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Nisbett KE, Vendruscolo LF, Koob GF. µ-Opioid receptor antagonism facilitates the anxiolytic-like effect of oxytocin in mice. Transl Psychiatry 2024; 14:125. [PMID: 38413576 PMCID: PMC10899625 DOI: 10.1038/s41398-024-02830-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/29/2024] Open
Abstract
Mood and anxiety disorders are leading causes of disability worldwide and are major contributors to the global burden of diseases. Neuropeptides, such as oxytocin and opioid peptides, are important for emotion regulation. Previous studies have demonstrated that oxytocin reduced depression- and anxiety-like behavior in male and female mice, and opioid receptor activation reduced depression-like behavior. However, it remains unclear whether the endogenous opioid system interacts with the oxytocin system to facilitate emotion regulation in male and female mice. We hypothesized that opioid receptor blockade would inhibit the anxiolytic- and antidepressant-like effects of oxytocin. In this study, we systemically administered naloxone, a preferential μ-opioid receptor antagonist, and then intracerebroventricularly administered oxytocin. We then tested mice on the elevated zero maze and the tail suspension tests, respective tests of anxiety- and depression-like behavior. Contrary to our initial hypothesis, naloxone potentiated the anxiolytic-like, but not the antidepressant-like, effect of oxytocin. Using a selective μ-opioid receptor antagonist, D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2, and a selective κ-opioid receptor antagonist, norbinaltorphimine, we demonstrate that μ-opioid receptor blockade potentiated the anxiolytic-like effect of oxytocin, whereas κ-opioid receptor blockade inhibited the oxytocin-induced anxiolytic-like effects. The present results suggest that endogenous opioids can regulate the oxytocin system to modulate anxiety-like behavior. Potential clinical implications of these findings are discussed.
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Affiliation(s)
- Khalin E Nisbett
- Graduate Program in Neuroscience, Graduate College, University of Illinois Chicago, Chicago, IL, 60607, USA.
- Stress & Addiction Neuroscience Unit, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore, MD, 21224, USA.
- Neurobiology of Addiction Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA.
| | - Leandro F Vendruscolo
- Stress & Addiction Neuroscience Unit, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore, MD, 21224, USA
| | - George F Koob
- Neurobiology of Addiction Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA
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Haile CN, Carper BA, Nolen TL, Kosten TA. The GABA B receptor positive allosteric modulator ASP8062 reduces operant alcohol self-administration in male and female Sprague Dawley rats. Psychopharmacology (Berl) 2021; 238:2587-2600. [PMID: 34228136 DOI: 10.1007/s00213-021-05881-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 05/21/2021] [Indexed: 12/19/2022]
Abstract
RATIONALE Pre-clinical evidence implicates the GABAergic system in mediating the reinforcing effects of alcohol and offers a therapeutic target for alcohol use disorder (AUD). The orthosteric GABAB receptor agonist baclofen decreases alcohol self-administration in animals and alcohol use in humans; however side effects limit its utility. Pre-clinical evidence shows positive allosteric GABAB receptor modulators also decrease alcohol self-administration without untoward side effects. OBJECTIVES We assessed the impact of the novel GABAB-positive allosteric modulator ASP8062 and baclofen on operant alcohol self-administration and their potential non-specific effects. METHODS The effects of ASP8062 (1 - 10 mg/kg, PO) and baclofen (0.3 - 3 mg/kg, IP) were evaluated in male and female rats lever pressing for alcohol (10%, w/v) under a fixed ratio 2 schedule of reinforcement. On the fourth consecutive day of vehicle, ASP8062 or baclofen administration, active and inactive lever presses, reinforcers earned, head entries, and estimated alcohol consumed were analyzed. Locomotor activity was assessed in separate groups of rats following dosing. RESULTS Both ASP8062 and baclofen decreased alcohol self-administration and amount consumed (g/kg) in male and female rats. ASP8062 decreased operant alcohol self-administration to a greater extent in male rats, whereas baclofen was more efficacious in female rats. ASP8062 did not alter locomotor activity in either sex, whereas baclofen (3.0 mg/kg) decreased activity in male rats yet (1.0 mg/kg) increased activity in female rats. CONCLUSIONS ASP8062 decreases alcohol reinforcement like baclofen but without non-specific effects which are influenced by sex. Results support further development of ASP8062 as a potential treatment for AUD in humans.
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Affiliation(s)
- Colin N Haile
- Department of Psychology & TIMES, University of Houston, 4849 Calhoun Rd, Houston, TX, 77204-6022, USA.
| | - Benjamin A Carper
- Biostatistics and Epidemiology Division, RTI International, Research Triangle Park, NC, USA
| | - Tracy L Nolen
- Biostatistics and Epidemiology Division, RTI International, Research Triangle Park, NC, USA
| | - Therese A Kosten
- Department of Psychology & TIMES, University of Houston, 4849 Calhoun Rd, Houston, TX, 77204-6022, USA
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Himmel HM. Safety pharmacology assessment of central nervous system function in juvenile and adult rats: effects of pharmacological reference compounds. J Pharmacol Toxicol Methods 2008; 58:129-46. [PMID: 18585470 DOI: 10.1016/j.vascn.2008.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 06/01/2008] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Recent EU/US pediatric legislation and FDA/EMEA guidelines recognize the potential differences in safety profiles of drugs in adults versus young patients. Hence safety studies are recommended to investigate key functional domains of e.g. the developing CNS. METHODS Selected psychoactive stimulants (caffeine, d-amphetamine, scopolamine) and depressants (baclofen, diazepam, haloperidol, chlorpromazine, imipramine, morphine) were characterized upon single administration with regard to behavioural parameters, locomotor activity, body temperature, pro-/anti-convulsive activity (pentylenetetrazole, PTZ), and nocifensive responses (hotplate) in neonatal (2 weeks), juvenile (4 weeks) and adult rats (8-9 weeks). RESULTS In vehicle-treated rats, behavioural patterns matured with age, locomotor activity and handling-induced rise in body temperature were enhanced, whereas PTZ convulsion threshold dose and nocifensive response latency decreased. Single test compound treatment elicited behavioural effects characteristic for psychoactive drugs with stimulating and depressing properties regardless of age. However, incidence of certain behaviours, and magnitude of effects on locomotor activity and body temperature varied with age and became generally more pronounced in adult rats. Pro-/anti-convulsive effects and delayed nocifensive responses did not differ between juvenile and adult rats. CONCLUSION CNS effects of selected psychoactive reference compounds were qualitatively similar, but quantitatively different in neonatal, juvenile and adult rats.
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Affiliation(s)
- Herbert M Himmel
- BHC-GDD-GED-NDS-SP, Safety Pharmacology, Bayer HealthCare AG, Wuppertal, Germany.
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Febo M, Jiménez-Rivera CA, Segarra AC. Estrogen and opioids interact to modulate the locomotor response to cocaine in the female rat. Brain Res 2002; 943:151-61. [PMID: 12088849 DOI: 10.1016/s0006-8993(02)02748-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Estrogen is known to modulate the behavioral response to cocaine; however the mechanisms by which this is accomplished is unknown. In this study we examine one possible candidate, the endogenous opioid system. Adult Sprague-Dawley rats were ovariectomized (OVX), half received Silastic implants with estradiol benzoate (OVX-EB), the other half received empty implants (OVX). After 1 week, spontaneous locomotor and stereotyped activity was measured for 60 min using an automated system. On day 2, locomotor activity was recorded for 30 min. Rats were injected with saline (SAL) or naloxone (NAL) (2 mg/kg, i.p.) and activity measured for the next 20 min. Each of these groups were further subdivided, one that received a saline injection (SAL) and another that received a cocaine injection (COC) (15 mg/kg, i.p.). Locomotor and stereotyped activities were recorded for 60 min. This resulted in the following injection groups: SAL-SAL, NAL-SAL, SAL-COC and NAL-COC. During habituation, OVX rats displayed an overall higher level of activity than OVX-EB rats. Similar to what is observed in males, naloxone significantly reduced locomotion and stereotyped behavior but only in OVX rats. Estrogen administration to OVX rats abolished the effect of naloxone. Surprisingly, when naloxone was administered prior to cocaine, an increase in cocaine-induced locomotor and stereotyped activity was observed, but only in OVX-EB rats. These results indicate that opioid modulation of cocaine-induced locomotor and stereotype activity in the female differs from that reported in the male. In addition in the female, the effect of opioids on cocaine-induced locomotor behavior is dependent on plasma levels of estrogen.
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Affiliation(s)
- Marcelo Febo
- Department of Physiology, School of Medicine, University of Puerto Rico, PO Box 365067, San Juan, PR 00936, USA
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Agmo A, Belzung C, Giordano M. Interactions between dopamine and GABA in the control of ambulatory activity. J Neural Transm (Vienna) 1996; 103:925-34. [PMID: 9013386 DOI: 10.1007/bf01291783] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ambulatory activity of male rats was quantified in an open field. The subjects were treated with DL-amphetamine and amfonelic acid alone or combined with the GABA transaminase inhibitors gamma-acetylen GABA (GAG) and sodium valproate as well as with the GABAA agonist THIP and the GABAB agonist baclofen. Subeffective doses of the GABAergic drugs did not modify the effects of moderate doses of the dopaminergic stimulants whereas effective doses continued to reduce ambulatory activity just as in the absence of dopaminergic activation. When DL-amphetamine or amfonelic acid were administered in doses that strongly enhanced ambulatory activity, doses of the GABAergic drugs that were inhibitory in the absence of dopaminergic stimulation were no longer effective. The mixed D1/D2 dopamine antagonist pimozide, the D1 antagonist SCH 23390 and the D2 antagonist sulpiride were then combined with subeffective doses of the GABA agonists. GAG, sodium valproate and baclofen were potentiated by pimozide and SCH 23390 but not by sulpiride. THIP was ineffective. These data show that GABAergic drugs had a reduced effect after stimulation of dopaminergic neurotransmission. On the other hand, when dopamine D1 receptors were blocked, nonselective GABA agonists and the GABAB agonist baclofen were potentiated. This was not the case for the GABAA agonist THIP, suggesting that the GABAA receptor is of slight importance for the interactions between GABA and dopamine in the control of ambulatory activity. No potentiation of GABAergic agonists was obtained after treatment with a dopamine D2 antagonist.
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Affiliation(s)
- A Agmo
- Laboratoire de Psychophysiologie, Faculté des Sciences, Université de Tours, France
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Phillips TJ, Shen EH. Neurochemical bases of locomotion and ethanol stimulant effects. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1996; 39:243-82. [PMID: 8894850 DOI: 10.1016/s0074-7742(08)60669-8] [Citation(s) in RCA: 158] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The locomotor stimulant effect produced by alcohol (ethanol) is one of a large number of measurable ethanol effects. Ethanol-induced euphoria in humans and locomotor stimulation in rodents, a potential animal model of human euphoria, have long been recognized and the latter has been extensively characterized. Since the euphoria produced by ethanol may influence the development of uncontrolled or excessive alcohol use, a solid understanding of the neurochemical substrates underlying such effects is important. Such an understanding for spontaneous locomotion and for ethanol's stimulant effects is beginning to emerge. Herein we review what is known about three neurochemical substrates of locomotion and of ethanol's locomotor stimulant effects. Several lines of research have implicated dopaminergic, GABAergic, and glutamatergic neurotransmitter systems in determining these behaviors. A large collection of work is cited, which strongly implicates the above-mentioned neurotransmitter substances in the control of spontaneous locomotion. A smaller, but persuasive, body of evidence suggests that central nervous system processes utilizing these transmitters are involved in determining the effects of ethanol on locomotion. Particular emphasis has been placed on the mesolimbic ventral tegmental area to nucleus accumbens dopaminergic pathway, and on the ventral pallidum/substantia innominata, where GABA and glutamate have been found to play a role in altering the activity of this dopaminergic pathway. Research on ethanol and drug locomotor sensitization, increased responsiveness to the substance with repeated administration, is also reviewed as a process that may be important in the development of drug addiction.
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Affiliation(s)
- T J Phillips
- Department of Veterans Affairs Medical Center, Oregon Health Sciences University, Portland 97201, USA
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Agmo A, Galvan A, Heredia A, Morales M. Naloxone blocks the antianxiety but not the motor effects of benzodiazepines and pentobarbital: experimental studies and literature review. Psychopharmacology (Berl) 1995; 120:186-94. [PMID: 7480551 DOI: 10.1007/bf02246192] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The role of opioid systems in the anticonflict effect of chlordiazepoxide, diazepam and pentobarbital was evaluated with a modified Vogel procedure. First, morphine, ineffective by itself, was combined with subeffective or marginally effective doses of the benzodiazepines in order to detect possible potentiation. However, the combined treatment reduced licking in the Vogel procedure as well as in a licking test where no shock was administered. Several doses of the benzodiazepines and pentobarbital were then administered in combination with several doses of the opiate antagonist naloxone. A dose-dependent inhibition of anticonflict effect was obtained. In an additional experiment, it was shown that naloxone blocked the effects of diazepam in the elevated plus-maze procedure. Motor deficiencies, as evaluated with a rotarod test, produced by the benzodiazepines and pentobarbital could not be antagonized by naloxone. It is concluded that opioids are important for the anticonflict but not for the motor effects of these drugs. An analysis of published studies concerning the interaction of opioids and benzodiazepines in several procedures supposed to reflect anxiolytic effects shows that the inhibition obtained with naloxone is reliable and not procedure specific. The mechanisms by which opiate antagonists produce this inhibition of anticonflict activity are not known. It is tentatively suggested that opioid activation associated with stress may be a necessary component of anxiolysis.
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Affiliation(s)
- A Agmo
- Laboratoire de Psychophysiologie, Université de Tours, Faculté des Sciences, France
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Paredes RG, Manero MC, Haller AE, Alvarado R, Agmo A. Sexual behavior enhances postictal behavioral depression in kindled rats: opioid involvement. Behav Brain Res 1992; 52:175-82. [PMID: 1294197 DOI: 10.1016/s0166-4328(05)80228-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Past research has demonstrated brain opioid and GABA release in response to ejaculation. In the present study we evaluated the potential role of these neurotransmitters in the postictal behavioral depression (PBD), after-discharge (AD) duration, and seizure intensity in rats kindled in the medial preoptic area (MPOA) and amygdala (AMG). The PBD, the AD duration and the seizure intensity were measured after a standard kindling stimulus and after a standard kindling stimulus applied 2 min after ejaculation. The PBD was significantly increased when the animals were stimulated 2 min after ejaculation. This increase was found in MPOA- but not in AMG-kindled rats. Ejaculation had no effect on AD duration or seizure intensity. Naloxone administration before the initiation of sexual behavior completely blocked the increase in PBD in MPOA-kindled rats. It is suggested, by indirect evidence, that opioid release during sexual behavior is added to the release associated with kindled seizures, increasing the duration of the PBD. Since sexual behavior lacked effect on AD duration or seizure intensity, no evidence could be found suggesting that functionally relevant amounts of GABA are released during this behavior.
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Affiliation(s)
- R G Paredes
- Escuela de Psicología, Universidad Anáhuac, Mexico DF
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Abstract
Naloxone, a nonspecific opioid antagonist, has been found to decrease the activity and social behavior of rats tested in pairs but the effects on individual locomotor activity have been equivocal. In the present study, groups of male Long-Evans hooded rats received naloxone (1 or 4 mg/kg, IP) or vehicle alone (isotonic saline) 30 min prior to testing sessions. Individual locomotor activity was measured in two activity boxes (41-cm3) equipped with two infrared photobeams using daily 30-min testing sessions for 5 consecutive days. Following a 1-week washout period (no testing), activity and social attraction (paired distance and contact) were examined in pairs of rats from each group using daily 15-min testing sessions for 4 consecutive days. Locomotor activity and its habituation were not significantly affected by naloxone in rats tested individually. However, both doses of naloxone significantly reduced paired locomotor activity compared to the control group. Measures of social attraction were not significantly affected by naloxone. The present findings suggest that naloxone does not produce nonspecific depressant effects on activity but rather may antagonize opioid release in situational contexts of high arousal (e.g., social activity) with consequent reduction of activity.
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Affiliation(s)
- C P Dokla
- Department of Psychology, Saint Anselm College, Manchester, NH 03102-1310
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Abstract
The discovery of different GABA receptor subtypes has stimulated research relating this neurotransmitter to a variety of behavioral functions and clinical disorders. The development of new and specific GABAergic compounds has made it possible to try to identify the specific functions of these receptors. The purpose of the present review is to evaluate the data regarding the functions of the GABA receptor subtypes in different behaviors such as motor function, reproduction, learning and memory, and aggressive-defensive behaviors. A description of GABAergic functions (stress, peripheral effects, thermoregulation) that might directly or indirectly affect behavior is also included. The possible involvement of GABA in different neurological and psychiatric disorders is also discussed. Although much research has been done trying to identify the possible role of GABA in different behaviors, the role of receptor subtypes has only recently attracted attention, and only preliminary data are available at present. It is therefore evident that still much work has to be done before a clear picture of the behavioral significance of these receptor subtypes can be obtained. Nevertheless, existing data are sufficient to justify the prediction that GABAergic agents, in the near future, will be much used in the field of behavioral pharmacology. It is hoped that the present review will contribute to this. Some specific suggestions concerning the most efficient way to pursue future research are also made.
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Affiliation(s)
- R G Paredes
- Department of Psychology, Universidad Anáhuac, Mexico City, Mexico
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Bayón A, Antón B. Diurnal rhythm of the in vivo release of enkephalin from the globus pallidus of the rat. REGULATORY PEPTIDES 1986; 15:63-70. [PMID: 3763960 DOI: 10.1016/0167-0115(86)90076-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The in vivo spontaneous release of enkephalin in the globus pallidus of the rat increases from noon to evening by 100%; during this period the local release of exogenous gamma-aminobutyric acid (GABA) decreases by 60%. These diurnal rhythms are more marked in the K+-stimulated release: enkephalin-induced output increases 6-fold while GABA decreases 10-fold during the afternoon and evening hours. Since pallidal enkephalin and GABA are involved in the control of locomotor activity we suggest that these rhythms may be linked to the circadian changes of activity in the rat.
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