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Szumlinski KK, Beltran J, van Doren E, Jimenez Chavez CL, Domingo-Gonzalez RD, Reyes CM, Ary AW, Lang A, Guo W, Worley PF, Huber KM. Evidence for phosphorylation-dependent, dynamic, regulation of mGlu5 and Homer2 in expression of cocaine aversion in mice. eNeuro 2023; 10:ENEURO.0423-22.2023. [PMID: 36973011 PMCID: PMC10131536 DOI: 10.1523/eneuro.0423-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Cocaine-induced changes in the expression of the glutamate-related scaffolding protein Homer2 influence this drug's psychostimulant and rewarding properties. In response to neuronal activity, Homer2 is phosphorylated on S117/S216 by calcium-calmodulin kinase IIα (CaMKIIα), which induces a rapid dissociation of mGlu5-Homer2 scaffolds. Herein, we examined the requirement for Homer2 phosphorylation in cocaine-induced changes in mGlu5-Homer2 coupling, to include behavioral sensitivity to cocaine. For this, mice with alanine point mutations at (S117/216)-Homer2 (Homer2AA/AA ) were generated and we determined their affective, cognitive and sensorimotor phenotypes, as well as cocaine-induced changes in conditioned reward and motor hyperactivity. The Homer2AA/AA mutation prevented activity-dependent phosphorylation of S216 Homer2 in cortical neurons, but Homer2AA/AA mice did not differ from wild-type controls with respect to Morris maze performance, acoustic startle, spontaneous or cocaine-induced locomotion. Homer2AA/AA mice exhibited signs of hypo-anxiety similar to the phenotype of transgenic mice with a deficit in signal-regulated mGluR5 phosphorylation (Grm5AA/AA ). However, opposite of Grm5AA/AA mice, Homer2AA/AA mice were less sensitive to the aversive properties of high-dose cocaine under both place- and taste-conditioning procedures. Acute injection with cocaine caused dissociation of mGluR5 and Homer2 in striatal lysates from WT, but not Homer2AA/AA mice, suggesting a molecular basis for the deficit in cocaine aversion. These findings indicate that CaMKIIα-dependent phosphorylation of Homer2 gates the negative motivational valence of high-dose cocaine via regulation of mGlu5 binding, furthering an important role for dynamic changes in mGlu5-Homer interactions in addiction vulnerability.Significance statementGlobally, psychostimulant use has again risen to reach epidemic proportions, particularly in the United States. Yet, we continue to face a knowledge gap regarding the biological bases of psychostimulant addiction vulnerability to inform disease prognosis and treatment-based recovery. Herein, we show that the psychomotor stimulant cocaine induces the uncoupling of the mGlu5 glutamate receptor from its scaffolding protein Homer2 in brain. Using a transgenic mouse model with deficits cocaine-induced uncoupling of mGlu5-Homer2, we demonstrate an important role for Homer2 scaffolding of mGlu5 in regulating cocaine's aversive properties, without influencing cocaine reward. Findings suggest that environmental factors, to include cocaine exposure, that affect mGlu5-Homer2 scaffolding dynamics may contribute to an individual's subjective response to cocaine to influence addiction vulnerability.
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Affiliation(s)
- K K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
- Department of Molecular, Cellular and Developmental Biology and the Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - J Beltran
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - E van Doren
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - C L Jimenez Chavez
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - R D Domingo-Gonzalez
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - C M Reyes
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - A W Ary
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - A Lang
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106-9660
| | - W Guo
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, Texas 75390
| | - P F Worley
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A
| | - K M Huber
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, Texas 75390
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Szumlinski KK, Shin CB. Kinase interest you in treating incubated cocaine-craving? A hypothetical model for treatment intervention during protracted withdrawal from cocaine. Genes Brain Behav 2017; 17:e12440. [PMID: 29152855 DOI: 10.1111/gbb.12440] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/06/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022]
Abstract
A diagnostic criterion for drug addiction, persistent drug-craving continues to be the most treatment-resistant aspect of addiction that maintains the chronic, relapsing, nature of this disease. Despite the high prevalence of psychomotor stimulant addiction, there currently exists no FDA-approved medication for craving reduction. In good part, this reflects our lack of understanding of the neurobiological underpinnings of drug-craving. In humans, cue-elicited drug-craving is associated with the hyperexcitability of prefrontal cortical regions. Rodent models of cocaine addiction indicate that a history of excessive cocaine-taking impacts excitatory glutamate signaling within the prefrontal cortex to drive drug-seeking behavior during protracted withdrawal. This review summarizes evidence that the capacity of cocaine-associated cues to augment craving in highly drug-experienced rats relates to a withdrawal-dependent incubation of glutamate release within prelimbic cortex. We discuss how stimulation of mGlu1/5 receptors increases the activational state of both canonical and noncanonical intracellular signaling pathways and present a theoretical molecular model in which the activation of several kinase effectors, including protein kinase C, extracellular signal-regulated kinase and phosphoinositide 3-kinase (PI3K) might lead to receptor desensitization to account for persistent cocaine-craving during protracted withdrawal. Finally, this review discusses the potential for existing, FDA-approved, pharmacotherapeutic agents that target kinase function as a novel approach to craving intervention in cocaine addiction.
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Affiliation(s)
- K K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California.,Department of Molecular, Cellular and Developmental Biology and the Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California
| | - C B Shin
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California
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Lee KM, Coelho MA, Sern KR, Szumlinski KK. Homer2 within the central nucleus of the amygdala modulates withdrawal-induced anxiety in a mouse model of binge-drinking. Neuropharmacology 2017; 128:448-459. [PMID: 29109058 DOI: 10.1016/j.neuropharm.2017.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/17/2017] [Accepted: 11/02/2017] [Indexed: 02/07/2023]
Abstract
A history of binge-drinking decreases protein expression of the glutamate-related scaffolding protein Homer2 within the central nucleus of the amygdala (CEA), coinciding with behavioral signs of negative affect. To assess the functional relevance of this protein change for withdrawal-induced hyper-anxiety, adult (PND 56) and adolescent (PND 28) male C57BL/6J mice were administered an intra-CEA infusion of an adeno-associated viral vector (AAV) carrying either cDNA to express Homer2 (H2-cDNA) or GFP as control. Mice underwent 14 days of binge-drinking under multi-bottle, limited-access conditions and were assayed for behavioral signs of negative affect during withdrawal using the light-dark box, marble burying, and forced swim tests (FST). Following behavioral testing, all animals experienced 5 days of drinking to evaluate the effects of prior alcohol experience and Homer2 manipulation on subsequent alcohol consumption. During protracted (4 weeks) withdrawal, adolescent alcohol-experienced GFP controls showed increased signs of negative affect across all 3 assays, compared to water-drinking GFP animals, and also showed elevated alcohol consumption during the subsequent drinking period. Homer2-cDNA infusion in adolescent-onset alcohol-drinking animals was anxiolytic and reduced subsequent alcohol consumption. Conversely, Homer2-cDNA was anxiogenic and increased drinking in water-drinking adolescents. Unfortunately, the data from adult-onset alcohol-drinking animals were confounded by low alcohol consumption and negligible behavioral signs of anxiety. Nevertheless, the present results provide novel cause-effect evidence supporting a role for CEA Homer2 in the regulation of both basal anxiety and the time-dependent intensification of negative affective states in individuals with a history of binge-drinking during adolescence.
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Affiliation(s)
- K M Lee
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, 93106-9660 CA, USA
| | - M A Coelho
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, 93106-9660 CA, USA
| | - K R Sern
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, 93106-9660 CA, USA
| | - K K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, 93106-9660 CA, USA; Department of Molecular, Cellular and Developmental Biology, The Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, 93106-9625 CA, USA.
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Jimenez SM, Healy AF, Coelho MA, Brown CN, Kippin TE, Szumlinski KK. Variability in prescription opioid intake and reinforcement amongst 129 substrains. Genes Brain Behav 2017; 16:709-724. [PMID: 28523735 DOI: 10.1111/gbb.12393] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/28/2022]
Abstract
Opioid abuse in the United States has reached epidemic proportions, with treatment admissions and deaths associated with prescription opioid abuse quadrupling over the past 10 years. Although genetics are theorized to contribute substantially to inter-individual variability in the development, severity and treatment outcomes of opioid abuse/addiction, little direct preclinical study has focused on the behavioral genetics of prescription opioid reinforcement and drug-taking. Herein, we employed different 129 substrains of mice currently available from The Jackson Laboratory (129S1/SvlmJ, 129X1/SvJ, 129S4/SvJaeJ and 129P3/J) as a model system of genetic variation and assayed mice for oral opioid intake and reinforcement, as well as behavioral and somatic signs of dependence. All substrains exhibited a dose-dependent increase in oral oxycodone and heroin preference and intake under limited-access procedures and all, but 129S1/SvlmJ mice, exhibited oxycodone reinforcement. Relative to the other substrains, 129P3/J mice exhibited higher heroin and oxycodone intake. While 129X1/SvJ exhibited the highest anxiety-like behavior during natural opioid withdrawal, somatic and behavior signs of precipitated withdrawal were most robust in 129P3/J mice. These results demonstrate the feasibility and relative sensitivity of our oral opioid self-administration procedures for detecting substrain differences in drug reinforcement/intake among 129 mice, of relevance to the identification of genetic variants contributing to high vs. low oxycodone reinforcement and intake.
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Affiliation(s)
- S M Jimenez
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA
| | - A F Healy
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA
| | - M A Coelho
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA
| | - C N Brown
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA
| | - T E Kippin
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA.,Department of Molecular, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA.,Institute for Collaborative Biotechnology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - K K Szumlinski
- Department of Psychological and Brain Sciences, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA.,Department of Molecular, Cellular and Developmental Biology and the Neuroscience Research Institute, Santa Barbara, CA, USA
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Goulding SP, Obara I, Lominac KD, Gould AT, Miller BW, Klugmann M, Szumlinski KK. Accumbens Homer2-mediated signaling: a factor contributing to mouse strain differences in alcohol drinking? Genes Brain Behav 2010; 10:111-26. [PMID: 20807241 DOI: 10.1111/j.1601-183x.2010.00647.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alcohol-induced increases in nucleus accumbens glutamate actively regulate alcohol consumption, and the alcohol responsiveness of corticoaccumbens glutamate systems relates to genetic variance in alcohol reward. Here, we extend earlier data for inbred mouse strain differences in accumbens glutamate by examining for differences in basal and alcohol-induced changes in the striatal expression of glutamate-related signaling molecules between inbred C57BL/6J and DBA2/J mice. Repeated alcohol treatment (8 × 2 g/kg) increased the expression of Group1 metabotropic glutamate receptors, the NR2a/b subunits of the N-methyl-D-aspartate receptor, Homer2a/b, as well as the activated forms of protein kinase C (PKC) epsilon and phosphoinositol-3-kinase within ventral, but not dorsal, striatum. Regardless of prior alcohol experience, C57BL/6J mice exhibited higher accumbens levels of mGluR1/5, Homer2a/b, NR2a and activated kinases vs. DBA2/J mice, whereas an alcohol-induced rise in dorsal striatum mGluR1/5 expression was observed only in C57BL/6J mice. We next employed virus-mediated gene transfer approaches to ascertain the functional relevance of the observed strain difference in accumbens Homer2 expression for B6/D2 differences in alcohol-induced glutamate sensitization, as well as alcohol preference/intake. Manipulating nucleus accumbens shell Homer2b expression actively regulated these measures in C57BL/6J mice, whereas DBA2/J mice were relatively insensitive to the neurochemical and behavioral effects of virus-mediated changes in Homer2 expression. These data support the over-arching hypothesis that augmented accumbens Homer2-mediated glutamate signaling may be an endophenotype related to genetic variance in alcohol consumption. If relevant to humans, such data pose polymorphisms affecting glutamate receptor/Homer2 signaling in the etiology of alcoholism.
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Affiliation(s)
- S P Goulding
- Department of Psychology and Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, USA
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Szumlinski KK, Lominac KD, Kleschen MJ, Oleson EB, Dehoff MH, Schwarz MK, Schwartz MK, Seeburg PH, Seeberg PH, Worley PF, Kalivas PW. Behavioral and neurochemical phenotyping of Homer1 mutant mice: possible relevance to schizophrenia. Genes Brain Behav 2005; 4:273-88. [PMID: 16011574 DOI: 10.1111/j.1601-183x.2005.00120.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Homer proteins are involved in the functional assembly of postsynaptic density proteins at glutamatergic synapses and are implicated in learning, memory and drug addiction. Here, we report that Homer1-knockout (Homer1-KO) mice exhibit behavioral and neurochemical abnormalities that are consistent with the animal models of schizophrenia. Relative to wild-type mice, Homer1-KO mice exhibited deficits in radial arm maze performance, impaired prepulse inhibition, enhanced 'behavioral despair', increased anxiety in a novel objects test, enhanced reactivity to novel environments, decreased instrumental responding for sucrose and enhanced MK-801- and methamphetamine-stimulated motor behavior. No-net-flux in vivo microdialysis revealed a decrease in extracellular glutamate content in the nucleus accumbens and an increase in the prefrontal cortex. Moreover, in Homer1-KO mice, cocaine did not stimulate a rise in frontal cortex extracellular glutamate levels, suggesting hypofrontality. These behavioral and neurochemical data derived from Homer1 mutant mice are consistent with the recent association of schizophrenia with a single-nucleotide polymorphism in the Homer1 gene and suggest that the regulation of extracellular levels of glutamate within limbo-corticostriatal structures by Homer1 gene products may be involved in the pathogenesis of this neuropsychiatric disorder.
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Affiliation(s)
- K K Szumlinski
- Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
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Szumlinski KK, Lominac KD, Frys KA, Middaugh LD. Genetic variation in heroin-induced changes in behaviour: effects of B6 strain dose on conditioned reward and locomotor sensitization in 129-B6 hybrid mice. Genes Brain Behav 2005; 4:324-36. [PMID: 16011579 DOI: 10.1111/j.1601-183x.2004.00111.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Substantial interindividual variability exists in the propensity to develop opiate addiction. Genetic variation in opiate reward may contribute to this variability. A large body of evidence indicates genetic variation in mice for several effects of opiate drugs. The present study examined heroin-induced place conditioning and locomotor sensitization in the two strains of mice employed most frequently in the generation of transgenic animals, C57BL/6J (B6) and 129X1/sVJ (129), as well as in groups of B6-129 hybrid mice, differing in their amount of B6 genetic background. Four pairings of 100 microg/kg of heroin elicited robust place conditioning and locomotor sensitization in B6 controls and in N(10) congenic B6-129 hybrid mice. In comparison, the identical treatment produced no locomotor sensitization and induced place aversion in 129 controls. No heroin-induced changes in the behaviour of N(3) congenic B6-129 hybrid mice or F5-8 non-congenic B6-129 hybrid mice were observed. The expression of place conditioning was not facilitated in any group by the administration of a heroin-priming injection prior to testing. These data indicate that genetic variation exists in mice for the rewarding and locomotor-sensitizing effects of heroin and that the capacity of heroin to induce conditioned reward and locomotor sensitization can be modulated in a B6 strain dose-dependent manner in B6-129 hybrid mice. Thus, strain differences in heroin responsiveness should be considered when examining transgenic lines on B6-129 backgrounds for opiate-induced changes in behaviour that may be relevant for addiction.
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Affiliation(s)
- K K Szumlinski
- Department of Physiology and Neuroscience, and Department of Psychiatry and Behavioral Sciences, Center for Drug and Alcohol Programs, Medical University of South Carolina, Charleston, SC, USA.
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Szumlinski KK, Kalivas PW. Novel ideas about novelty. Commentary on Badiani and Robinson drug-induced neurobehavioral plasticity: the role of environmental context. Behav Pharmacol 2004; 15:373-6. [PMID: 15343062 DOI: 10.1097/00008877-200409000-00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Glick SD, Maisonneuve IM, Szumlinski KK. Mechanisms of action of ibogaine: relevance to putative therapeutic effects and development of a safer iboga alkaloid congener. Alkaloids Chem Biol 2002; 56:39-53. [PMID: 11705115 DOI: 10.1016/s0099-9598(01)56006-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- S D Glick
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
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Trantham H, Szumlinski KK, McFarland K, Kalivas PW, Lavin A. Repeated cocaine administration alters the electrophysiological properties of prefrontal cortical neurons. Neuroscience 2002; 113:749-53. [PMID: 12182882 PMCID: PMC5509069 DOI: 10.1016/s0306-4522(02)00246-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently it has become clear that some of the symptoms of addiction such as relapse to drug-taking behavior arise, in part, from a dysfunction in cognitive and emotional processing. This realization has promoted investigations into the physiology and pathophysiology of forebrain circuits that are both innervated by dopamine and play an important role in cognitive processing, including the prefrontal cortex. In order to study long-term neuroadaptations occurring in the prefrontal cortex of the rat as a consequence of psychostimulant administration, cocaine was repeatedly administered in either a contingent or a non-contingent manner. At least 2 weeks following the last cocaine injection, in vivo intracellular recordings were made from neurons located in the deep layers of the prefrontal cortex. Repeated cocaine administration abolished the presence of membrane bistability normally present in neurons located in the limbic prefrontal cortex. These results indicate that repeated exposure to cocaine produces enduring changes in the basal activity of neurons in the prefrontal cortex that may contribute to previously identify cognitive and emotional dysfunctions in cocaine addicts.
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Affiliation(s)
- H Trantham
- Department of Physiology and Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, 403 BSB Building, Charleston, SC 29425, USA
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Szumlinski KK, Haskew RE, Balogun MY, Maisonneuve IM, Glick SD. Iboga compounds reverse the behavioural disinhibiting and corticosterone effects of acute methamphetamine: Implications for their antiaddictive properties. Pharmacol Biochem Behav 2001; 69:485-91. [PMID: 11509208 DOI: 10.1016/s0091-3057(01)00564-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study investigated the effects of pretreatment with the putative antiaddictive compound, ibogaine (IBO), and its synthetic derivative, 18-methoxycoronaridine (18-MC), on the changes in behaviour in an elevated plus maze and the changes in corticosterone (CORT) produced by a low dose of methamphetamine (METH). In the elevated plus maze, the acute administration of METH (0.1 mg/kg ip, -20 min) produced an increase in both the number and the duration of open arm entries relative to saline (SAL)-treated controls. No effect of METH administration was observed on the total number of arm entries. These data indicated that METH alone produced either anxiolysis or behavioural disinhibition in this paradigm. More consistent with the latter possibility, the open arm behaviour of METH controls was associated with an increase in plasma levels of CORT, supporting a facilitatory role for CORT in this METH-induced effect. Pretreatment with both IBO and 18-MC (40 mg/kg ip, 19 h earlier) antagonized the behavioural disinhibiting effects of acute METH without altering locomotor activity. In addition, both iboga agents antagonized the increase in CORT produced by METH. These data provide insight into yet another potential mechanism through which iboga compounds may exert their antiaddictive effects, a reversal of the behavioural disinhibiting properties of stimulant drugs. Furthermore, these data indicate that this reversal is related to effects of iboga compounds on the stimulation of neuroendocrine systems by stimulant drugs.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA.
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Abstract
Currently, no effective therapy has been approved for the treatment of addiction to stimulant drugs (e.g., cocaine, amphetamine and its methylated derivatives). However, preclinical studies indicate that the naturally-occurring indole alkaloid, ibogaine, and a synthetic iboga alkaloid congener, 18-methoxycoronaridine (18-MC), attenuate stimulant self-administration in laboratory animals. The in vivo pharmacological interactions between iboga agents and stimulant drugs are unclear. Ibogaine enhances the increase in accumbal dopamine produced by the acute administration of stimulant drugs. Consistent with these data, both ibogaine and 18-MC potentiate the expression of stimulant-induced motor behaviors in acute and chronic stimulant-treated animals. To account for the paradox between their effects on self-administration and motor behavior, we proposed that iboga agents interfere with stimulant self-administration by increasing sensitivity to their psychomotor-activating effects. However, this interpretation is contradicted by very recent observations that 18-MC is without effect on the dopamine response to acute cocaine and that both ibogaine and 18-MC block the expression of sensitized levels of dopamine in the nucleus accumbens produced by chronic cocaine administration. Thus, a positive relationship exists between the effects of iboga pretreatment on stimulant-induced dopamine sensitization and stimulant self-administration behavior. These data indicate that iboga agents might attenuate stimulant self-administration by reversing the neuroadaptations theoretically implicated in drug craving and compulsive drug-seeking behavior.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience, MC-136, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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Abstract
RATIONALE Behavioral sensitization, induced by the chronic administration of psychomotor stimulants, serves as an experimental model for the development of behavioral pathology. Although many factors are known to influence the sensitization produced by indirect dopamine agonists, such as cocaine and the amphetamines, less is known about factors that influence the behavioral sensitization produced by direct dopamine receptor agonists. OBJECTIVE As the extent to which behavioral sensitization is expressed following the repeated administration of indirect dopamine agonists can depend upon a period of drug abstinence, the present study determined the effects of drug abstinence on the expression of locomotor sensitization to the D2/D3 receptor agonist, quinpirole (QNP). METHODS Male and female rats were administered ten, twice weekly, injections of 0.5 mg/kg QNP or saline (SAL), and then received one of five QNP doses (0-1.0 mg/kg; n=7-10/dose) in two dose-response tests for locomotor sensitization, conducted at 3 and 15 days following the cessation of chronic treatment. RESULTS The sensitized locomotor response of QNP-treated animals was similar on the 2 test days in both male and female subjects. Compared to males, female rats displayed greater locomotor responding to QNP, both during chronic treatment and on the dose-response tests for sensitization. CONCLUSIONS QNP locomotor sensitization is (a) not influenced by 2 weeks of QNP abstinence and (b) can be influenced by the sex of the animal. It is suggested that direct and indirect dopamine agonists produce locomotor sensitization via distinct mechanisms that differ in sensitivity to the passage of time but are both influenced by sex-specific variables.
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Affiliation(s)
- K K Szumlinski
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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Glick SD, Maisonneuve IM, Szumlinski KK. 18-Methoxycoronaridine (18-MC) and ibogaine: comparison of antiaddictive efficacy, toxicity, and mechanisms of action. Ann N Y Acad Sci 2000; 914:369-86. [PMID: 11085336 DOI: 10.1111/j.1749-6632.2000.tb05211.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
18-MC, a novel iboga alkaloid congener, is being developed as a potential treatment for multiple forms of drug abuse. Like ibogaine (40 mg/kg), 18-MC (40 mg/kg) decreases the intravenous self-administration of morphine and cocaine and the oral self-administration of ethanol and nicotine in rats; unlike ibogaine, 18-MC does not affect responding for a nondrug reinforcer (water). Both ibogaine and 18-MC ameliorate opioid withdrawal signs. Both ibogaine and 18-MC decrease extracellular levels of dopamine in the nucleus accumbens, but only ibogaine increases extracellular levels of serotonin in the nucleus accumbens. Both ibogaine and 18-MC block morphine-induced and nicotine-induced dopamine release in the nucleus accumbens; only ibogaine enhances cocaine-induced increases in accumbal dopamine. Both ibogaine and 18-MC enhance the locomotor and/or stereotypic effects of stimulants. Ibogaine attenuates, but 18-MC potentiates, the acute locomotor effects of morphine; both compounds attenuate morphine-induced locomotion in morphine-experienced rats. Ibogaine produces whole body tremors and, at high doses (> or = 100 mg/kg), cerebellar damage; 18-MC does not produce these effects. Ibogaine, but not 18-MC, decreases heart rate at high doses. While 18-MC and ibogaine have similar affinities for kappa opioid and possibly nicotinic receptors, 18-MC has much lower affinities than ibogaine for NMDA and sigma-2 receptors, sodium channels, and the 5-HT transporter. Both 18-MC and ibogaine are sequestered in fat and, like ibogaine, 18-MC probably has an active metabolite. The data suggest that 18-MC has a narrower spectrum of actions and will have a substantially greater therapeutic index than ibogaine.
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Affiliation(s)
- S D Glick
- Department of Pharmacology and Neuroscience, Albany Medical College, New York 12208, USA.
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Szumlinski KK, Herrick-Davis K, Teitler M, Maisonneuve IM, Glick SD. Behavioural sensitization to cocaine is dissociated from changes in striatal NMDA receptor levels. Neuroreport 2000; 11:2785-8. [PMID: 10976963 DOI: 10.1097/00001756-200008210-00035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Changes in glutamate transmission and alterations in glutamate receptor expression produced by the repeated administration of psychomotor stimulant drugs are considered an important neuroadaptation underlying the development and expression of behavioural and neurochemical sensitization to stimulant drugs. Two parallel experiments investigated the effects of repeated cocaine administration (five, once daily injections of 15 mg/kg, i.p.; 2 weeks withdrawal) on the expression of behavioural sensitization in response to a cocaine challenge (20 mg/kg, i.p.) and the changes in NMDA receptor binding in pooled tissue from the nucleus accumbens and the striatum. Compared with acute cocaine controls (n = 11), animals administered cocaine repeatedly displayed a sensitized stereotypic response to the cocaine challenge injection (n = 8). Despite this, no differences in either NMDA receptor density or affinity were observed between rats administered repeatedly with cocaine or saline, as indexed by [3H]MK-801 binding. The present findings call to question the rationale for NMDA receptor-based pharmacotherapies for the treatment of the enduring symptomatology of stimulant addiction.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience, Albany Medical College, NY 12208, USA
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Szumlinski KK, Maisonneuve IM, Glick SD. 18-Methoxycoronaridine differentially alters the sensitized behavioral and dopaminergic responses to repeated cocaine and morphine administration. Implications for sensitization in the mediation of drug addiction. Ann N Y Acad Sci 2000; 909:275-9. [PMID: 10911941 DOI: 10.1111/j.1749-6632.2000.tb06694.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K K Szumlinski
- Department of Pharmacology and Neuroscience, Albany Medical College, New York 12208, USA.
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Szumlinski KK, Balogun MY, Maisonneuve IM, Glick SD. Interactions between iboga agents and methamphetamine sensitization: studies of locomotion and stereotypy in rats. Psychopharmacology (Berl) 2000; 151:234-41. [PMID: 10972470 DOI: 10.1007/s002130000478] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
RATIONALE The phenomenon of sensitization has been theoretically implicated in mediating various aspects of drug addiction. Recent dose-response studies demonstrated that pretreatment with the putative antiaddictive agent, ibogaine (IBO), and a synthetic iboga alkaloid congener, 18-methoxycoronaridine (18-MC), increase the potency of cocaine to elicit behavioral sensitization, an effect proposed to contribute, in part, to their ability to attenuate drug self-administration. OBJECTIVES As abuse of the methylated amphetamine derivative, methamphetamine (METH), is a growing public health concern, the present study determined the interactions between IBO and 18-MC and the expression of METH-induced behavioral sensitization. METHODS The effects of pretreatment with 18-MC (40 mg/kg, IP, 19 h earlier) on the expression of METH-induced locomotion (0, 0.25, 0.5, 1 and 2 mg/kg, IP) and the effects of pretreatment with either IBO or 18-MC on the expression of METH-induced stereotypy (2 and 4 mg/kg, IP) were assessed in rats treated chronically with either METH (4 mg/kg daily for 7 days) or saline. RESULTS Compared to vehicle-pretreated controls, 18-MC produced an overall enhancement in METH-induced locomotion in rats treated chronically, but not acutely, with METH. In addition, both iboga agents increased the stereotypic response to METH. CONCLUSIONS Iboga agents augment both the locomotor and stereotypic effects of METH in a manner consistent with previous reports for cocaine. Thus, it appears that iboga agents interact in a similar manner with the neural mechanisms mediating motor hyperactivity induced by the chronic administration of stimulant drugs.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience, Albany Medical College, NY 12208, USA.
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Szumlinski KK, McCafferty CA, Maisonneuve IM, Glick SD. Interactions between 18-methoxycoronaridine (18-MC) and cocaine: dissociation of behavioural and neurochemical sensitization. Brain Res 2000; 871:245-58. [PMID: 10899291 DOI: 10.1016/s0006-8993(00)02424-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The phenomenon of sensitization has been implicated in various aspects of drug addiction. As such, the present study determined the effects of a potential anti-addictive agent, 18-methoxycoronaridine (18-MC; 40 mg/kg, IP, 19 h earlier), on the expression of sensitization following the repeated administration of cocaine (COC; five once daily injections of 15 mg/kg, IP) or saline. The effects of 18-MC on COC metabolism were also assessed. Compared to vehicle controls, 18-MC significantly enhanced the expression of COC-induced locomotion (0, 10, 20 and 40 mg/kg, IP) in chronic COC treated rats only. In both acute and chronic COC rats, 18-MC potentiated the stereotypy induced by higher COC doses (20 and 40 mg/kg, IP). In contrast, 18-MC abolished the sensitized dopamine (DA) response in the nucleus accumbens (NAC) to COC (20 mg/kg), without altering the DA response of acute COC rats. None of the interactions between 18-MC and COC appear to be related to alterations in COC metabolism as no effect of 18-MC pretreatment was observed on extracellular levels of COC or two of its metabolites, benzoylecogonine and norcocaine. From the present findings, it is concluded that the enhancement of COC-induced behaviour produced by 18-MC pretreatment is independent of effects on either COC pharmacokinetics or COC-induced alterations in DA transmission. However, given that 18-MC decreases the self-administration of COC in laboratory animals, it is proposed that the anti-addictive efficacy of 18-MC might be related to an ability to selectively block the expression of sensitized extracellular levels of DA in the NAC in rats with previous COC experience.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience (MC-136), Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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Abstract
To investigate a possible basis for the proposed anti-addictive property of ibogaine, the effects of ibogaine (40 mg/kg, i.p., 19 h earlier) on the expression of sensitization induced by cocaine were investigated. Ibogaine pretreatment potentiated the increase in the stereotypic effects of a cocaine challenge (20 mg/kg) in both sensitized (5 x 15 mg/kg, i.p.) and acutely treated rats. However, while ibogaine pretreatment did not significantly alter the dopamine response in the nucleus accumbens to acute cocaine, it abolished the expression of cocaine-induced dopamine sensitization. This result demonstrates that ibogaine pretreatment can reverse one of the neuroadaptations produced by chronic cocaine administration, an effect that may contribute to its putative anti-addictive property.
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Affiliation(s)
- K K Szumlinski
- Center for Neuropharmacology and Neuroscience, MC-136, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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Szumlinski KK, Maisonneuve IM, Glick SD. The potential anti-addictive agent, 18-methoxycoronaridine, blocks the sensitized locomotor and dopamine responses produced by repeated morphine treatment. Brain Res 2000; 864:13-23. [PMID: 10793182 DOI: 10.1016/s0006-8993(00)02069-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
18-Methoxycoronaridine (18-MC), a novel synthetic iboga congener, attenuates the reinforcing efficacy of morphine, disrupts some signs of morphine withdrawal in physically dependent rats and attenuates the dopamine response in the nucleus accumbens to acute morphine. The present study further investigated the interactions between 18-MC and morphine by examining the effects of 18-MC (40 mg/kg, i.p., 19 h earlier) on the expression of dopamine sensitization in the nucleus accumbens in response to morphine (20 mg/kg, i.p.) and on the dose-effect curves for morphine-induced locomotion (0-30 mg/kg, i.p.) in rats treated either acutely or repeatedly (five, once daily, injections of 20 mg/kg, i.p.) with morphine. Compared to vehicle pretreated controls, 18-MC increased the potency of morphine, shifting the dose-response curve to the left, in acute morphine treated rats; however, 18-MC did not alter the potency of morphine in rats treated repeatedly with morphine. Repeated morphine administration induced locomotor sensitization in approximately 50% of the rats tested; in vehicle pretreated rats, the morphine dose-response curve was shifted to the left in sensitized as compared to non-sensitized rats. In 18-MC pretreated rats, sensitized and non-sensitized rats responded similarly to morphine, revealing a blockade of sensitization by 18-MC. Consistent with this behavioural finding, 18-MC pretreatment completely abolished the sensitized dopamine response in the nucleus accumbens expressed by rats repeatedly treated with morphine. It is suggested that the potential anti-addictive efficacy of 18-MC might be related to an ability to restore normal functioning to a hypersensitive mesolimbic dopamine system produced by previous repeated morphine administration.
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Affiliation(s)
- K K Szumlinski
- Department of Pharmacology and Neuroscience (MC-136), Albany Medical College, 47 New Scotland Avenue, Albany, NY, USA.
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Abstract
Pretreatment (19 h) with the putative antiaddictive agent, ibogaine, has been shown previously to potentiate cocaine-induced locomotion in rats. The present study demonstrates that the magnitude of this effect of ibogaine is dependent on the previous cocaine history of the animal, on the time following ibogaine treatment, and on the number of ibogaine treatments. Compared to rats with no previous cocaine experience, ibogaine pretreatment (40 mg/kg, IP, 19 h earlier) markedly enhanced the expression of locomotor sensitization in response to a cocaine challenge injection (7.5 mg/kg) in rats that were chronically treated with cocaine (15 mg/ kg, IP, daily for 5 days). Tolerance to cocaine-induced locomotor sensitization appeared to occur in vehicle-pretreated chronic cocaine controls. Following a second series of identical treatments (beginning 3-4 days after the initial treatment series), locomotor responding to the cocaine challenge was further enhanced by a second ibogaine injection in chronically cocaine-treated animals. Twenty-four hours later, when animals were challenged again with cocaine in the absence of any further ibogaine pretreatment, the effect of ibogaine had dissipated. Consistent with previous studies from this laboratory, these data demonstrate that ibogaine can enhance sensitivity to the psychomotor stimulant effect of cocaine. The results of the present study further indicate that the extent of this effect depends on the animal's history of exposure to both ibogaine and cocaine.
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Affiliation(s)
- K K Szumlinski
- Department of Pharmacology and Neuroscience, Albany Medical College, NY 12208, USA
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Szumlinski KK, Maisonneuve IM, Glick SD. Pretreatment with the putative anti-addictive drug, ibogaine, increases the potency of cocaine to elicit locomotor responding: a study with acute and chronic cocaine-treated rats. Psychopharmacology (Berl) 1999; 145:227-33. [PMID: 10463325 DOI: 10.1007/s002130051053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RATIONALE Results of single-dose studies suggest that the effects of pretreatment with the putative anti-addictive compound, ibogaine, on drug-induced locomotor behavior depends on the previous drug history of the animal. OBJECTIVES To compare the effects of ibogaine pretreatment on the dose-locomotor response function for cocaine in rats treated chronically with either saline or cocaine. METHODS Rats were chronically treated with either cocaine (15 mg/kg, IP, once daily for 5 days, followed by 2 week withdrawal) or saline. Ibogaine (40 mg/kg, IP) or vehicle was administered and 19 h later, a cocaine dose-locomotor response test was conducted (0, 5, 10, 20 and 40 mg/kg, IP). RESULTS Chronic cocaine administration augmented the locomotor response to cocaine in chronic cocaine-treated rats, compared to acutely treated controls. Ibogaine pretreatment enhanced the locomotor effects of cocaine in both chronic and acute cocaine groups. Furthermore, due to the shape of the dose-response curve, in chronic cocaine but not in acute cocaine rats, ibogaine pretreatment enhanced the locomotor response to 5 and 10 mg/kg cocaine while decreasing the locomotor response to 40 mg/kg cocaine. CONCLUSIONS These data demonstrate definitively that ibogaine can enhance sensitivity to the locomotor stimulant effects of cocaine, an effect which depends, in part, on the previous cocaine history of the animal.
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Affiliation(s)
- K K Szumlinski
- Department of Pharmacology and Neuroscience, Albany Medical College, NY 12208, USA.
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Abstract
The neural basis of ibogaine's effects on drug-related behaviours is unclear. One possibility is that ibogaine interferes with the shared capacity of many addictive agents to stimulate brain dopamine activity, but reports of ibogaine effects on dopamine activity have been inconsistent. Our study suggests such inconsistencies may result from variations in prior drug exposure. If ibogaine blocks dopamine activity, then it should, like dopamine blockers, decrease preference for natural rewards such as sweet solutions. However, 40 mg/kg ibogaine i.p. did not decrease preference for a glucose + saccharin solution when it was administered to male Long Evans rats 24 h prior to test in Experiment 1. Nor did ibogaine attenuate conditioned preference for a neutral flavour previously paired with sweet taste in Experiment 2. In Experiment 3, effects of 40 mg/kg ibogaine on amphetamine-induced locomotion were investigated in drug-naive and drug-experienced (four prior doses of 1.5 mg/kg amphetamine) rats. Locomotion was significantly lower in those ibogaine-treated rats that had previously been exposed to amphetamine than in those that had not. Thus, ibogaine may serve to decrease induced levels of dopamine activity in drug-experienced animals or humans from elevated, sensitized levels back to baseline levels. This could lead to a reduction of sensitized levels of drug craving in addiction.
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Affiliation(s)
- J R Blackburn
- Department of Psychology, McMaster University, Hamilton, Ontario, Canada.
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Szumlinski KK, Allan M, Talangbayan H, Tracey A, Szechtman H. Locomotor sensitization to quinpirole: environment-modulated increase in efficacy and context-dependent increase in potency. Psychopharmacology (Berl) 1997; 134:193-200. [PMID: 9399384 DOI: 10.1007/s002130050442] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study examines whether behavioural sensitization to the dopamine agonist, quinpirole, reflects an increase in the drug's potency and/or efficacy to induce locomotion, and how these parameters are influenced by environmental context. Three experiments were conducted in which animals received either chronic quinpirole (10 x 0.5 mg/kg, twice weekly) or saline injections in either the home cage environment, an alternate environment or the testing environment (activity monitors), followed by a dose-response test for the expression of sensitization in the activity monitors. Compared to the acute dose-response relationship, chronic quinpirole increased the maximum response. This increase in efficacy was significantly higher in animals treated with quinpirole in a non-home cage environment compared to those that received chronic treatment in the home cage. A leftward shift in the dose-effect function was observed only in animals with prior drug experience in the testing environment. Results indicate that locomotor sensitization to quinpirole reflects an environment-modulated increase in the drug's efficacy, and an environment-dependent increase in drug potency. Efficacy and potency may be subject to sensitization by non-associational and associational mechanisms, respectively.
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Affiliation(s)
- K K Szumlinski
- Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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