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Gopalsamy B, Chia JSM, Farouk AAO, Sulaiman MR, Perimal EK. Zerumbone-Induced Analgesia Modulated via Potassium Channels and Opioid Receptors in Chronic Constriction Injury-Induced Neuropathic Pain. Molecules 2020; 25:molecules25173880. [PMID: 32858809 PMCID: PMC7503342 DOI: 10.3390/molecules25173880] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022] Open
Abstract
Zerumbone, a monocyclic sesquiterpene from the wild ginger plant Zingiber zerumbet (L.) Smith, attenuates allodynia and hyperalgesia. Currently, its mechanisms of action in neuropathic pain conditions remain unclear. This study examines the involvement of potassium channels and opioid receptors in zerumbone-induced analgesia in a chronic constriction injury (CCI) neuropathic pain mice model. Male Institute of Cancer Research (ICR) mice were subjected to CCI and behavioral responses were tested on day 14. Responses toward mechanical allodynia and thermal hyperalgesia were tested with von Frey's filament and Hargreaves' tests, respectively. Symptoms of neuropathic pain were significantly alleviated following treatment with zerumbone (10 mg/kg; intraperitoneal, i.p.). However, when the voltage-dependent K+ channel blocker tetraethylammonium (TEA, 4 mg/kg; i.p.), ATP-sensitive K+ channel blocker, glibenclamide (GLIB, 10 mg/kg; i.p.); small-conductance Ca2+-activated K+ channel inhibitor apamin (APA, 0.04 mg/kg; i.p.), or large-conductance Ca2+-activated K+ channel inhibitor charybdotoxin (CHAR, 0.02 mg/kg; i.p.) was administered prior to zerumbone (10 mg/kg; i.p.), the antiallodynic and antihyperalgesic effects of zerumbone were significantly reversed. Additionally, non-specific opioid receptors antagonist, naloxone (NAL, 10 mg/kg; i.p.), selective µ-, δ- and κ-opioid receptor antagonists; β-funaltrexamine (β-FN, 40 mg/kg; i.p.), naltrindole (20 mg/kg; s.c.), nor-binaltorphamine (10 mg/kg; s.c.) respectively attenuated the antiallodynic and antihyperalgesic effects of zerumbone. This outcome clearly demonstrates the participation of potassium channels and opioid receptors in the antineuropathic properties of zerumbone. As various clinically used neuropathic pain drugs also share this similar mechanism, this compound is, therefore, a highly potential substitute to these therapeutic options.
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Affiliation(s)
- Banulata Gopalsamy
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Jasmine Siew Min Chia
- Centre for Community Health Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia;
| | - Ahmad Akira Omar Farouk
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Mohd Roslan Sulaiman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Enoch Kumar Perimal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, University of Adelaide, Adelaide 5000, Australia
- Correspondence: ; Tel./Fax: +61-603-8947-2774
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Fisher C, Johnson K, Okerman T, Jurgenson T, Nickell A, Salo E, Moore M, Doucette A, Bjork J, Klein AH. Morphine Efficacy, Tolerance, and Hypersensitivity Are Altered After Modulation of SUR1 Subtype K ATP Channel Activity in Mice. Front Neurosci 2019; 13:1122. [PMID: 31695594 PMCID: PMC6817471 DOI: 10.3389/fnins.2019.01122] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/04/2019] [Indexed: 01/26/2023] Open
Abstract
ATP-sensitive potassium (KATP) channels are found in the nervous system and are downstream targets of opioid receptors. KATP channel activity can effect morphine efficacy and may beneficial for relieving chronic pain in the peripheral and central nervous system. Unfortunately, the KATP channels exists as a heterooctomers, and the exact subtypes responsible for the contribution to chronic pain and opioid signaling in either dorsal root ganglia (DRG) or the spinal cord are yet unknown. Chronic opioid exposure (15 mg/kg morphine, s.c., twice daily) over 5 days produces significant downregulation of Kir6.2 and SUR1 in the spinal cord and DRG of mice. In vitro studies also conclude potassium flux after KATP channel agonist stimulation is decreased in neuroblastoma cells treated with morphine for several days. Mice lacking the KATP channel SUR1 subunit have reduced opioid efficacy in mechanical paw withdrawal behavioral responses compared to wild-type and heterozygous littermates (5 and 15 mg/kg, s.c., morphine). Using either short hairpin RNA (shRNA) or SUR1 cre-lox strategies, downregulation of SUR1 subtype KATP channels in the spinal cord and DRG of mice potentiated the development of morphine tolerance and withdrawal. Opioid tolerance was attenuated with intraplantar injection of SUR1 agonists, such as diazoxide and NN-414 (100 μM, 10 μL) compared to vehicle treated animals. These studies are an important first step in determining the role of KATP channel subunits in antinociception, opioid signaling, and the development of opioid tolerance, and shed light on the potential translational ability of KATP channel targeting pharmaceuticals and their possible future clinical utilization. These data suggest that increasing neuronal KATP channel activity in the peripheral nervous system may be a viable option to alleviate opioid tolerance and withdrawal.
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Affiliation(s)
- Cole Fisher
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Kayla Johnson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Travis Okerman
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Taylor Jurgenson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Austin Nickell
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Erin Salo
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Madelyn Moore
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Alexis Doucette
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - James Bjork
- Department of Biomedical Sciences, Medical School Duluth, Duluth, MN, United States
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
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Antinociceptive effect of flavonol and a few structurally related dimethoxy flavonols in mice. Inflammopharmacology 2019; 27:1155-1167. [PMID: 30850920 DOI: 10.1007/s10787-019-00579-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/26/2019] [Indexed: 10/27/2022]
Abstract
Previous reports suggest flavonoids as potent analgesic compounds. Based on these observations, the present study investigated the antinociceptive action of flavonol, 3', 4'-dimethoxy flavonol, 6, 3'-dimethoxy flavonol, 7, 2'-dimethoxy flavonol, and 7, 3'-dimethoxy flavonol and the possible mechanisms involved in these effects. The antinociceptive effect of the investigated compounds in doses of 25, 50, 100, and 200 mg/kg was evaluated in male Swiss albino mice using the acetic acid test, formalin-induced nociception, and hot water tail immersion test. The role of opioid, tryptaminergic, adrenergic, dopaminergic, GABAergic, and K+ATP channels in producing the antinociceptive effect was also studied using appropriate interacting agents. Treatment with flavonol and dimethoxy flavonols resulted in a significant reduction in the number of abdominal constrictions in the acetic acid test, a significant inhibition of the paw-licking/biting response time in both the phases of formalin nociception and also a significant increase in mean reaction time in the hot water tail immersion test. These observations revealed the antinociceptive effect of dimethoxy flavonols. The role of opioid, serotonergic (5HT3), and dopaminergic system was identified in the antinociceptive effect of flavonol and all dimethoxy derivatives investigated. In addition, the role of GABAergic, K+ATP channel, and α-2 adrenergic mechanisms were also observed in the antinociceptive action of some of the investigated compounds. The present study identified the antinociceptive effect of flavonol and dimethoxy flavonols in mice acting through different neuronal pathways.
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Chronic administration of 5-HT1A receptor agonist relieves depression and depression-induced hypoalgesia. ScientificWorldJournal 2014; 2014:405736. [PMID: 24592167 PMCID: PMC3921963 DOI: 10.1155/2014/405736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/31/2013] [Indexed: 11/17/2022] Open
Abstract
Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively. We found that acute administration of 8-OH-DPAT increased locomotor activity and pain thresholds in the sham rats but had no effect on the OB rats. In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level. Increased pain thresholds were also observed in the sham rats after the chronic administration. These results demonstrated that chronic administration of 8-OH-DPAT reversed the depression-induced decrease in pain sensitivity in rats, suggesting that 5-HT1A receptor may play a role in the depression-associated hypoalgesia.
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Capim SL, Gonçalves GM, dos Santos GC, Marinho BG, Vasconcellos ML. High analgesic and anti-inflammatory in vivo activities of six new hybrids NSAIAs tetrahydropyran derivatives. Bioorg Med Chem 2013; 21:6003-10. [DOI: 10.1016/j.bmc.2013.07.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/11/2013] [Accepted: 07/21/2013] [Indexed: 10/26/2022]
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Capim SL, Carneiro PH, Castro PC, Barros MR, Marinho BG, Vasconcellos ML. Design, Prins-cyclization reaction promoting diastereoselective synthesis of 10 new tetrahydropyran derivatives and in vivo antinociceptive evaluations. Eur J Med Chem 2012; 58:1-11. [DOI: 10.1016/j.ejmech.2012.09.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 09/24/2012] [Accepted: 09/27/2012] [Indexed: 11/28/2022]
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De Paz-Campos MA, Chávez-Piña AE, Ortiz MI, Castañeda-Hernández G. Evidence for the Participation of ATP-sensitive Potassium Channels in the Antinociceptive Effect of Curcumin. Korean J Pain 2012; 25:221-7. [PMID: 23091682 PMCID: PMC3468798 DOI: 10.3344/kjp.2012.25.4.221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 12/27/2022] Open
Abstract
Background It has been reported that curcumin, the main active compound of Curcuma longa, also known as turmeric, exhibits antinociceptive properties. The aim of this study was to examine the participation of ATP-sensitive potassium channels (KATP channels) and, in particular, that of the L-arginine-nitric oxide-cyclic GMP-KATP channel pathway, in the antinociceptive effect of curcumin. Methods Pain was induced by the intraplantar injection of 1% formalin in the right hind paw of Wistar rats. Formalin-induced flinching behavior was interpreted as an expression of nociception. The antinociceptive effect of oral curcumin was explored in the presence and absence of local pretreatment with L-NAME, an inhibitor of nitric oxide synthase, ODQ, an inhibitor of soluble guanylyl cyclase, and glibenclamide, a blocker of KATP channels. Results Oral curcumin produced a dose-dependent antinociceptive effect in the 1% formalin test. Curcumin-induced antinociception was not altered by local L-NAME or ODQ, but was significantly impaired by glibenclamide. Conclusions Our results confirm that curcumin is an effective antinociceptive agent. Curcumin-induced antinociception appears to involve the participation of KATP channels at the peripheral level, as local injection of glibenclamide prevented its effect. Activation of KATP channels, however, does not occur by activation of the L-arginine-nitric oxide-cGMP-KATP channel pathway.
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Affiliation(s)
- Marco Antonio De Paz-Campos
- Department of Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico, DF, Mexico
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Macedo-Junior SJ, Nascimento FP, Luiz-Cerutti M, Santos ARS. Role of pertussis toxin-sensitive G-protein, K+ channels, and voltage-gated Ca2+ channels in the antinociceptive effect of inosine. Purinergic Signal 2012; 9:51-8. [PMID: 22806273 DOI: 10.1007/s11302-012-9327-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/26/2012] [Indexed: 12/20/2022] Open
Abstract
Inosine is the first metabolite of adenosine. It exerts an antinociceptive effect by activating the adenosine A(1) and A(2A) receptors. We have previously demonstrated that inosine exhibits antinociceptive properties in acute and chronic mice models of nociception. The aim of this study was to investigate the involvement of pertussis toxin-sensitive G-protein-coupled receptors, as well as K(+) and Ca(2+) channels, in the antinociception promoted by inosine in the formalin test. Mice were pretreated with pertussis toxin (2.5 μg/site, i.t., an inactivator of G(i/0) protein); after 7 days, they received inosine (10 mg/kg, i.p.) or morphine (2.5 mg/kg, s.c., used as positive control) immediately before the formalin test. Another group of animals received tetraethylammonium (TEA) or 4-aminopyridine (4-AP) (1 μg/site, i.t., a non-specific voltage-gated K(+) channel blockers), apamin (50 ng/site, i.t., a small conductance Ca(2+)-activated K(+) channel blocker), charybdotoxin (250 pg/site, i.t., a large-conductance Ca(2+)-activated K(+) channel blocker), glibenclamide (100 μg/site, i.t., an ATP-sensitive K(+) channel blocker) or CaCl(2) (200 nmol/site, i.t.). Afterwards, the mice received inosine (10 mg/kg, i.p.), diclofenac (10 mg/kg, i.p., a positive control), or morphine (2.5 mg/kg, s.c., a positive control) immediately before the formalin test. The antinociceptive effect of inosine was reversed by the pre-administration of pertussis toxin (2.5 μg/site, i.t.), TEA, 4-aminopyridine, charybdotoxin, glibenclamide, and CaCl(2), but not apamin. Further, all K(+) channel blockers and CaCl(2) reversed the antinociception induced by diclofenac and morphine, respectively. Taken together, these data suggest that the antinociceptive effect of inosine is mediated, in part, by pertussis toxin-sensitive G-protein coupled receptors and the subsequent activation of voltage gated K(+) channel, large conductance Ca(2+)-activated and ATP-sensitive K(+) channels or inactivation of voltage-gated Ca(2+) channels. Finally, small conductance Ca(2+)-activated K(+) channels are not involved in the antinociceptive effect of inosine.
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Affiliation(s)
- Sérgio José Macedo-Junior
- Laboratório de Neurobiologia da Dor e Inflamação, Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Trindade, Florianópolis, SC, 88040-900, Brazil
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Du X, Wang C, Zhang H. Activation of ATP-sensitive potassium channels antagonize nociceptive behavior and hyperexcitability of DRG neurons from rats. Mol Pain 2011; 7:35. [PMID: 21569593 PMCID: PMC3113320 DOI: 10.1186/1744-8069-7-35] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 05/14/2011] [Indexed: 01/06/2023] Open
Abstract
Background Nociceptive responses to noxious stimuli are initiated at peripheral nociceptor terminals. Ion channels play a vital role in pain signal initiation and conduction. Activation of KATP channels has been implicated in mediating the analgesic effects of agents such as morphine. However, systematic studies regarding the effects of KATP activators on nociception and neuronal excitability are scarce. Results In this study, we describe the antagonistic effects of KATP activators pinacidil and diazoxide on nocifensive behavior induced by bradykinin (BK), thermo and mechanical stimuli, and the bradykinin-induced hyperexcitability of DRG neurons. We also found that KATP activators can moderately activate KATP in DRG neurons. Because the effects of KATP activators can be reversed by the KATP blocker glyburide, direct activation of KATP is most likely the underlying mechanism. Conclusion This systematic study clearly demonstrates that activation of KATP could have significant modulatory effects on the excitability of sensory neurons and thus on sensory behaviors, such as nociception. KATP activators can be evaluated clinically for the treatment of pain symptoms.
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Affiliation(s)
- Xiaona Du
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.
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Hajhashemi V, Amin B. Effect of glibenclamide on antinociceptive effects of antidepressants of different classes. Clinics (Sao Paulo) 2011; 66:321-5. [PMID: 21484053 PMCID: PMC3059867 DOI: 10.1590/s1807-59322011000200023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 11/08/2010] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES The purpose of this work was to determine whether the intraperitoneal administration of glibenclamide as a K ATP channel blocker could have an effect on the antinociceptive effects of antidepressants with different mechanisms of action. METHODS Three antidepressant drugs, amitriptyline as a dual-action, nonselective inhibitor of noradrenaline and a serotonin reuptake inhibitor, fluvoxamine as a selective serotonin reuptake inhibitor and maprotiline as a selective noradrenaline reuptake inhibitor, were selected, and the effect of glibenclamide on their antinociceptive activities was assessed in male Swiss mice (25-30 g) using a formalin test. DISCUSSION None of the drugs affected acute nociceptive responses during the first phase. Amitriptyline (5, 10 mg/ kg), maprotiline (10, 20 mg/kg) and fluvoxamine (20 and 30 mg/kg) effectively inhibited pain induction caused by the second phase of the formalin test. Glibenclamide (5 mg/kg) alone did not alter licking behaviors based on a comparison with the control group. However, the pretreatment of animals with glibenclamide (10 and 15 mg/kg) partially reversed the antinociceptive effects of fluvoxamine but not those of maprotiline. In addition, the highest dose of glibenclamide (15 mg/kg) partially prevented the analgesic effect of amitriptyline. CONCLUSION Therefore, it seems that adenosine triphosphate-dependent potassium channels have a major role in the analgesic activity of amitriptyline and fluvoxamine.
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Affiliation(s)
- Valiollah Hajhashemi
- Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
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Raffa RB, Pergolizzi JV. Deciphering the mechanism(s) of action of natural products: analgesic peroxide oil as example. J Clin Pharm Ther 2010; 36:283-98. [PMID: 21545611 DOI: 10.1111/j.1365-2710.2010.01190.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND There are multiple reports of natural products having therapeutic effect. In an era of evidence-based medicine, clinical trials inform clinical decisions regarding use of the product, but prevailing preference is to identify and use a single 'active ingredient'. Yet, the clinical benefit of a natural product might derive from the fortuitous combination of its multiple components. Therefore, the elucidation of the mechanism(s) of action of natural products is important, but presents significant challenges. This article examines this issue using peroxide oil (essential oxygen oil) as an illustrative example. OBJECTIVE To review the published literature of a natural product in an effort to elucidate postulated mechanism(s) of action of a complex mixture. METHODS The clinical and preclinical literature was reviewed from the perspective of its contribution to elucidating a mechanism of analgesic action of a natural product. RESULTS Peroxide oil contains ingredients that are associated with analgesic mechanisms, such inhibition of lipid peroxidation and arachidonic acid metabolism and non-opioid, glibenclamide-sensitive receptor-mediated and K(ATP) -NO-cGMP channel pathways. CONCLUSION Although its exact mechanism remains unknown, peroxide oil provides an example of how a natural product can be evaluated for plausible mechanistic explanation of its purported therapeutic efficacy. Such an approach seems valuable, since, as in this case, the constituents appear to contribute in an additive or synergistic manner, something not possible with a single substance.
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Affiliation(s)
- R B Raffa
- Temple University School of Pharmacy, Philadelphia, PA 19140, USA.
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Silveira JWS, Dias QM, Del Bel EA, Prado WA. Serotonin receptors are involved in the spinal mediation of descending facilitation of surgical incision-induced increase of Fos-like immunoreactivity in rats. Mol Pain 2010; 6:17. [PMID: 20331882 PMCID: PMC2860347 DOI: 10.1186/1744-8069-6-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 03/23/2010] [Indexed: 01/27/2023] Open
Abstract
Background Descending pronociceptive pathways may be implicated in states of persistent pain. Paw skin incision is a well-established postoperative pain model that causes behavioral nociceptive responses and enhanced excitability of spinal dorsal horn neurons. The number of spinal c-Fos positive neurons of rats treated intrathecally with serotonin, noradrenaline or acetylcholine antagonists where evaluated to study the descending pathways activated by a surgical paw incision. Results The number of c-Fos positive neurons in laminae I/II ipsilateral, lamina V bilateral to the incised paw, and in lamina X significantly increased after the incision. These changes: remained unchanged in phenoxybenzamine-treated rats; were increased in the contralateral lamina V of atropine-treated rats; were inhibited in the ipsilateral lamina I/II by 5-HT1/2B/2C (methysergide), 5-HT2A (ketanserin) or 5-HT1/2A/2C/5/6/7 (methiothepin) receptors antagonists, in the ipsilateral lamina V by methysergide or methiothepin, in the contralateral lamina V by all the serotonergic antagonists and in the lamina X by LY 278,584, ketanserin or methiothepin. Conclusions We conclude: (1) muscarinic cholinergic mechanisms reduce incision-induced response of spinal neurons inputs from the contralateral paw; (2) 5-HT1/2A/2C/3 receptors-mediate mechanisms increase the activity of descending pathways that facilitates the response of spinal neurons to noxious inputs from the contralateral paw; (3) 5-HT1/2A/2C and 5-HT1/2C receptors increases the descending facilitation mechanisms induced by incision in the ipsilateral paw; (4) 5-HT2A/3 receptors contribute to descending pronociceptive pathways conveyed by lamina X spinal neurons; (5) α-adrenergic receptors are unlikely to participate in the incision-induced facilitation of the spinal neurons.
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Affiliation(s)
- João Walter S Silveira
- Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, University of Sao Paulo, Ribeirão Preto, SP 14049-900, Brazil
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Savitz J, Lucki I, Drevets WC. 5-HT(1A) receptor function in major depressive disorder. Prog Neurobiol 2009; 88:17-31. [PMID: 19428959 DOI: 10.1016/j.pneurobio.2009.01.009] [Citation(s) in RCA: 396] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 12/22/2008] [Accepted: 01/29/2009] [Indexed: 10/21/2022]
Abstract
Dysfunction of the serotonin 1A receptor (5-HT(1A)) may play a role in the genesis of major depressive disorder (MDD). Here we review the pharmacological, post-mortem, positron emission tomography (PET), and genetic evidence in support of this statement. We also touch briefly on two MDD-associated phenotypes, cognitive impairment and somatic pain. The results of pharmacological challenge studies with 5-HT(1A) receptor agonists are indicative of blunted endocrine responses in depressed patients. Lithium, valproate, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and other treatment, such as electroconvulsive shock therapy (ECT), all increase post-synaptic 5-HT(1A) receptor signaling through either direct or indirect effects. Reduced somatodendritic and postsynaptic 5-HT(1A) receptor numbers or affinity have been reported in some post-mortem studies of suicide victims, a result consistent with well-replicated PET analyses demonstrating reduced 5-HT(1A) receptor binding potential in diverse regions such as the dorsal raphe, medial prefrontal cortex (mPFC), amygdala and hippocampus. 5-HT(1A) receptor knockout (KO) mice display increased anxiety-related behavior, which, unlike in their wild-type counterparts, cannot be rescued with antidepressant drug (AD) treatment. In humans, the G allele of a single nucleotide polymorphism (SNP) in the 5-HT(1A) receptor gene (HTR1A; rs6295), which abrogates a transcription factor binding site for deformed epidermal autoregulatory factor-1 (Deaf-1) and Hes5, has been reported to be over-represented in MDD cases. Conversely, the C allele has been associated with better response to AD drugs. We raise the possibility that 5-HT(1A) receptor dysfunction represents one potential mechanism underpinning MDD and other stress-related disorders.
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Affiliation(s)
- Jonathan Savitz
- Section on Neuroimaging in Mood and Anxiety Disorders, Mood and Anxiety Disorders Program, NIH/NIMH, Bethesda, MD 20892, United States.
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Antinociceptive activity of Tilia americana var. mexicana inflorescences and quercetin in the formalin test and in an arthritic pain model in rats. Neuropharmacology 2008; 56:564-71. [PMID: 19027760 DOI: 10.1016/j.neuropharm.2008.10.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 10/22/2008] [Accepted: 10/24/2008] [Indexed: 11/23/2022]
Abstract
Tilia species are well known around the world for their properties in traditional medicine. Antinociceptive activity of hexane, methanol and aqueous extracts from Tilia americana var. mexicana inflorescences was evaluated in the pain-induced functional impairment model in rats (PIFIR). A preliminar 300 mg/kg dosage of aqueous extracts i.p., but not the same dose of methanol or hexane extract, produced an antinociceptive response in rats similar to that of tramadol (17.8 mg/kg i.p.). A dose-response curve from aqueous extract allowed the determination of ED(50) = 364.97 mg/kg in comparison to ED(50) = 10.35 mg/kg for tramadol in this model. A previous HPLC-DAD analysis corroborated by an HPLC-MS technique in this study demonstrated the flavonoid composition in this Tilia aqueous extract revealing the presence of glycosides mainly derived from quercetin. Thus, Tilia aqueous extract and quercetin were tested at 30 and/or 100 mg/kg dosages i.p. in the PIFIR and formalin models producing a significant and dose-dependent antinociceptive response resembling that produced by a total and a partial agonist of 5-HT(1A) receptors like 8-OH-DPAT (0.1 mg/kg, s.c.) and buspirone (5 mg/kg, i.p.), respectively. In all the treatments, antinociceptive response was inhibited in the presence of WAY 100635 (0.12 mg/kg, i.p.). Our results support the analgesic activity of T. americana var. mexicana inflorescences attributed by folk medicine; they also indicate that quercetin is partly responsible for this pharmacological activity that is likely mediated by serotonin 5-HT(1A) receptors.
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Ocaña M, Entrena JM, Baeyens JM, Del Pozo E. The antinociceptive effect of morphine is reversed by okadaic acid in morphine-naive but not in morphine-tolerant mice. Pharmacol Biochem Behav 2006; 86:21-6. [PMID: 17234262 DOI: 10.1016/j.pbb.2006.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 12/05/2006] [Accepted: 12/07/2006] [Indexed: 10/23/2022]
Abstract
The activation of specific subtypes of serine/threonine protein phosphatases (PPs) plays a role in the antinociceptive effect of acute morphine, but it is not known whether these enzymes are involved in morphine-induced antinociception in morphine-tolerant animals. We evaluated the effects of both okadaic acid (a selective inhibitor of some serine/threonine PPs) and its inactive analogue L-norokadaone on the antinociception induced by morphine in morphine-naive and -tolerant female mice in the tail-flick test. Okadaic acid (0.01 and 1 pg/mouse, i.c.v.), but not L-norokadaone (1 pg/mouse, i.c.v.), antagonized in a dose-dependent way the antinociception induced by morphine (1-16 mg/kg, s.c.) in morphine-naive animals. However, both okadaic acid (0.01 and 1 pg/mouse, i.c.v.) and L-norokadaone (1 pg/mouse, i.c.v.) were unable to modify the antinociceptive effect of morphine in morphine-tolerant mice. These results suggest that in morphine-induced thermal analgesia, the role of serine/threonine PPs highly sensitive to okadaic acid is different in morphine-tolerant and morphine-naive female mice.
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Affiliation(s)
- María Ocaña
- Department of Pharmacology and Neuroscience Institute, School of Medicine, University of Granada, Avenida de Madrid 12, E-18012 Granada, Spain
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Wei H, Pertovaara A. 5-HT1A receptors in endogenous regulation of neuropathic hypersensitivity in the rat. Eur J Pharmacol 2006; 535:157-65. [PMID: 16545367 DOI: 10.1016/j.ejphar.2006.02.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 02/09/2006] [Accepted: 02/13/2006] [Indexed: 11/28/2022]
Abstract
The role of medullary and spinal 5-HT(1A) receptors in endogenous regulation of neuropathic hypersensitivity was studied. When administered in the rostroventromedial medulla or subcutaneously, WAY-100635, a 5-HT(1A) receptor antagonist, attenuated mechanical hypersensitivity in rats with a spinal nerve injury. Thermal or mechanical nociception outside of the injured area was not influenced by medial medullary or subcutaneous administration of WAY-100635. Intrathecal administration of WAY-100635 had no significant effect on pain-related behavior. Suppression of mechanical hypersensitivity induced by medial medullary administration of WAY-100635 was reversed by intrathecal administration of WAY-100635 or atipamezole, an alpha2-adrenoceptor antagonist, but not by naloxone, an opioid receptor antagonist. The results indicate that endogenous release of 5-HT, via action on medial medullary 5-HT(1A) receptors, tonically suppresses descending inhibition in neuropathic animals. Following medial medullary administration of a 5-HT(1A) receptor antagonist, descending pain regulatory pathways are disinhibited. This leads to selective attenuation of neuropathic hypersensitivity, due to action on spinal 5-HT(1A) receptors and alpha2-adrenoceptors.
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Affiliation(s)
- Hong Wei
- Biomedicum Helsinki, Institute of Biomedicine/Physiology, POB 63, 00014 University of Helsinki, Finland
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Ocaña M, Cendán CM, Cobos EJ, Entrena JM, Baeyens JM. Potassium channels and pain: present realities and future opportunities. Eur J Pharmacol 2005; 500:203-19. [PMID: 15464034 DOI: 10.1016/j.ejphar.2004.07.026] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2004] [Indexed: 01/11/2023]
Abstract
Four families of potassium channels with different structures, functional characteristics and pharmacological sensitivity, are distinguished in neurons: voltage-gated (K(v)), calcium-activated (K(Ca)), inward rectifier (K(ir)) and two-pore (K(2P)) K(+) channels. During the last 15 years, numerous studies have demonstrated that the opening of some of these K(+) channels plays an important role in the antinociception induced by agonists of many G-protein-coupled receptors (alpha(2)-adrenoceptors, opioid, GABA(B), muscarinic M(2), adenosine A(1), serotonin 5-HT(1A) and cannabinoid receptors), as well as by other antinociceptive drugs (nonsteroidal antiinflammatory drugs [NSAIDs], tricyclic antidepressants, etc.) and natural products. Several specific types of K(+) channels are involved in antinociception. The most widely studied are the ATP-sensitive K(+) channels (K(ATP)), members of the K(ir) family, which participate in the antinociception induced by many drugs that activate them in both the central and the peripheral nervous system. The opening of G-protein-regulated inwardly rectifying K(+) channels (GIRK or K(ir)3), K(v)1.1 and two types of K(Ca) channels, the small- and large-conductance calcium-activated K(+) channels (SK and BK channels, respectively), also play a role in the antinociceptive effect of different drugs and natural products. Recently, drugs that open K(+) channels by direct activation (such as openers of neuronal K(v)7 and K(ATP) channels) have been shown to produce antinociception in models of acute and chronic pain, which suggests that other neuronal K(+) channels (e.g. K(v)1.4 channels) may represent an interesting target for the development of new K(+) channel openers with antinociceptive effects.
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Affiliation(s)
- María Ocaña
- Department of Pharmacology and Neurosciences Institute, School of Medicine, University of Granada, Avenida de Madrid 12, E-18012 Granada, Spain
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Bonnefont J, Chapuy E, Clottes E, Alloui A, Eschalier A. Spinal 5-HT1A receptors differentially influence nociceptive processing according to the nature of the noxious stimulus in rats: effect of WAY-100635 on the antinociceptive activities of paracetamol, venlafaxine and 5-HT. Pain 2005; 114:482-490. [PMID: 15777873 DOI: 10.1016/j.pain.2005.01.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Revised: 11/13/2004] [Accepted: 01/24/2005] [Indexed: 10/25/2022]
Abstract
The regulation of nociceptive processing by 5-HT at the spinal level is intricate since the neurotransmitter has been implicated in both pro and antinociception. The aim of our study was to investigate, according to the nature of the noxious stimulus, how the blockade of spinal 5-HT(1A) receptors could influence the antinociceptive actions of exogenous 5-HT as well as two analgesics involving endogenous 5-HT, paracetamol and venlafaxine. Rats were submitted either to the formalin test (tonic pain) or the paw pressure test (acute pain). WAY-100635 (40 microg/rat, i.t.), a selective 5-HT(1A) receptor antagonist, had no intrinsic action in either test. However, in the formalin test, it blocked the antinociceptive action of 5-HT (50 microg/rat, i.t.) and paracetamol (300 mg/kg, i.v.) in both phases of biting/licking behaviour and that of venlafaxine (2.5 mg/kg, s.c.) in the late phase only. In the paw pressure test, the combination of sub-effective doses of 5-HT (0.01 microg/rat, i.t.), paracetamol (50 mg/kg, i.v.) or venlafaxine (20 mg/kg, s.c.) with WAY-100635 led to a significant antinociceptive effect, which seems to depend on the reinforcement of the activity of inhibitory GABAergic interneurones. In conclusion, both direct stimulation of the spinal 5-HT(1A) receptors by 5-HT, and indirect stimulation using paracetamol or venlafaxine can differently influence pain transmission. We propose that the nature of the applied nociceptive stimulus would be responsible for the dual effect of the 5-HT(1A) receptors rather than the hyperalgesic state or the supraspinal integration of the pain message.
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Affiliation(s)
- Jérôme Bonnefont
- EA 3848, Pharmacologie Fondamentale et Clinique de la Douleur, Faculté de Médecine, 28 place Henri Dunant, 63001 Clermont-Ferrand, France Institut de Pharmacologie et de Biologie Structurale, CNRS UMR5089, 205 route de Narbonne, 31077 Toulouse, France
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Moncada A, Cendán CM, Baeyens JM, Del Pozo E. Inhibitors of serine/threonine protein phosphatases antagonize the antinociception induced by agonists of alpha 2 adrenoceptors and GABAB but not kappa-opioid receptors in the tail flick test in mice. Pain 2005; 114:212-20. [PMID: 15733647 DOI: 10.1016/j.pain.2004.12.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Revised: 12/01/2004] [Accepted: 12/13/2004] [Indexed: 11/22/2022]
Abstract
We previously reported that serine/threonine protein phosphatases (PPs) play a role in the antinociception induced by the mu-opioid receptor agonist morphine. In this study we evaluated the possible involvement of PPs on the antinociception induced by agonists of others G protein-coupled receptors in the tail flick test in mice. The subcutaneous administration of clonidine (0.25-4 mg/kg), baclofen (2-32 mg/kg) or U50,488H (2-16 mg/kg) (agonists of alpha(2) adrenoceptors, GABA(B) and kappa-opioid receptors, respectively) produced dose-dependent antinociception. The antinociceptive effects of clonidine and baclofen were antagonized in a dose-dependent way by the protein phosphatase inhibitors okadaic acid (0.001-10 pg/mouse, i.c.v.) and cantharidin (0.001-10 ng/mouse, i.c.v.), and okadaic acid was 1000 times more potent than cantharidin in producing this effect. The effects of these drugs appear to be specifically due to the blockade of PPs, since L-norokadaone (an analogue of okadaic acid that has no effect on PPs) did not modify clonidine- or baclofen-induced antinociception over the wide range of doses used (0.001-1000 pg/mouse, i.c.v.). On the other hand, the antinociception induced by activation of kappa-opioid receptors with U50,488H was not modified by okadaic acid or cantharidin. In conclusion, our data support the idea that serine/threonine PPs are differentially involved in the antinociceptive effects of several agonists of G protein-coupled receptors in mice.
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Affiliation(s)
- Ana Moncada
- Department of Pharmacology and Neurosciences Institute, School of Medicine, University of Granada, Avenida de Madrid 12, E-18012 Granada, Spain
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Sivarao DV, Newberry K, Lodge NJ. Effect of the 5HT1A receptor partial agonist buspirone on colorectal distension-induced pseudoaffective and behavioral responses in the female Wistar rat. Eur J Pharmacol 2004; 494:23-9. [PMID: 15194447 DOI: 10.1016/j.ejphar.2004.04.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 04/14/2004] [Accepted: 04/21/2004] [Indexed: 11/23/2022]
Abstract
In the present study, we have evaluated the visceral analgesic property of buspirone, a 5HT(1A) receptor partial agonist, on colorectal distension-induced mean arterial pressure and behavioral changes in anesthetized and awake Wistar rats, respectively. The selection of the rat strain was based on the observation that anesthetized Wistar rats exhibited a more prominent mean arterial pressure change in response to colorectal distention when compared to other strains (Sprague-Dawley, Wistar-Kyoto and Spontaneously Hypertensive). Buspirone dose-dependently (0.1-1 mg/kg, i.v.) antagonized mean arterial pressure change over a range of distensions (10-90 mmHg). In parallel studies conducted in awake animals, buspirone (1-5 mg/kg, s.c.) attenuated the abdominal withdrawal response, a nociceptive behavior, in response to colorectal distension. This effect was antagonized by co-administration of the 5-HT(1A) receptor antagonist N-[2-[4-(2-Methoxyphenyl)-1-piperazinyl]ethyl]-N-2- pyridinylcyclohexanecarboxamide (WAY-100635) (5 mg/kg, s.c.). We conclude that buspirone exhibits significant visceral analgesic property in two models of abdominal nociception.
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Affiliation(s)
- Digavalli V Sivarao
- Neuroscience Drug Discovery (3CD-422), Pharmaceutical Research Institute, Bristol Myers Squibb Co., 5 Research Parkway, Wallingford, CT 06067, USA.
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Alves DP, Soares AC, Francischi JN, Castro MSA, Perez AC, Duarte IDG. Additive antinociceptive effect of the combination of diazoxide, an activator of ATP-sensitive K+ channels, and sodium nitroprusside and dibutyryl-cGMP. Eur J Pharmacol 2004; 489:59-65. [PMID: 15063156 DOI: 10.1016/j.ejphar.2004.02.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 02/03/2004] [Accepted: 02/10/2004] [Indexed: 11/23/2022]
Abstract
Using the rat paw pressure test, in which increased sensitivity is induced by intraplantar injection of prostaglandin E2, we assessed the antinociceptive effect of the ATP-sensitive K+ channel opener diazoxide and the large-conductance Ca(2+)-activated K+ channel opener NS-1619 (1,3-dihydro-1-[2-hydroxy-5-(trifluoromethyl) phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one) on the peripheral hyperalgesia induced by prostaglandin E2. Diazoxide, administered locally into the right hindpaw (20, 38, 75, 150, 300 and 600 microg), elicited a dose-dependent antinociceptive effect on prostaglandin E2-induced hyperalgesia (2 microg/paw). The effect of diazoxide at the dose of 300 microg/paw was shown to be local since it did not produce any effect when administered in the contralateral paw. The action of diazoxide (300 microg/paw) as an ATP-sensitive K+ channel opener seems to be specific, since its effect was antagonized in a dose-dependent manner by glibenclamide (40, 80 and 160 microg/paw), a specific blocker of these channels, while tetraethylammonium (7.5, 15 and 30 microg/paw), dequalinium (12.5, 25 and 50 microg/paw) or charybdotoxin (0.5, 1 and 2 microg/paw), blockers of voltage-dependent K+ channels and of small- and large-conductance Ca(2+)-activated K+ channels, respectively, were not able to abolish the antinociception induced by diazoxide. The peripheral antinociceptive effect of diazoxide was not prevented by prior administration of naloxone (12.5, 25 and 50 microg/paw), an opioid receptor antagonist, or methylene blue (75, 125 and 300 microg/paw), an agent that inhibits the activation of guanylate cyclase by nitric oxide. A low dose of diazoxide (20 microg/paw) administered together with a low dose of sodium nitroprusside (125 microg/paw) or dibutyryl cGMP (db-cGMP, 50 microg/paw) induced a marked antinociceptive effect similar to that observed when each drug was administered alone. NS1619 (75, 150 and 300 microg/paw), a specific opener of large-conductance Ca(2+)-activated K+ channels, had no antinociceptive action on prostaglandin E2-induced hyperalgesia. This series of experiments provides evidence for a peripheral antinociceptive action of diazoxide and supports the suggestion that the activation of ATP-sensitive K+ channels could be the mechanism by which sodium nitroprusside and db-cGMP induce peripheral antinociception, excluding the involvement of large-contuctance Ca(2+)-activated K+ channels in the process.
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Affiliation(s)
- Daniela P Alves
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6622-Campus da Pampulha, CEP 31.270.100, Belo Horizonte MG, Brazil
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Liang JH, Wang XH, Liu RK, Sun HL, Ye XF, Zheng JW. Buspirone-induced antinociception is mediated by L-type calcium channels and calcium/caffeine-sensitive pools in mice. Psychopharmacology (Berl) 2003; 166:276-83. [PMID: 12552360 DOI: 10.1007/s00213-002-1327-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2002] [Accepted: 10/14/2002] [Indexed: 10/20/2022]
Abstract
RATIONALE Previous studies have shown that buspirone, a partial 5-HT(1A) receptor agonist, produces antinociceptive effects in rats and mice; Ca(2+) plays a critical role as a second messenger in mediating nociceptive transmission. 5-HT(1A) receptors have been proven to be coupled functionally with various types of Ca(2+) channels in neurons, including N-, P/Q-, T-, or L-type. It was of interest to investigate the involvement of extracellular/intracellular Ca(2+) in buspirone-induced antinociception. OBJECTIVES To determine whether central serotonergic pathways participate in the antinociceptive processes of buspirone, and investigate the involvement of Ca(2+) mechanisms, particularly L-voltage-gated Ca(2+) channels and Ca(2+)/caffeine-sensitive pools, in buspirone-induced antinociception. METHODS Antinociception was assessed using the hot-plate test (55 degrees C, hind-paw licking latency) in mice treated with either buspirone (1.25-20 mg/kg i.p.) alone or the combination of buspirone and fluoxetine (2.5-10 mg/kg i.p.), 5-HTP (25 mg/kg i.p.), nimodipine (2.5-10 mg/kg i.p.), nifedipine (2.5-10 mg/kg i.p.), CaCl(2) (25-200 nmol per mouse i.c.v.), EGTA (5-30 nmol per mouse i.c.v.), or ryanodine (0.25-2 nmol per mouse i.c.v.). RESULTS Buspirone dose dependently increased the licking latency in the hot-plate test in mice. This effect of buspirone was enhanced by fluoxetine, 5-HTP, nimodipine, and nifedipine. Interestingly, central administration of Ca(2+) reversed the antinociceptive effects of buspirone. In contrast to these, ryanodine or EGTA administered centrally potentiated buspirone-induced antinociception. CONCLUSIONS Decreasing neuronal Ca(2+) levels potentiated buspirone-induced antinociception; conversely, increasing intracellular Ca(2+) abolished the antinociceptive effects of buspirone. These results suggest that Ca(2+) influx from extracellular fluid and release of Ca(2+) from Ca(2+)/caffeine-sensitive microsomal pools may be involved in buspirone-induced antinociception.
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Affiliation(s)
- Jian-Hui Liang
- Department of Neuropharmacology, National Institute on Drug Dependence, Peking University, 38 Xueyuan Road, 100083, Beijing, P.R. China.
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Abstract
Upon receipt in the dorsal horn (DH) of the spinal cord, nociceptive (pain-signalling) information from the viscera, skin and other organs is subject to extensive processing by a diversity of mechanisms, certain of which enhance, and certain of which inhibit, its transfer to higher centres. In this regard, a network of descending pathways projecting from cerebral structures to the DH plays a complex and crucial role. Specific centrifugal pathways either suppress (descending inhibition) or potentiate (descending facilitation) passage of nociceptive messages to the brain. Engagement of descending inhibition by the opioid analgesic, morphine, fulfils an important role in its pain-relieving properties, while induction of analgesia by the adrenergic agonist, clonidine, reflects actions at alpha(2)-adrenoceptors (alpha(2)-ARs) in the DH normally recruited by descending pathways. However, opioids and adrenergic agents exploit but a tiny fraction of the vast panoply of mechanisms now known to be involved in the induction and/or expression of descending controls. For example, no drug interfering with descending facilitation is currently available for clinical use. The present review focuses on: (1) the organisation of descending pathways and their pathophysiological significance; (2) the role of individual transmitters and specific receptor types in the modulation and expression of mechanisms of descending inhibition and facilitation and (3) the advantages and limitations of established and innovative analgesic strategies which act by manipulation of descending controls. Knowledge of descending pathways has increased exponentially in recent years, so this is an opportune moment to survey their operation and therapeutic relevance to the improved management of pain.
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Affiliation(s)
- Mark J Millan
- Department of Psychopharmacology, Institut de Recherches Servier, 125 Chemin de Ronde, 78290 Croissy/Seine, Paris, France.
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Soares AC, Duarte IDG. Dibutyryl-cyclic GMP induces peripheral antinociception via activation of ATP-sensitive K(+) channels in the rat PGE2-induced hyperalgesic paw. Br J Pharmacol 2001; 134:127-31. [PMID: 11522604 PMCID: PMC1572924 DOI: 10.1038/sj.bjp.0704224] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2001] [Revised: 05/22/2001] [Accepted: 06/12/2001] [Indexed: 01/12/2023] Open
Abstract
1. Using the rat paw pressure test, in which increased sensitivity is induced by intraplantar injection of prostaglandin E2, we studied the action of several K(+) channel blockers in order to determine what types of K(+) channels could be involved in the peripheral antinociception induced by dibutyrylguanosine 3 : 5'-cyclic monophosphate (DbcGMP), a membrane permeable analogue of cyclic GMP. 2. DbcGMP elicited a dose-dependent (50, 75, 100 and 200 microg paw(-1)) peripheral antinociceptive effect. The effect of the 100 microg dose of DbcGMP was considered to be local since only a higher dose (300 microg paw(-1)) produced antinociception in the contralateral paw. 3. The antinociceptive effect of DbcGMP (100 microg paw(-1)) was dose-dependently antagonized by intraplantar administration of the sulphonylureas tolbutamide (20, 40 and 160 microg) and glibenclamide (40, 80 and 160 microg), selective blockers of ATP-sensitive K(+) channels. 4. Charybdotoxin (2 microg paw(-1)), a selective blocker of high conductance Ca(2+)-activated K(+) channels, and apamin (10 microg paw(-1)), a selective blocker of low conductance Ca(2+)-activated K(+) channels, did not modify the peripheral antinociception induced by DbcGMP. 5. Tetraethylammonium (2 mg paw(-1)), 4-aminopyridine (200 microg paw(-1)) and cesium (800 paw(-1)), non-selective voltage-gated potassium channel blockers, also had no effect. 6. Based on this experimental evidence, we conclude that the activation of ATP-sensitive K(+) channels could be the mechanism by which DbcGMP induces peripheral antinociception, and that Ca(2+)-activated K(+) channels and voltage-dependent K(+) channels appear not to be involved in the process.
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Affiliation(s)
- A C Soares
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100, Belo Horizonte, Brazil
| | - I D G Duarte
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100, Belo Horizonte, Brazil
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Bardin L, Tarayre JP, Koek W, Colpaert FC. In the formalin model of tonic nociceptive pain, 8-OH-DPAT produces 5-HT1A receptor-mediated, behaviorally specific analgesia. Eur J Pharmacol 2001; 421:109-14. [PMID: 11399266 DOI: 10.1016/s0014-2999(01)01029-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The experiments examined antinociceptive and intrinsic behavioral effects induced by the prototypical 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-[di-n-propylamino] tetralin) in rats. 8-OH-DPAT (0.01-2.5 mg/kg, subcutaneous (s.c.)) reduced both the paw licking and paw elevation induced by (2.5%) formalin injection into the plantar surface of the right hindpaw; it also produced forepaw treading. All of these effects were completely blocked by pretreatment with WAY 100635 (N-(2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride) (0.16 mg/kg, s.c.); prazosin (0.63 mg/kg, s.c.) inhibited forepaw treading, but not 8-OH-DPAT's action on paw elevation and paw licking. Repeated injection of 8-OH-DPAT (0.63 mg/kg, s.c.) twice daily for 4 days, markedly reduced 8-OH-DPAT's ability to produce forepaw treading, but exerted only little and inconsistent effects on its paw licking and paw elevation-inhibiting action. The data indicate that 8-OH-DPAT exerts an analgesic action in the formalin model of tonic nociceptive pain; this action is mediated by 5-HT(1A) receptors, and is not confounded by the productive sign (i.e., forepaw treading) of the 5-HT syndrome which 8-OH-DPAT also induces.
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Affiliation(s)
- L Bardin
- Centre de Recherche Pierre-Fabre, 17 Avenue Jean Moulin, F-81106 Cédex, Castres, France.
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González LG, Portillo E, Del Pozo E, Baeyens JM. Changes in [(3)H]glibenclamide binding to mouse forebrain membranes during morphine tolerance. Eur J Pharmacol 2001; 418:29-37. [PMID: 11334862 DOI: 10.1016/s0014-2999(01)00932-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The characteristics of specific binding of the ATP-sensitive K(+) (K(ATP)) channel blocker [3H]glibenclamide to forebrain membranes (P(2) fraction, 4 degrees C) obtained from morphine-naive and -tolerant mice were evaluated. Morphine tolerance was induced by osmotic minipumps that released 45 mg/kg/day of morphine subcutaneously for 6 days. This treatment enhanced the antinociceptive ED(50) of morphine without changing its E(max). In morphine-naive animals, (1) both the association and the dissociation of [3H]glibenclamide were biphasic; (2) [3H]glibenclamide was displaced by other sulfonylureas (order of potency: glibenclamide>glipizide&z.Gt;tolbutamide) with pseudo-Hill coefficients lower than unity and biphasic Hofstee plots; and (3) Scatchard plots of saturation experiments were curvilinear, showed a Hill coefficient of 0.81+/-0.04 and suggested the presence of two binding sites with a K(D) of 0.13 and 3.17 nM and a B(max) of 12.30 and 84.47 fmol/mg protein, respectively. By contrast, in membranes obtained from morphine-tolerant animals, (1) the Scatchard plots showed only one population of binding sites with a K(D) of 0.87 nM and a B(max) of 77.99 fmol/mg protein, and the Hill coefficient was very close to unity (0.96+/-0.1); (2) competition experiments (using glibenclamide as displacer) showed a pseudo-Hill coefficient of 0.99+/-0.04; and (3) dissociation experiments showed only one phase of dissociation. These results suggest that [3H]glibenclamide binds to two different sites in membranes obtained from morphine-naive animals, but to only one site in morphine-tolerant animals. Consequently, it seems that morphine tolerance in mice involves adaptive changes in K(ATP) channels.
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Affiliation(s)
- L G González
- Departamento de Farmacología e Instituto de Neurociencias, Facultad de Medicina, Universidad de Granada, Avda. Madrid 11, E-18012, Granada, Spain
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Ardid D, Alloui A, Brousse G, Jourdan D, Picard P, Dubray C, Eschalier A. Potentiation of the antinociceptive effect of clomipramine by a 5-ht(1A) antagonist in neuropathic pain in rats. Br J Pharmacol 2001; 132:1118-26. [PMID: 11226143 PMCID: PMC1572640 DOI: 10.1038/sj.bjp.0703897] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2000] [Revised: 10/30/2000] [Accepted: 12/11/2000] [Indexed: 11/08/2022] Open
Abstract
The benefit of antidepressant treatment in human neuropathic pain is now well documented, but the effect is limited and slow to appear. It has been demonstrated that the association of a 5-HT(1A) antagonist and a serotoninergic antidepressant reduced the delay of action and increases the thymoanaleptic effect of the drug. The purpose of this work was to evaluate the combination of an antidepressant and a 5-HT(1A) antagonist in animal models of chronic neuropathic pain. We studied the antinociceptive effect of the co-administration of clomipramine and a 5-HT(1A) antagonist (WAY 100,635) in a pain test applied in normal rats and in two models of neurogenic sustained pain (mononeuropathic and diabetic rats). The results show an increase in the antinociceptive effect of acutely injected clomipramine due to WAY 100,635 in these models, which is majored when the two drugs are repeatedly injected. The 5-HT(1A) antagonist reduced the delay of onset and increased the maximal antinociceptive effect of clomipramine. These new findings argue for using the combination of an antidepressant and a 5-HT(1A) antagonist in human neuropathic pain therapy.
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Affiliation(s)
- D Ardid
- EPI INSERM 9904, Laboratoire de pharmacologie Médicale, Faculté de médecine, 63001 Clermont-Ferrand Cedex, France.
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Soares AC, Leite R, Tatsuo MA, Duarte ID. Activation of ATP-sensitive K(+) channels: mechanism of peripheral antinociceptive action of the nitric oxide donor, sodium nitroprusside. Eur J Pharmacol 2000; 400:67-71. [PMID: 10913586 DOI: 10.1016/s0014-2999(00)00355-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Using the rat paw pressure test, in which sensitivity is increased by intraplantar injection of prostaglandin E(2) (PGE(2)), we conducted a study using several K(+) channel blockers. The objective was to determine what types of K(+) channels could be involved in the peripheral antinociceptive action of the nitric oxide donor sodium nitroprusside (SNP). SNP elicited a dose-dependent (250 and 500 microgram/paw) peripheral antinociceptive effect, which was considered local, since only higher doses produced an effect in the contralateral paw. The effect of SNP (500 microgram/paw) was dose-dependently antagonized by intraplantar administration of the sulfonylureas tolbutamide (20, 40 and 160 microgram) and glibenclamide (40, 80 and 160 microgram), selective blockers of ATP-sensitive K(+) channels. Charybdotoxin (2 microgram/paw), a selective blocker of high conductance Ca(2+)-activated K(+) channels, and apamin (10 microgram/paw), a selective blocker of low conductance Ca(2+)-activated K(+) channels, did not modify the peripheral antinociception induced by SNP. Tetraethylammonium (2 mg/paw), 4-aminopyridine (200 microgram/paw) and cesium (800 microgram/paw) also had no effect. Based on this experimental evidence, we conclude that the activation of ATP-sensitive K(+) channels could be the mechanism by which nitric oxide, donated by SNP, induces peripheral antinociception, and that Ca(2+)-activated K(+) channels and voltage-dependent K(+) channels appear not to be involved in the process.
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Affiliation(s)
- A C Soares
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus da Pampulha, CEP: 31.270.100, Minas Gerais, Belo Horizonte, Brazil
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