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Kirihara Y, Takechi M, Kurosaki K, Kobayashi Y, Saito Y, Takeuchi T. Effects of an anesthetic mixture of medetomidine, midazolam, and butorphanol in rats-strain difference and antagonism by atipamezole. Exp Anim 2015; 65:27-36. [PMID: 26424468 PMCID: PMC4783648 DOI: 10.1538/expanim.15-0036] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
An anesthetic mixture of medetomidine (MED), midazolam (MID), and butorphanol (BUT) has
been used in laboratory animals. We previously reported that this anesthetic mixture
produced closely similar anesthetic effects in BALB/c and C57BL/6J strains. We also
demonstrated the efficacy of atipamezole (ATI), an antagonist of MED that produced quick
recovery from anesthesia in mice. Anesthetics have various anesthetic effects among animal
strains. However, the differences in the effects of anesthetic mixtures in rats are
unclear. In the present study, we first examined effects of the abovementioned anesthetic
mixture using three different rat strains: Wistar (WST), Sprague-Dawley (SD), and Fischer
344 (F344). Second, we examined how different dosages and optimum injection timing of ATI
affected recovery from anesthesia in rats. We used the anesthetic score to measure
anesthetic duration and a pulse oximeter to monitor vital signs. We found no significant
differences in anesthetic duration among the three different strains. However, recovery
from anesthesia in the SD strain took significantly longer than in the other strains. The
antagonistic effects of ATI (0.15 mg/kg and 0.75 mg/kg) were equivalent when administered
at 30 min after anesthetic mixture administration. The antagonistic effects of ATI 0.75
mg/kg were stronger than those of ATI 0.15 mg/kg at 10 min after anesthetic mixture
administration. This anesthetic mixture is a useful drug that can induce similar
anesthetic effects in three different strains and has an antagonist, ATI, that makes rats
quickly recover from anesthesia. These results may contribute to the welfare of laboratory
animals.
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Affiliation(s)
- Yumiko Kirihara
- Department of Experimental Animals, Interdisciplinary Center for Science Research, Organization for Research, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
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Bhuvad SB, Nishteswar K, Acharya R, Nariya MB. Comparative anti-inflammatory and analgesic activities of leaf powder and decoction of Chirabilva [Holoptelea integrifolia (Roxb.) Planch]. Ayu 2014; 35:339-43. [PMID: 26664243 PMCID: PMC4649570 DOI: 10.4103/0974-8520.153788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Background: Ethno-medical claims indicate that leaf of Holoptelea integrifolia (Roxb.) Planch is being used in pain, inflammatory conditions by the Koya tribes. Aim: To evaluate and compare the anti-inflammatory and analgesic activity of leaves of H. integrifolia in powder and decoction forms. Materials and Methods: The leaves of H. integrifolia were made into powder and decoction form using guidelines mentioned in Ayurvedic Pharmacopeia of India. The anti-inflammatory activity of test drug was evaluated against carrageenan and formalin induced paw edema and analgesic activity with formalin induced paw licking and tail flick response using Wistar albino rats. Results: Administration of leaf powder showed insignificant inhibition of carrageenan induced paw edema at 1 h (21.62%) compared to the control group. Administration of decoction of leaves showed insignificant inhibition of carrageenan induced paw edema at 1 h (18.12%) and 3 h (9.78%). Administration of leaf powder decreased the paw edema at 24 h (37.65%) and 48 h (66.30%) while treatment with leaf decoction showed apparent decrease in paw edema at 24 h (13.68%) and 48 h (52.42%) but failed to reach at significant level of formalin induced paw edema in rats. The test drugs did not produce any effect on radiant heat induced pain in rats and formalin induced paw licking response. Conclusion: Leaf decoction of H. integrifolia has better anti-inflammatory activity than leaf powder while they have not shown significant analgesic effects in both the experimental models.
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Affiliation(s)
- Sushama B Bhuvad
- Department of Dravyaguna, Institute for Postgraduate Teaching and Research in Ayurveda, Gujarat Ayurved University, Jamnagar, Gujarat, India
| | - K Nishteswar
- Department of Dravyaguna, Institute for Postgraduate Teaching and Research in Ayurveda, Gujarat Ayurved University, Jamnagar, Gujarat, India
| | - Rabinarayan Acharya
- Department of Dravyaguna, Institute for Postgraduate Teaching and Research in Ayurveda, Gujarat Ayurved University, Jamnagar, Gujarat, India
| | - Mukesh B Nariya
- Department of Pharmacology Laboratory, Institute for Postgraduate Teaching and Research in Ayurveda, Gujarat Ayurved University, Jamnagar, Gujarat, India
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3
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Makino K, Kohase H, Sanada T, Umino M. Phenylephrine Suppresses the Pain Modulation of Diffuse Noxious Inhibitory Control in Rats. Anesth Analg 2010; 110:1215-21. [DOI: 10.1213/ane.0b013e3181d2a768] [Citation(s) in RCA: 16] [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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Jinks SL, Carstens E, Antognini JF. Nitrous oxide-induced analgesia does not influence nitrous oxide's immobilizing requirements. Anesth Analg 2009; 109:1111-6. [PMID: 19762738 DOI: 10.1213/ane.0b013e3181b5a2a7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Nitrous oxide (N(2)O) acts on supraspinal noradrenergic neurons to produce analgesia, but it is unclear if analgesia contributes to N(2)O's immobilizing effects. We tested the hypothesis that N(2)O minimum alveolar anesthetic concentration (MAC) is unchanged after selective ablation of supraspinal noradrenergic neurons, or in naïve animals at N(2)O exposure timepoints when analgesia is absent. METHODS We determined tailflick latency (TFL) and hindpaw withdrawal latency (HPL) under 70% N(2)O, N(2)O MAC, and isoflurane MAC before and after intracerebroventricular injections of anti-dopamine-beta hydroxylase conjugated to saporin (SAP-DBH; n = 7), or a control antibody conjugated to saporin (n = 5). In a separate group of naive rats (n = 8), N(2)O MAC was determined at 25-45 min after initiation of N(2)O exposure (during peak analgesia) and again at 120-140 min (after TFL and HPL returned to baseline). RESULTS After 30 min of N(2)O exposure, TFL and HPL increased significantly but declined back to baseline within 120 min. N(2)O did not produce analgesia in rats that received SAP-DBH. However, N(2)O and isoflurane MAC were not significantly different between SAP-DBH and control-injected animals (Mean +/- sd for N(2)O: 1.7 +/- 0.1 atm vs 1.7 +/- 0.2 atm; isofurane: 1.6 +/- 0.2% vs 1.7 +/- 0.2%). In naïve animals, N(2)O MAC was not different at the 30 min period compared with the 120 min period (1.8 +/- 0.1 atm vs 1.8 +/- 0.2 atm). CONCLUSIONS Destroying brainstem noradrenergic neurons or prolonged exposure to N(2)O removes its analgesic effects, but does not change MAC. The immobilizing mechanism of N(2)O is independent from its analgesic effects.
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Affiliation(s)
- Steven L Jinks
- Department of Anesthesiology and Pain Medicine, University of California School of Medicine, Davis, CA 95616, USA.
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5
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Abstract
Multiple neuroprotective agents have shown benefit for the treatment of acute spinal cord injury (SCI) in animal studies. However, clinical trials have, thus far, been uniformly disappointing. This review explores reasons for discrepancies between promising animal studies and disappointing clinical trials and potential barriers to extrapolation of research results from animals to humans. The three major barriers disclosed are: differences in injury type between laboratory-induced SCI and clinical SCI, difficulties in interpreting functional outcome in animals, and inter-species and interstrain differences in pathophysiology of SCI. These barriers can impair the effectiveness of animal models of SCI to predict human outcomes. While some of these barriers can be overcome, others are inherent to the animal models.
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Affiliation(s)
- Aysha Z Akhtar
- Physicians Committee for Responsible Medicine, Washington, D.C. 20016, USA.
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6
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Dopamine D2-Like Receptor in the Nucleus Accumbens Is Involved in the Antinociceptive Effect of Nitrous Oxide. Anesth Analg 2008; 106:1904-9. [DOI: 10.1213/ane.0b013e318172b15b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Emmanouil DE, Quock RM. Advances in understanding the actions of nitrous oxide. Anesth Prog 2007; 54:9-18. [PMID: 17352529 PMCID: PMC1821130 DOI: 10.2344/0003-3006(2007)54[9:aiutao]2.0.co;2] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 09/09/2006] [Indexed: 02/07/2023] Open
Abstract
Nitrous oxide (N(2)O) has been used for well over 150 years in clinical dentistry for its analgesic and anxiolytic properties. This small and simple inorganic chemical molecule has indisputable effects of analgesia, anxiolysis, and anesthesia that are of great clinical interest. Recent studies have helped to clarify the analgesic mechanisms of N(2)O, but the mechanisms involved in its anxiolytic and anesthetic actions remain less clear. Findings to date indicate that the analgesic effect of N(2)O is opioid in nature, and, like morphine, may involve a myriad of neuromodulators in the spinal cord. The anxiolytic effect of N(2)O, on the other hand, resembles that of benzodiazepines and may be initiated at selected subunits of the gamma-aminobutyric acid type A (GABA(A)) receptor. Similarly, the anesthetic effect of N(2)O may involve actions at GABA(A) receptors and possibly at N-methyl-D-aspartate receptors as well. This article reviews the latest information on the proposed modes of action for these clinical effects of N(2)O.
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Affiliation(s)
- Dimitris E Emmanouil
- Department of Pediatric Dentistry, School of Dentistry, Athens University, Athens, Greece.
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8
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Antognini JF, Atherley RJ, Dutton RC, Laster MJ, Eger EI, Carstens E. The excitatory and inhibitory effects of nitrous oxide on spinal neuronal responses to noxious stimulation. Anesth Analg 2007; 104:829-35. [PMID: 17377089 DOI: 10.1213/01.ane.0000255696.11833.24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Because of the logistical obstacles to measurement under hyperbaric conditions, the effect of nitrous oxide (N2O) alone on spinal neuronal responses has not been tested. We hypothesized that, like other inhaled anesthetics, N2O would depress spinal neuronal responses to noxious stimulation. METHODS The lumbar spinal cord was exposed in rats anesthetized with isoflurane. Mechanically ventilated rats were placed into a hyperbaric chamber and needle electrodes were inserted into the hindpaws. Isoflurane administration was discontinued and anesthesia converted to N2O by pressurizing the chamber with N2O. A microelectrode was inserted into the lumbar cord using computer-controlled motors and a hydraulic microdrive. Neuronal responses to electrical stimulation of the hindpaw were sought at 1.5, 2, and 2.5 atm N2O (0.8-1.3 minimum alveolar concentration). RESULTS Increasing N2O partial pressures variably affected neuronal responses to a 2 s 100-Hz electrical stimulus. Neuronal depth and neuronal response were correlated, with superficial neurons tending to be facilitated, while deeper neurons were depressed; (overall responses were 1331 +/- 408, 1594 +/- 383, and 1578 +/- 500 impulses/min at 1.5, 2, and 2.5 atm N2O, respectively; mean, standard error). N2O did not affect neuronal responses to a repetitive "windup" stimulus. Infusion of the N-methyl-d-aspartate blocker MK-801 into separate rats increased the neuronal response to the 100-Hz stimulus (from 781 +/- 216 to 1352 +/- 269 impulses/min, P < 0.05). CONCLUSIONS N2O facilitated superficial spinal neuronal responses to noxious stimulation while depressing deeper neurons. These results suggest that anesthetic partial pressures of N2O have divergent effects on spinal neuronal responses to noxious stimulation, the specific responses depending on the depth of the spinal neurons.
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Affiliation(s)
- Joseph F Antognini
- Department of Anesthesiology and Pain Medicine, University of California, Davis, California 95616, USA.
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9
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Vahle-Hinz C, Detsch O, Hackner C, Kochs E. Corresponding minimum alveolar concentrations of isoflurane and isoflurane/nitrous oxide have divergent effects on thalamic nociceptive signalling. Br J Anaesth 2007; 98:228-35. [PMID: 17210736 DOI: 10.1093/bja/ael332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Suppression of nociceptive signalling in the thalamus is considered to contribute significantly to the anaesthetic state. Assuming additivity of anaesthetic mixtures, our study assessed the effects of corresponding minimum alveolar concentrations (MACs) of isoflurane and isoflurane/nitrous oxide on thalamic nociceptive signalling. METHODS Nociceptive response activity (elicited by controlled radiant heat stimuli applied to cutaneous receptive fields) of single thalamic neurons was compared in rats anaesthetized at approximately 1.1 and approximately 1.4 MAC isoflurane with that at approximately 1.1 and approximately 1.4 MAC isoflurane/nitrous oxide. RESULTS Under baseline anaesthesia ( approximately 0.9 MAC isoflurane), noxious stimulation elicited excitatory responses in all neurons (n = 19). These responses were uniformly suppressed at approximately 1.1 and approximately 1.4 MAC isoflurane. In contrast, at approximately 1.1 and approximately 1.4 MAC isoflurane/nitrous oxide, excitatory responses no different to baseline were still present in 64 and 37% of the neurons, respectively. CONCLUSIONS These data demonstrate a pronounced nitrous oxide-induced response variability. It appears that, with respect to thalamic transfer of nociceptive information, the interaction of isoflurane and nitrous oxide may not be compatible with the concept of additivity and that the antinociceptive potency of nitrous oxide is considerably less than previously reported.
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Affiliation(s)
- C Vahle-Hinz
- Institut für Neurophysiologie und Pathophysiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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10
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Lariviere WR, Sattar MA, Melzack R. Inflammation-Susceptible Lewis Rats Show Less Sensitivity Than Resistant Fischer Rats in the Formalin Inflammatory Pain Test and With Repeated Thermal Testing. J Neurophysiol 2006; 95:2889-97. [PMID: 16452262 DOI: 10.1152/jn.00608.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Comparisons between Lewis and Fischer inbred strains of rats are used frequently to study the effect of inherent differences in function of the hypothalamic-pituitary-adrenal axis on pain-relevant traits, including differential susceptibility to chronic inflammatory disease and differential responsiveness to analgesic drugs. Increasing use of genetic models including transgenic knockout mice and inbred strains of rodents has raised our awareness of, and the importance of, thorough characterization (or phenotyping) of the strains of rodents being compared. Furthermore, genetic variability in analgesic sensitivity is correlated with, and may be caused by, genetically determined baseline sensitivity. Thus in this study, baseline inflammatory and thermal nociceptive sensitivities were measured in awake male and female Lewis and Fischer rats to examine whether the results could explain relevant strain differences reported in the literature. The effect of maternal separation was also examined and no effect was found on nociceptive sensitivity, corticosterone responses, or the development of adjuvant-induced arthritis, a model of rheumatoid arthritis. Lewis rats and female rats were more sensitive to thermal nociception in the tail withdrawal test (mean of 3 trials) than Fischer rats and male rats, respectively. Unexpectedly, the more inflammation-susceptible Lewis rats were less sensitive in the formalin inflammatory nociception test, and showed a significant decrease in sensitivity with repeated thermal nociceptive testing, whereas Fischer rats did not. These results affect the interpretation of previously observed results. Further study of the underlying mechanisms and the relevance to differential susceptibility to chronic inflammation is warranted.
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Affiliation(s)
- William R Lariviere
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Suite A 1305 Scaife Hall, 3550 Terrace St., Pittsburgh, PA 15261, USA.
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11
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Sato Y, Seo N, Kobayashi E. Genetic background differences between FVB and C57BL/6 mice affect hypnotic susceptibility to pentobarbital, ketamine and nitrous oxide, but not isoflurane. Acta Anaesthesiol Scand 2006; 50:553-6. [PMID: 16643223 DOI: 10.1111/j.1399-6576.2006.001002.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Pharmacogenomics has allowed us to identify the mechanisms underlying much of the inherited variability in drug response. There have been several reports of strain-dependent anesthetic actions in rodents, indicating that significant genetic differences exist in the hypnotic and antinociceptive effects of various anesthetics. METHODS Loss of righting reflex was used to compare the hypnotic action of pentobarbital, ketamine, nitrous oxide and isoflurane between two genetically different populations of mice, C57BL/6 with black hair and Friends virus B (FVB) with white hair. RESULTS C57BL/6 mice were more susceptible than FVB mice to the hypnotic effects of ketamine, pentobarbital and nitrous oxide. However, the sensitivity to isoflurane did not differ between C57BL/6 and FVB mice. CONCLUSION Genetic background affects the hypnotic susceptibility to some anesthetic agents in mice. Our results indicate that there may be a different genetic basis for the operation of hypnosis between isoflurane and other anesthetics, such as pentobarbital, ketamine and nitrous oxide.
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Affiliation(s)
- Y Sato
- Department of Anesthesiology, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan
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Greenwood-Van Meerveld B, Johnson AC, Cochrane S, Schulkin J, Myers DA. Corticotropin-releasing factor 1 receptor-mediated mechanisms inhibit colonic hypersensitivity in rats. Neurogastroenterol Motil 2005; 17:415-22. [PMID: 15916629 DOI: 10.1111/j.1365-2982.2005.00648.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The potential relationship between stress and irritable bowel syndrome (IBS) symptomatology suggests a possible role for stress-mediating hormones, such as corticotropin-releasing factor (CRF), in the altered perception of stimuli in IBS patients. In previous studies, Wistar-Kyoto (WKY) rats with genetic indices of high anxiety demonstrated colonic hypersensitivity coupled with a high basal level of CRF within the central nervous system. In the current study we tested the hypothesis that a selective, non-peptide CRF1 receptor antagonist, antalarmin, would inhibit hypersensitivity in the WKY rat colon. Colonic sensitivity was determined by monitoring a visceromotor behavioural response during innocuous levels of colorectal distention (30 mmHg). In high anxiety WKY rats we found that antalarmin (20 mg kg-1, i.p.) significantly decreased the visceromotor response induced by colorectal distention. In a second study central administration (i.c.v.) of CRF was used to induce colonic hypersensitivity in lower anxiety Fischer 344 (F-344) rats, and in this model, antalarmin significantly inhibited the CRF-induced colonic hypersensitivity. In summary, a selective CRF1 receptor antagonist, antalarmin, inhibits colonic hypersensitivity apparent in WKY rats or in F-344 rats given a central administration of CRF. Our findings suggest that CRF1 receptor antagonism may represent a novel therapeutic approach for the treatment of IBS.
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Affiliation(s)
- B Greenwood-Van Meerveld
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Ramsay DS, Leroux BG, Rothen M, Prall CW, Fiset LO, Woods SC. Nitrous oxide analgesia in humans: acute and chronic tolerance. Pain 2005; 114:19-28. [PMID: 15733627 PMCID: PMC1416628 DOI: 10.1016/j.pain.2004.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Revised: 09/26/2004] [Accepted: 11/01/2004] [Indexed: 11/24/2022]
Abstract
Electrical tooth stimulation was used to investigate whether humans develop tolerance to nitrous oxide (N(2)O) analgesia within a single administration as well as over repeated administrations. In a double-blind cross-over experiment, 77 subjects received a 40-min administration of 38% N(2)O at one session and placebo gas at the other. The sessions were separated by 1 week and the order of gas administration was counterbalanced. Acute analgesic tolerance developed for pain threshold but not for detection threshold. There was no evidence of a hyperalgesic rebound effect following cessation of the N(2)O administration. In a second double-blind experiment, 64 subjects received both 30-min of placebo gas and 30-min of 35% N(2)O, separated by a 35-min gas wash-out period, during each of five sessions. Sensory thresholds were assessed prior to drug or placebo administration (baseline) and between 7-12 and 25-30 min of gas administration. A control group of 16 subjects received only placebo gas at these five sessions. During a sixth session, the experimental procedures were similar to the previous sessions except that the control group received N(2)O for the first time and the experimental group was sub-divided to test for conditioned drug effects. For both detection and pain threshold measures, acute tolerance developed during the initial N(2)O exposure and chronic tolerance developed over repeated administrations. Although chronic tolerance developed, a test for Pavlovian drug conditioning found no evidence of conditioned effects on sensory thresholds. In conclusion, acute and chronic tolerance develop to N(2)O's analgesic effects in humans.
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Affiliation(s)
- Douglas S Ramsay
- Department of Dental Public Health Sciences, University of Washington, Box 357475, Seattle, WA 98195-7475, USA.
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14
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Terner JM, Lomas LM, Smith ES, Barrett AC, Picker MJ. Pharmacogenetic analysis of sex differences in opioid antinociception in rats. Pain 2003; 106:381-391. [PMID: 14659521 DOI: 10.1016/j.pain.2003.08.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Sex differences in opioid antinociception have been reported in rodents and monkeys, with opioids being more potent in males than females. In the present study, the influence of rat strain on sex differences in opioid antinociception was examined in a warm water tail-withdrawal procedure. Antinociceptive tests were conducted with the high-efficacy micro-opioid morphine, and the less efficacious opioids buprenorphine, butorphanol and nalbuphine. Baseline nociceptive latencies were consistently higher in males than their female counterparts. Sex differences in opioid antinociception were observed in all strains tested, with the opioids being more potent and/or effective in males. The magnitude of the sex differences was related to the relative efficacy of the opioid, with morphine, buprenorphine, butorphanol and nalbuphine being on average 2.2-, 2.6-, 15.9- and 11.9-fold more potent in males. Sex differences also varied markedly across strains, with large differences consistently obtained in the F344 and F344-Sasco strains, moderate differences in the ACI, DA, Lewis, Sprague Dawley, Wistar and Wistar-Kyoto strains, and small differences in the Long Evans-Blue Spruce, Long Evans, Brown Norway and Holtzman strains. When compared across strains, there was no relationship between sex differences in nociceptive sensitivity and opioid sensitivity. These findings provide strong support for the role of genetic factors in determining sex differences in opioid antinociception, and suggest that the use of low-efficacy opioids, coupled with the use of rat strains that display small and large sex differences in opioid antinociception, may provide a sensitive tool to investigate the mechanisms underlying sex differences in opioid antinociception.
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Affiliation(s)
- Jolan M Terner
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3270, USA
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15
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Eicher SD, Dalley JW. Indicators of acute pain and fly avoidance behaviors in Holstein calves following tail-docking. J Dairy Sci 2002; 85:2850-8. [PMID: 12487452 DOI: 10.3168/jds.s0022-0302(02)74372-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous work showed that the banding process of docking minimally affected mature cows' behavior and physiology, but cutting off the necrotic tail increased haptoglobin. Additionally the docked cows had more flies on the rear legs and exhibited more fly avoidance behaviors. Because many producers dock young calves while they are in hutches where fly problems are more pronounced, we investigated changes in behavior and physiology of young calves following docking by banding. Twenty calves (3 to 5 wk of age) were assigned to a docked or control group, at each of two locations (Indiana and Wisconsin). After applying a band to dock the tail, calves were tested every 15 min for sensitivity to heat below the band at the Indiana location. Calf behavior was recorded for 2 h postbanding and analyzed continuously for that period. After 3 wk, tails were removed and then 1 wk later, fly counts and fly avoidance behaviors were observed at both locations. Tails were sensitive to heat below the banding site, for 60 to 120 min postbanding (mean 87 min). Banded calves were more active than control calves during the 2 h following banding. Percentage of time spent lying was greater for control calves, and the percentage of time spent walking was greater for docked than control calves. More importantly, movements of the head to touch the tail were increased for banded calves (eight-fold more movements). Fly avoidance behaviors directed toward the rear of the calf were evident at noon or in the afternoon. Ear twitches were more frequent for the docked calves and less frequent in the morning for all calves. Licking was more frequent for the docked calves at 1200 and 1600 h. Tail swings were most frequent at 1200 and more frequent for control calves. Two acute phase proteins, haptoglobin and alpha1 acid-glycoprotein, were not different at any time. In this study, calves that were banded at 3-wk-of-age showed behaviors indicative of discomfort for 2 h, were attacked by more flies, and showed increased fly avoidance behaviors when docked.
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Affiliation(s)
- S D Eicher
- USDA-ARS, Livestock Behavior Research Unit, 125 S. Russell St., 216 Poultry, Purdue University, West Lafayette, IN 47907, USA.
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16
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Ohashi Y, Stowell JM, Nelson LE, Hashimoto T, Maze M, Fujinaga M. Nitrous oxide exerts age-dependent antinociceptive effects in Fischer rats. Pain 2002; 100:7-18. [PMID: 12435454 DOI: 10.1016/s0304-3959(02)00098-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nitrous oxide (N(2)O) is an inhalational anesthetic/analgesic gas that has been used for clinical practice for more than a century. While its anesthetic mechanisms remain largely unknown, the underlying analgesic mechanisms are now being unraveled. It has been proposed that N(2)O induces opioid peptide release in the midbrain, leading to the activation of descending noradrenergic inhibitory neurons, which modulates pain processing within the spinal cord. Because descending noradrenergic inhibitory neurons are not functional at birth we posit that N(2)O only becomes an effective analgesic/antinociceptive agent in young patients when the descending noradrenergic inhibitory neurons become fully functional. In the present study, we have examined the age-dependence of N(2)O-induced antinociceptive effects on the formalin test. Fischer rats of various ages (7-, 15-, 19-, 23-, and 29-day-old, and adult) were injected 5% formalin into the hind paw during exposure to 75% N(2)O. Both their behavioral responses and changes in Fos-like immunoreactivity in the spinal cord were assessed as markers of N(2)O's antinociceptive effect. Adult-like antinociceptive responses to N(2)O, both behaviorally and immunohistochemically, were only present in rats older than 3 weeks (23- and 29-day-old). These findings support our hypothesis that N(2)O lacks antinociceptive effects in the very young animals.
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Affiliation(s)
- Yoko Ohashi
- Department of Anesthetics and Intensive Care, Imperial College of Science, Technology and Medicine, London, SW10 9NH, UK
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Arreto CD, Robert C, Limoge A, Gaudy JF. Use of the jaw opening reflex for assessing the effects of local anaesthetics in freely moving rats. J Pharmacol Toxicol Methods 2002; 48:45-51. [PMID: 12750041 DOI: 10.1016/s1056-8719(03)00020-0] [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: 11/20/2022]
Abstract
INTRODUCTION In order to characterize a nonbehavioral model for assessing local anaesthetic (LA) activity, the effects of different LA agents (articaine, bupivacaine, procaine, and tetracaine) were measured in the conscious rat using the jaw-opening reflex (JOR). METHODS One hundred sixty rats were chronically implanted with stimulating electrodes in the dental pulp of the low incisor. While animals were conscious and unrestrained, the JOR threshold was measured electrophysiologically via electrodes wrapped around the digastric muscle. Each LA was administered in the infratemporal area. The increase of the JOR threshold was assessed during a 3-h period following injection. RESULTS Statistical analysis of the data showed a dose-dependent response to the four drugs tested. When the highest dose of each drug (articaine and procaine: 24 mg kg(-1), bupivacaine: 6 mg kg(-1), tetracaine: 3 mg kg(-1)) was administered (i) an immediate effect was observed for tetracaine and bupivacaine, whereas a 5-min delay was needed for articaine and procaine to act on the JOR threshold and (ii) an increase (>60%) of the JOR threshold was observed. The effects lasted 90 min for articaine, 45 min for procaine and bupivacaine, and 15 min for tetracaine before a return to baseline values. DISCUSSION The rat JOR response combined with infratemporal injection of test drugs can be used for the pharmacological evaluation of LAs.
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Affiliation(s)
- C-D Arreto
- Laboratoire d'Anatomie fonctionnelle de l'appareil manducateur, Université René Descartes-Paris 5, 1, rue Maurice Arnoux, 92 120, Montrouge, France.
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Abstract
Nitrous oxide (N2O), or laughing gas, has been used for clinical anesthesia for more than a century and is still commonly used. While the anesthetic/hypnotic mechanisms of N2O remain largely unknown, the underlying mechanisms of its analgesic/antinociceptive effects have been elucidated during the last several decades. Evidence to date indicate that N2O induces opioid peptide release in the periaqueductal gray area of the midbrain leading to the activation of the descending inhibitory pathways, which results in modulation of the pain/nociceptive processing in the spinal cord. The types of opioid peptide induced by N2O and the subtypes of opioid receptors that mediate the antinociceptive effects of N2O appear to depend on various factors including the species and/or strain, the regions of the brain, and the paradigms of behavior testing used for the experiments. Among three types of descending inhibitory pathways, the descending noradrenergic inhibitory pathway seems to play the most prominent role. The specific elements involved are now being resolved.
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Affiliation(s)
- Masahiko Fujinaga
- Magill Department of Anaesthesia, Intensive Care and Pain Management Chelsea and Westminster Hospital, London, UK.
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Mills CD, Hains BC, Johnson KM, Hulsebosch CE. Strain and model differences in behavioral outcomes after spinal cord injury in rat. J Neurotrauma 2001; 18:743-56. [PMID: 11526981 DOI: 10.1089/089771501316919111] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spinal cord injury (SCI) results in loss of function below the level of injury and the development of chronic central pain (CCP) syndromes. Since different strains may develop and express chronic pain behaviors differently, we evaluated behavioral outcomes (locomotor recovery and the development of mechanical and thermal allodynia) in three commonly used strains of rats (Long-Evans, Wistar, and Sprague-Dawley) using two models of SCI. The two models examined were contusion at T10 (NYU impactor, 12.5 mm height) and the T13 hemisection. Mechanical stimulation (von Frey filaments) revealed significantly lower baseline responses for Long-Evans rats and significantly higher baseline paw withdrawal latencies to thermal stimulation for Wistar rats compared to the other strains. Following contusion SCI, Long-Evans rats had the highest percentage of animals that developed mechanical allodynia (73%), while Sprague-Dawley rats had the highest percentages (75%) following hemisection SCI. Interestingly, the Sprague-Dawley rats had the highest percentage (87%) to develop thermal allodynia following contusion SCI, while 100% of both Long-Evans and Sprague Dawley rats developed thermal allodynia in the hemisection model. Locomotor recovery after SCI was similar for each model in that Long-Evans rats recovered slower and to a lesser extent than the other strains. In each model, Sprague-Dawley rats recovered faster and achieved greater function. Overall, the hemisection model produced a larger percentage of animals that developed CCP and had greater responses to mechanical stimulation. Thus, it appears that strain selection has a greater impact on locomotor recovery and model selection has a greater impact on the development of CCP following SCI. Furthermore, these results suggest that genetic factors may play a role in recovery following SCI.
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Affiliation(s)
- C D Mills
- Department of Anatomy and Neurosciences. University of Texas Medical Branch at Galveston, 77555-1043, USA
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Antinociceptive action of nitrous oxide is mediated by stimulation of noradrenergic neurons in the brainstem and activation of [alpha]2B adrenoceptors. J Neurosci 2001. [PMID: 11125002 DOI: 10.1523/jneurosci.20-24-09242.2000] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although nitrous oxide (N(2)O) has been used to facilitate surgery for >150 years, its molecular mechanism of action is not yet defined. Having established that N(2)O-induced release of norepinephrine mediates the analgesic action at alpha(2) adrenoceptors in the spinal cord, we now investigated whether activation of noradrenergic nuclei in the brainstem is responsible for this analgesic action and which alpha(2) adrenoceptor subtype mediates this property. In rats, Fos immunoreactivity was examined in brainstem noradrenergic nuclei after exposure to nitrous oxide. After selective lesioning of noradrenergic nuclei by intracerebroventricular application of the mitochondrial toxin saporin, coupled to the antibody directed against dopamine beta hydroxylase (DbetaH-saporin), the analgesic and sedative actions of N(2)O were determined. Null mice for each of the three alpha(2) adrenoceptor subtypes (alpha(2A), alpha(2B), and alpha(2C)), and their wild-type cohorts, were tested for their antinociceptive and sedative response to N(2)O. Exposure to N(2)O increased expression of Fos immunoreactivity in each of the pontine noradrenergic nuclei (A5, locus coeruleus, and A7). DbetaH-saporin treatment eliminated nearly all of the catecholamine-containing neurons in the pons and blocked the analgesic but not the sedative effects of N(2)O. Null mice for the alpha(2B) adrenoceptor subtype exhibited a reduced or absent analgesic response to N(2)O, but their sedative response to N(2)O was intact. Our results support a pivotal role for noradrenergic pontine nuclei and alpha(2B) adrenoceptors in the analgesic, but not the sedative effects of N(2)O. Previously we demonstrated that the analgesic actions of alpha(2) adrenoceptor agonists are mediated by the alpha(2A) subtype; taken together with these data we propose that exogenous and endogenous alpha(2) adrenoceptor ligands activate different alpha(2) adrenoceptor subtypes to produce their analgesic action.
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