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Evaluation of acute and chronic nociception in subchronically administered MK-801-induced rat model of schizophrenia. Behav Pharmacol 2021; 32:571-580. [PMID: 34494988 DOI: 10.1097/fbp.0000000000000651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Patients diagnosed with schizophrenia have been reported to exhibit atypically low pain sensitivity and to vary in their experience of chronic pain. To the best of our knowledge, there has yet to be an animal study that provides information concerning the relationship between models of schizophrenia and pain. In the present study, we investigated several distinct nociceptive behaviors in a translational rat model of schizophrenia (0. 5 mg/kg MK-801, twice a day for 7 days followed by a 7-day washout period). The presence of the expected cognitive deficit was confirmed with novel object recognition (NOR) paradigm prior to nociception testing. MK-801-treated rats with lack of novelty interest in NOR testing showed: hyposensitivity to thermal and mechanical stimuli; short-term hypoalgesia followed by augmented hyperalgesia in response to formalin-induced spontaneous nociception and increased thermal and mechanical hyperalgesia in the complete Freund's adjuvant (CFA) induced chronic pain model. In conclusion, MK-801 induced antinociception effects for thermal stimuli in rats that were consistent with the decreased pain sensitivity observed in schizophrenia patients. Additionally, the amplified biphasic response exhibited by the MK-801 group in the formalin-induced spontaneous nociception test affirms the suitability of the test as a model of acute to delayed pain transition.
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Atwal N, Winters BL, Vaughan CW. Endogenous cannabinoid modulation of restraint stress-induced analgesia in thermal nociception. J Neurochem 2019; 152:92-102. [PMID: 31571215 DOI: 10.1111/jnc.14884] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/25/2019] [Indexed: 11/30/2022]
Abstract
It is thought that endogenous cannabinoids have a role in the analgesia induced by specific forms of stress. We examined if the role of endogenous cannabinoids is also dependent upon the mode of nociception, and whether this could be altered by drugs which block their enzymatic degradation. In C57BL/6 mice, restraint stress produced analgesia in the hot-plate and plantar tests, two thermal pain assays that engage distinct supraspinal and spinal nociceptive pathways. Stress-induced analgesia in the hot-plate test was abolished by pre-treatment with the opioid receptor antagonist naltrexone but was unaffected by the cannabinoid receptor antagonist 1-(2,4-Dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide (AM281). By contrast, stress-induced analgesia in the plantar test was abolished by pre-treatment with naltrexone plus AM281, but not by either antagonist individually. Remarkably, inhibiting the breakdown of endocannabinoids, with the dual fatty acid amide hydrolase and monoacylglycerol lipase inhibitor JZL195, rescued stress-induced analgesia in the hotplate test when endogenous opioid signalling was blocked by naltrexone. Furthermore, JZL195 recruited analgesia induced by sub-threshold restraint stress in both thermal pain assays. These findings indicate the role of endocannabinoids in stress-induced analgesia differs with the type of thermal pain behaviour. However, by inhibiting their breakdown, endocannabinoids can be recruited to substitute for endogenous opioid signalling when their activity is blocked, indicating a degree of redundancy between opioid and cannabinoid systems. Together these data suggest targeting endocannabinoid breakdown could provide an alternative, or adjuvant to mainstream analgesics such as opioids.
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Affiliation(s)
- Nicholas Atwal
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Bryony L Winters
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Christopher W Vaughan
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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Bahremand T, Payandemehr P, Riazi K, Noorian AR, Payandemehr B, Sharifzadeh M, Dehpour AR. Modulation of the anticonvulsant effect of swim stress by agmatine. Epilepsy Behav 2018; 78:142-148. [PMID: 29195160 DOI: 10.1016/j.yebeh.2017.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 10/29/2017] [Accepted: 11/05/2017] [Indexed: 02/07/2023]
Abstract
Agmatine is an endogenous l-arginine metabolite with neuroprotective effects in the stress-response system. It exerts anticonvulsant effects against several seizure paradigms. Swim stress induces an anticonvulsant effect by activation of endogenous antiseizure mechanisms. In this study, we investigated the interaction of agmatine with the anticonvulsant effect of swim stress in mice on pentylenetetrazole (PTZ)-induced seizure threshold. Then we studied the involvement of nitric oxide (NO) pathway and endogenous opioid system in that interaction. Swim stress induced an anticonvulsant effect on PTZ seizures which was opioid-independent in shorter than 1-min swim durations and opioid-dependent with longer swims, as it was completely reversed by pretreatment with naltrexone (NTX) (10mg/kg), an opioid receptor antagonist. Agmatine significantly enhanced the anticonvulsant effect of opioid-independent shorter swim stress, in which a combination of subthreshold swim stress duration (45s) and subeffective dose of agmatine (1mg/kg) revealed a significantly higher seizure threshold compared with either one. This effect was significantly reversed by NO synthase inhibitor NG-nitro-l-arginine (L-NAME (Nω-Nitro-L-arginine methyl ester), 5mg/kg), suggesting an NO-dependent mechanism, and was unaffected by NTX (10mg/kg), proving little role for endogenous opioids in the interaction. Our data suggest that pretreatment of animals with agmatine acts additively with short swim stress to exert anticonvulsant responses, possibly by mediating NO pathway.
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Affiliation(s)
- Taraneh Bahremand
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Pooya Payandemehr
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Kiarash Riazi
- Hotchkiss Brain Institute, Department of Physiology & Pharmacology, University of Calgary, Canada
| | - Ali Reza Noorian
- Stroke Program, Kaiser Permanente Orange County, Irvine, CA, United States
| | - Borna Payandemehr
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Sharifzadeh
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Khan J, Benavent V, Korczeniewska OA, Benoliel R, Eliav E. Exercise-Induced Hypoalgesia Profile in Rats Predicts Neuropathic Pain Intensity Induced by Sciatic Nerve Constriction Injury. THE JOURNAL OF PAIN 2014; 15:1179-1189. [DOI: 10.1016/j.jpain.2014.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 01/07/2023]
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Souvlis T, Wright A. The tolerance effect: its relevance to analgesia produced by physiotherapy interventions. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/ptr.1997.2.4.227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Quintero GC, Herrera J, Bethancourt J. Cortical NR2B NMDA subunit antagonism reduces inflammatory pain in male and female rats. J Pain Res 2011; 4:301-8. [PMID: 22003303 PMCID: PMC3191929 DOI: 10.2147/jpr.s24703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background Studies have shown that N-methyl-D-aspartate (NMDA) receptors play a critical role in pain processing at different levels of the central nervous system. Methods In this study, we used adult Wistar rats to examine gender differences in the effects of NR2B NMDA antagonism at the level of the anterior cingulate cortex in phasic pain, and in the first and second phases of a formalin test. Rats underwent stereotactic surgery for cannula implantation in the anterior cingulate cortex. After recovery, paw withdrawal latency to a noxious thermal stimulus was assessed. Rats were also subjected to a formalin pain test whereby 60 μL of 5% formalin was injected into the right hind paw. Results Female and male rats that received Ro 25-6981, an NR2B antagonist, before formalin injection showed significantly reduced pain responses to the formalin test compared with saline-injected control rats (P < 0.05). No gender differences in phasic pain responses were found in rats treated with Ro 25-6981. Conclusion These results suggest that cortical antagonism of the NR2B subunit reduces inflammatory pain levels in both genders of rat.
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Affiliation(s)
- Gabriel C Quintero
- Institute of Scientific Research and High Technology Services (INDICASAT-AIP), Center for Neurosciences, Panama
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Takahashi T, Morinobu S, Iwamoto Y, Yamawaki S. Effect of paroxetine on enhanced contextual fear induced by single prolonged stress in rats. Psychopharmacology (Berl) 2006; 189:165-73. [PMID: 17031709 DOI: 10.1007/s00213-006-0545-6] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 07/29/2006] [Indexed: 11/28/2022]
Abstract
RATIONALE Single prolonged stress (SPS) is an animal model of posttraumatic stress disorder (PTSD) that can reproduce enhanced hypothalamo-pituitary-adrenal negative feedback. OBJECTIVES We examined whether SPS can produce an enhanced psychophysiological reactivity to laboratory stressors unrelated to trauma and whether paroxetine (PRX) can alleviate the enhanced anxiety and fear response in rats subjected to SPS. Furthermore, the effect of PRX on pain sensitivity was examined in rats with and without SPS. METHODS Rats were subjected to SPS (restraint for 2 h, forced swim for 20 min, and ether anesthesia) and then kept undisturbed for 14 days. After that, contextual fear response was assessed. Twenty-four hours after foot shock conditioning, freezing behavior was measured during reexposure to the shock environment for 3 min. Pain sensitivity was assessed by the flinch-jump test. PRX (0.01, 0.03, or 0.1 mg/mL) was chronically administered orally in drinking water. RESULTS Rats subjected to SPS showed a significant increase in contextual freezing compared to rats without SPS. Chronic administration of PRX at concentrations of 0.03 and 0.1 mg/mL (which produced serum concentrations similar to those that are clinically relevant) caused significant suppression of the enhanced contextual freezing. Acute administration of PRX at a dose producing clinically relevant serum concentrations did not affect the enhanced freezing. CONCLUSIONS Our results suggest that SPS can reproduce behavioral alteration similar to that observed in patients with PTSD, and this elevated fear response can be alleviated by the chronic administration of PRX at doses producing clinically relevant serum concentrations.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Conditioning, Psychological
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Electroshock
- Ether/pharmacology
- Fear/drug effects
- Fear/psychology
- Freezing Reaction, Cataleptic/drug effects
- Male
- Motor Activity/drug effects
- Pain Measurement
- Pain Threshold/drug effects
- Paroxetine/blood
- Paroxetine/pharmacology
- Paroxetine/therapeutic use
- Rats
- Rats, Sprague-Dawley
- Restraint, Physical
- Selective Serotonin Reuptake Inhibitors/blood
- Selective Serotonin Reuptake Inhibitors/pharmacology
- Selective Serotonin Reuptake Inhibitors/therapeutic use
- Stress Disorders, Post-Traumatic/drug therapy
- Stress Disorders, Post-Traumatic/psychology
- Swimming
- Vocalization, Animal/drug effects
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Affiliation(s)
- Terumichi Takahashi
- Department of Psychiatry and Neurosciences, Division of Frontier Medical Science, Hiroshima University, Minami-ku, Hiroshima, 734-8551, Japan
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Fazli-Tabaei S, Yahyavi SH, Nouri M, Zartab H, Javid G, Loghavi S, Zarrindast MR. Dopamine receptor mechanism(s) and antinociception and tolerance induced by swim stress in formalin test. Behav Pharmacol 2006; 17:341-7. [PMID: 16914952 DOI: 10.1097/01.fbp.0000224383.63744.69] [Citation(s) in RCA: 7] [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
In the present study, involvement of D1 and D2 dopamine receptors in the antinociception and tolerance induced by water swim stress in the formalin test has been investigated. Water swim stress at 20 degrees C temperature induced antinociception in both phases of the formalin test. Intraperitoneal administration of the D2 dopamine receptor antagonist, sulpiride (25 and 50 mg/kg) reduced swim stress-induced antinociception in the second phase of the formalin test. A higher dose of the D1 dopamine receptor antagonist, SCH23390 (0.1 mg/kg, intraperitoneal) also reduced swim stress-induced antinociception in both phases of the test. Exposure to 3 min water swimming stress, once daily for 3 days, induced tolerance to swim stress-induced antinociception in the second phase of the formalin test. Administration of sulpiride (12.5, 25 and 50 mg/kg), during exposure to water swimming stress (once daily for 3 days), decreased tolerance in the second phase, whereas the antagonist (12.5 and 50 mg/kg) increased pain scores in the first phase of the formalin test. Sulpiride (25 mg/kg) treatment however, once daily for 3 days with no water swimming stress, did not alter swim stress-induced antinociception (0.5, 1 and 3 min tests). Similarly, repeated treatment with SCH23390 (0.05 mg/kg) and water swimming stress did not alter tolerance induced by water swimming stress. Repeated administration of the antagonist in the absence of water swimming stress also did not change swim stress-induced antinociception. The results may indicate a possible involvement of both dopamine D1 and D2 receptors in the antinociception induced by swim stress and D2 receptor mechanism in the tolerance induced by repeated swim stress.
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Fazli-Tabaei S, Yahyavi SH, Alagheband P, Samie HR, Safari S, Rastegar F, Zarrindast MR. Cross-tolerance between antinociception induced by swim-stress and morphine in formalin test. Behav Pharmacol 2006; 16:613-9. [PMID: 16286812 DOI: 10.1097/00008877-200512000-00003] [Citation(s) in RCA: 9] [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
The present study investigated cross-tolerance between antinociception induced by water swim-stress and morphine in the formalin test. Intraperitoneal administration of morphine (3, 6 and 9 mg/kg) induced dose-dependent antinociception in both phases of the formalin test. Mice treated with a lower dose of morphine (25 mg/kg), once daily for 3 days, showed tolerance to antinociception induced by a lower test dose of morphine (3 mg/kg). Similar repeated treatments with a higher dose of morphine (50 mg/kg) produced tolerance to antinociception induced by different test doses of morphine (3, 6 and 9 mg/kg). Exposure to water swim-stress, once daily for 2 or 3 days in order to induce tolerance, also decreased morphine-induced antinociception. Swim-stress exposure for 2 or 3 days also tends to potentiate tolerance induced by a lower dose of morphine. Acute swim-stress of different durations (0.5, 1 and 3 min) induced antinociception in both phases of the formalin test, which was not reduced by naloxone, but showed even more antinociception in the second phase. The response to swim stress was decreased in mice treated with higher doses of morphine, but not those animals that received swimming stress (3 min) once daily for 2-3 days, in order to induce habituation to swim-stress-induced antinociception. The results may indicate a possible cross-tolerance between antinociception induced by morphine and by swim stress.
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Kolesnikov Y, Cristea M, Oksman G, Torosjan A, Wilson R. Evaluation of the tail formalin test in mice as a new model to assess local analgesic effects. Brain Res 2005; 1029:217-23. [PMID: 15542077 DOI: 10.1016/j.brainres.2004.09.058] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2004] [Indexed: 10/26/2022]
Abstract
Opioids are effective topical analgesics in the radiant heat tailflick assay and display synergistic interactions with a number of other classes of drugs. To determine whether these actions extend to other types of nociception, we examined the actions of topical morphine and lidocaine in a tail formalin assay in the mouse. Formalin responses in the tail were similar to those seen in the hind paw, but were limited to licking. Unlike the traditional hind paw assay, the time-course of nociceptive behavior in the tail was monophasic; lasting 40-60 min. Morphine, MK-801 and acetylsalicylic acid (ASA) were active systemically in the tail formalin assay with potencies similar to those seen in the second phase of the paw formalin test. Both morphine and lidocaine were active topically in the tail formalin assay, although their time-course of action appeared to be shorter than that of the formalin. However, morphine displayed ceiling effect not seen when it was administered systemically. Lidocaine also had a ceiling effect. When given together, the response to the combination was supra-additive, consistent with our prior studies showing synergy in the radiant heat tailflick assay. These studies validate the formalin assay in the tail and support the topical actions of opioids and other drugs in a second pain model. They also suggest supra-additive interactions between morphine and lidocaine similar to those previously seen. The tail formalin assay will be valuable in assessing the activity of topical drugs.
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Affiliation(s)
- Yuri Kolesnikov
- Department of Anesthesiology and Critical Care, Memorial-Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10021, USA.
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Vendruscolo LF, Takahashi RN. Synergistic interaction between mazindol, an anorectic drug, and swim-stress on analgesic responses in the formalin test in mice. Neurosci Lett 2004; 355:13-6. [PMID: 14729223 DOI: 10.1016/j.neulet.2003.10.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The present study examined the interaction between mazindol (MZ), an anorectic drug extensively used in Brazil and opioid/non-opioid endogenous analgesic systems activated by swim-stress. Further, the role of opioid, dopamine and N-methyl-D-aspartate (NMDA) receptors in mediating the analgesic effect was evaluated. The stress-induced analgesia of a 3-min swimming at 32 degrees C (opioid/non-opioid) and 20 degrees C (non-opioid) were assessed using the formalin test. Male Swiss mice were intraperitoneally injected with naloxone (1.0 mg/kg), sulpiride (3.0 mg/kg), MK-801 (0.075 mg/kg) or saline/vehicle 15 min prior, and with MZ (0.5 mg/kg) or saline/vehicle 5 min prior to swimming. The dose of MZ (0.5 mg/kg) did not cause analgesic effect, however, the association of MZ and swim-stress at both temperatures displayed synergistic interaction on analgesia that was blocked by sulpiride and MK-801 but not by naloxone. The present results suggest that MZ and swim-stress acted synergistically on analgesic responses, involving mainly the non-opioid component and possibly mediated by dopamine D2 receptors and NMDA receptors.
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Affiliation(s)
- Leandro Franco Vendruscolo
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, R. Ferreira Lima, 82, Florianópolis, SC 88015-420, Brazil
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Zarrindast MR, Vousooghi N, Sahebgharani M. Imipramine-induced antinociception in the formalin test. Receptor mechanisms involved and effect of swim stress. Pharmacology 2003; 68:154-61. [PMID: 12784087 DOI: 10.1159/000070173] [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] [Received: 10/10/2002] [Accepted: 01/24/2003] [Indexed: 11/19/2022]
Abstract
This study concerned the effect of swim stress on imipramine-induced antinociception in mice. The data showed that intraperitoneal (i.p.) administration of different doses of imipramine (10-40 mg/kg) and 0.5-3 min of swim stress (17 degrees C) induced antinociception in the first and second phases of the formalin test. Low period of swim stress (10 s) with low doses of imipramine (2.5, 5 and 10 mg/kg i.p.), which did not have any effect by themselves, in combination showed antinociception in the second phase of the test. Either yohimbine (0.5 mg/kg i.p.) or naloxone (1 mg/kg i.p.) reversed the response induced by the combination of low doses of imipramine plus swim stress. Yohimbine (1 mg/kg i.p.) decreased the response of imipramine (20 mg/kg i.p.) but not that of 30 s swim stress in the second phase. However, naloxone (1 mg/kg i.p.) reduced the antinociception induced by imipramine (20 mg/kg i.p.) or 30 s swim stress in the second phase of the test, the combination of imipramine with swim stress was not altered by yohimbine or naloxone. Prazosin induced antinociception by itself in the first phase of the test and increased swim-stress-induced antinociception with no interaction. It is concluded that antinociception induced by imipramine in the second phase of formalin test may be mediated through alpha(2)-adrenoceptor antagonists. The results indicate that the responses of swim stress and imipramine may be mediated by an opioid mechanism, but the combination of both drugs induced higher antinociceptive effects.
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Affiliation(s)
- Mohammad-Reza Zarrindast
- Department of Pharmacology, School of Medicine, Tehran University of Medical Science, Tehran, Iran.
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Mingoti GZ, Pereira RN, Monteiro CMR. Fertility of male adult rats submitted to forced swimming stress. Braz J Med Biol Res 2003; 36:677-81. [PMID: 12715088 DOI: 10.1590/s0100-879x2003000500016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32 degrees C daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 +/- 1.25 s for control males vs 26.0 +/- 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 +/- 5.41 vs 127.02 +/- 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis.
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Affiliation(s)
- G Z Mingoti
- Departamento de Produ o e Sa de Animal, Medicina Veterin ria, Universidade Estadual Paulista, Ara atuba, SP, Brasil.
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Heinricher MM, Schouten JC, Jobst EE. Activation of brainstem N-methyl-D-aspartate receptors is required for the analgesic actions of morphine given systemically. Pain 2001; 92:129-38. [PMID: 11323134 DOI: 10.1016/s0304-3959(00)00480-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The analgesic actions of opioids are in large part mediated by activation of brainstem pain modulating neurons that depress nociceptive transmission at the level of the dorsal horn. The present study was designed to characterize the contribution of N-methyl-D-aspartate (NMDA)- and non-NMDA-mediated excitatory transmission within the rostral ventromedial medulla (RVM) to the activation of brainstem inhibitory output neurons and analgesia produced by systemic morphine administration. The NMDA receptor antagonist D-2-amino-5-phosophonopentanoic acid (AP5), the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione disodium (CNQX) or saline was infused into the RVM of lightly anesthetized rats while recording the activity of identified pain modulating neurons: 'off-cells', thought to inhibit nociceptive transmission, and 'on-cells', thought to facilitate nociception. Nociceptive responsiveness (tail flick latency) was not affected by either antagonist. AP5, but not CNQX, attenuated or blocked activation and disinhibition of off-cells and the antinociception produced by systemically administered morphine. Reflex-related discharge of on-cells was unaffected by AP5, but significantly attenuated by CNQX. The present results highlight two important aspects of RVM pain modulatory circuits. First, morphine given systemically produces its analgesic effect at least in part by recruiting an NMDA-mediated excitatory process to activate off-cells within the RVM. This excitatory process may play a role in the analgesic synergy produced by simultaneous mu-opioid activation at different levels of the neuraxis. Second, reflex-related activation of on-cells is mediated by a non-NMDA receptor, and this activation does not appear to play a significant role in regulating reflex responses to acute noxious stimuli. Excitatory amino acid-mediated excitation thus has at least two distinct roles within the RVM, activating off-cells and on-cells under different conditions.
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Affiliation(s)
- M M Heinricher
- Department of Neurological Surgery, Oregon Health Sciences University, OR, Portland 97201, USA.
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Chung KM, Song DK, Huh SO, Kim YH, Choi MR, Suh HW. Supraspinal NMDA and non-NMDA receptors are differentially involved in the production of antinociception by morphine and beta-endorphin administered intracerebroventricularly in the formalin pain model. Neuropeptides 2000; 34:158-66. [PMID: 11021975 DOI: 10.1054/npep.2000.0805] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Our previous studies have demonstrated that supraspinal glutamate receptors are differentially involved in the antinociception induced by morphine and beta-endorphin given intracerebroventricularly (i.c.v.) in the tail-flick and hot-plate tests. The formalin pain test was used in the present study. Injection of mice with formalin solution (2%, 10 microl) into the hindpaw intraplantarly produced the first (0-5 min) and second (20-40 min) phases of formalin responses. The formalin responses in the both phases were attenuated dose-dependently by morphine (0.125-1 microg) or beta-endorphin (0.125-1 microg) administered i.c.v. 5 min before. The antinociceptive effect of morphine was slightly more potent in the second phase whereas the effect of beta-endorphin was more pronounced in the first phase. MK-801 (0.1-1 microg), a non-competitive NMDA receptor antagonist, and CNQX (0.05-0.5 microg), a non-NMDA antagonist, given i.c.v., produced antinociceptive effect in the both phases, but only in a partial manner. Both MK-801 (0.05 microg) and CNQX (0.01 microg), at the dose which had no intrinsic effect, reversed the antinociceptive effect of beta-endorphin (1 microg) observed during the second, but not the first, phase partially but significantly. However, the antinociceptive effect of morphine (1 microg) was not affected by the same dose of MK-801 or CNQX given i.c.v. Our results indicate that, at the supraspinal level, both NMDA and non-NMDA receptors are involved in the production of antinociception induced by supraspinally administered beta-endorphin, but not morphine, in the formalin pain model.
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Affiliation(s)
- K M Chung
- Department of Pharmacology and Institute of Natural Medicine, College of Medicine, Hallym University, 1 Okchun-Dong, Chunchon, Kangwon-Do 200-702, S. Korea
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16
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Abstract
Opioid and psychostimulant drugs have long been used for the relief of chronic pain in the clinical situation. Animal studies confirm that these drugs alleviate persistent or tonic pain. Little is known, however, about the neural systems underlying the suppression of tonic pain except that they are different from those mediating the suppression of phasic (i.e., sharp and short-lasting) pain. Although spinal and brainstem-descending pain suppression mechanisms play a role in mediating the inhibition of tonic pain, it appears that this response is additionally mediated by the activation of mechanisms lying rostral to the brainstem. Recent studies suggest that the activation of mesolimbic dopamine (DA) neurons, arising from the cell bodies of the ventral tegmental area (VTA) and projecting to the nucleus accumbens (NAcc), plays an important role in mediating the suppression of tonic pain. Other studies suggest that this pain-suppression system involving the activation of mesolimbic DA neurons is naturally triggered by exposure to stress, through the endogenous release of opioids and substance P (SP) in the midbrain.
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Affiliation(s)
- N Altier
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montreal, Quebec, Canada
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17
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Bell RL, Soignier RD, Olson RD, Vaccarino AL. Reduction of stress-induced analgesia following ethanol exposure in mice. Life Sci 1998; 63:731-6. [PMID: 9740310 DOI: 10.1016/s0024-3205(98)00328-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the present study, we examined the effects of ethanol treatment on the subsequent expression of opioid and nonopioid forms of swim stress-induced analgesia (SSIA). In Experiment 1, mice were injected with ethanol (2.5 g/kg, i.p.) or an equal volume of saline once a day for two days. Animals received no treatment on day 3. On day 4, the animals were tested for opioid (3-min swim in water maintained at 32 degrees C) or nonopioid (3-min swim in water maintained at 20 degrees C) SSIA in the hotplate test (52 degrees C). Mice pretreated with ethanol injections showed a decrease in nonopioid SSIA, but not in opioid SSIA. In Experiment 2, mice were given an ethanol solution (10%) or tap water to drink for 15 days. On day 16, all animals were given tap water to drink. On day 17, the animals were tested for opioid or nonopioid SSIA. Neither form of SSIA was modified in mice that drank the ethanol solution. These results show that ethanol pretreatment can modify nonopioid endogenous analgesic responses in mice. Further, the route of administration influences the effects of ethanol pretreatment on SSIA.
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Affiliation(s)
- R L Bell
- Department of Psychology, University of New Orleans, LA 70148, USA
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18
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Bespalov A, Kudryashova M, Zvartau E. Prolongation of morphine analgesia by competitive NMDA receptor antagonist D-CPPene (SDZ EAA 494) in rats. Eur J Pharmacol 1998; 351:299-305. [PMID: 9721021 DOI: 10.1016/s0014-2999(98)00324-0] [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
A possible future clinical application of NMDA receptor antagonists is the control of the development of opiate analgesic tolerance. Therefore, the ability of NMDA receptor antagonists to modify the acute analgesic effects of opiates becomes increasingly important. The present study sought to evaluate the analgesic potency of combined administration of morphine (5-20 mg/kg) and a competitive NMDA receptor antagonist D-CPPene (SDZ EAA 494; 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid; 0.3-5.6 mg/kg) in the tail-flick and tail-pinch tests with rats. It was found that D-CPPene significantly increased the duration of morphine analgesia, but there was hardly any evidence for potentiation of morphine analgesia shortly after morphine administration. This effect could only in part be attributed to the D-CPPene-induced disruption of the development of 'learned hyperresponsiveness' (i.e., acquisition of decreased latencies to escape from repeated exposures to noxious stimulation). In addition, the plasma concentration of morphine was not affected by concurrent treatment with D-CPPene.
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Affiliation(s)
- A Bespalov
- Department of Psychopharmacology, Institute of Pharmacology, Pavlov Medical University, St.-Petersburg, Russia.
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19
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Hopkins E, Spinella M, Pavlovic ZW, Bodnar RJ. Alterations in swim stress-induced analgesia and hypothermia following serotonergic or NMDA antagonists in the rostral ventromedial medulla of rats. Physiol Behav 1998; 64:219-25. [PMID: 9748086 DOI: 10.1016/s0031-9384(98)00055-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Serotonergic, NMDA, or opioid antagonists in the rostral ventromedial medulla (RVM) reduce morphine analgesia elicited from the periaqueductal gray (PAG). Continuous (CCWS) and intermittent (ICWS) cold-water swims elicit respective naltrexone-insensitive and naltrexone-sensitive analgesic responses. CCWS analgesia is reduced by systemic NMDA receptor antagonism and by systemic, but not intrathecal serotonergic antagonism. ICWS analgesia is reduced by both systemic and intrathecal serotonergic antagonism, but unaffected by systemic NMDA antagonism. The present study evaluated whether serotonergic (methysergide: 5-10 microg) or competitive [AP7 (2-amino-7-phosphonoheptanoic acid): 0.01-0.1 microg] or non-competitive [MK-801 (dizocilipine maleate): 0.3-3 microg] NMDA antagonists in the RVM altered CCWS and ICWS analgesia and hypothermia as well as basal nociceptive latencies. Methysergide in the RVM significantly potentiated CCWS, but not ICWS analgesia. In contrast, AP7 in the RVM significantly potentiated ICWS analgesia. Antagonist-induced changes in either hypothermia or basal nociception failed to account for any alterations in stress-induced analgesia. These data suggest that serotonergic, but not NMDA, receptors in the RVM may mediate collateral inhibition between mesencephalic morphine analgesia and naltrexone-insensitive CCWS analgesia.
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Affiliation(s)
- E Hopkins
- Neuropsychology Doctoral Subprogram, Queens College, City University of New York, Flushing 11367, USA
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20
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Kavaliers M, Choleris E. Sex differences in N-methyl-D-aspartate involvement in kappa opioid and non-opioid predator-induced analgesia in mice. Brain Res 1997; 768:30-6. [PMID: 9369297 DOI: 10.1016/s0006-8993(97)00569-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
There are suggestions of sex differences in N-methyl-D-aspartate (NMDA) receptor system involvement in the mediation of analgesia. The present study examined the effects of the specific, competitive NMDA antagonist, NPC 12626, on the nociceptive (50 degrees C hot plate) responses of reproductive male and female laboratory mice exposed to (i) an ethologically relevant aversive stimulus, the odor of a predator and (ii) administration of the kappa opiate agonist, U69,593. A 30-s exposure to 2-propylithietane, the major component of weasel odor, elicited a 'non-opioid' analgesia that was in both sexes insensitive to naloxone and the kappa opiate antagonist nor-binaltorphimine. In male mice this non-opioid analgesia was antagonized by NPC 1262, while in reproductive females the predator-induced analgesia was insensitive to NPC 12626. Similarly, NPC 12626 attenuated the analgesic effects of the kappa opiate agonist, U69,593, in male mice while having no significant effects on the equivalent levels of kappa opiate analgesia in females. These results show that there are sex differences in NMDA involvement in the expression and, or mediation of both non-opioid stress-induced and kappa opiate-mediated analgesia.
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Affiliation(s)
- M Kavaliers
- Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada.
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21
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Fuchs PN, Melzack R. Repeated cold water swim produces delayed nociceptive responses, but not analgesia, for tonic pain in the rat. Exp Neurol 1997; 145:303-7. [PMID: 9184133 DOI: 10.1006/exnr.1997.6445] [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: 02/04/2023]
Abstract
Earlier studies have demonstrated that cold water swim (CWS) produces stress-induced analgesia in tests of brief, phasic pain and produces a delayed nociceptive response (DNR) for more prolonged tonic pain. The present study reports the effect of repeated CWS on tonic pain, as measured by the formalin test. One group of rats was exposed to a 3.5-min swim in 2 degrees C water immediately prior to the formalin injection, to a 1.5-min swim at 50 min, and to another 1.5-min swim at 100 min postformalin injection. Compared to the no-swim control group, subjects which received repeated CWS had dramatically altered formalin pain responses. Formalin responses began just over 3 h postformalin injection, peaked at 4 h, and were still present at 5 h. Inspection of individual responses revealed a substantial degree of variability in the onset of responses, although the magnitude and duration of the formalin pain response remained at the same levels as those of control subjects. The lack of a decrease in the magnitude and duration of the delayed formalin responses indicates that repeated CWS does not produce analgesia for tonic pain. The period of stress, therefore, produces pain suppression but not loss of the mechanisms that subsequently underlie the pain. Earlier controls have ruled out peripheral mechanisms (such as retention of the formalin in the paw tissue). Rather, a memory mechanism appears to have been indicated and it is not lost, but persists until it can be manifested. Further research is needed to study the mechanisms responsible for the DNR.
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Affiliation(s)
- P N Fuchs
- Department of Psychology, McGill University, Montreal, Quebec, Canada
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22
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Abstract
The N-methyl-D-aspartate (NMDA) receptor has been implicated in mechanisms of tolerance to morphine-induced analgesia. The present study examined the role of the NMDA receptor in the development of tolerance to stress-induced analgesia (SIA). In the first experiment, mice were exposed to a stressor (a 3-min forced swim in water maintained at 32 degrees C) once daily for 15 consecutive days. Analgesia was measured 2 min after stress on the first and last day using the hot-plate test. To examine the role of the NMDA receptor in the development of tolerance to SIA mice were treated daily with the non-competitive NMDA receptor antagonist, MK-801, 15 min before swimming. Pretreatment with MK-801 was found to block both analgesia and tolerance. In a second experiment, to examine whether SIA and tolerance to SIA are mediated by similar or different mechanisms, mice were injected daily with MK-801 after analgesia had dissipated (1 h following swim). Tolerance to SIA was blocked by delayed injections of MK-801. These results suggest that the NMDA receptor is involved in mechanisms of tolerance to SIA, independent of its role in analgesia.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, LA 70148, USA
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23
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Altier N, Stewart J. Opioid receptors in the ventral tegmental area contribute to stress-induced analgesia in the formalin test for tonic pain. Brain Res 1996; 718:203-6. [PMID: 8773788 DOI: 10.1016/0006-8993(96)00121-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Exposure to stress can induce analgesia in the formalin test for tonic pain. Here, we report that blockade of opioid receptors by bilateral infusions of naltrexone methylbromide (NMB) (0.1 microgram/0.5 microliter/side) in the ventral tegmental area (VTA) in the midbrain can reduce stress-induced analgesia in this test. These findings indicate that endogeneous opioids act in the VTA to mediate stress-induced analgesia in tonic pain.
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Affiliation(s)
- N Altier
- Department of Psychology, Concordia University, Montreal, Canada
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24
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Hartell NA, Headley PM. NMDA-receptor contribution to spinal nociceptive reflexes: influence of stimulus parameters and of preparatory surgery. Neuropharmacology 1996; 35:1567-72. [PMID: 9025104 DOI: 10.1016/s0028-3908(96)00029-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The contribution of NMDA receptors to nociceptive reflexes has been assessed both in awake rats and in electrophysiological tests on alpha-chloralose anaesthetized spinalized rats prepared with different degrees of surgery. Single motor unit activity was recorded in response to alternating noxious mechanical and electrical stimuli applied to one hindpaw, and the results compared with paw pressure withdrawal reflexes in awake rats. There was little contribution by NMDA receptors to nociceptive paw pinch responses either in awake rats or in rats prepared with minimal surgery, but following extensive lumbar surgery the contribution increased significantly to a level similar to that seen in the wind-up component of responses elicited by electrical stimulation. Surgery therefore has effects several segments from the sensory input that it generates. It enhances the NMDA receptor contribution in responses to some but not all types of afferent input.
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Affiliation(s)
- N A Hartell
- Department of Pharmaceutical and Biological Sciences, Aston University, Birmingham, U.K
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25
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Hartvig P, Valtysson J, Lindner KJ, Kristensen J, Karlsten R, Gustafsson LL, Persson J, Svensson JO, Oye I, Antoni G. Central nervous system effects of subdissociative doses of (S)-ketamine are related to plasma and brain concentrations measured with positron emission tomography in healthy volunteers. Clin Pharmacol Ther 1995; 58:165-73. [PMID: 7648766 DOI: 10.1016/0009-9236(95)90194-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Plasma concentrations, maximum regional brain concentrations, and specific regional binding in the brain after administration of 0, 0.1, and 0.2 mg/kg doses of (S)-ketamine were measured in a randomized, double-blind, crossover study in five volunteers and were related to induced effects such as analgesia, amnesia, and mood changes. Specific binding in the brain was assessed by simultaneous administration of (S)-[N-methyl-11C]ketamine quantified by positron emission tomography. High radioactivities in the brain corresponded to regional distribution of N-methyl-D-aspartate receptor complexes. A significant and dose-dependent reduction of binding was measured as a result of displacement of (S)-[N-methyl-11C]ketamine. Memory impairment and psychotomimetic effects were related to dose, plasma concentration 4 minutes after administration, and decreased regional binding of (S)-ketamine in the brain and were consistently seen at plasma and maximum regional brain (S)-ketamine concentrations higher than 70 and 500 ng/ml, respectively. The magnitude of specific binding of (S)-ketamine, measured with positron emission tomography, can be related directly to drug effects.
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Affiliation(s)
- P Hartvig
- Uppsala University PET Centre, University Hospital, Sweden
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26
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Spinella M, Bodnar RJ. Nitric oxide synthase inhibition selectively potentiates swim stress antinociception in rats. Pharmacol Biochem Behav 1994; 47:727-33. [PMID: 7516079 DOI: 10.1016/0091-3057(94)90180-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Since nitric oxide (NO) has been implicated in nociceptive processing, the present study examined whether NO synthase inhibition with either Nw-nitro-L-arginine (L-NA) or its methyl ester (L-NAME) would alter antinociception elicited by either continuous (CCWS) or intermittent cold-water swims (ICWS) on the tail-flick and jump tests. Whereas CCWS antinociception on both tests was significantly potentiated by a dose range of L-NA (0.1-4 mg/kg IP) and L-NAME (1 mg/kg IP), ICWS antinociception was largely unaffected by these manipulations. In contrast, administration of the less active D isomer (D-NAME) failed to alter CCWS antinociception and reduced ICWS antinociception. The ability of NO synthase inhibition to potentiate CCWS antinociception could not be explained by changes in CCWS hypothermia. Since ICWS antinociception is mediated by mu-opioid manipulations and CCWS antinociception is sensitive to delta-opioid and nonopioid manipulations, this indicates that NO synthase inhibition may be acting upon a selective form of pain inhibition.
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Affiliation(s)
- M Spinella
- Department of Psychology, Queens College, City University of New York, Flushing 11367
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27
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Saucier DM, Kavaliers M. Antagonistic effects of the selective, competitive N-methyl-D-aspartate (NMDA) receptor antagonist, NPC 12626, on kappa opiate-induced analgesia in male deer mice. Brain Res 1994; 637:292-6. [PMID: 8180809 DOI: 10.1016/0006-8993(94)91247-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The present study examined the effects of the competitive NMDA antagonist, NPC 12626, on the analgesic effects of the specific kappa opiate receptor agonist, U69,593, in male deer mice. Intraperitoneal (i.p.) administration of NPC 12626 had no effect on the basal nociceptive sensitivity of reproductive male deer mice, as measured by latency of response to a thermal (50 degrees C) surface. NPC 12626 dose-dependently (0.05-1.0 mg/kg) reduced U69,593-induced analgesia. NPC 12626 at 1.0 mg/kg attenuated U69,593-induced analgesia in a manner comparable to that produced by the specific kappa opiate antagonist, nor-binaltorphimine. In contrast, this dose of NPC 12626 potentiated the analgesia produced by the predominantly mu agonist morphine (1.0 mg/kg). The non-competitive NMDA antagonist, MK-801, which has been previously indicated to affect kappa opiate analgesia, significantly reduced at 1.0 mg/kg, but did not block, the analgesia produced by U69,593 and in contrast to NPC 12626, slightly reduced morphine-induced analgesia. These findings suggest that the NMDA antagonist, NPC 12626, may, either directly or indirectly, have effects on kappa opiate receptor mediated mechanisms.
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Affiliation(s)
- D M Saucier
- Department of Psychology, University of Western Ontario, London, Canada
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28
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Kamei J, Iwamoto Y, Hitosugi H, Misawa M, Nagase H, Kasuya Y. Differential mediation of cold water swim stress-induced antinociception by delta-opioid receptor subtypes in diabetic mice. Life Sci 1994; 54:PL425-30. [PMID: 8196487 DOI: 10.1016/0024-3205(94)90127-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The involvement of delta-opioid receptor subtypes in cold water swim stress (CWSS)-induced antinociception in diabetic mice was compared with that in non-diabetic mice. Three-minute swim stress produced significant antinociception in both diabetic and non-diabetic mice as determined by the tail-pinch test. However, the extent of CWSS-induced antinociception in diabetic mice was significantly greater than that in non-diabetic mice. Pretreatment with naltriben, a selective delta 2-opioid receptor antagonist, significantly attenuated CWSS-induced antinociception in both non-diabetic and diabetic mice. In contrast, although 7-benzylidenenaltrexone, a selective delta 1-opioid receptor antagonist, significantly attenuated CWSS-induced antinociception in diabetic mice, it had no effect in non-diabetic mice. These results suggest that CWSS-induced antinociception in non-diabetic mice is mediated by delta 2-opioid receptors, whereas CWSS-induced antinociception in diabetic mice is mediated by both delta 1- and delta 2-opioid receptors. Furthermore, the enhanced CWSS-induced antinociception in diabetic mice may be due to the activation of delta 1-opioid receptors.
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Affiliation(s)
- J Kamei
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan
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29
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Kristensen JD, Karlsten R, Gordh T, Berge OG. The NMDA antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) has antinociceptive effect after intrathecal injection in the rat. Pain 1994; 56:59-67. [PMID: 8159442 DOI: 10.1016/0304-3959(94)90150-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This behavioral study was performed in order to delineate the antinociceptive effects of and the influence on motor function of a highly potent, competitive NMDA receptor antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP). After intrathecal (i.t.) administration of CPP to chronically catheterized rats, antinociception was studied in 3 different nociceptive tests: the tail-flick test, the hot-plate test, and the formalin test. The lowest dose producing visible motor dysfunction was 1 nmol, with 2 of 8 animals showing slight ataxia. Dose-related motor dysfunction and apparent sedation was present after 5 and 10 nmol. Dose-related antinociception was evident in the thermal tests following doses that produced little or no motor dysfunction. In the tail-flick test, the antinociceptive effect was attenuated at higher doses, resulting in a bell-shaped dose-response relationship. Dose-related antinociception was found in both the first and second phase of the formalin test following doses from 0.25 up to 1 nmol. The present study shows that the competitive NMDA antagonist CPP has an antinociceptive effect in doses that do not affect motor function. Furthermore, antinociception was evident in both phasic and tonic nociceptive tests. Finally, the dose-response relationship in the tail-flick test was bell-shaped. As discussed this indicates that NMDA receptors may be involved in functionally divergent nociceptive systems.
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Affiliation(s)
- Jens D Kristensen
- Department of Anaesthesiology, University Hospital, UppsalaSweden Astra Pain Control AB, SödertäljeSweden
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30
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Akinci MK, Johnston GA. Sex differences in acute swim stress-induced changes in the binding of MK-801 to the NMDA subclass of glutamate receptors in mouse forebrain. J Neurochem 1993; 61:2290-3. [PMID: 8245979 DOI: 10.1111/j.1471-4159.1993.tb07472.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Acute swim stress (3 min at 32 degrees C) in mice produces increases in the binding of MK-801 to the NMDA subclass of glutamate receptors to forebrain membranes prepared from male mice. Scatchard analyses indicate that the observed increases in the binding of MK-801 in membranes from male mice are the result of changes in the affinity and density of low-affinity binding sites and in the density of high-affinity binding sites. In female mice, any changes in the binding of MK-801 appear to be much less pronounced and restricted to the low-affinity binding sites. These results are in contrast to the situation with binding to GABA receptors where acute swim stress increases GABA binding in forebrain membranes much more in female than in male mice. This indicates significant sex differences in the responses of receptors for the major excitatory and inhibitory transmitters to acute swim stress. These rapid changes in MK-801 binding may result from changes in endogenous modulators as appears to be the case in the acute swim stress-induced changes in GABA binding. As with GABA binding, the endogenous modulators are likely to include steroids, the sex differences reflecting differences in modulation by gonadal steroids and the stress-induced changes reflecting differences in modulation by adrenal steroids. Estradiol, progesterone, and corticosterone treatments have been reported by other workers to influence the properties of glutamate receptors.
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Affiliation(s)
- M K Akinci
- Department of Pharmacology, University of Sydney, Australia
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31
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Abstract
This paper is the fifteenth installment of our annual review of research concerning the opiate system. It includes papers published during 1992 involving the behavioral, non-analgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal and renal function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.
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Affiliation(s)
- G A Olson
- Department of Psychology, University of New Orleans, LA 70148
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32
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Porro CA, Cavazzuti M. Spatial and temporal aspects of spinal cord and brainstem activation in the formalin pain model. Prog Neurobiol 1993; 41:565-607. [PMID: 8284437 DOI: 10.1016/0301-0082(93)90044-s] [Citation(s) in RCA: 146] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- C A Porro
- Istituto di Fisiologia Umana, Universita' di Modena, Italy
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33
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Vaccarino AL, Marek P, Kest B, Weber E, Keana JF, Liebeskind JC. NMDA receptor antagonists, MK-801 and ACEA-1011, prevent the development of tonic pain following subcutaneous formalin. Brain Res 1993; 615:331-4. [PMID: 8364741 DOI: 10.1016/0006-8993(93)90045-o] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Subcutaneous injection of formalin produces a biphasic pain response: an early, transient phase followed by a late tonic phase. The present study examined the involvement of the N-methyl-D-aspartic acid (NMDA) receptor in the development of the late pain produced following subcutaneous injection of formalin into the hind paw in mice. Blockade of the NMDA receptor by its non-competitive antagonist, MK-801, prior to formalin injection, but not after, reduced pain during the late phase. Similarly, blockade of the NMDA receptor allosteric site by the novel glycine site antagonist, ACEA-1011, also reduced the pain response in the late phase. These results suggest that the development of the late phase of formalin pain is due to NMDA-mediated activity during the early phase.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, Lakefront, LA 70148
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34
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Kamei J, Hitosugi H, Misawa M, Nagase H, Kasuya Y. Delta-opiod receptor-mediated forced swimming stress-induced antinociception in the formalin test. Psychopharmacology (Berl) 1993; 113:15-8. [PMID: 7862822 DOI: 10.1007/bf02244327] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Forced swimming stress-induced antinociception (FSSIA) was assessed using the formalin test. Male ICR mice, weighing about 30 g, were forced to swim in water at 20 degrees C for 3 min. In unstressed mice, SC injection of formalin (0.5%) to the hindpaw caused a biphasic response: an immediate nociceptive response (first phase) followed by a tonic response (second phase). Although forced swimming stress (FSS) had no effect on the duration of the first-phase response, FSS significantly reduced the duration of the second-phase response. The effect of FSSIA on the second-phase response was blocked by naltrindole (1 mg/kg, SC), a selective delta-opioid receptor antagonist, but not by beta-funaltrexamine (20 mg/kg, SC), a selective mu-opioid receptor antagonist. These results indicate that FSS may selectively reduce the second phase of the formalin-induced nociceptive response, primarily through delta-opioid receptors.
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Affiliation(s)
- J Kamei
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan
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Vaccarino AL, Marek P, Liebeskind JC. Stress-induced analgesia prevents the development of the tonic, late phase of pain produced by subcutaneous formalin. Brain Res 1992; 572:250-2. [PMID: 1319270 DOI: 10.1016/0006-8993(92)90478-r] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Subcutaneous injection of formalin produces a biphasic pain response: a transient early phase followed by a tonic late phase. It has recently been suggested that development of the late phase depends upon the presence of the early one. In support of this suggestion, we now demonstrate that blocking the early phase by stress-induced analgesia prevents development of the late phase, whereas the same stressor given after the first phase does not. Both phases are manifested when stress-induced analgesia is blocked by the N-methyl-D-aspartate (NMDA) or opiate antagonists, MK-801 and naloxone.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of California, Los Angeles 90024
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