, Rupani G, Young CJ, Patil PG, Apfelbaum JL. Midazolam does not influence intravenous fentanyl-induced analgesia in healthy volunteers. Pharmacol Biochem Behav 1996; 55:275-80. [PMID: 8951965 DOI: 10.1016/s0091-3057(96)00082-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of saline and intravenous midazolam (0.5, 1, and 2 mg per 70 kg) in combination with intravenous fentanyl (0.1 mg/70 kg) were examined on pain induced by a cold pressor test. Healthy volunteers (six females, six males) were enrolled in a prospective, double-blind, randomized, crossover trial in which mood and psychomotor performance were also examined. Five minutes and 135 min postinjection subjects immersed their forearm in ice cold water for 3 min while assessments of pain were recorded. During the first immersion, subjects reported significantly lower pain intensity and bothersomeness ratings after having been injected with fentanyl, relative to the saline condition, but the addition of midazolam neither increased nor decreased pain reports. During the second immersion (approximately 2.5 h postinjection) pain ratings did not differ between the drug and saline conditions. Mood-altering and psychomotor-impairing effects of the drug combination were dose related. We conclude that midazolam at the doses and route of administration tested neither potentiates nor decreases the analgesia produced by fentanyl in a cold-pressor pain assay.
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Affiliation(s)
- J P Zacny
- Department of Anesthesia & Critical Care, University of Chicago, IL 60637, USA
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Tassorelli C, Micieli G, Osipova V, Rossi F, Nappi G. Pupillary and cardiovascular responses to the cold-pressor test. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1995; 55:45-9. [PMID: 8690850 DOI: 10.1016/0165-1838(95)00026-t] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Little is known about the structures and mechanisms involved in the autonomic response to sensory and nociceptive stimulation. In this study, we recorded simultaneously pupil diameter, blood pressure, heart rate and pain levels during a cold-pressor test in 10 healthy subjects. The aim was to evaluate the different components of the Autonomic Nervous System involved in the response to a thermal-painful stimulus. A biphasic pupillary response was observed: an initial, short-lasting mydriasis, followed by a miotic phase, this latter characterized by rhythmic fluctuations of pupil diameter. The blood pressure response was monophasic with a moderate increase observed from the second minute of the test. Pain intensities remained stable on medium-high levels throughout the test. The topical application of thymoxamine and homatropine clarified some aspects of the pupillary response. The systemic administration of naloxone suggested a role of opiates in the modulation of pupillary and cardiovascular response to the cold-pressor test.
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Affiliation(s)
- C Tassorelli
- Department of Neurology, University of Pavia, Italy
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49
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Pirec V, Patterson TH, Thapar P, Apfelbaum JL, Zacny JP. Effects of subanesthetic concentrations of nitrous oxide on cold-pressor pain in humans. Pharmacol Biochem Behav 1995; 51:323-9. [PMID: 7667348 DOI: 10.1016/0091-3057(94)00388-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nitrous oxide (N2O) has analgesic properties as determined in both animal and human research. In the present study, we sought to determine whether N2O given in subanesthetic concentrations would reduce cold pressor (CP)-induced pain. A crossover, double-blind study was conducted in 10 healthy volunteers. Each subject participated in four separate sessions, and in each session the effects of one of four concentrations of N2O in oxygen (0, 20, 30, and 40%) were assessed. The duration of inhalation was 40 min, and within each session, subjects immersed their nondominant arm in water (2-3 degrees C) twice for 3 min (at 10 and 30 min intrainhalation). Pain intensity, the degree to which the pain was bothersome (measured on a verbal scale of 0-10, 0 = "not at all" and 10 = "extremely" painful/bothersome), and pain quality [measured by the short-form McGill Pain Questionnaire (SF-MPQ)] were assessed during the forearm immersion. Mood effects were measured with the use of visual analogue scales (VAS) in the presence and absence of pain. Self-reported pain intensity and bothersomeness, SF-MPQ ratings of "sharp pain" and "throbbing pain," and VAS rating of "unpleasant bodily sensations" were significantly reduced by N2O (p < 0.05) in a concentration-dependent manner. Nitrous oxide had a number of effects on mood (e.g., increased VAS ratings of "stimulated," "high," "coasting," "carefree," and "having pleasant bodily sensations"). The cold-water immersion also influenced mood, but had little impact on modulating N2O effects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V Pirec
- Department of Anesthesia, Pritzker School of Medicine, University of Chicago, IL 60637, USA
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50
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Zacny JP, Coalson D, Young C, Klafta J, Rupani G, Thapar P, Choi M, Apfelbaum JL. A dose-response study of the effects of intravenous midazolam on cold pressor-induced pain. Anesth Analg 1995; 80:521-5. [PMID: 7864418 DOI: 10.1097/00000539-199503000-00015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of intravenous midazolam (0.75, 1.5, and 3 mg/70 kg) were examined and compared to that of fentanyl (0.1 mg/70 kg; positive control) and saline on pain induced by a cold pressor test. Both sensory and affective components of the pain response were assessed, as there is some evidence that benzodiazepines reduce the affective component. Healthy volunteers (three females, nine males) were enrolled in a prospective, double-blind, randomized, cross-over trial in which mood and psychomotor performance were also examined. Five minutes and 135 min postinjection, subjects immersed their forearm in ice-cold water for 3 min while assessments of pain were recorded. During the first immersion, subjects reported significantly lower pain intensity and bothersomeness ratings after having been injected with fentanyl, relative to the saline and midazolam conditions, which did not differ significantly from each other. Fentanyl and midazolam had prototypical mood altering and psychomotor impairing effects. We conclude that midazolam in our laboratory setting at the doses and route of administration studied had no effects on either the sensory or affective components of the pain experience.
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Affiliation(s)
- J P Zacny
- Department of Anesthesia and Critical Care, University of Chicago, Illinois 60637
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