1
|
Manke HN, Nunn SS, Sulima A, Rice KC, Riley AL. Effects of Serial Polydrug Use on the Rewarding and Aversive Effects of the Novel Synthetic Cathinone Eutylone. Brain Sci 2023; 13:1294. [PMID: 37759895 PMCID: PMC10526358 DOI: 10.3390/brainsci13091294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND As individual synthetic cathinones become scheduled and regulated by the Drug Enforcement Administration (DEA), new ones regularly are produced and distributed. One such compound is eutylone, a novel third-generation synthetic cathinone whose affective properties (and abuse potential) are largely unknown. The following experiments begin to characterize these effects and how they may be impacted by drug history (a factor affecting reward/aversion for other drugs of abuse). METHODS Eutylone was assessed for its ability to induce conditioned taste avoidance (CTA; aversive effect) and conditioned place preference (CPP; rewarding effect) and their relationship (Experiment 1). Following this, the effects of exposure to cocaine or 3,4-methylenedioxymethamphetamine [MDMA] on eutylone's affective properties were investigated (Experiment 2). RESULTS Eutylone produced dose-dependent CTA and CPP (Experiment 1), and these endpoints were unrelated. Pre-exposure to cocaine and MDMA differentially impacted taste avoidance induced by eutylone (MDMA > cocaine) and did not impact eutylone-induced place preference. CONCLUSIONS These data indicate that eutylone, like other synthetic cathinones, has co-occurring, independent rewarding and aversive effects that may contribute to its abuse potential and that these effects are differentially impacted by drug history. Although these studies begin the characterization of eutylone, future studies should examine the impact of other factors on eutylone's affective properties and its eventual reinforcing effects (i.e., intravenous self-administration [IVSA]) to predict its use and abuse liability.
Collapse
Affiliation(s)
- Hayley N. Manke
- Psychopharmacology Laboratory, Center for Neuroscience and Behavior, Department of Neuroscience, American University, 4400 Massachusetts Ave, NW, Washington, DC 20016, USA; (H.N.M.)
| | - Samuel S. Nunn
- Psychopharmacology Laboratory, Center for Neuroscience and Behavior, Department of Neuroscience, American University, 4400 Massachusetts Ave, NW, Washington, DC 20016, USA; (H.N.M.)
| | - Agnieszka Sulima
- Drug Design and Synthesis Section, National Institute on Drug Abuse (NIDA), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Bethesda, MD 20892, USA (K.C.R.)
| | - Kenner C. Rice
- Drug Design and Synthesis Section, National Institute on Drug Abuse (NIDA), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Bethesda, MD 20892, USA (K.C.R.)
| | - Anthony L. Riley
- Psychopharmacology Laboratory, Center for Neuroscience and Behavior, Department of Neuroscience, American University, 4400 Massachusetts Ave, NW, Washington, DC 20016, USA; (H.N.M.)
| |
Collapse
|
2
|
Allen DC, Grant KA. Discriminative Stimulus Effects and Metabolism of Ethanol in Rhesus Monkeys. Alcohol Clin Exp Res 2019; 43:1909-1917. [PMID: 31237691 PMCID: PMC6721990 DOI: 10.1111/acer.14142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 06/17/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Animal models are an essential feature of drug and pharmacotherapy development for treating alcohol use disorders (AUDs). The rhesus macaque is a robust animal model for many aspects of AUDs particularly in exploiting individual differences in oral self-administration of ethanol (EtOH), endocrine orchestration of stress response, and menstrual cycle characteristics. However, the clearance rates of EtOH have not been reported in this species, and the GABAA and N-methyl-D-aspartate (NMDA) receptor involvement in EtOH's discriminative stimulus effects has not been fully characterized. METHODS EtOH clearance rates following 2 doses of EtOH on separate days (0.5 and 1.0 g/kg, i.g.) were determined in 8 young adult male rhesus macaques. The EtOH was given by nasogastric gavage, and repeated blood samples were taken over 5 hours without sedation. Next, all subjects were trained on a 2-choice 1.0 g/kg EtOH (i.g.) versus water discrimination with a 60-minutes pretreatment period to capture peak blood EtOH concentration (BEC). Substitution testing was conducted with GABAA ligands pentobarbital (i.g. and i.m.) and midazolam (i.g.), as well as NMDA antagonist MK-801 (i.m.). RESULTS Peak BECs were 34 and 87 mg/dl for 0.5 and 1.0 g/kg doses, respectively, and occurred at 66 and 87 minutes following gavage. All GABAA and NMDA ligands tested resulted in responding on the EtOH-appropriate lever with the potency ranking of MK-801 (ED50 : 0.017 mg/kg) > midazolam (ED50 : 1.6 mg/kg) > pentobarbital (ED50 : 3.7 mg/kg) > EtOH (ED50 : 700 mg/kg, or 0.7 g/kg) in these subjects. CONCLUSIONS These results suggest that the compound discriminative stimulus effects of EtOH are highly consistent across species, providing further support for the rhesus macaque as strong model for pharmacotherapy development for AUD.
Collapse
Affiliation(s)
- Daicia C. Allen
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
- Current address: Department of Psychology, Vanderbilt University, Nashville, TN
| | - Kathleen A. Grant
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR
| |
Collapse
|
3
|
Risca HI, Baker LE. Contribution of monoaminergic mechanisms to the discriminative stimulus effects of 3,4-methylenedioxypyrovalerone (MDPV) in Sprague-Dawley rats. Psychopharmacology (Berl) 2019; 236:963-971. [PMID: 30554256 PMCID: PMC6571067 DOI: 10.1007/s00213-018-5145-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 12/03/2018] [Indexed: 12/21/2022]
Abstract
RATIONALE 3,4-Methylenedioxypyrovalerone (MDPV) is a popular synthetic cathinone reported to have a high abuse potential. Recent preclinical research indicates the psychopharmacology of MDPV is comparable to cocaine. Despite a recent influx of research on the psychopharmacology of MDPV, few studies have employed preclinical drug discrimination methods to discern the neurochemical mechanisms involved in its interoceptive stimulus effects. OBJECTIVE The aim of this study was to evaluate a variety of monoaminergic agents for substitution, potentiation, or antagonism in rats trained to discriminate MDPV. METHODS Male Sprague-Dawley rats were trained to discriminate 0.5 (experiment 1) or 1 mg/kg MDPV (experiment 2) from saline under an FR 20 schedule of food reinforcement. In experiment 1, MDMA, MDA, and their respective optical isomers (0.75-3 mg/kg), cocaine (2.5-20 mg/kg), GBR 12909 (5-40 mg/kg), and desipramine (3.2-10 mg/kg) were assessed for substitution. GBR 12909 (40 mg/kg) and desipramine (3.2 mg/kg) were subsequently assessed for potentiation of the MDPV cue. In experiment 2, stimulus antagonism tests were conducted with dopamine antagonists (Sch 23390, haloperidol) and serotonin antagonists (pirenperone, MDL100907, WAY 100635). RESULTS The MDMA and MDA enantiomers produced divergent results, with virtually no substitution by (-)-MDMA or (-)-MDA, partial substitution with (+)-MDA, and full substitution with (+)-MDMA, as well as full substitution by the racemates, (±)-MDMA and (±)-MDA. Consistent with previous findings, cocaine fully substituted for MDPV. Although no dose of GBR 12909 or desipramine substituted for MDPV, these reuptake inhibitors enhanced the discriminative stimulus effects of lower MDPV doses. Both D1 (Sch 23390) and D2 (haloperidol) DA antagonists attenuated 1 mg/kg MDPV discrimination, whereas none of the 5-HT antagonists assessed altered MDPV discrimination. CONCLUSIONS These findings indicate MDPV's interoceptive stimulus effects are mediated predominantly by dopaminergic actions, although serotonergic and/or noradrenergic modulation of these effects cannot be ruled out. Further investigations into the neurochemical actions involved in the discriminative stimulus effects of MDPV may serve to inform medication discovery and development for the treatment of MDPV abuse.
Collapse
Affiliation(s)
- Harmony I Risca
- Department of Psychology, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - Lisa E Baker
- Department of Psychology, Western Michigan University, Kalamazoo, MI, 49008, USA.
| |
Collapse
|
4
|
Allen DC, Ford MM, Grant KA. Cross-Species Translational Findings in the Discriminative Stimulus Effects of Ethanol. Curr Top Behav Neurosci 2019; 39:95-111. [PMID: 28341943 PMCID: PMC5612861 DOI: 10.1007/7854_2017_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The progress on understanding the pharmacological basis of ethanol's discriminative stimulus effects has been substantial, but appears to have plateaued in the past decade. Further, the cross-species translational efforts are clear in laboratory animals, but have been minimal in human subject studies. Research findings clearly demonstrate that ethanol produces a compound stimulus with primary activity through GABA and glutamate receptor systems, particularly ionotropic receptors, with additional contribution from serotonergic mechanisms. Further progress should capitalize on chemogenetic and optogenetic techniques in laboratory animals to identify the neural circuitry involved in mediating the discriminative stimulus effects of ethanol. These infrahuman studies can be guided by in vivo imaging of human brain circuitry mediating ethanol's subjective effects. Ultimately, identifying receptors systems, as well as where they are located within brain circuitry, will transform the use of drug discrimination procedures to help identify possible treatment or prevention strategies for alcohol use disorder.
Collapse
Affiliation(s)
- Daicia C Allen
- Department of Behavioral Neurosciences, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Matthew M Ford
- Department of Behavioral Neurosciences, Oregon Health & Science University, Portland, OR, 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Kathleen A Grant
- Department of Behavioral Neurosciences, Oregon Health & Science University, Portland, OR, 97239, USA.
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA.
| |
Collapse
|
5
|
Abstract
As investigators, we use many methodologies to answer both practical and theoretical questions in our field. Occasionally, we must stop and collect the latest findings or trends and then look forward to where our ideas, findings, and hypotheses may take us. Similar to volumes that were published in previous years on drug discrimination (Glennon and Young, Drug discrimination applications to medicinal chemistry and drug studies. Wiley, Hoboken, 2011; Ho et al., Drug discrimination and state dependent learning. Academic Press, New York, 1978), this collection in Current Topics in Behavioral Neurosciences serves as a current analysis of the continued value of the drug discrimination procedure to the fields of pharmacology, neuroscience, and psychology and as a stepping stone to where drug discrimination methodology can be applied next, in both a practical and theoretical sense. This final chapter represents one investigator's perspective on the utility and possibilities for a methodology that she fell in love with over 30 years ago.
Collapse
Affiliation(s)
- Ellen A Walker
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, PA, USA.
| |
Collapse
|
6
|
Abstract
Inhalants are a loosely organized category of abused compounds defined entirely by their common route of administration. Inhalants include volatile solvents, fuels, volatile anesthetics, gasses, and liquefied refrigerants, among others. They are ubiquitous in modern society as ingredients in a wide variety of household, commercial, and medical products. Persons of all ages abuse inhalants but the highest prevalence of abuse is in younger adolescents. Although inhalants have been shown to act upon a host of neurotransmitter receptors, the stimulus effects of the few inhalants which have been trained or tested in drug discrimination procedures suggest that their discriminative stimulus properties are mediated by a few key neurotransmitter receptor systems. Abused volatile solvent inhalants have stimulus effects that are similar to a select group of GABAA positive modulators comprised of benzodiazepines and barbiturates. In contrast the stimulus effects of nitrous oxide gas appear to be at least partially mediated by uncompetitive antagonism of NMDA receptors. Finally, volatile anesthetic inhalants have stimulus effects in common with both GABAA positive modulators as well as competitive NMDA antagonists. In addition to a review of the pharmacology underlying the stimulus effects of inhalants, the chapter also discusses the scientific value of utilizing drug discrimination as a means of functionally grouping inhalants according to their abuse-related pharmacological properties.
Collapse
Affiliation(s)
- Keith L Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, Room 746, P.O. Box 980613, Richmond, VA, 23298-0613, USA.
| |
Collapse
|
7
|
Porter JH, Prus AJ, Overton DA. Drug Discrimination: Historical Origins, Important Concepts, and Principles. Curr Top Behav Neurosci 2019; 39:3-26. [PMID: 29637526 DOI: 10.1007/7854_2018_40] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Research on the stimulus properties of drugs began with studies on state dependent learning during the first half of the twentieth century. From that research, an entirely new approach evolved called drug discrimination. Animals (including humans) could discriminate the presence or absence of a drug; once learned, the drug could serve as a discriminative stimulus, signaling the availability or nonavailability of reinforcement. Early drug discrimination research involved the use of a T-maze task, which evolved in the 1970s into a two-lever operant drug discrimination task that is still used today. A number of important concepts and principles of drug discrimination are discussed. (1) The discriminative stimulus properties of drugs are believed in large part to reflect the subjective effects of drugs. While it has been impossible to directly measure subjective effects in nonhuman animals, drug discrimination studies in human subjects have generally supported the belief that discriminative stimulus properties of drugs in nonhuman animals correlate highly with subjective effects of drugs in humans. In addition to the ability of the drug discrimination procedure to measure the subjective effects of drugs, it has a number of other strengths that help make it a valuable preclinical assay. (2) Drug discrimination can be used for classification of drugs based on shared discriminative stimulus properties. (3) The phenomena of tolerance and cross-tolerance can be studied with drug discrimination. (4) Discriminative stimulus properties of drugs typically have been found to be stereospecific, if a drug is comprised of enantiomers. (5) Discriminative stimulus properties of drugs reflect specific CNS activity at neurotransmitter receptors. (6) Both human and nonhuman subjects display individual differences in their sensitivity to discriminative stimuli and drugs. (7) The drug discrimination procedure has been used extensively as a preclinical assay in drug development. This chapter is the first in the volume The Behavioural Neuroscience of Drug Discrimination, which includes chapters concerning the discriminative stimulus properties of various classes of psychoactive drugs as well as sections on the applications and approaches for using this procedure.
Collapse
Affiliation(s)
- Joseph H Porter
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA.
| | - Adam J Prus
- Northern Michigan University, Marquette, MI, USA
| | | |
Collapse
|
8
|
Contribution of NMDA glutamate and nicotinic acetylcholine receptor mechanisms in the discrimination of ethanol-nicotine mixtures. Behav Pharmacol 2016; 24:617-22. [PMID: 23928692 DOI: 10.1097/fbp.0b013e3283654216] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ethanol and nicotine are commonly coabused drugs, and the incidence of codependence is greater than would be expected on the basis of the summed probability of dependence on each drug alone. Previous findings from our laboratory and others suggest that interactive mechanisms at the level of discriminative stimulus (S(D)) effects may contribute to this coabuse phenomenon. Specifically, ethanol overshadows the nicotine S(D) whereas nicotine potentiates the stimulus salience of ethanol when the two drugs are conditioned as a drug mixture. The goal of the current study was to begin to delineate the pharmacological bases of these ethanol-nicotine interactions. Three groups of C57BL/6J mice were trained to discriminate 0.8 mg/kg nicotine + 0.5 g/kg ethanol (0.8 N + 0.5 E), 0.8 N + 1.0 E, or 0.8 N + 2.0 E. An NMDA receptor antagonist (MK-801) and three nACh receptor ligands were tested for their ability to generalize from or antagonize, respectively, the drug mixtures. MK-801 fully generalized from the 0.8 N + 1.0 E and 0.8 N + 2.0 E mixtures and partially generalized from 0.8 N + 0.5 E. In contrast, nACh receptor ligands had minimal influence in blocking the perception of 0.8 N + 1.0 E and 0.8 N + 2.0 E mixtures, and only mecamylamine partially blocked 0.8 N+0.5 E. Reduced and enhanced contributions of nACh and NMDA receptors, respectively, in the discrimination of ethanol-nicotine mixtures may contribute to the overshadowing and potentiation phenomena observed previously.
Collapse
|
9
|
Jackson KJ, Walters CL, Miles MF, Martin BR, Damaj MI. Characterization of pharmacological and behavioral differences to nicotine in C57Bl/6 and DBA/2 mice. Neuropharmacology 2009; 57:347-55. [PMID: 19619563 DOI: 10.1016/j.neuropharm.2009.07.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 07/08/2009] [Accepted: 07/10/2009] [Indexed: 10/20/2022]
Abstract
Approximately 50-70% of the risk for developing nicotine dependence is attributed to genetics; therefore, it is of great significance to characterize the genetic mechanisms involved in nicotine reinforcement and dependence in hopes of generating better smoking cessation therapies. The overall goal of these studies was to characterize behavioral and pharmacological responses to nicotine in C57Bl/6 (B6) and DBA/2 (D2) mice, two inbred strains commonly used for genetic studies on behavioral traits. B6 and D2 mice where subjected to a battery of behavioral tests to measure nicotine's acute effects, calcium-mediated antinociceptive responses, tolerance to chronic treatment with osmotic mini pumps, and following three days of nicotine withdrawal. In general, D2 mice were less sensitive than B6 mice to the acute effects of nicotine, but were more sensitive to blockade of nicotine-induced antinociceptive responses by a calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitor. B6, but not D2 mice, developed tolerance to nicotine and nicotine conditioned place preference (CPP). While B6 and D2 mice both expressed some physical withdrawal signs, affective withdrawal signs were not evident in D2 mice. These results provide a thorough, simultaneous evaluation of the pharmacological and behavioral differences to experimenter-administered nicotine as measured in several behavioral tests of aspects that contribute to smoking behavior. The B6 and D2 strains show wide phenotypic differences in their responses to acute or chronic nicotine. These results suggest that these strains may be useful progenitors for future genetic studies on nicotine behaviors across batteries of mouse lines such as the BXD recombinant inbred panel.
Collapse
Affiliation(s)
- Kia J Jackson
- Department of Pharmacology and Toxicology, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
| | | | | | | | | |
Collapse
|
10
|
Shelton KL, Slavova-Hernandez G. Characterization of an inhaled toluene drug discrimination in mice: effect of exposure conditions and route of administration. Pharmacol Biochem Behav 2009; 92:614-20. [PMID: 19268500 DOI: 10.1016/j.pbb.2009.02.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/17/2009] [Accepted: 02/25/2009] [Indexed: 01/05/2023]
Abstract
The drug discrimination procedure in animals has been extensively utilized to model the abuse related, subjective effects of drugs in humans, but it has seldom been used to examine abused volatile inhalants like toluene. The present study sought to characterize the temporal aspects of toluene's discriminative stimulus as well assess toluene blood concentrations under identical exposure conditions. B6SJLF1/J mice were trained to discriminate 10 min of exposure to 6000 ppm inhaled toluene vapor from air. Toluene vapor concentration dependently substituted for the training exposure condition with longer exposures to equivalent concentrations producing greater substitution than shorter exposures. Toluene's discriminative stimulus effects dissipated completely by 60 min after the cessation of exposure. Injected liquid toluene dose-dependently substituted for toluene vapor as well as augmenting the discriminative stimulus effects of inhaled toluene. Toluene blood concentrations measured under several exposure conditions which produced full substitution were all nearly identical suggesting that the concentration of toluene in the animal tissues at the time of testing determined discriminative performance. These results indicate that the discriminative stimulus effects of inhaled toluene vapor are likely mediated by CNS effects rather than by its pronounced peripheral stimulus effects.
Collapse
Affiliation(s)
- Keith L Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298-0613, USA.
| | | |
Collapse
|
11
|
Solinas M, Panlilio LV, Justinova Z, Yasar S, Goldberg SR. Using drug-discrimination techniques to study the abuse-related effects of psychoactive drugs in rats. Nat Protoc 2007; 1:1194-206. [PMID: 17406402 DOI: 10.1038/nprot.2006.167] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Drug-discrimination (DD) techniques can be used to study abuse-related effects by establishing the interoceptive effects of a training drug (e.g., cocaine) as a cue for performing a specific operant response (e.g., lever pressing reinforced by food). During training with this protocol, pressing one lever is reinforced when the training drug is injected before the start of the session, and responding on a second lever is reinforced when vehicle is injected before the session. Lever choice during test sessions can then be used as an indication of whether a novel drug has effects similar to the training drug, or whether a potential therapeutic alters the effects of the training drug. Although training can be lengthy (up to several months), the pharmacological specificity of DD procedures make them a perfect complement to other techniques used to study drug-abuse phenomena, such as intravenous self-administration and conditioned place-preference procedures.
Collapse
Affiliation(s)
- Marcello Solinas
- Centre National de la Recherche Scientifique UMR 6187, University of Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France.
| | | | | | | | | |
Collapse
|
12
|
Becker HC, Crissman AM, Studders S, Kelley BM, Middaugh LD. Differential Neurosensitivity to the Discriminative Stimulus Properties of Ethanol in C57BL/6J and C3H/He Mice. Alcohol Clin Exp Res 2006; 28:712-9. [PMID: 15166645 DOI: 10.1097/01.alc.0000125351.09265.f0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND A large body of evidence suggests that the interoceptive cue associated with ethanol intoxication is complex and dependent on a number of environmental and biological factors. Despite the fact that mice have been widely used to study genetic influences on sensitivity to various actions of ethanol, few studies have used mice to examine sensitivity to the discriminative stimulus effects of ethanol. The purpose of this study was to compare sensitivity to the discriminative stimulus effects of ethanol in two inbred mouse strains, namely C57BL/6J and C3H/He mice. METHODS Adult male C57BL/6J and C3H/He mice were trained to discriminate between ethanol and saline using a two-lever food reinforcement operant procedure. Once criterion discrimination performance was achieved, dose-response functions were determined from generalization tests. Additional experiments were conducted to determine whether differences in discrimination performance were related to differential blood/brain ethanol levels in the two mouse strains. RESULTS A greater proportion of C57BL/6J mice acquired the discrimination and required fewer trials to achieve criterion performance compared with C3H/He mice with a 1.0 g/kg ethanol training dose. This deficit in acquisition was overcome when the training dose was increased to 2.0 g/kg for C3H/He mice. In a second experiment, a 1.5 g/kg training dose of ethanol was used for both strains. Again, a greater proportion of C57BL/6J mice acquired the discrimination and required fewer training trials to achieve criterion performance compared with C3H/He mice. Blood ethanol levels did not differ between the strains after administration of the 1.5 g/kg training dose. However, blood and brain ethanol levels did differ between the strains after doses of ethanol were administered that produced equivalent discrimination performance. CONCLUSIONS Results indicate that ethanol discrimination was more readily acquired and maintained in C57BL/6J mice than C3H/He mice. Ethanol dose-response functions generated from generalization tests also clearly demonstrated greater sensitivity to the discriminative stimulus properties of ethanol in C57BL/6J mice compared with the C3H/He strain. This differential sensitivity to the interoceptive cue produced by ethanol does not seem to be related to learning or pharmacokinetic differences between the two inbred strains.
Collapse
Affiliation(s)
- Howard C Becker
- Medical Research, Department of Veterans Affairs, Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina, USA.
| | | | | | | | | |
Collapse
|
13
|
Li M, Wessinger WD, McMillan D. Effects of amphetamine-CNS depressant combinations and of other CNS stimulants in four-choice drug discriminations. J Exp Anal Behav 2005; 84:77-97. [PMID: 16156138 PMCID: PMC1243898 DOI: 10.1901/jeab.2005.09-04] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three pigeons were trained to discriminate among 5 mg/kg pentobarbital, 2 mg/kg amphetamine, a combination of these two drugs at these doses, and saline using a four-choice procedure (amphetamine-pentobarbital group). Three other pigeons were trained to discriminate among 5 mg/kg morphine, 2 mg/kg methamphetamine, a combination of these two drugs at these doses, and saline (methamphetamine-morphine group). After 10 to 13 months of training, the pigeons averaged more than 90% of their responses on the appropriate key during training sessions. In subsequent testing, dose-response curves were determined for the individual drugs, for a wide range of dose combinations of the training drugs, and for two drugs to which the pigeons had not been exposed previously (pseudoephedrine and nicotine). After low test doses of the training drugs, pigeons responded on the saline key. As the dose increased, responding on the key associated with that drug during training sessions increased. When training drugs were combined at doses that were not discriminable when given alone, responding occurred on the saline key. When a discriminable dose of one training drug was combined with a nondiscriminable dose of the other training drug, responding occurred on the key associated with the discriminable dose. When both drugs were given at discriminable doses, responding almost always occurred on the drug-combination key. The response-rate decreasing effects of pentobarbital and amphetamine were mutually antagonized when the drugs were combined, but the rate-decreasing effects of morphine and methamphetamine were not. After low doses of pseudoephedrine and nicotine, pigeons in both groups responded on the saline key. After higher doses of pseudoephedrine and nicotine, responding in the amphetamine-pentobarbital group occurred primarily on the amphetamine key. In the methamphetamine-morphine group, higher doses of pseudoephedrine and especially nicotine engendered more responding on the combination key than had occurred in the other group. The four-choice procedure can reveal subtle effects in the discrimination of individual drugs and drug combinations that are not apparent with procedures offering fewer response alternatives.
Collapse
Affiliation(s)
- Mi Li
- University of Arkansas for Medical Sciences
| | - William D Wessinger
- University of Arkansas for Medical Sciences
- Reprints may be obtained from W.D. Wessinger, Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, e-mail:
| | | |
Collapse
|
14
|
Crissman AM, Studders SL, Becker HC. Tolerance to the discriminative stimulus effects of ethanol following chronic inhalation exposure to ethanol in C57BL/6J mice. Behav Pharmacol 2004; 15:569-75. [PMID: 15577455 DOI: 10.1097/00008877-200412000-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A significant consequence of chronic ethanol (EtOH) exposure is the development of tolerance. The present study was designed to investigate tolerance to the discriminative stimulus properties of EtOH following chronic EtOH exposure. Adult male C57BL/6J mice were trained to discriminate EtOH (1.00 g/kg; i.p.) from saline, using a food-reinforced two-lever operant task. Following acquisition and establishment of criterion discrimination performance, a series of generalization tests were conducted to generate a baseline EtOH dose-response curve with a calculated ED50 dose of 0.42 g/kg. Mice were then placed into control (air) or EtOH inhalation chambers for 64 h. In Experiment 1, discriminative stimulus generalization tests with the EtOH ED50 dose conducted 24 h following chronic EtOH (or air) exposure did not yield significantly different EtOH responding, although a trend towards reduced sensitivity to the EtOH cue (tolerance) was evident. In Experiment 2, a cumulative dosing procedure (ED50=0.37 g/kg) was employed, yielding a baseline EtOH dose-response function with a calculated ED50 dose of 0.37 g/kg. At 24 h following chronic EtOH exposure, re-determination of the EtOH dose-response curve revealed a significant shift to the right, with more than a twofold increase in the ED50 value (ED50=1.09 g/kg) compared to the control air exposure condition (ED50=0.49 g/kg). This apparent tolerance to the EtOH cue dissipated in chronic EtOH-exposed mice tested 48 h following the inhalation treatment (ED50=0.51 g/kg). These results demonstrate tolerance to the discriminative stimulus effects of EtOH in C57BL/6J mice following chronic EtOH exposure in inhalation chambers.
Collapse
Affiliation(s)
- A M Crissman
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | | | | |
Collapse
|
15
|
Abstract
C57BL/6J (B6) and DBA/2J (D2) inbred mice show pronounced differences in ethanol-induced behaviors, such as loss of righting reflex and locomotor activation, among others. They also differ in measures of conditioned place preference and oral self-administration of ethanol. In the current study, I examined whether B6 and D2 mice differed in their expression of the N-methyl-D-aspartate (NMDA) receptor-mediated component of the discriminative stimulus effects of ethanol. B6 and D2 mice were trained to discriminate ethanol (1.5 g/kg, i.p.) from saline in a two-choice, milk-reinforced operant procedure. After training was completed, substitution and response rate dose-effect curves were generated for ethanol; the uncompetitive NMDA antagonists phencyclidine and ketamine; and the competitive NMDA antagonist D-CPPene. Dose-effect curves were also generated for midazolam, cocaine, m-chlorophenylpiperazine (mCPP), morphine, and gamma-hydroxybutyric acid (GHB). B6 and D2 mice learned the ethanol-versus-saline discrimination. Phencyclidine produced near full substitution for ethanol in both strains, whereas ketamine fully substituted for ethanol only in B6 mice. D-CPPene partially substituted for ethanol in both strains. Moderate doses of phencyclidine produced greater response rate-increasing effects in B6 mice than in D2 mice, and high doses of phencyclidine were more potent for suppressing response rates in D2 mice. In contrast, D-CPPene had similar response rate-increasing effects in both strains, but high doses produced more potent response rate-decreasing effects in B6 mice. Among the other drugs tested, only midazolam produced substantial substitution for ethanol. Taken together, these findings seem to indicate that the behavioral effects of NMDA antagonists differ between strains, but that the NMDA-mediated component of the discriminative stimulus effects of ethanol is similar in B6 and D2 mice.
Collapse
Affiliation(s)
- Keith L Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, PO Box 980613, Richmond, VA 23298-0613, USA.
| |
Collapse
|
16
|
Fernández-Vidal JM, Spear NE, Molina JC. Adolescent rats discriminate a mild state of ethanol intoxication likely to act as an appetitive unconditioned stimulus. Alcohol 2003; 30:45-60. [PMID: 12878274 DOI: 10.1016/s0741-8329(03)00093-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Practically no information is available in relation to the capability of the adolescent animal in terms of discriminating postabsorptive effects of ethanol. Three experiments were conducted to analyze whether young, genetically heterogeneous rats discriminate different stages of the process of intoxication exerted by a low dose (0.5 g/kg) of ethanol. An ethanol pharmacokinetic profile was first examined to select two stages within the process of ethanol intoxication that, as a function of the corresponding blood ethanol concentrations (BECs), could represent two potentially discriminable drug states. In a second experiment, sucrose was available when the BECs of rats peaked or were of a lesser magnitude (5 and 30 min postadministration time, respectively). When animals were tested under similar or different drug states relative to the training procedure, no behavioral evidence indicative of differential sucrose expectancy was obtained. In Experiment 3, rats discriminated each of the previously defined ethanol states from a non-drug state. Unexpectedly, it was also found that the pharmacological effects of the 0.5-g/kg dose of ethanol are likely to support appetitive associative learning that involves the taste of sucrose as a conditioned stimulus. The apparent positive affective components of the state of ethanol intoxication have rarely been observed in genetically heterogeneous rats with rather brief experiences with the drug's effects.
Collapse
|
17
|
Littleton J, Little H. Interactions Between Alcohol and Nicotine Dependence: A Summary of Potential Mechanisms and Implications for Treatment. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02504.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
18
|
Miranda F, Orozco G, Velázquez-Martínez DN. Full substitution of the discriminative cue of a 5-HT(1A/1B/2C) agonist with the combined administration of a 5-HT(1B/2C) and a 5-HT(1A) agonist. Behav Pharmacol 2002; 13:303-11. [PMID: 12218511 DOI: 10.1097/00008877-200207000-00007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study examined whether animals attend to the individual components of the cue produced by a drug that stimulates different 5-hydroxytryptamine (5-HT) receptor populations, using a drug discrimination task based on the conditioned taste aversion (CTA) procedure. The training drug was indorenate (5-methoxytryptamine beta-methylcarboxylate) (INDO) that has been described as a 5-HT(1A/2C/1B) agonist able to exert discriminative control in both operant and CTA procedures. The principal objective was to examine generalization with the combined administration of agonists for the different receptor sites that may mimic the mechanism of action of the training drug. Male Wistar rats, deprived of water, were trained to discriminate INDO from saline; during the drug trials, the administration of INDO preceded saccharin-LiCl pairings, while, during the saline trials, the administration of saline preceded the saccharin-saline pairings. In generalization tests, INDO, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, a 5-HT(1A) agonist), 1-(3-trifluoromethylphenyl)piperazine (TFMPP, a 5-HT(1B) agonist), alpha-methyl-5-HT (a 5-HT(2C) agonist) or 2-methyl-5-HT (a 5-HT(3) agonist), were administered alone or in combination. The results showed that 8-OH-DPAT, TFMPP and alpha-methyl-5-HT produced dose-dependent generalization, up to 88% in the case of 8-OH-DPAT. The combined administration of the following pairs of drugs, 8-OH-DPAT+TFMPP or 8-OH-DPAT+ alpha-methyl-5-HT, at doses that produced only 15-55% generalization when administered alone, produced greater than 80% generalization to INDO. However, the single administration of 2-methyl-5-HT produced only saline-like responding and its combined administration with 8-OH-DPAT did not modify the generalization produced by the single administration of 8-OH-DPAT. These results suggest that animals attend to the individual components of the drug cue; in the case of INDO, which has three elements, each mediated by a different receptor subpopulation (5-HT(1A), 5-HT(1B) and 5-HT(2C) ), the separate stimulation of at least two receptor subpopulations was 'interpreted' by the subject as the presence of the training drug.
Collapse
MESH Headings
- 5-Methoxytryptamine/analogs & derivatives
- 5-Methoxytryptamine/pharmacology
- Animals
- Behavior, Animal
- Cues
- Discrimination Learning/drug effects
- Discrimination Learning/physiology
- Dose-Response Relationship, Drug
- Drinking/drug effects
- Generalization, Psychological/drug effects
- Male
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT1B
- Receptor, Serotonin, 5-HT2C
- Receptors, Serotonin/drug effects
- Receptors, Serotonin, 5-HT1
- Serotonin Receptor Agonists/pharmacology
Collapse
|
19
|
|
20
|
Shelton KL, Grant KA. Discriminative Stimulus Effects of Ethanol in C57BL/6J and DBA/2J Inbred Mice. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02601.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
21
|
Metcalf BR, Stahl JM, Allen JD, Woolfolk DR, Soto PL. Discrimination of gamma-hydroxybutyrate and ethanol administered separately and as a mixture in rats. Pharmacol Biochem Behav 2001; 70:31-41. [PMID: 11566140 DOI: 10.1016/s0091-3057(01)00579-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The physiological effects of gamma-hydroxybutyrate (GHB) are complex and not yet clearly defined. GHB has been labeled as a recreational drug and is reported to be frequently coabused with ethanol (ETH). Other studies have yielded discrepant results as to the interaction between GHB and ETH. Thus, the present study investigated extensively the discriminative stimulus of GHB and ETH and a mixture of the two compounds. Thirty male Long-Evans rats were divided into three groups and trained to discriminate doses of either 300 mg/kg GHB, 1000 mg/kg ETH, or a mixture (MIX: 150 mg/kg GHB+500 mg/kg ETH) from vehicle on a two-lever fixed-ratio (FR) 10 schedule of food reinforcement. Dose-response curves were attained in each group with its respective training drugs. GHB and ETH did not cross-generalize in the ETH- and GHB-trained rats, respectively. However, when the effects of the MIX were tested in the GHB- and ETH-trained rats, a greater than additive response was observed. Testing also revealed that the MIX-trained rats did not perceive a novel stimulus but a near-equal contribution from GHB and ETH. This study provides evidence of a complex relationship between GHB and ETH and opposes previous work reporting cross-generalization between GHB and ETH.
Collapse
Affiliation(s)
- B R Metcalf
- Psychology Program, Hawaii Pacific University, 1188 Fort Street Mall, Honolulu, HI 96813, USA.
| | | | | | | | | |
Collapse
|
22
|
Stolerman IP, Olufsen K. Generalisation of ethanol with drug mixtures containing a positive modulator of the GABA(A) receptor and an NMDA antagonist. Neuropharmacology 2001; 40:123-30. [PMID: 11077078 DOI: 10.1016/s0028-3908(00)00100-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ethanol is thought to produce its discriminative stimulus effect by actions on two or more neurotransmitter systems. To test this idea further, rats were trained to discriminate mixtures of two drugs from vehicle in two-lever procedures with food reinforcers presented on a tandem variable-interval fixed ratio schedule. After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests. Rats trained to discriminate a mixture of chlordiazepoxide (5.0 mg/kg, s. c.) plus dizocilpine (0.08 mg/kg, i.p.) yielded a mean of 76% drug-appropriate responding when tested with ethanol (3.0 g/kg, i.g. ). However, when rats were trained with an 8.0 mg/kg dose of pentobarbitone in a mixture with 0.08 mg/kg of dizocilpine, the same dose of ethanol produced only 33% drug-appropriate responding. After retraining with pentobarbitone (12 mg/kg) plus dizocilpine (0.04 mg/kg), ethanol (3.0 g/kg, i.g.) produced 75% drug-appropriate responding. Pentobarbitone and dizocilpine administered alone produced full, dose-related generalisation, but there was no generalisation to (+)-amphetamine (0.025-0.8 mg/kg, s.c.). Thus, ethanol substituted for mixtures in which the GABA(A)-modulatory component had equal or greater salience than the NMDA-antagonist component. Doses of ethanol that generalised with the drug mixtures always reduced overall rates of responding as compared with control rates. Nevertheless, these data provide further support for the hypothesis that ethanol produces a compound stimulus comprised of elements resembling the effects of positive modulators of GABA(A) receptors and those of NMDA antagonists.
Collapse
Affiliation(s)
- I P Stolerman
- Section of Behavioural Pharmacology, Institute of Psychiatry, King's College London, De Crespigny Park, SE5 8AF, London, UK.
| | | |
Collapse
|
23
|
Abstract
The compound stimulus hypothesis of ethanol discrimination predicts that a history of training to discriminate drugs that mimic individual elements of the ethanol stimulus should attenuate stimulus control by other stimulus elements (associative blocking). Rats were trained initially to discriminate either chlordiazepoxide (5 mg / kg s.c., n = 10) or dizocilpine (0.08 mg / kg i.p., n = 10) from vehicle in two-lever procedures with food reinforcers presented on a tandem variable-interval fixed ratio schedule. Control rats received 'sham training' (vehicle injections only, n = 9). All subjects were then trained to discriminate ethanol (1.5 g / kg intragastrically (i.g.)) until discrimination accuracy reached 95%. Chlordiazepoxide (1.25-10.0 mg / kg s.c.) produced more drug-appropriate responding in rats with a previous history of training to discriminate chlordiazepoxide than in either of the other two groups, but stimulus control by dizocilpine was not attenuated. Equivalent results were obtained in rats with a previous history of training to discriminate dizocilpine. Ethanol (0.375-3.0 g / kg i.g.) produced similar dose-related increases in drug-appropriate responding in all three groups. Thus, previous discrimination training modified the characteristics of ethanol discrimination in a way that may be explained by persistence of the original discriminations. The lack of evidence for associative blocking contrasts with results of previous experiments on the discrimination of compound stimuli produced by administering drug mixtures. The findings provide limited support for the hypothesis that ethanol produces a compound stimulus that includes elements of positive modulation of gamma-aminobutyric acid (GABA(A)) receptors and of N-methyl-D-aspartate (NMDA) antagonism.
Collapse
Affiliation(s)
- I P Stolerman
- Section of Behavioural Pharmacology, Institute of Psychiatry, King's College, London, UK.
| | | |
Collapse
|