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Bedard ML, Huang XP, Murray JG, Nowlan AC, Conley SY, Mott SE, Loyack SJ, Cline CA, Clodfelter CG, Dasgupta N, Krumm B, Roth BL, McElligott ZA. Xylazine is an agonist at kappa opioid receptors and exhibits sex-specific responses to opioid antagonism. ADDICTION NEUROSCIENCE 2024; 11:100155. [PMID: 39086495 PMCID: PMC11290297 DOI: 10.1016/j.addicn.2024.100155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Xylazine is in the unregulated drug supply at increasing rates, usually combined with fentanyl, necessitating understanding of its pharmacology. Despite commentary from politicians, and public health officials, it is unknown how xylazine impacts naloxone efficacy, and. few studies have examined it alone. Here, we examine the impact of xylazine alone and in combination with fentanyl on several behaviors in mice. Surprisingly, naloxone precipitates withdrawal from xylazine and fentanyl/xylazine coadministration, with enhanced sensitivity in females. Further, xylazine is a full agonist at kappa opioid receptors, a potential mechanism for its naloxone sensitivity. Finally, we demonstrate surprising effects of xylazine to kappa opioid antagonism, which are relevant for public health considerations. These data address an ongoing health crisis and will help inform critical policy and healthcare decisions.
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Affiliation(s)
- Madigan L. Bedard
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Xi-Ping Huang
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Jackson G. Murray
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Alexandra C. Nowlan
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Sara Y. Conley
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Program in Neuroscience, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Sarah E. Mott
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Samuel J. Loyack
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Calista A. Cline
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Caroline G. Clodfelter
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Nabarun Dasgupta
- Injury Prevention Research Center, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Brian Krumm
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
| | - Bryan L. Roth
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill Eshelman School of Pharmacy; Chapel Hill, 27599, USA
| | - Zoe A. McElligott
- Department of Pharmacology, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill; Chapel Hill, 27599, USA
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Sharp JL, Pearson T, Smith MA. Sex differences in opioid receptor mediated effects: Role of androgens. Neurosci Biobehav Rev 2022; 134:104522. [PMID: 34995646 PMCID: PMC8872632 DOI: 10.1016/j.neubiorev.2022.104522] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/19/2021] [Accepted: 01/02/2022] [Indexed: 12/26/2022]
Abstract
An abundance of data indicates there are sex differences in endogenous opioid peptides and opioid receptors, leading to functional differences in sensitivity to opioid receptor mediated behaviors between males and females. Many of these sex differences are mediated by the effects of gonadal hormones on the endogenous opioid system. Whereas much research has examined the role of ovarian hormones on opioid receptor mediated endpoints, comparatively less research has examined the role of androgens. This review describes what is currently known regarding the influence of androgens on opioid receptor mediated endpoints and how androgens may contribute to sex differences in these effects. The review also addresses the clinical implications of androgenic modulation of opioid receptor mediated behaviors and suggests future lines of research for preclinical and clinical investigators. We conclude that further investigation into androgenic modulation of opioid receptor mediated effects may lead to new options for addressing conditions such as chronic pain and substance use disorders.
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Affiliation(s)
- Jessica L Sharp
- Department of Psychology and Program in Neuroscience, Davidson College, United States
| | - Tallia Pearson
- Department of Psychology and Program in Neuroscience, Davidson College, United States
| | - Mark A Smith
- Department of Psychology and Program in Neuroscience, Davidson College, United States.
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3
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The kappa-opioid receptor agonist, nalfurafine, blocks acquisition of oxycodone self-administration and oxycodone's conditioned rewarding effects in male rats. Behav Pharmacol 2020; 31:792-797. [PMID: 32804774 DOI: 10.1097/fbp.0000000000000581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mu-opioid receptor (MOR) agonists are highly efficacious for the treatment of pain but have significant abuse liability. Recently, we reported that nalfurafine, when combined with oxycodone at a certain ratio, reduced the reinforcing effects of oxycodone in rats while producing additive antinociceptive effects. Questions remain, however, including if the combination will function as a reinforcer in drug-naïve rats, and if the combination produces aversive effects that could explain nalfurafine's ability to reduce oxycodone self-administration? In the present study, we investigated nalfurafine's ability to reduce acquisition of oxycodone self-administration when the two were self-administered as a mixture in drug-naïve rats and nalfurafine's ability to attenuate a conditioned place preference (CPP) induced by oxycodone. In the self-administration study, male Sprague-Dawley rats self-administered intravenous injections of oxycodone (0.056 mg/kg/injection), an oxycodone/nalfurafine combination (0.056/0.0032 mg/kg/injection), or saline under fixed-ratio schedules of reinforcement for 20 days to compare rates of acquisition of drug taking. In the CPP assay, male Sprague-Dawley rats received subcutaneous injections of either saline, oxycodone (3.2 mg/kg), nalfurafine (0.18 mg/kg), or an oxycodone/nalfurafine combination at the same ratio used in the self-administration study (3.2 mg/kg/0.18 mg/kg). All subjects self-administering oxycodone alone met acquisition criteria. However, only 13% of subjects self-administering oxycodone/nalfurafine met criteria, and no subjects acquired self-administration of saline. Oxycodone, but not nalfurafine alone or the oxycodone/nalfurafine combination, produced rewarding effects in rats in the CPP test. These findings suggest that the combination of oxycodone and nalfurafine will be less habit forming in opioid-naïve patients than oxycodone alone.
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Qualitative sex differences in pain processing: emerging evidence of a biased literature. Nat Rev Neurosci 2020; 21:353-365. [PMID: 32440016 DOI: 10.1038/s41583-020-0310-6] [Citation(s) in RCA: 326] [Impact Index Per Article: 81.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2020] [Indexed: 02/07/2023]
Abstract
Although most patients with chronic pain are women, the preclinical literature regarding pain processing and the pathophysiology of chronic pain has historically been derived overwhelmingly from the study of male rodents. This Review describes how the recent adoption by a number of funding agencies of policies mandating the incorporation of sex as a biological variable into preclinical research has correlated with an increase in the number of studies investigating sex differences in pain and analgesia. Trends in the field are analysed, with a focus on newly published findings of qualitative sex differences: that is, those findings that are suggestive of differential processing mechanisms in each sex. It is becoming increasingly clear that robust differences exist in the genetic, molecular, cellular and systems-level mechanisms of acute and chronic pain processing in male and female rodents and humans.
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Shirai T, Yano M, Natsume T, Awaga Y, Itani Y, Hama A, Matsuda A, Takamatsu H. Pharmacologic Modulation of Noxious Stimulus-evoked Brain Activation in Cynomolgus Macaques Observed with Functional Neuroimaging. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE 2019; 59:94-103. [PMID: 31753062 DOI: 10.30802/aalas-jaalas-18-000143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Maintaining effective analgesia during invasive procedures performed under general anesthesia is important for minimizing postoperative complications and ensuring satisfactory patient wellbeing and recovery. While patients under deep sedation may demonstrate an apparent lack of response to noxious stimulation, areas of the brain related to pain perception may still be activated. Thus, these patients may still experience pain during invasive procedures. The current study used anesthetized or sedated cynomolgus macaques and functional magnetic resonance imaging (fMRI) to assess the activation of the parts of the brain involved in pain perception during the application of peripheral noxious stimuli. Noxious pressure applied to the foot resulted in the bilateral activation of secondary somatosensory cortex (SII) and insular cortex (Ins), which are both involved in pain perception, in macaques under either propofol or pentobarbital sedation. No activation of SII/Ins was observed in macaques treated with either isoflurane or a combination of medetomidine, midazolam, and butorphanol. No movement or other reflexes were observed in response to noxious pressure during stimulation under anesthesia or sedation. The current findings show that despite the lack of visible behavioral symptoms of pain during anesthesia or sedation, brain activation suggests the presence of pain depending on the anesthetic agent used. These data suggest that fMRI could be used to noninvasively assess pain and to confirm the analgesic efficacy of currently used anesthetics. By assessing analgesic efficacy, researchers may refine their experiments, and design protocols that improve analgesia under anesthesia.
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Page S, Mavrikaki MM, Lintz T, Puttick D, Roberts E, Rosen H, Carroll FI, Carlezon WA, Chartoff EH. Behavioral Pharmacology of Novel Kappa Opioid Receptor Antagonists in Rats. Int J Neuropsychopharmacol 2019; 22:735-745. [PMID: 31613314 PMCID: PMC7145521 DOI: 10.1093/ijnp/pyz054] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/09/2019] [Accepted: 10/10/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND New treatments for stress-related disorders including depression, anxiety, and substance use disorder are greatly needed. Kappa opioid receptors are expressed in the central nervous system, including areas implicated in analgesia and affective state. Although kappa opioid receptor agonists share the antinociceptive effects of mu opioid receptor agonists, they also tend to produce negative affective states. In contrast, selective kappa opioid receptor antagonists have antidepressant- and anxiolytic-like effects, stimulating interest in their therapeutic potential. The prototypical kappa opioid receptor antagonists (e.g., norBNI, JDTic) have an exceptionally long duration of action that complicates their use in humans, particularly in tests to establish safety. This study was designed to test dose- and time-course effects of novel kappa opioid receptor antagonists with the goal of identifying short-acting lead compounds for future medication development. METHODS We screened 2 novel, highly selective kappa opioid receptor antagonists (CYM-52220 and CYM-52288) with oral efficacy in the warm water tail flick assay in rats to determine initial dose and time course effects. For comparison, we tested existing kappa opioid receptor antagonists JDTic and LY-2456302 (also known as CERC-501 or JNJ-67953964). RESULTS In the tail flick assay, the rank order of duration of action for the antagonists was LY-2456302 < CYM-52288 < CYM-52220 << JDTic. Furthermore, LY-2456302 blocked the depressive (anhedonia-producing) effects of the kappa opioid receptor agonist U50,488 in the intracranial self-stimulation paradigm, albeit at a higher dose than that needed for analgesic blockade in the tail flick assay. CONCLUSIONS These results suggest that structurally diverse kappa opioid receptor antagonists can have short-acting effects and that LY-2456302 reduces anhedonia as measured in the intracranial self-stimulation test.
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Affiliation(s)
- Sarah Page
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - Maria M Mavrikaki
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - Tania Lintz
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - Daniel Puttick
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - Edward Roberts
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA
| | - Hugh Rosen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA
| | - F Ivy Carroll
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - William A Carlezon
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA
| | - Elena H Chartoff
- Research Triangle Institute, Research Triangle Park, NC,Correspondence: Dr E. H. Chartoff, PhD, McLean Hospital, MRC 218, 115 Mill Street, Belmont, MA 02478 ()
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Custodio-Patsey L, Donahue RR, Fu W, Lambert J, Smith BN, Taylor BK. Sex differences in kappa opioid receptor inhibition of latent postoperative pain sensitization in dorsal horn. Neuropharmacology 2019; 163:107726. [PMID: 31351975 DOI: 10.1016/j.neuropharm.2019.107726] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/11/2019] [Accepted: 07/25/2019] [Indexed: 12/31/2022]
Abstract
Tissue injury produces a delicate balance between latent pain sensitization (LS) and compensatory endogenous opioid receptor analgesia that continues for months, even after re-establishment of normal pain thresholds. To evaluate the contribution of mu (MOR), delta (DOR), and/or kappa (KOR) opioid receptors to the silencing of chronic postoperative pain, we performed plantar incision at the hindpaw, waited 21 days for the resolution of hyperalgesia, and then intrathecally injected subtype-selective ligands. We found that the MOR-selective inhibitor CTOP (1-1000 ng) dose-dependently reinstated mechanical hyperalgesia. Two DOR-selective inhibitors naltrindole (1-10 μg) and TIPP[Ψ] (1-20 μg) reinstated mechanical hyperalgesia, but only at the highest dose that also produced itching, licking, and tail biting. Both the prototypical KOR-selective inhibitors nor-BNI (0.1-10 μg) and the newer KOR inhibitor with more canonical pharmocodynamic effects, LY2456302 (0.1-10 μg), reinstated mechanical hyperalgesia. Furthermore, LY2456302 (10 μg) increased the expression of phosphorylated signal-regulated kinase (pERK), a marker of central sensitization, in dorsal horn neurons but not glia. Sex studies revealed that LY2456302 (0.3 μg) reinstated hyperalgesia and pERK expression to a greater degree in female as compared to male mice. Our results suggest that spinal MOR and KOR, but not DOR, maintain LS within a state of remission to reduce the intensity and duration of postoperative pain, and that endogenous KOR but not MOR analgesia is greater in female mice.
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Affiliation(s)
- Lilian Custodio-Patsey
- Department of Physiology, College of Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA
| | - Renée R Donahue
- Department of Physiology, College of Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA
| | - Weisi Fu
- Department of Physiology, College of Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA
| | - Joshua Lambert
- Department of Statistics, College of Arts and Sciences, University of Kentucky, 302 Multidisciplinary Science Building, Lexington, KY, 40536-0082, USA
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA; Department of Neuroscience, College of Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA
| | - Bradley K Taylor
- Department of Anesthesiology, Pittsburgh Center for Pain Research, and the Pittsburgh Project to End Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA.
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Abstract
All preclinical procedures for analgesic drug discovery involve two components: 1) a "pain stimulus" (the principal independent variable), which is delivered to an experimental subject with the intention of producing a pain state; and 2) a "pain behavior" (the principal dependent variable), which is measured as evidence of that pain state. Candidate analgesics are then evaluated for their effectiveness to reduce the pain behavior, and results are used to prioritize drugs for advancement to clinical testing. This review describes a taxonomy of preclinical procedures organized into an "antinociception matrix" by reference to their types of pain stimulus (noxious, inflammatory, neuropathic, disease related) and pain behavior (unconditioned, classically conditioned, operant conditioned). Particular emphasis is devoted to pain behaviors and the behavioral principals that govern their expression, pharmacological modulation, and preclinical-to-clinical translation. Strengths and weaknesses are compared and contrasted for procedures using each type of behavioral outcome measure, and the following four recommendations are offered to promote strategic use of these procedures for preclinical-to-clinical analgesic drug testing. First, attend to the degree of homology between preclinical and clinical outcome measures, and use preclinical procedures with behavioral outcome measures homologous to clinically relevant outcomes in humans. Second, use combinations of preclinical procedures with complementary strengths and weaknesses to optimize both sensitivity and selectivity of preclinical testing. Third, take advantage of failed clinical translation to identify drugs that can be back-translated preclinically as active negative controls. Finally, increase precision of procedure labels by indicating both the pain stimulus and the pain behavior in naming preclinical procedures.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Minervini V, Dahal S, France CP. Behavioral Characterization of κ Opioid Receptor Agonist Spiradoline and Cannabinoid Receptor Agonist CP55940 Mixtures in Rats. J Pharmacol Exp Ther 2016; 360:280-287. [PMID: 27903642 DOI: 10.1124/jpet.116.235630] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022] Open
Abstract
Pain is a significant clinical problem, and there is a need for more effective treatments with reduced adverse effects that currently limit the use of μ opioid receptor agonists. Synthetic κ opioid receptor agonists have no abuse liability and well-documented antinociceptive effects; however, adverse effects (diuresis, dysphoria) preclude their use in the clinic. Combining κ opioids with nonopioid drugs (cannabinoid receptor agonists) allows for smaller doses of each drug to produce antinociception. This study tested whether a potentially useful effect of the κ opioid receptor agonist 2-(3,4-dichlorophenyl)-N-methyl-N-[(5R,7S,8S)-7-pyrrolidin-1-yl-1-oxaspiro[4.5]decan-8-yl] (spiradoline; antinociception) is selectively enhanced by the cannabinoid receptor agonist 2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl) cyclohexyl]-5-(2-methyloctan-2-yl)phenol (CP55940). Cumulative dose-response functions were determined in eight male Sprague-Dawley rats for spiradoline (0.032-32.0 mg/kg, i.p.) and CP55940 (0.0032-1.0 mg/kg, i.p.) for antinociception, hypothermia, food-maintained responding, and diuresis. Alone, each drug dose dependently increased tail withdrawal latencies from 50°C water, decreased body temperature by ∼4°C, and eliminated food-maintained responding. Spiradoline, but not CP55940, significantly increased urine output at doses that eliminated responding. Smaller doses of spiradoline and CP55940 in mixtures (3:1, 1:1, and 1:3 spiradoline:CP55940) had effects comparable to those observed with larger doses of either drug administered alone: the interaction was additive for antinociception and additive or greater than additive for hypothermia and food-maintained responding. Collectively, these data fail to provide support for the use of these mixtures for treating acute pain; however, κ opioid/cannabinoid mixtures might be useful for treating pain under other conditions (e.g., chronic pain), but only if the adverse effects of both drugs are not enhanced in mixtures.
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Affiliation(s)
- Vanessa Minervini
- Departments of Pharmacology (V.M., S.D., C.P.F.) and Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Sujata Dahal
- Departments of Pharmacology (V.M., S.D., C.P.F.) and Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Charles P France
- Departments of Pharmacology (V.M., S.D., C.P.F.) and Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas
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Hestehave S, Munro G, Pedersen TB, Abelson KSP. Antinociceptive effects of voluntarily ingested buprenorphine in the hot-plate test in laboratory rats. Lab Anim 2016; 51:264-272. [PMID: 27681372 DOI: 10.1177/0023677216668553] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Researchers performing experiments on animals should always strive towards the refinement of experiments, minimization of stress and provision of better animal welfare. An adequate analgesic strategy is important to improve post-operative recovery and welfare in laboratory rats and mice. In addition, it is desirable to provide post-operative analgesia using methods that are minimally invasive and stressful. This study investigated the antinociceptive effects of orally administered buprenorphine ingested in Nutella® in comparison with subcutaneous buprenorphine administration. By exposing the animal to a thermal stimulus using a hot plate, significant antinociceptive effects of voluntarily ingested buprenorphine administered in Nutella® were demonstrated. This was evident at doses of 1.0 mg/kg 60 and 120 min post administration ( P < 0.01), although antinociceptive effects were not as marked as with subcutaneous administration, and had a later onset. It is advised to administer the oral formulation of buprenorphine in Nutella® in a 10-fold higher dose, as well as approximately 60 min earlier, than with the more commonly employed subcutaneous route of administration.
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Affiliation(s)
- Sara Hestehave
- 1 Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,2 H Lundbeck A/S, Valby, Denmark
| | | | | | - Klas S P Abelson
- 1 Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Chartoff EH, Mavrikaki M. Sex Differences in Kappa Opioid Receptor Function and Their Potential Impact on Addiction. Front Neurosci 2015; 9:466. [PMID: 26733781 PMCID: PMC4679873 DOI: 10.3389/fnins.2015.00466] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/23/2015] [Indexed: 11/23/2022] Open
Abstract
Behavioral, biological, and social sequelae that lead to drug addiction differ between men and women. Our efforts to understand addiction on a mechanistic level must include studies in both males and females. Stress, anxiety, and depression are tightly linked to addiction, and whether they precede or result from compulsive drug use depends on many factors, including biological sex. The neuropeptide dynorphin (DYN), an endogenous ligand at kappa opioid receptors (KORs), is necessary for stress-induced aversive states and is upregulated in the brain after chronic exposure to drugs of abuse. KOR agonists produce signs of anxiety, fear, and depression in laboratory animals and humans, findings that have led to the hypothesis that drug withdrawal-induced DYN release is instrumental in negative reinforcement processes that drive addiction. However, these studies were almost exclusively conducted in males. Only recently is evidence available that there are sex differences in the effects of KOR activation on affective state. This review focuses on sex differences in DYN and KOR systems and how these might contribute to sex differences in addictive behavior. Much of what is known about how biological sex influences KOR systems is from research on pain systems. The basic molecular and genetic mechanisms that have been discovered to underlie sex differences in KOR function in pain systems may apply to sex differences in KOR function in reward systems. Our goals are to discuss the current state of knowledge on how biological sex contributes to KOR function in the context of pain, mood, and addiction and to explore potential mechanisms for sex differences in KOR function. We will highlight evidence that the function of DYN-KOR systems is influenced in a sex-dependent manner by: polymorphisms in the prodynorphin (pDYN) gene, genetic linkage with the melanocortin-1 receptor (MC1R), heterodimerization of KORs and mu opioid receptors (MORs), and gonadal hormones. Finally, we identify several gaps in our understanding of “if” and “how” DYN and KORs modulate addictive behavior in a sex-dependent manner. Future work may address these gaps by building on the mechanistic studies outlined in this review. Ultimately this will enable the development of novel and effective addiction treatments tailored to either males or females.
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Affiliation(s)
- Elena H Chartoff
- Department of Psychiatry, Harvard Medical School, McLean Hospital Belmont, MA, USA
| | - Maria Mavrikaki
- Department of Psychiatry, Harvard Medical School, McLean Hospital Belmont, MA, USA
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Norouzi Javidan A, Yazdi Samadi F, Latifi S, Jafari Nodoushan M, Mobedi H. A novel controlled release drug delivery system for naltrexone administration combined with intermittent morphine to induce antinociception. J Drug Deliv Sci Technol 2014. [DOI: 10.1016/s1773-2247(14)50082-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Freet CS, Wheeler RA, Leuenberger E, Mosblech NAS, Grigson PS. Fischer rats are more sensitive than Lewis rats to the suppressive effects of morphine and the aversive kappa-opioid agonist spiradoline. Behav Neurosci 2013; 127:763-70. [PMID: 24128363 PMCID: PMC3973147 DOI: 10.1037/a0033943] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Data have suggested that rats avoid intake of an otherwise palatable saccharin cue when paired with a drug of abuse, at least, in part, because the value of the taste cue pales in anticipation of the availability of the highly rewarding drug. Earlier support for this hypothesis was provided by the finding that, relative to the less sensitive Fischer rats, Lewis rats exhibit greater avoidance of a saccharin cue when paired with a rewarding sucrose or cocaine unconditioned stimulus (US), but not when paired with the aversive agent, lithium chloride. More recent data, however, have shown that Fischer rats actually exhibit greater, not less, avoidance of the same saccharin cue when morphine serves as the US. Therefore, Experiment 1 evaluated morphine-induced suppression of intake of the taste cue in Lewis and Fischer rats when the morphine US was administered subcutaneously, rather than intraperitoneally. Experiment 2 examined the effect of strain on the suppression of intake of the saccharin cue when paired with spiradoline, a selective kappa-opioid receptor agonist. The results confirmed that Fischer rats are more responsive to the suppressive effects of morphine than Lewis rats, and that Fischer rats also exhibit greater avoidance of the saccharin cue when paired with spiradoline, despite the fact that spiradoline is devoid of reinforcing properties. Taken together, the data suggest that the facilitated morphine-induced suppression observed in Fischer rats, compared with Lewis rats, may reflect an increased sensitivity to the aversive, kappa-mediated properties of opiates.
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Affiliation(s)
- Christopher S Freet
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine
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Rasakham K, Liu-Chen LY. Sex differences in kappa opioid pharmacology. Life Sci 2010; 88:2-16. [PMID: 20951148 DOI: 10.1016/j.lfs.2010.10.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 09/24/2010] [Accepted: 10/06/2010] [Indexed: 12/31/2022]
Abstract
In recent years it has become apparent that sex is a major factor involved in modulating the pharmacological effects of exogenous opioids. The kappa opioid receptor (KOPR) system is a potential therapeutic target for pain, mood disorders and addiction. In humans mixed KOPR/MOPR ligands have been found to produce greater analgesia in women than men. In contrast, in animals, selective KOPR agonists have been found to produce greater antinociceptive effects in males than females. Collectively, the studies indicate that the direction and magnitude of sex differences of KOPR-mediated antinociception/analgesia are dependent on species, strain, ligand and pain model examined. Of interest, and less studied, is whether sex differences in other KOPR-mediated effects exist. In the studies conducted thus far, greater effects of KOPR agonists in males have been found in neuroprotection against stroke and suppression of food intake behavior. On the other hand, greater effects of KOPR agonists were found in females in mediation of prolactin release. In modulation of drugs of abuse, sex differences in KOPR effects were observed but appear to be dependent on the drug examined. The mechanism(s) underlying sex differences in KOPR-mediated effects may be mediated by sex chromosomes, gonadal hormonal influence on organization (circuitry) and/or acute hormonal influence on KOPR expression, distribution and localization. In light of the diverse pharmacology of KOPR we discuss the need for future studies characterizing the sexual dimorphism of KOPR neural circuitry and in examining other behaviors and processes that are modulated by the KOPR.
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Affiliation(s)
- Khampaseuth Rasakham
- Department of Pharmacology and Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, United States
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Wakley AA, Craft RM. Antinociception and sedation following intracerebroventricular administration of Δ⁹-tetrahydrocannabinol in female vs. male rats. Behav Brain Res 2010; 216:200-6. [PMID: 20692296 DOI: 10.1016/j.bbr.2010.07.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 07/23/2010] [Accepted: 07/28/2010] [Indexed: 10/19/2022]
Abstract
Systemically administered cannabinoids produce greater antinociceptive and sedative effects in female compared to male rats. Sex differences in the brain endocannabinoid system have also been reported. The aim of this study was to determine whether sex differences in antinociceptive and motoric effects of a cannabinoid can be attributed to supraspinal mechanisms. Vehicle or Δ⁹-tetrahydrocannabinol (THC, 100 μg) was administered i.c.v., and behavioral effects were compared between gonadally intact male and female rats, and among females in different estrous stages (early proestrus, late proestrus, estrus and diestrus). Antinociception on the tail withdrawal and paw pressure tests after i.c.v. THC was slightly but not significantly greater in females (pooled across estrous stages) compared to males. THC suppressed locomotor activity similarly in all groups, with the exception that only males showed hyperlocomotion at 4 h post-injection. When females in the four estrous stages were compared, females in late proestrus showed significantly greater THC-induced antinociception than females in estrus (and males). These results suggest that supraspinal mechanisms may contribute to greater systemic THC effects in females compared to males, and to estrous stage-dependent differences in THC effects among females.
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Affiliation(s)
- Alexa A Wakley
- Department of Psychology, Washington State University, Pullman, WA 99164-4820, United States.
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16
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Cataldo G, Lovric J, Chen CC, Pytte CL, Bodnar RJ. Ventromedial and medial preoptic hypothalamic ibotenic acid lesions potentiate systemic morphine analgesia in female, but not male rats. Behav Brain Res 2010; 214:301-16. [PMID: 20678986 DOI: 10.1016/j.bbr.2010.05.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 05/25/2010] [Accepted: 05/26/2010] [Indexed: 11/30/2022]
Abstract
Sex differences in systemic morphine analgesia occur with male rodents displaying significantly greater analgesic magnitudes and potencies than females. Neonatal androgenization, and to a lesser degree, adult ovariectomy enhance systemic morphine analgesia in female rats, implicating both organizational and activational effects of gonadal hormones. The neuroanatomical circuits sensitive to sex-related hormones by which females display a smaller opiate analgesic effect is not clear, but the ventromedial (VMH) and medial preoptic (MPOA) hypothalamic nuclei are critical in the monitoring of estradiol and other sex hormone levels. To assess the contribution of these nuclei to sex and adult gonadectomy differences in systemic morphine analgesia, intact male, intact female and adult ovariectomized (OVEX) female rats received bilateral saline (SAL) or ibotenic acid (IBO) microinjections into either the VMH or MPOA. Following surgeries, baseline tail-flick latencies over 120 minutes (min) were assessed over 4 days in all nine groups with intact females tested in the estrus phase of their cycle. All animals then received an ascending series of morphine (1.0, 2.5, 5.0, 7.5, 10.0mg/kg) injections 30min prior to the tail-flick test time course with 8-12 day inter-injection intervals between doses. Baseline latencies failed to differ between SAL-treated intact males and females, but were significantly higher in SAL-treated OVEX females. Both VMH IBO and MPOA IBO lesions increased baseline latencies in intact male and female rats, but not in OVEX females. SAL-treated intact males (ED(50)=4.0mg/kg) and SAL-treated OVEX females (ED(50)=3.5mg/kg) displayed significantly greater potencies of systemic morphine analgesia than SAL-treated intact females (ED(50)=6.3mg/kg), confirming previous gender and gonadectomy differences. Neither VMH IBO (ED(50)=3.7 mg/kg) nor MPOA IBO (ED(50)=4.1mg/kg) males differed from SAL-treated males in the potency of systemic morphine analgesia. In contrast, VMH IBO (ED(50)=4.1mg/kg) and MPOA IBO (ED(50)=3.5mg/kg) intact females displayed significantly greater potencies in systemic morphine analgesia than SAL-treated intact females. However, VMH IBO OVEX (ED(50)=3.5mg/kg) and MPOA IBO OVEX (ED(50)=3.9 mg/kg) failed to differ from SAL-treated OVEX females in the potency of systemic morphine analgesia. The magnitudes of systemic morphine analgesia as measured by Maximum Percentage Effect values displayed similar patterns, but lesser degrees, of effects. These data suggest that VMH and MPOA nuclei act to tonically inhibit endogenous pain-inhibitory circuits in the intact female, but not intact male brain, and that removal of circulating gonadal hormones by OVEX and/or excitotoxic destruction of these estrogen receptor accumulating nuclei disinhibit the female analgesic response to systemic morphine.
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Affiliation(s)
- Giuseppe Cataldo
- Department of Psychology, Queens College, City University of New York, Flushing, NY, United States
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Bodnar RJ, Kest B. Sex differences in opioid analgesia, hyperalgesia, tolerance and withdrawal: central mechanisms of action and roles of gonadal hormones. Horm Behav 2010; 58:72-81. [PMID: 19786031 DOI: 10.1016/j.yhbeh.2009.09.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 09/11/2009] [Accepted: 09/18/2009] [Indexed: 01/05/2023]
Abstract
This article reviews sex differences in opiate analgesic and related processes as part of a Special Issue in Hormones and Behavior. The research findings on sex differences are organized in the following manner: (a) systemic opioid analgesia across mu, delta and kappa opioid receptor subtypes and drug efficacy at their respective receptors, (b) effects of the activational and organizational roles of gonadal steroid hormones and estrus phase on systemic analgesic responses, (c) sex differences in spinal opioid analgesia, (d) sex differences in supraspinal opioid analgesia and gonadal hormone effects, (e) the contribution of genetic variance to analgesic sex differences, (f) sex differences in opioid-induced hyperalgesia, (g) sex differences in tolerance and withdrawal-dependence effects, and (h) implications for clinical therapies.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology, Queens College, The Graduate Center, City University of New York, NY 11367, USA.
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Mogil JS, Bailey AL. Sex and gender differences in pain and analgesia. PROGRESS IN BRAIN RESEARCH 2010; 186:141-57. [PMID: 21094890 DOI: 10.1016/b978-0-444-53630-3.00009-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
It is a clinical reality that women make up the large majority of chronic pain patients, and there is now consensus from laboratory experiments that when differences are seen, women are more sensitive to pain than men. Research in this field has now begun to concentrate on finding explanations for this sex difference. Although sex differences in sociocultural, psychological, and experiential factors likely play important roles, evidence largely from animal studies has revealed surprisingly robust and often qualitative sex differences at low levels of the neuraxis. Although not yet able to affect clinical practice, the continued study of sex differences in pain may have important implications for the development of new analgesic strategies.
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Affiliation(s)
- Jeffrey S Mogil
- Department of Psychology and Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada.
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The role of the periaqueductal gray in the modulation of pain in males and females: are the anatomy and physiology really that different? Neural Plast 2009; 2009:462879. [PMID: 19197373 PMCID: PMC2633449 DOI: 10.1155/2009/462879] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 10/17/2008] [Indexed: 01/11/2023] Open
Abstract
Anatomical and physiological studies conducted in the 1960s identified the periaqueductal gray (PAG) and its descending projections to the rostral ventromedial medulla (RVM) and spinal cord dorsal horn, as a primary anatomical pathway mediating opioid-based analgesia. Since these initial studies, the PAG-RVM-spinal cord pathway has been characterized anatomically and physiologically in a wide range of vertebrate species. Remarkably, the majority of these studies were conducted exclusively in males with the implicit assumption that the anatomy and physiology of this circuit were the same in females; however, this is not the case. It is well established that morphine administration produces greater antinociception in males compared to females. Recent studies indicate that the PAG-RVM pathway contributes to the sexually dimorphic actions of morphine. This manuscript will review our anatomical, physiological, and behavioral data identifying sex differences in the PAG-RVM pathway, focusing on its role in pain modulation and morphine analgesia.
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Paller CJ, Campbell CM, Edwards RR, Dobs AS. Sex-based differences in pain perception and treatment. PAIN MEDICINE 2009; 10:289-99. [PMID: 19207233 DOI: 10.1111/j.1526-4637.2008.00558.x] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This review highlights research on sex-based differences in pain perception and treatment. We sought to illuminate the complex factors contributing to differences in pain and analgesic responses between males and females, ranging from psychosocial to biological processes. DESIGN We reviewed published studies of pain induction by chemical, electric, heat, surgical, or psychological means, and opioid and nonopioid analgesia comparing responses in men and women. RESULTS A substantial body of research indicates that women experience greater clinical pain, suffer greater pain-related distress, and show heightened sensitivity to experimentally induced pain compared with men. Research on sex-based differences in the pain experience and treatment is beginning to uncover patterns that may enable tailoring of pain treatment to individual characteristics. The factors underpinning sex differences in the experience of pain are multifactorial and complex; for example, psychosocial factors such as pain-related catastrophizing may explain sex-based differences in reporting certain types of pain, as women tend to use catastrophizing to a greater degree. Gonadal hormone levels in cycling women also have a substantial impact on pain perception and analgesic response. Women perceive more pain during the luteal phase, and estrogen antagonists provide long-term pain relief in certain situations. CONCLUSIONS Collectively, greater understanding of the factors that commonly and differentially affect the disparity in pain perception, as well as analgesic response, are beginning to illuminate research targets and promising areas of therapeutic intervention for improved pain management.
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Affiliation(s)
- Channing J Paller
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Dahan A, Kest B, Waxman AR, Sarton E. Sex-specific responses to opiates: animal and human studies. Anesth Analg 2008; 107:83-95. [PMID: 18635471 DOI: 10.1213/ane.0b013e31816a66a4] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It is widely reported that analgesic drugs acting at mu, kappa, and delta opioid-receptors display quantitative and qualitative differences in effect in males and females. These sex-related differences are not restricted to the analgesic/antinociceptive properties of opioids, but are also present in opioid-induced side effects, such as changes in respiration, locomotor activity, learning/memory, addiction, and changes in the cardiovascular system. An increasing number of well-controlled animal and human studies directly examining the issue of sex in the potency of opioids show that, although sex may affect opioid analgesia, the direction and magnitude of sex differences depend on many interacting variables. These include those specific to the drug itself, such as dose, pharmacology, and route and time of administration, and those particular to the subject, such as species, type of pain, genetics, age, and gonadal/hormonal status. In the current review, we systematically present these animal and human studies and discuss the data in relation to the depending variables. Although the observed sex differences in opioid effect may be clinically relevant, lack of knowledge on other factors involved in the large variability in patient opioid analgesic sensitivity should compel practitioners to customize their dosing regimens based on individual requirements.
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Affiliation(s)
- Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, P5-Q, 2300 RC Leiden, The Netherlands.
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Bijur PE, Esses D, Birnbaum A, Chang AK, Schechter C, Gallagher EJ. Response to morphine in male and female patients: analgesia and adverse events. Clin J Pain 2008; 24:192-8. [PMID: 18287823 DOI: 10.1097/ajp.0b013e31815d3619] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND There is little agreement about a differential response of men and women to opioid analgesics. Some experimental and clinical studies have shown that women have a better response to opioids, others have found no difference, and still others have found opioids to be more effective analgesics for men than women. OBJECTIVES To assess sex differences in analgesic response to morphine and incidence of adverse events in patients receiving a dose of 0.1 mg intravenous morphine/kg. METHODS Secondary analysis of the control arms of 6 randomized clinical trials that compared 0.1 mg/kg intravenous morphine with other opioids or other doses of morphine in patients aged 21 to 65 with acute pain. The setting was an academic medical center Emergency Department serving primarily Latino and African-American patients. Change in self-reported pain intensity from baseline to 30 minutes postbaseline on a validated and reproducible 11-point numerical rating scale and count of adverse events were the primary outcomes. RESULTS The sample consisted of 211 women and 144 men. The mean change in pain from baseline to 30 minutes postbaseline was 3.7 in women, 3.6 men (difference=0.04; 95% confidence interval: -0.52, 0.60). In women without nausea before administration of morphine, the incidence of adverse events was 18.3% versus 10.7% in men without initial nausea (difference=7.6%; 95% confidence interval: -2.0, 17.2). DISCUSSION Men and women presenting to the Emergency Department did not have a differential response to a single weight-based dose of morphine for alleviation of acute pain. Women without baseline nausea had more adverse events than men.
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Affiliation(s)
- Polly E Bijur
- Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
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Avsaroglu H, Sommer R, Hellebrekers LJ, van Zutphen LFM, van Lith HA. The effects of buprenorphine on behaviour in the ACI and BN rat inbred strains. Lab Anim 2008; 42:171-84. [DOI: 10.1258/la.2007.007017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Summary Buprenorphine is a partial μ, κ agonist that has been shown to influence spontaneous behaviour in animals. Previously, we have demonstrated significant differences in the analgesic response to buprenorphine between the August Copenhagen Irish (ACI)/SegHsd and the Brown Norway (BN)/RijHsd inbred rat strains. The purpose of this study was to determine whether these strains also differed in their behavioural response to buprenorphine in order to provide an additional parameter for the genetic analysis and localization of genes involved in this response. Male and female rats of both strains were used ( n = 6/strain/sex) for this study. Each rat was subjected, respectively, to three treatment regimens at 15:00 h: (A) unchallenged; (B) intravenous saline; (C) intravenous buprenorphine (0.05 mg/kg) according to a crossover design. The relative duration (s/h) of locomotion, grooming, drinking and eating behaviour was subsequently determined from 15:30 to 07:00 h using the automatic registration system, Laboratory Animal Behaviour Registration and Analysis System™. Significant strain differences were observed in unchallenged behaviour between the ACI and the BN rats. ACI rats, but not BN rats, responded to buprenorphine treatment with decreased levels of locomotion, drinking and eating behaviour. The same treatment resulted in an increased grooming behaviour in both strains. Slight but significant sex differences were observed for locomotion and eating in the analysis of variance procedure, but did not reach the level of statistical significance in the multiple comparison procedure. The results of this study emphasize the possibility that strain-specific effects must be taken into account when using behavioural parameters for the assessment of the analgesic effects of buprenorphine in rats.
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Affiliation(s)
- H Avsaroglu
- Department of Animals, Science and Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | - R Sommer
- Department of Animals, Science and Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | - L J Hellebrekers
- Department of Equine Sciences and Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | - L F M van Zutphen
- Department of Animals, Science and Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | - H A van Lith
- Department of Animals, Science and Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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Smith MA, Cole KT, Gergans SR, Iordanou JC, Lyle MA, Schmidt KT. Effects of environmental enrichment on sensitivity to mu, kappa, and mixed-action opioids in female rats. Physiol Behav 2008; 94:563-8. [PMID: 18456292 DOI: 10.1016/j.physbeh.2008.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 02/15/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
Several studies report that environmental enrichment enhances sensitivity to opioid receptor agonists in male rats. Very few studies have examined the effects of enrichment in female rats, and thus it is not clear whether females are similarly sensitive to these effects. Consequently, the purpose of the present study was to examine the effects of environmental enrichment on sensitivity to representative mu, kappa, and mixed-action opioids in female rats. Following a protocol established in males, females were obtained at weaning and randomly assigned to two groups immediately upon arrival: isolated rats were housed individually with no visual or tactile contact with other rats; enriched rats were housed in groups of four in large cages and given various novel objects on a regular basis. After 6 weeks under these conditions, the antinociceptive effects of mu (morphine, levorphanol), kappa (spiradoline, U69,593), and mixed-action (buprenorphine, butorphanol) opioids were examined in a warm-water, tail-withdrawal procedure. All the opioids examined produced dose-dependent increases in antinociception; however, no differences in opioid sensitivity were observed between the two groups. To determine whether these findings were consistent across behavioral endpoints, the antidiuretic effects of representative mu opioids, and the diuretic effects of representative kappa opioids, were examined in female rats reared under isolated or enriched conditions for 10 weeks. Similar to that seen in the antinociceptive experiment, no significant differences in opioid sensitivity were observed between groups. These data indicate that environmental enrichment does not alter sensitivity to the effects of opioid receptor agonists in female rats, and suggest that females may respond differently to environmental enrichment than males.
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Affiliation(s)
- Mark A Smith
- Department of Psychology and Program in Neuroscience, Davidson College, Davidson, NC 28035-7037, USA.
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25
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The role of gonadal hormones on opioid receptor protein density in arthritic rats. Eur J Pharmacol 2008; 578:177-84. [DOI: 10.1016/j.ejphar.2007.08.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 08/17/2007] [Accepted: 08/23/2007] [Indexed: 11/23/2022]
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Johnson JA, Robertson SA, Pypendop BH. Antinociceptive effects of butorphanol, buprenorphine, or both, administered intramuscularly in cats. Am J Vet Res 2007; 68:699-703. [PMID: 17605603 DOI: 10.2460/ajvr.68.7.699] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To characterize the antinociceptive action of IM-administered butorphanol, buprenorphine, or a combination of both by use of a thermal threshold method in cats. ANIMALS 2 male and 4 female domestic cats. PROCEDURES In a controlled, masked, randomized, crossover study design, thermal thresholds were measured by use of a thermal threshold-testing device developed for cats. Each cat received 4 treatments 1 week apart, consisting of 2 simultaneous IM injections in a random order (butorphanol-saline [0.9% NaCl] solution, buprenorphine-saline solution, butorphanol-buprenorphine, and saline solution-saline solution). The tester was unaware of the treatment given. Thermal thresholds were measured prior to injection, at intervals up to 12 hours, and at 22 hours after injection. RESULTS There was no significant change in threshold over time after saline solution administration. All 3 opioid treatment groups had significant increases in thermal threshold, compared with pretreatment values (butorphanol, from 50 minutes to 8 hours; buprenorphine, from 35 minutes to 5 hours; and butorphanol-buprenorphine, from 50 minutes to 8 hours). Thermal thresholds did not differ significantly among opioid treatments at any time points, and thermal thesholds of only 2 opioid treatments (butorphanol at 50 minutes and butorphanol-buprenorphine at 8 hours) were significantly different from that of saline solution. CONCLUSIONS AND CLINICAL RELEVANCE All 3 opioid treatments provided similar antinociception, although there was considerable intercat variability in the response to the different opioid treatments. This emphasizes the importance of assessing each patient individually and applying the treatment that works best for that patient.
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Affiliation(s)
- Jacob A Johnson
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
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Bernal SA, Morgan MM, Craft RM. PAG mu opioid receptor activation underlies sex differences in morphine antinociception. Behav Brain Res 2007; 177:126-33. [PMID: 17118467 PMCID: PMC1868665 DOI: 10.1016/j.bbr.2006.10.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2006] [Revised: 10/13/2006] [Accepted: 10/28/2006] [Indexed: 01/03/2023]
Abstract
Given the findings that (1) systemic opioid antinociception varies by estrous stage in females and (2) the magnitude of sex differences in opioid antinociception is negatively correlated with opioid agonist efficacy, we hypothesized that sex differences in the function of the descending pain modulatory system are likely influenced by estrous stage in females and by the number of available opioid receptors therein. The present study tested these hypotheses by (1) comparing antinociception produced by morphine microinjection to the ventral periaqueductal gray (vPAG) in females at different stages of the estrous cycle and (2) examining systemic morphine antinociception in males versus females under conditions of reduced vPAG mu opioid receptor availability. When estrous stage of females was not controlled for (Experiment 1), there was no significant sex difference in tail withdrawal antinociception following morphine microinjection (0.3-10microg), although morphine was more potent in males than females in producing immobility. Experiment 2 showed that intra-vPAG morphine produced less antinociception and immobility in estrus than in diestrus females; that is, only estrus females' response to morphine was lower than that of males. Experiment 3 showed that microinjection of the irreversible mu opioid antagonist beta-funaltrexamine (beta-FNA) into the vPAG shifted the systemic morphine dose-effect curve farther to the right in females than in males. That is, a reduction in available vPAG mu opioid receptors had a greater impact on opioid antinociception in females than in males, suggesting that females have fewer vPAG mu opioid receptors than males. Overall, these data suggest that ovarian hormones and PAG mu opioid receptor density contribute to sex differences in antinociception produced by morphine.
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Affiliation(s)
- Scott A Bernal
- Department of Psychology, Washington State University, Pullman, WA 99164-4820, United States
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Davis CM, Roma PG, Dominguez JM, Riley AL. Morphine-induced place conditioning in Fischer and Lewis rats: acquisition and dose-response in a fully biased procedure. Pharmacol Biochem Behav 2007; 86:516-23. [PMID: 17306352 DOI: 10.1016/j.pbb.2007.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 01/08/2007] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
The Fischer (F344) and Lewis (LEW) rat strains differ on a variety of behavioral assays examining the effects of morphine, with many of the differences observed during acquisition of behavioral responses. The results of these studies and others examining endogenous physiology and the biochemical effects of morphine suggest that F344 rats are more sensitive to morphine than LEW rats. However, LEW animals have shown greater conditioned place preferences (CPP) to 4 mg/kg than F344 rats. CPP is a popular assay of drug reward in which acquisition of the preference can be measured across multiple conditioning cycles, yet this aspect of CPP has not been assessed in F344 and LEW rats. As part of an ongoing effort to fully characterize the conditioned rewarding effects of abused drugs in these strains, the present study assessed the effects of 0, 1, 4 and 10 mg/kg subcutaneous (SC) morphine in adult male F344 and LEW rats (n=12/strain/dose). A fully biased place conditioning procedure was employed where morphine's effects were paired with the initially non-preferred chamber on Day 1, saline was paired with the preferred chamber on Day 2 and drug-free access to the entire apparatus was allowed on Day 3. This conditioning and testing regimen was repeated for four consecutive cycles. The F344 animals acquired CPP at 1 mg/kg only; this effect emerged after only two conditioning cycles. LEW rats never acquired a CPP at any dose tested. Peak blood morphine levels following SC injections of 1, 4 or 10 mg/kg revealed no significant strain or dose effects. These behavioral data are consistent with the hypothesis that F344 rats are more sensitive to the rewarding effects of morphine than LEW rats. Additional implications for the Fischer-Lewis model of drug abuse and the utility of CPP acquisition procedures are discussed.
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Affiliation(s)
- Catherine M Davis
- Psychopharmacology Laboratory, Department of Psychology, American University, Washington, DC 20016, USA.
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29
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Loyd DR, Murphy AZ. Sex differences in the anatomical and functional organization of the periaqueductal gray-rostral ventromedial medullary pathway in the rat: a potential circuit mediating the sexually dimorphic actions of morphine. J Comp Neurol 2006; 496:723-38. [PMID: 16615128 PMCID: PMC2823481 DOI: 10.1002/cne.20962] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Previous studies have demonstrated that morphine, administered systemically or directly into the periaqueductal gray (PAG), produces a significantly greater degree of antinociception in males in comparison with females. Because the midbrain PAG and its descending projections to the rostral ventromedial medulla (RVM) constitute an essential neural circuit for opioid-based analgesia, the present studies were conducted to determine whether sex differences in the anatomical organization of the PAG-RVM pathway, and its activation during persistent inflammatory pain, could account for sex-based differences in opioid analgesia. In the rat, retrograde tracing was combined with Fos immunocytochemistry to investigate sexual dimorphism in the organization of the PAG-RVM circuit and its activation by persistent inflammatory pain induced by intraplantar injection of complete Freund's adjuvant (CFA). The ability of morphine to suppress the activation of the PAG-RVM circuit was also examined. Sexually dimorphic retrograde labeling was observed within the dorsomedial and lateral/ventrolateral PAG at all rostrocaudal levels, with females having significantly more PAG-RVM output neurons in comparison with males. While no sex differences were noted in the activation of the PAG by persistent inflammatory pain, significantly more PAG-RVM cells were activated in males in comparison with females. Systemic administration of morphine significantly suppressed CFA-induced Fos in the PAG in males only. The results of these studies demonstrate that both the anatomical organization and the functional activation of the PAG-RVM circuit are sexually dimorphic and may provide the anatomical substrate for sex-based differences in morphine analgesia.
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Affiliation(s)
- Dayna R Loyd
- Department of Biology, Center for Behavioral Neuroscience, Georgia State University, Atlanta, 30302-4010, USA
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Elliott JC, Picker MJ, Sparrow AJ, Lysle DT. Dissociation between sex differences in the immunological, behavioral, and physiological effects of kappa- and delta-opioids in Fischer rats. Psychopharmacology (Berl) 2006; 185:66-75. [PMID: 16397747 DOI: 10.1007/s00213-005-0267-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 11/08/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE The sex of the individual can have a profound effect on sensitivity to the effects of opioids. Recently, our laboratory provided the first evidence that females may be more sensitive to the immune-altering effects of mu-opioids than males. However, it remains unknown whether kappa- and delta-opioids produce sexually dimorphic effects on immune responses. OBJECTIVE The present study sought to determine whether kappa- and delta-opioids produce differential immunological effects in males and females using the memory-T-cell-dependent in vivo inflammatory response contact hypersensitivity (CHS). As sex differences in the magnitude of opioid effects can be outcome-specific, additional experiments were conducted to compare the immunological effects of kappa- and delta-opioids with other behavioral and physiological effects. MATERIALS AND METHODS Contact hypersensitivity was induced in male and female Fischer rats. Prior to elicitation of CHS, animals were administered selected doses of the kappa-opioid spiradoline (0.2-20 mg/kg), delta-opioid SNC80 (1-10 mg/kg), or vehicle. The antinociceptive and diuretic effects of spiradoline were also assessed in males and females, as were the locomotor effects of SNC80. RESULTS Spiradoline produced significantly greater enhancement of CHS in females than males, but produced comparable antinociceptive and diuretic effects in both sexes. By contrast, SNC80 did not significantly affect the course of CHS in either sex, but females were significantly more sensitive to its locomotor stimulatory effects. CONCLUSIONS These results demonstrate that females are more sensitive than males to the CHS-altering effects of spiradoline and that sex differences in the magnitude and direction of opioid-induced sex differences are outcome dependent.
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Affiliation(s)
- Jay C Elliott
- Department of Psychology, CB #3270, Davie Hall, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3270, USA.
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31
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Abstract
It is becoming increasingly evident that the sex of an organism is a critical determinant of responsiveness to opioid analgesics. However, the factors that determine the magnitude and direction of sex differences in opioid antinociception have not been fully elucidated. One factor that has received attention is the relative efficacy of the opioid. This review summarizes recent findings in which opioid efficacy was systematically manipulated as an independent variable to probe underlying sex differences in opioid system function. Overall, in rodents and nonhuman primates, mu and kappa opioids are generally more potent and effective in males than in females. The data indicate that although sex differences in the potency of high efficacy opioids such as morphine are generally less than 3.0-fold, sex differences with lower efficacy opioids can be greater than 90-fold. Moreover, that these drugs can function as full agonists in males while functioning as antagonists in females under identical conditions suggests some fundamental sex difference in opioid system function. In addition to efficacy, a number of other variables can affect the outcomes of these studies, including the drug history, genotype, and nociceptive stimulus modality, duration, and intensity. These factors may interact with opioid efficacy to determine the specific conditions under which sex differences are observed. The testing of low efficacy opioids by other laboratories and under other experimental conditions will determine the extent to which this variable affords a strategic research tool. The potential utility of low efficacy opioids in other domains of behavioral pharmacology is also discussed.
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MESH Headings
- Analgesics, Opioid/therapeutic use
- Female
- Genotype
- Humans
- Male
- Pain/drug therapy
- Receptors, Opioid/analysis
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, kappa/physiology
- Sex Characteristics
- Species Specificity
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Affiliation(s)
- Andrew C Barrett
- Alcohol and Drug Abuse Research Center, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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Terner JM, Lomas LM, Lewis JW, Husbands SM, Picker MJ. Effects of the long-lasting kappa opioid 2-(3,4-dichlorophenyl)-N-methyl-N-[(1S)-1-(3-isothiocyanatophenyl)-2-(1-pyrrolidinyl) ethyl] acetamide in a drug discrimination and warm water tail-withdrawal procedure. Behav Pharmacol 2006; 16:665-70. [PMID: 16286819 DOI: 10.1097/00008877-200512000-00010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although studies suggest that 2-(3,4-dichlorophenyl-N-methyl-N-[(1S)-1-(3-isothiocyanatophenyl)-2-(1-pyrrolidinyl) ethyl] acetamide (DIPPA) has transient kappa-opioid-mediated agonist effects followed by long-lasting kappa-antagonist effects, its behavioral and pharmacological actions have not been systematically examined and there is evidence suggesting that some of its effects are species dependent. The purpose of this investigation was to examine the actions of DIPPA in different behavioral procedures and in three species. In a pigeon drug discrimination procedure, DIPPA and the kappa-opioids U50,488 and ICI-199441 substituted fully for the stimulus effects produced by spiradoline. For DIPPA, this effect was observed between 0.25 and 4 h after administration. In a warm water tail-withdrawal procedure, DIPPA failed to produce antinociception in rats or mice even when relatively high doses were tested using pretreatment intervals ranging from 0.25 to 24 h. In this procedure, DIPPA antagonized the effects of spiradoline and U50,488 in mice. In rats, DIPPA antagonized the effects of U50,488 but not those of spiradoline. Taken together, these results suggest that DIPPA may function as a low-efficacy kappa-opioid and have a long duration of action, and there may be some species differences in its behavioral profile. This profile of action, however, differs from other low-efficacy kappa-opioids.
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Affiliation(s)
- Jolan M Terner
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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33
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34
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Cataldo G, Bernal S, Markowitz A, Ogawa S, Ragnauth A, Pfaff DW, Bodnar RJ. Organizational manipulation of gonadal hormones and systemic morphine analgesia in female rats: effects of adult ovariectomy and estradiol replacement. Brain Res 2005; 1059:13-9. [PMID: 16153618 DOI: 10.1016/j.brainres.2005.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 08/03/2005] [Accepted: 08/05/2005] [Indexed: 11/26/2022]
Abstract
Previous research has indicated the importance of sex in mediating the larger magnitude of mu-opioid receptor agonist-induced analgesia in male relative to female rodents. Whereas manipulations involving the adult activational effects of gonadal hormones minimally alter these analgesic sex differences, manipulations involving neonatal organizational effects of gonadal hormones have previously been shown to profoundly affect morphine analgesia. Thus, adult male rats neonatally castrated on the first day after birth displayed reductions in morphine analgesia relative to sham-operated males, and adult female rats neonatally treated with testosterone propionate on the first day after birth displayed enhancements in morphine analgesia relative to vehicle-treated females. Because neonatal androgenization in female rats produces an anovulatory syndrome that could change their adult hormonal milieu, the present study examined whether adult ovariectomy altered the magnitude of systemic morphine analgesia (1-5 mg/kg) in neonatal androgenized female rats relative to neonatal vehicle-treated female rats as well as gonadal steroid hormone replacement with estradiol benzoate. Intact male rats displayed significantly greater magnitudes and potencies (2- to 2.3-fold leftward shift) of systemic morphine analgesia than female rats treated neonatally with either vehicle (1-5 mg/kg) or testosterone (1.7-5 mg/kg). In turn, neonatal androgenized female rats displayed significantly greater magnitudes of systemic morphine (1, 5 mg/kg) analgesia than vehicle-treated female rats accompanied by a smaller 20% leftward shift in potency. Adult ovariectomy minimally affected morphine analgesia in neonatal vehicle-treated females, while significantly reducing the magnitude (1 mg/kg), but not the potency of morphine analgesia in neonatal androgenized female rats. Estradiol replacement therapy significantly increased the magnitude of morphine analgesia in both groups at some doses, but only changed the potency (20-30%) in females treated neonatally with vehicle. Taken together, these data suggest a limited organizational-activational gonadal hormone interaction in the mediation of systemic morphine analgesia in female rats.
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Affiliation(s)
- G Cataldo
- Department of Psychology, Queens College, City University of New York, Flushing, NY 11367, USA
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35
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Stoffel EC, Ulibarri CM, Folk JE, Rice KC, Craft RM. Gonadal hormone modulation of mu, kappa, and delta opioid antinociception in male and female rats. THE JOURNAL OF PAIN 2005; 6:261-74. [PMID: 15820914 PMCID: PMC1420268 DOI: 10.1016/j.jpain.2004.12.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 11/11/2004] [Accepted: 12/23/2004] [Indexed: 11/20/2022]
Abstract
UNLABELLED Previous studies suggest that sex differences in morphine antinociception in rodents might be attributed to the activational effects of gonadal hormones. The present study determined whether hormonal modulation of opioid antinociception in adult rats extends to opioids other than the prototypic mu agonist morphine. Male and female rats were sham-gonadectomized (sham-GDX) or gonadectomized (GDX) and replaced with no hormone, estradiol (E2, females), progesterone (P4, females), E2+P4 (females), or testosterone (males). Approximately 28 days later, nociception was evaluated on the 50 degrees C hot plate and warm water tail withdrawal tests before and after subcutaneous administration of hydromorphone, buprenorphine, U50,488, or SNC 80. In sham-GDX (gonadally intact) rats, the mu agonists and U50,488 were less effective in females than in males in at least one nociceptive test, and the delta agonist SNC 80 was less effective in males than in females. In males, gonadectomy tended to decrease, and testosterone tended to increase antinociception produced by 3 of the 4 agonists. In females, gonadectomy and hormone treatment had more variable effects, although E2 tended to decrease mu opioid antinociception. The present results suggest that activational effects of gonadal hormones are relatively modest and somewhat inconsistent on antinociception produced by various opioid agonists in the adult rat. PERSPECTIVE This study demonstrates that reproductive hormones such as testosterone in males and estradiol in females do not consistently modulate sensitivity to the analgesic effects of opioids in the adult organism.
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MESH Headings
- Analgesics, Opioid/metabolism
- Analgesics, Opioid/pharmacology
- Animals
- Estrogens/metabolism
- Estrogens/pharmacology
- Estrous Cycle/physiology
- Female
- Gonadal Steroid Hormones/metabolism
- Gonadal Steroid Hormones/pharmacology
- Male
- Orchiectomy
- Ovariectomy
- Pain/drug therapy
- Pain/metabolism
- Pain/physiopathology
- Pain Measurement/drug effects
- Progesterone/metabolism
- Progesterone/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid/drug effects
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/metabolism
- Sex Characteristics
- Testosterone/metabolism
- Testosterone/pharmacology
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Affiliation(s)
- Erin C. Stoffel
- From the Department of Psychology, Washington State University, Pullman, Washington
| | - Catherine M. Ulibarri
- From the Departments of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington
| | - John E. Folk
- From the Department of Laboratory of Medicinal Chemistry, NIDDK, NIH, Bethesda, Maryland
| | - Kenner C. Rice
- From the Department of Laboratory of Medicinal Chemistry, NIDDK, NIH, Bethesda, Maryland
| | - Rebecca M. Craft
- From the Department of Psychology, Washington State University, Pullman, Washington
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Cook CD, Nickerson MD. Nociceptive sensitivity and opioid antinociception and antihyperalgesia in Freund's adjuvant-induced arthritic male and female rats. J Pharmacol Exp Ther 2004; 313:449-59. [PMID: 15608071 DOI: 10.1124/jpet.104.077792] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study was designed to examine sex differences in complete Freund's adjuvant (CFA)-induced mechanical hyperalgesia and sex differences in opioid antinociception and anti-hyperalgesia. Female rats developed inflammation and hyperalgesia faster and exhibited greater peak hyperalgesia than male rats. In arthritic (CFA-treated) rats, lower thresholds were observed during estrus and proestrus, and in nonarthritic (vehicle-treated) rats, lower thresholds were observed during proestrus. Morphine and oxycodone were more potent in male than female arthritic rats, and butorphanol was more potent and effective in male than female arthritic rats. The potency of morphine was increased in arthritic rats, although to a greater magnitude in males. The potency of oxycodone was increased in male but not female arthritic rats. The potency of butorphanol was increased in arthritic male rats and the maximal antinociceptive effect of butorphanol was increased in arthritic female rats, but it did not result in greater than 20% antinociception. Morphine, oxycodone, and butorphanol all produced antihyperalgesic effects (returning thresholds of arthritic rats to the thresholds of nonarthritic rats) with greater potency in males than females. The peripherally acting opioid agonist loperamide produced intermediate levels of antinociception in male and female arthritic rats and no antinociception in nonarthritic rats. Loperamide was more potent in male than female arthritic rats at producing antihyperalgesia. These data demonstrate sex differences in arthritis-induced hyperalgesia and responsiveness to opioid analgesics. In arthritic rats, the antinociceptive effects of opioid agonists are most probably mediated by both central and peripheral opioid receptors, whereas their antihyperalgesic effects are mediated primarily by actions at peripheral opioid receptors.
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Affiliation(s)
- Charles D Cook
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
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37
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Fillingim RB, Gear RW. Sex differences in opioid analgesia: clinical and experimental findings. Eur J Pain 2004; 8:413-25. [PMID: 15324773 DOI: 10.1016/j.ejpain.2004.01.007] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 01/30/2004] [Indexed: 11/30/2022]
Abstract
Sex differences in analgesic responses to opioids have received increasing attention in recent years. This article examines the literature on sex differences in opioid analgesia, including the results of studies from the authors' own laboratories. In general, nonhuman animal studies suggest more robust opioid analgesic responses in males relative to females; however, the human studies completed to date seem to indicate greater opioid analgesia among females. The most consistent evidence of sex differences in analgesia comes from studies of kappa-agonist-antagonists administered to patients following oral surgery. These data indicate more robust analgesia in females, and dose-response characteristics suggest that these agents possess both analgesic and antianalgesic properties, and the agonists may produce these effects in different proportions for women versus men. In contrast, the data from laboratory pain models in humans suggest greater analgesic effects in women in response mu-opioid agonists but not kappa-agonist-antagonists. Multiple mechanisms may explain sex differences in opioid analgesia, including gonadal hormonal effects, pharmacokinetics and pharmacodynamics, genetic influences, balance of analgesic/antianalgesic processes, and psychological factors. However, the disparity of results obtained from different pain models--animals versus humans and clinical pain versus experimental pain in humans--suggests that the models themselves are mechanistically different. Additional investigation is warranted in order to further explicate the nature of sex differences in opioid analgesia and to elucidate the underlying mechanisms.
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Affiliation(s)
- Roger B Fillingim
- Public Health Services and Research, College of Dentistry, University of Florida, 1600 SW Archer Road, Room D8-44A, P.O. Box 100404, Gainesville, FL 32610-0404, USA.
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38
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Vucković S, Prostran M, Ivanović M, Todorović Z, Stojanović R, Nesić Z, Matić I, Milovanović S. [Opioid analgesics]. VOJNOSANIT PREGL 2004; 61:413-21. [PMID: 15552538 DOI: 10.2298/vsp0404413v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Sonja Vucković
- Medicinski fakultet, Institut za klinicku farmakologiju, farmakologiju i toksikologiju, Beograd, Srbija i Crna Gora
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39
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Kovacic U, Zele T, Osredkar J, Sketelj J, Bajrović FF. Sex-related differences in the regeneration of sensory axons and recovery of nociception after peripheral nerve crush in the rat. Exp Neurol 2004; 189:94-104. [PMID: 15296839 DOI: 10.1016/j.expneurol.2004.05.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 04/14/2004] [Accepted: 05/13/2004] [Indexed: 11/29/2022]
Abstract
Sex-related differences regarding the regeneration of nociceptive axons and the recovery of nociception after sural nerve crush injury were examined in rats. The elongation rate of the fastest regenerating sensory axons in females started to increase after the first 6 days. This resulted in about 15% greater axon elongation distance at 8 days after crush in female than in male rats as determined by the nerve pinch test. The number of regenerating sensory axons in female and male rats, however, was not different. The recovery of nociception in the instep started earlier and was more extensive in females than in males during the entire 24-week recovery period, so that the pain sensitive area was finally about 20% larger in females than in males. Although ovariectomy significantly reduced plasma estradiol concentration in female rats, it did not change the elongation distance of regenerating nociceptive axons, which remained significantly greater than in male rats. Elimination of the cells in the distal nerve segment by freezing revealed that a more effective cell support in the distal nerve segment is probably responsible for faster regeneration of nociceptive axons in females than in males, rather than the circulating female sex hormones.
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Affiliation(s)
- Uros Kovacic
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
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40
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Terner JM, Lomas LM, Smith ES, Barrett AC, Picker MJ. Pharmacogenetic analysis of sex differences in opioid antinociception in rats. Pain 2003; 106:381-391. [PMID: 14659521 DOI: 10.1016/j.pain.2003.08.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Sex differences in opioid antinociception have been reported in rodents and monkeys, with opioids being more potent in males than females. In the present study, the influence of rat strain on sex differences in opioid antinociception was examined in a warm water tail-withdrawal procedure. Antinociceptive tests were conducted with the high-efficacy micro-opioid morphine, and the less efficacious opioids buprenorphine, butorphanol and nalbuphine. Baseline nociceptive latencies were consistently higher in males than their female counterparts. Sex differences in opioid antinociception were observed in all strains tested, with the opioids being more potent and/or effective in males. The magnitude of the sex differences was related to the relative efficacy of the opioid, with morphine, buprenorphine, butorphanol and nalbuphine being on average 2.2-, 2.6-, 15.9- and 11.9-fold more potent in males. Sex differences also varied markedly across strains, with large differences consistently obtained in the F344 and F344-Sasco strains, moderate differences in the ACI, DA, Lewis, Sprague Dawley, Wistar and Wistar-Kyoto strains, and small differences in the Long Evans-Blue Spruce, Long Evans, Brown Norway and Holtzman strains. When compared across strains, there was no relationship between sex differences in nociceptive sensitivity and opioid sensitivity. These findings provide strong support for the role of genetic factors in determining sex differences in opioid antinociception, and suggest that the use of low-efficacy opioids, coupled with the use of rat strains that display small and large sex differences in opioid antinociception, may provide a sensitive tool to investigate the mechanisms underlying sex differences in opioid antinociception.
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Affiliation(s)
- Jolan M Terner
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3270, USA
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41
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42
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Abstract
This paper is the twenty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2002 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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43
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Abstract
In humans, kappa agonist-antagonist opioids such as nalbuphine have been proposed to produce both analgesia and anti-analgesia by acting at distinct receptors. The anti-analgesia appears to be greater in men, which may contribute to the greater nalbuphine analgesia observed in women. Kappa agonist-antagonists are also known to produce sexually dimorphic antinociception in nonhuman species but are generally more potent in males; anti-analgesia has not been reported in animals. The aim of the present study was to determine if nalbuphine anti-analgesia can be detected in the rat. Since nalbuphine anti-analgesia is more sensitive to naloxone antagonism than its analgesic effect, low doses of naloxone were combined with nalbuphine. Using the Randall-Selitto paw-withdrawal test, nalbuphine (0.5-10 mg/kg) induced dose-dependent antinociception in the rat. The antinociceptive effect of nalbuphine (0.5 or 1 mg/kg) was not enhanced by lower doses of naloxone but was antagonized by higher doses. These data do not support the hypothesis that the naloxone-sensitive anti-analgesic effect of nalbuphine observed in humans is present in the rat and could explain, at least in part, the opposite direction of the sex differences for kappa agonist-antagonist opioid analgesia observed in these two species.
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Affiliation(s)
- Sachia G Khasar
- Department of Oral and Maxillofacial Surgery, University of California, San Francisco, CA 94143, USA
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44
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Affiliation(s)
- Gary B Rollman
- Department of Psychology, University of Western Ontario, London, Ontario, Canada.
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45
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Stoffel EC, Ulibarri CM, Craft RM. Gonadal steroid hormone modulation of nociception, morphine antinociception and reproductive indices in male and female rats. Pain 2003; 103:285-302. [PMID: 12791435 PMCID: PMC1420267 DOI: 10.1016/s0304-3959(02)00457-8] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to examine how gonadal steroid hormones modulate basal nociception and morphine antinociception relative to regulating reproduction in the adult rat. Male and female Sprague-Dawley rats were either gonadectomized (GDX) or sham-gonadectomized (sham); GDX males were implanted subcutaneously with capsules containing testosterone (T), estradiol (E2), dihydrotestosterone (DHT), E2 and DHT, or nothing (0). GDX females received E2, T, or empty (0) capsules immediately after surgery, and vehicle or progesterone (P4) injections at 4-day intervals. Basal nociception and morphine antinociception were tested 28 days after surgery on 50 degrees C and 54 degrees C hotplate tests, and reproductive behavior and physiology were assessed shortly thereafter. There were no significant differences in baseline hotplate latencies among the male treatment groups, but morphine was significantly more potent in sham and GDX+T males than in GDX+0 males. The ability of T to increase morphine's potency was approximated by its major metabolites E2 and DHT, given together but not alone. Baseline hotplate latencies were higher in sham females tested during diestrus than in those tested during estrus. Morphine was significantly more potent in sham females tested during proestrus and diestrus than in those tested during estrus. Baseline hotplate latencies were significantly higher, and morphine was significantly less potent in GDX+E2, GDX+E2/P4 and GDX+T females than in GDX+0 females. All group differences in basal nociception and morphine antinociception observed on the 50 degrees C hotplate test were smaller and generally non-significant on the 54 degrees C hotplate test. Steroid manipulations produced the expected changes in reproductive behaviors and steroid-sensitive organs. These results demonstrate that in adult rats, gonadal steroid manipulations, that are physiologically relevant, modulate (1) basal nociception in females but not males, and (2) morphine's antinociceptive potency in both males and females.
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Affiliation(s)
- Erin C Stoffel
- Department of Psychology, Washington State University, Pullman, WA 99164-4820, USA Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA
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46
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Abstract
Historically, biomedical research has been conducted almost exclusively with male subjects. A growing number of studies now demonstrate sex differences in analgesia produced both by drugs and by environmental stimuli. This review summarizes the current literature on sex differences in analgesia produced by opioids, cholinergics and other drugs, and by stress, exercise and other environmental manipulations. A brief overview of the physiological mechanisms underlying sex differences in analgesia is provided, as well as suggestions for future research. It is not yet known whether the development of sex-specific analgesia treatment guidelines is warranted.
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Affiliation(s)
- Rebecca M Craft
- Department of Psychology, Washington State University, CB 644820 Pullman, WA 99164-4820, USA.
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Abstract
BACKGROUND Numerous experimental studies, conducted primarily over the past 10 years, show that there are sex differences in opioid analgesia. This review summarizes the published literature on sex differences in analgesia produced by acute administration of drugs acting at mu-, kappa-, and delta-opioid receptors, in animals and humans. Additionally, methodological issues in research into opioid sex differences are discussed. CONCLUSIONS Procedural variables that may influence the outcome of studies examining sex differences in opioid analgesia include modality and intensity of the noxious stimulus used in the pain test, opioid type (efficacy and selectivity), and experimental design and data analytic techniques. Subject variables that may be important to consider include subject genotype and gonadal steroid hormone state of the subject at the time of analgesia testing. Evidence is provided for multiple mechanisms underlying sex differences in opioid analgesia, including both pharmacokinetic and pharmacodynamic factors. Future research directions are suggested, such as examining sex differences in opioid tolerance development, sex differences in opioid analgesia using models of acute inflammatory pain and chronic pain, and sex differences in effects of opioids other than analgesia, which may limit their therapeutic use.
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Smith MA, Gordon KA, Craig CK, Bryant PA, Ferguson ME, French AM, Gray JD, McClean JM, Tetirick JC. Interactions between opioids and cocaine on locomotor activity in rats: influence of an opioid's relative efficacy at the mu receptor. Psychopharmacology (Berl) 2003; 167:265-73. [PMID: 12669175 DOI: 10.1007/s00213-003-1388-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2002] [Accepted: 12/14/2002] [Indexed: 11/25/2022]
Abstract
RATIONALE Cocaine and mu opioid agonists increase central dopamine concentrations and produce robust interactions at both neurochemical and behavioral levels. Although the interactions between cocaine and high-efficacy mu opioids have been well characterized, the interactions between cocaine and lower efficacy opioids have not been as extensively examined. OBJECTIVE The purpose of this study was to examine the interactions between cocaine and opioids possessing a range of relative efficacy at the mu receptor. METHODS Male, Long-Evans rats were habituated to an open-field, locomotor activity chamber, and the effects of cocaine and various opioids were tested under a cumulative dosing procedure. In this procedure, a selected dose of an opioid was administered during the first component of a session, with increasing doses of cocaine administered during subsequent components. RESULTS When administered alone, cocaine produced dose-dependent increases in locomotor activity that was stable across 5 weeks of behavioral testing. The high-efficacy mu opioid levorphanol, and the low-efficacy opioids buprenorphine, butorphanol, nalbuphine and (-)-pentazocine, dose-dependently enhanced the effects of cocaine at doses that did not alter locomotor activity when administered alone. In contrast, the opioid antagonist naloxone, and to a lesser extent, the kappa opioid spiradoline attenuated the effects of cocaine at doses that did not alter locomotor activity when administered alone. Across an extensive dose range, the low-efficacy opioid nalorphine failed to alter cocaine's locomotor-activating effects. CONCLUSIONS These data suggest that low-efficacy opioids possessing significant mu-agonist activity (e.g. buprenorphine, butorphanol, nalbuphine, (-)-pentazocine) may potentiate the effects of cocaine in a manner similar to that typically observed with high-efficacy mu opioids.
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Affiliation(s)
- Mark A Smith
- Department of Psychology, Davidson College, NC 28035-7037, USA.
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Wilson SG, Smith SB, Chesler EJ, Melton KA, Haas JJ, Mitton B, Strasburg K, Hubert L, Rodriguez-Zas SL, Mogil JS. The heritability of antinociception: common pharmacogenetic mediation of five neurochemically distinct analgesics. J Pharmacol Exp Ther 2003; 304:547-59. [PMID: 12538806 DOI: 10.1124/jpet.102.041889] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The heritability of nociception and antinociception has been well established in the mouse. The pharmacogenetics of morphine analgesia are fairly well characterized, but far less is known about other analgesics. The purpose of this work was to begin the systematic genetic study of non-mu-opioid analgesics. We tested mice of 12 inbred mouse strains for baseline nociceptive sensitivity (49 degrees C tail-withdrawal assay) and subsequent antinociceptive sensitivity to systemic administration of (trans)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide methane-sulfonate hydrate (U50,488; 10-150 mg/kg), a kappa-opioid receptor agonist; (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone (WIN55,212-2; 0.5-480 mg/kg), a synthetic cannabinoid receptor agonist; epibatidine (7.5-150 microg/kg), a nicotinic receptor agonist; clonidine (0.1-5 mg/kg), an alpha(2)-adrenergic receptor agonist; and, for purposes of comparison, the prototypic mu-opioid receptor agonist, morphine (5-200 mg/kg). Robust interstrain variability was observed in nociceptive sensitivity and in the antinociceptive effects of each of the drugs, with extreme-responding strains exhibiting antinociceptive potencies differing up to 37-fold. Unexpectedly, we observed moderate-to-high genetic correlations of strain sensitivities to the five drugs (r = 0.39-0.77). We also found moderate-to-high correlations between baseline nociceptive sensitivity and subsequent analgesic response to each drug (r = 0.33-0.68). The generalizability of these findings was established in follow-up experiments investigating morphine and clonidine inhibition of formalin test nociception. Despite the fact that each drug activates a unique receptor, our results suggest that the potency of each drug is affected by a common set of genes. However, the genes in question may affect antinociception indirectly, via a primary action on baseline nociceptive sensitivity.
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Affiliation(s)
- Sonya G Wilson
- Department of Psychology and Program in Neuroscience, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
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Terner JM, Barrett AC, Cook CD, Picker MJ. Sex differences in (-)-pentazocine antinociception: comparison to morphine and spiradoline in four rat strains using a thermal nociceptive assay. Behav Pharmacol 2003; 14:77-85. [PMID: 12576884 DOI: 10.1097/00008877-200302000-00008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The present study examined the influence of sex on the antinociceptive effects of (-)-pentazocine, morphine and spiradoline in four rat strains, using a warm-water (50, 52 and 55 degrees C) tail-withdrawal procedure. In F344, Lewis, Sprague-Dawley (SD) and Wistar rats, baseline latencies decreased with increases in water temperature, and at each water temperature latencies were longer in males than in their female counterparts. Morphine and spiradoline produced maximal or near maximal antinociceptive effects in males and females of each strain. Whereas morphine was generally more potent in males, sex differences were not consistently observed with spiradoline. In contrast, there were marked sex differences with (-)-pentazocine, and in each strain (-)-pentazocine was more potent and produced a greater maximal effect in males. The magnitude of the sex differences varied markedly across strains, with (-)-pentazocine being 2.5-fold more potent in males of the F344 strain, but 11-fold more potent in males of the Wistar strain. When collapsed across nociceptive stimulus intensities, sex differences were largest in the Wistar and Lewis strains and smallest in the SD and F344 strains. The present findings indicate that there are marked sex differences in (-)-pentazocine antinociception, and that the magnitude of this effect is genotype dependent.
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Affiliation(s)
- J M Terner
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3270, USA.
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