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Rysztak LG, Jutkiewicz EM. The role of enkephalinergic systems in substance use disorders. Front Syst Neurosci 2022; 16:932546. [PMID: 35993087 PMCID: PMC9391026 DOI: 10.3389/fnsys.2022.932546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/29/2022] [Indexed: 12/13/2022] Open
Abstract
Enkephalin, an endogenous opioid peptide, is highly expressed in the reward pathway and may modulate neurotransmission to regulate reward-related behaviors, such as drug-taking and drug-seeking behaviors. Drugs of abuse also directly increase enkephalin in this pathway, yet it is unknown whether or not changes in the enkephalinergic system after drug administration mediate any specific behaviors. The use of animal models of substance use disorders (SUDs) concurrently with pharmacological, genetic, and molecular tools has allowed researchers to directly investigate the role of enkephalin in promoting these behaviors. In this review, we explore neurochemical mechanisms by which enkephalin levels and enkephalin-mediated signaling are altered by drug administration and interrogate the contribution of enkephalin systems to SUDs. Studies manipulating the receptors that enkephalin targets (e.g., mu and delta opioid receptors mainly) implicate the endogenous opioid peptide in drug-induced neuroadaptations and reward-related behaviors; however, further studies will need to confirm the role of enkephalin directly. Overall, these findings suggest that the enkephalinergic system is involved in multiple aspects of SUDs, such as the primary reinforcing properties of drugs, conditioned reinforcing effects, and sensitization. The idea of dopaminergic-opioidergic interactions in these behaviors remains relatively novel and warrants further research. Continuing work to elucidate the role of enkephalin in mediating neurotransmission in reward circuitry driving behaviors related to SUDs remains crucial.
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Affiliation(s)
- Lauren G. Rysztak
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Emily M. Jutkiewicz
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Emily M. Jutkiewicz,
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2
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Panenka WJ, Procyshyn RM, Lecomte T, MacEwan GW, Flynn SW, Honer WG, Barr AM. Methamphetamine use: a comprehensive review of molecular, preclinical and clinical findings. Drug Alcohol Depend 2013; 129:167-79. [PMID: 23273775 DOI: 10.1016/j.drugalcdep.2012.11.016] [Citation(s) in RCA: 295] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 12/11/2022]
Abstract
Methamphetamine (MA) is a highly addictive psychostimulant drug that principally affects the monoamine neurotransmitter systems of the brain and results in feelings of alertness, increased energy and euphoria. The drug is particularly popular with young adults, due to its wide availability, relatively low cost, and long duration of psychoactive effects. Extended use of MA is associated with many health problems that are not limited to the central nervous system, and contribute to increased morbidity and mortality in drug users. Numerous studies, using complementary techniques, have provided evidence that chronic MA use is associated with substantial neurotoxicity and cognitive impairment. These pathological effects of the drug, combined with the addictive properties of MA, contribute to a spectrum of psychosocial issues that include medical and legal problems, at-risk behaviors and high societal costs, such as public health consequences, loss of family support and housing instability. Treatment options include pharmacological, psychological or combination therapies. The present review summarizes the key findings in the literature spanning from molecular through to clinical effects.
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Affiliation(s)
- William J Panenka
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
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3
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Zhang Y, Schlussman SD, Butelman ER, Ho A, Kreek MJ. Effects of withdrawal from chronic escalating-dose binge cocaine on conditioned place preference to cocaine and striatal preproenkephalin mRNA in C57BL/6J mice. Neuropharmacology 2012; 63:322-9. [PMID: 22504589 DOI: 10.1016/j.neuropharm.2012.03.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/13/2012] [Accepted: 03/25/2012] [Indexed: 10/28/2022]
Abstract
UNLABELLED Relapse is a serious problem for the effective treatment of cocaine addiction. RATIONALE Examining cocaine re-exposure-induced behavioral and neurobiological alterations following chronic escalating-dose binge cocaine administration and withdrawal may provide insight into the neurobiological basis of cocaine relapse. OBJECTIVES Our goal was to determine how exposure to chronic escalating-dose cocaine affects development of subsequent cocaine-induced conditioned place preference (CPP) and changes in endogenous opioid systems. METHODS Mice were injected with either escalating-dose binge cocaine (15-30 mg/kg/injection × 3/day) or saline for 14-days and conditioned with 15 mg/kg of cocaine or saline (once per day for 10-days), starting either 1 or 14-days after the last day of binge injections. RESULTS Mice exposed to chronic escalating cocaine did not develop CPP to cocaine when conditioning commenced on the first day of withdrawal (CPP test on day 10 of withdrawal). By contrast, mice did develop CPP to cocaine when conditioning started on the 14th day of withdrawal (CPP test on day 24 of withdrawal). Furthermore, preproenkephalin (Penk) mRNA levels in caudate putamen were significantly higher in mice that received 14-day withdrawal from escalating-dose binge cocaine before the CPP procedure (tested 24 days post-binge) than those that received 1-day withdrawal (tested 10 days post-binge). CONCLUSIONS The rewarding effect of cocaine was blunted in early withdrawal from chronic escalating exposure, but recovered in more prolonged withdrawal. Time-dependent elevations in Penk mRNA levels may be part of the underlying mechanisms of this effect.
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Affiliation(s)
- Yong Zhang
- The Laboratory of the Biology of Addictive Diseases, The Rockefeller University, 1230 York Avenue, Box 171, New York, NY 10065, USA.
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Trigo JM, Martin-García E, Berrendero F, Robledo P, Maldonado R. The endogenous opioid system: a common substrate in drug addiction. Drug Alcohol Depend 2010; 108:183-94. [PMID: 19945803 DOI: 10.1016/j.drugalcdep.2009.10.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/30/2009] [Accepted: 10/28/2009] [Indexed: 12/17/2022]
Abstract
Drug addiction is a chronic brain disorder leading to complex adaptive changes within the brain reward circuits that involve several neurotransmitters. One of the neurochemical systems that plays a pivotal role in different aspects of addiction is the endogenous opioid system (EOS). Opioid receptors and endogenous opioid peptides are largely distributed in the mesolimbic system and modulate dopaminergic activity within these reward circuits. Chronic exposure to the different prototypical drugs of abuse, including opioids, alcohol, nicotine, psychostimulants and cannabinoids has been reported to produce significant alterations within the EOS, which seem to play an important role in the development of the addictive process. In this review, we will describe the adaptive changes produced by different drugs of abuse on the EOS, and the current knowledge about the contribution of each component of this neurobiological system to their addictive properties.
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Affiliation(s)
- José Manuel Trigo
- Laboratori de Neurofarmacologia, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, PRBB, Barcelona, Spain
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Soderman AR, Unterwald EM. Cocaine-induced mu opioid receptor occupancy within the striatum is mediated by dopamine D2 receptors. Brain Res 2009; 1296:63-71. [PMID: 19699185 DOI: 10.1016/j.brainres.2009.08.035] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 08/07/2009] [Accepted: 08/07/2009] [Indexed: 11/29/2022]
Abstract
Previous studies by our laboratory have demonstrated that the mu opioid receptor antagonist, CTAP, blocks the rewarding effects of cocaine when it is injected directly into the nucleus accumbens or ventral tegmental area (VTA). This finding suggests that cocaine is causing the release of endogenous opioid peptides which activate mu opioid receptors within the nucleus accumbens and VTA. The purpose of the present study was to characterize the dose-response and time-course of mu receptor occupancy following systemic cocaine administration and to determine if release of endogenous opioids by cocaine is mediated by activation of D1 or D2 dopamine receptors. Quantitative in vitro receptor autoradiography was used to measure the regional displacement of (3)H-DAMGO binding following cocaine administration. Adult male Sprague-Dawley rats were given intraperitoneal (i.p.) injections of cocaine and their brains were removed at various times and prepared for mu opioid receptor quantitation. To determine the role of dopamine D1 and D2 receptors in the effect of cocaine on mu receptor occupancy, rats were injected with the selective D1 or D2 receptor antagonists SCH23390 or eticlopride prior to cocaine. For all studies, (3)H-DAMGO binding to mu opioid receptors was measured in the nucleus accumbens, caudate putamen, frontal cortex, olfactory tubercle and VTA. Results demonstrate that cocaine administration caused a time- and dose-dependent reduction in (3)H-DAMGO binding within the nucleus accumbens core and shell. The reduction in mu receptor binding was attenuated by pretreatment with eticlopride. These results suggest that cocaine, acting via D2 dopamine receptors, can cause the release of an endogenous opioid peptide that binds to mu opioid receptors within the nucleus accumbens.
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Affiliation(s)
- Avery R Soderman
- Department of Pharmacology, Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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6
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Isola R, Zhang H, Tejwani GA, Neff NH, Hadjiconstantinou M. Acute nicotine changes dynorphin and prodynorphin mRNA in the striatum. Psychopharmacology (Berl) 2009; 201:507-16. [PMID: 18807250 DOI: 10.1007/s00213-008-1315-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 08/21/2008] [Indexed: 11/30/2022]
Abstract
RATIONALE Nicotine displays rewarding and aversive effects, and while dopamine has been linked with nicotine's reward, the neurotransmitter(s) involved with aversion remains speculative. The kappa-dynorphinergic system has been associated with negative motivational and affective states, and whether dynorphin (Dyn) contributes to the behavioral pharmacology of nicotine is a pertinent question. OBJECTIVE We determined whether administration of a single dose of nicotine alters the biosynthesis of Dyn in the striatum of mice. RESULTS Nicotine free base, 1 mg/kg, sc, induced a biphasic, protracted increase of striatal Dyn, an initial rise by 1 h, which declined to control levels by 2 h, and a subsequent increase, between 6 and 12 h, lasting over 24 h. At 1 h, the nicotine effect was dose dependent, with doses>or=0.5 mg/kg inducing a response. Prodynorphin mRNA increased by 30 min for over 24 h, and in situ hybridization demonstrated elevated signal in caudate/putamen and nucleus accumbens. The nicotinic antagonist mecamylamine prevented the Dyn response, and a similar effect was observed with D1- and D2-like dopamine receptor antagonists, SCH 23390, sulpiride, and haloperidol. The glutamate NMDA receptor antagonist MK-801 reversed the nicotine-induced increase of Dyn, while the AMPA antagonist NBQX had a marginal effect. CONCLUSIONS We interpret our findings to indicate that acute nicotine enhances the synthesis and release of striatal Dyn. We propose that nicotine influences Dyn primarily through dopamine release and that glutamate plays a modulatory role. A heightened dynorphinergic tone may contribute to the aversive effects of nicotine in naive animals and first-time tobacco smokers.
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Affiliation(s)
- Raffaella Isola
- Department of Psychiatry, College of Medicine, Ohio State University, Columbus, OH 43210, USA
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Puig-Ramos A, Santiago GS, Segarra AC. U-69593, a kappa opioid receptor agonist, decreases cocaine-induced behavioral sensitization in female rats. Behav Neurosci 2008; 122:151-60. [PMID: 18298258 DOI: 10.1037/0735-7044.122.1.151] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study was designed to investigate if the kappa opioid system regulates the locomotor response to cocaine in the female rat and to determine if the effect is dependent on estradiol treatment. Adult rats were ovariectomized (OVX) and half received an estradiol (OVX-EB) implant. After a week, rats were injected for 5 consecutive days with vehicle or with the kappa opioid receptor (KOPr) agonist U-69593 (0.16, 0.32, and 0.64 mg/kg) 15 min prior to cocaine injection (15 mg/kg). Following a 7-day drug-free period, rats were challenged with cocaine (Day 13). The locomotor response to cocaine was measured on Days 1, 5, and 13. U-69593 (0.32 mg/kg) decreased cocaine-induced locomotor activity in drug-naïve OVX rats and in those that received the OVX-EB implant. These results indicate that the acute effects of U-69593 are independent of estradiol treatment. Repeated exposure to U-69593 (0.32 mg/kg) prior to cocaine decreased the development of behavioral sensitization in OVX-EB-implanted rats. This decrease in cocaine-induced hyperlocomotion persisted after 1 week of cocaine withdrawal. These data indicate that the KOPr system participates in estradiol modulation of cocaine-induced behavioral sensitization in the female rat.
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Affiliation(s)
- Anabel Puig-Ramos
- Department of Physiology, University of Puerto Rico, School of Medicine, San Juan, Puerto Rico
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Bourque M, Liu B, Dluzen DE, Di Paolo T. Tamoxifen protects male mice nigrostriatal dopamine against methamphetamine-induced toxicity. Biochem Pharmacol 2007; 74:1413-23. [PMID: 17825264 DOI: 10.1016/j.bcp.2007.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 07/06/2007] [Accepted: 07/09/2007] [Indexed: 12/01/2022]
Abstract
The selective estrogen receptor modulator tamoxifen and estradiol were shown to protect nigrostriatal dopamine concentration loss by methamphetamine in female mice whereas male mice were protected only by tamoxifen. The present study examined the protective properties of tamoxifen in male mice on several nigrostriatal dopaminergic markers and body temperature. Intact male mice were administered 12.5 or 50 microg tamoxifen 24 h before methamphetamine treatment. Basal body temperatures of male mice remained unchanged by the tamoxifen treatment. Methamphetamine reduced striatal dopamine and its metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid concentrations, striatal and substantia nigra dopamine and vesicular monoamine transporter specific binding as well substantia nigra dopamine and vesicular monoamine transporter mRNA levels and increased striatal preproenkephalin mRNA levels. These methamphetamine effects were not altered by 12.5 microg tamoxifen except for increased striatal dopamine metabolites and turnover. Tamoxifen at 50 microg reduced the methamphetamine effect on striatal dopamine concentration, dopamine transporter specific binding and prevented the increase in preproenkephalin mRNA levels; in the substantia nigra tamoxifen prevented the decrease of dopamine transporter mRNA levels. The present results show a tamoxifen dose-dependent prevention of loss of various dopaminergic markers against methamphetamine-induced toxicity in male mice. Since this is the only known hormonal protection of male mice against methamphetamine toxicity, these findings provide important new information on specific parameters of nigrostriatal dopaminergic function preserved by tamoxifen.
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Affiliation(s)
- Mélanie Bourque
- Molecular Endocrinology and Oncology Research Center, Laval University Medical Center, CHUL, Quebec City, Quebec G1V 4G2, Canada
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9
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Perreault ML, Graham D, Scattolon S, Wang Y, Szechtman H, Foster JA. Cotreatment with the kappa opioid agonist U69593 enhances locomotor sensitization to the D2/D3 dopamine agonist quinpirole and alters dopamine D2 receptor and prodynorphin mRNA expression in rats. Psychopharmacology (Berl) 2007; 194:485-96. [PMID: 17619861 DOI: 10.1007/s00213-007-0855-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 06/08/2007] [Indexed: 11/30/2022]
Abstract
RATIONALE The repeated coadministration of the kappa opioid receptor agonist U69593 with the D2/D3 dopamine (DA) agonist quinpirole (QNP) potentiates locomotor sensitization induced by QNP. Behavioral evidence has implicated both pre- and postsynaptic changes as being involved in this augmentation. OBJECTIVES The objectives of this study were to obtain supporting molecular evidence of pre- and/or postsynaptic alterations in the DA system with U69593/QNP cotreatment and to examine the relationship of such changes to locomotor sensitization. MATERIALS AND METHODS Gene expression of D1 and D2 receptors (D1R and D2R), the DA transporter, as well as the endogenous opioid prodynorphin (DYN), in the basal ganglia was examined by in situ hybridization in rats after one or ten drug injections. RESULTS After one injection, changes that were specific to U69593/QNP cotreatment were decreased D1R and D2R messenger RNA (mRNA) in the nucleus accumbens (Acb) shell and increased DYN mRNA in the dorsal striatum (STR). After ten injections, U69593/QNP-specific changes were decreased D2R mRNA in substantia nigra (SN) and increased DYN mRNA in STR and Acb core. Only in U69593/QNP rats was the sensitized locomotor performance on injection ten positively correlated with DYN mRNA levels in Acb and STR. CONCLUSIONS Distinct alterations of D2R and DYN mRNA levels in SN and Acb/STR, respectively, strengthen the evidence implicating pre- and postsynaptic changes in augmented locomotor sensitization to U69593/QNP cotreatment. It is suggested that repeated U69593/QNP cotreatment may augment locomotor sensitization to QNP by activating D1R-expressing DYN neurons and attenuating presynaptic D2R function.
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Affiliation(s)
- Melissa L Perreault
- Department of Psychiatry and Behavioural Neurosciences, Health Science Centre, Room 4N7, McMaster University, Hamilton, ON, Canada.
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10
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Jabourian M, Pérez S, Ezan P, Glowinski J, Deniau JM, Kemel ML. Impact of 6-hydroxydopamine lesions and cocaine exposure on mu-opioid receptor expression and regulation of cholinergic transmission in the limbic-prefrontal territory of the rat dorsal striatum. Eur J Neurosci 2007; 25:1546-56. [PMID: 17425581 DOI: 10.1111/j.1460-9568.2007.05375.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Information processing within the striatum is regulated by local circuits involving dopamine, cholinergic interneurons and neuropeptides released by recurrent collaterals of striatal output neurons. In the limbic-prefrontal territory of the dorsal striatum, enkephalin inhibits the NMDA-evoked release of acetylcholine directly through micro-opioid receptors (MORs) located on cholinergic interneurons and indirectly through MORs of output neurons of striosomes. In this territory, we investigated the consequence of changes in dopamine transmission, bilateral 6-hydroxydopamine-induced degeneration of striatal dopaminergic innervation or cocaine (acute and chronic) exposure on (i) MOR expression in both cholinergic interneurons and output neurons of striosomes, and (ii) the direct and indirect enkephalin-MOR regulations of the NMDA-evoked release of acetylcholine. Expression of MORs in cholinergic interneurons was preserved after 6-hydroxydopamine and down-regulated after cocaine treatments. Accordingly, the direct enkephalin-MOR control of acetylcholine release was preserved after 6-hydroxydopamine treatment and lost after cocaine exposure. Expression of MORs in output neurons of striosomes was down-regulated in the 6-hydroxydopamine situation and either preserved or up-regulated after acute or chronic cocaine exposure, respectively. Accordingly, the indirect enkephalin-MOR control of acetylcholine release disappeared in the 6-hydroxydopamine situation but surprisingly, despite preservation of MORs in striosomes, disappeared after cocaine treatment. Showing that MORs of striosomes are still functional in this situation, the MOR agonist [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin inhibited the NMDA-evoked release of acetylcholine after cocaine exposure. Therefore, alteration in the regulation of cholinergic transmission by the enkephalin-MOR system might play a major role in the motivational and cognitive disorders associated with dopamine dysfunctions in fronto-cortico-basal ganglia circuits.
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Affiliation(s)
- Maritza Jabourian
- INSERM U667, Collège de France, 11 place Marcelin Berthelot, F-75231 Paris Cedex 05, France
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D'Addario C, Di Benedetto M, Izenwasser S, Candeletti S, Romualdi P. Role of serotonin in the regulation of the dynorphinergic system by a kappa-opioid agonist and cocaine treatment in rat CNS. Neuroscience 2006; 144:157-64. [PMID: 17055175 DOI: 10.1016/j.neuroscience.2006.09.008] [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] [Received: 07/08/2006] [Revised: 09/05/2006] [Accepted: 09/10/2006] [Indexed: 10/24/2022]
Abstract
It has been shown that chronic cocaine increases prodynorphin mRNA in the caudate putamen and decreases it in the hypothalamus. In addition, treatment with a kappa-opioid receptor agonist produced the opposite effect on prodynorphin gene expression in these brain regions and also evoked a decrease in the hippocampus. It is already known that kappa-opioid receptor agonists decrease the development of sensitization to some of the behavioral effects of cocaine. The serotonin system has also been shown to regulate dynorphin gene expression and a continuous infusion of fluoxetine induced prodynorphin gene expression in the same pattern as the kappa-opioid agonist (+)(5a,7a,8b)-N-methyl-N-[7-(1-pyrrolidinyl)-1 oxaspiro[4.5]dec-8-yl]-benzeneacetamide (U-69593) in the brain regions investigated. It is interesting to note that treatment with a continuous infusion of cocaine produced different effects on this parameter. To determine whether serotonin plays a role in the regulation of prodynorphin mRNA by kappa-opioid agonists or cocaine, rats were treated with the serotonin depleter parachloroamphetamine (PCA). Beginning 24 h later, rats were treated with the selective kappa-opioid agonist U-69593 for 5 days or continuously with cocaine for 7 days and prodynorphin mRNA was measured. Prodynorphin mRNA was decreased significantly in the hypothalamus, caudate putamen, and hippocampus of rats treated with a single injection of PCA. Subsequent to PCA administration the effects of U-69593 or cocaine on prodynorphin mRNA were differentially affected across brain regions. Prodynorphin gene expression was still increased by U-69593 treatment in the hypothalamus and decreased in the caudate putamen. Cocaine treatment still produced a decrease in this parameter in the hypothalamus and an increase in the caudate putamen. In contrast, in the hippocampus, the decrease in prodynorphin mRNA produced by U-69593 was no longer evident after PCA and cocaine, which previously had no effect, now increased it in the serotonin-depleted group. These findings suggest that serotonin is necessary to maintain normal levels of dynorphin mRNA in all of the investigated brain areas and that the regulation of prodynorphin mRNA expression by chronic treatment with a kappa-opioid receptor agonist or cocaine requires serotonin in the hippocampus, but not in the hypothalamus or caudate putamen.
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Affiliation(s)
- C D'Addario
- Department of Pharmacology, University of Bologna, Irnerio 48, Bologna, 40126 Italy
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12
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Izawa R, Jaber M, Deroche-Gamonet V, Sillaber I, Kellendonk C, Le Moal M, Tronche F, Piazza PV. Gene expression regulation following behavioral sensitization to cocaine in transgenic mice lacking the glucocorticoid receptor in the brain. Neuroscience 2006; 137:915-24. [PMID: 16326019 DOI: 10.1016/j.neuroscience.2005.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Revised: 09/20/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
Several findings suggest that glucocorticoid hormones influence the propensity of an individual to develop cocaine abuse. These hormones activate two related transcription factors, the glucocorticoid receptor and the mineralocorticoid receptor. We have shown previously that mice carrying a mutation of the glucocorticoid receptor gene specifically in neural cells, glucocorticoid receptor knock-out in the brain, show a dramatic decrease in cocaine-induced self-administration and no behavioral sensitization to this drug, two experimental procedures considered relevant models of addiction. Here, we investigated in glucocorticoid receptor knock-out in the brain mice the consequences of this mutation at the level of the expression of neuropeptide, dopamine receptor and glutamate receptor subunit mRNAs. We quantified mRNA levels in the cortex, striatum and accumbens under basal conditions and following acute or repeated cocaine treatments. Our results show that, under basal conditions, neuropeptide (substance P, dynorphin) and dopamine receptor (D1, D2) mRNAs were decreased in glucocorticoid receptor knock-out in the brain mice in the dorsal striatum but not in the accumbens. However, cocaine-induced changes in the levels of these mRNAs were not modified in glucocorticoid receptor knock-out in the brain mice. In contrast, mutant mice showed altered response in mRNA levels of N-methyl-D-aspartate, GLUR5 and GLUR6 glutamate receptor subunits as well as of enkephalin following cocaine administration. These modifications may be associated to decrease of behavioral effects of cocaine observed in glucocorticoid receptor knock-out in the brain mice.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Brain Chemistry/drug effects
- Brain Chemistry/genetics
- Cocaine/pharmacology
- Dopamine Uptake Inhibitors/pharmacology
- Dynorphins/biosynthesis
- Enkephalins/biosynthesis
- Gene Expression Regulation
- In Situ Hybridization
- Kainic Acid/metabolism
- Male
- Mice
- Mice, Transgenic
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Dopamine D1/drug effects
- Receptors, Dopamine D2/drug effects
- Receptors, Glucocorticoid/drug effects
- Receptors, Glucocorticoid/metabolism
- Receptors, Kainic Acid/biosynthesis
- Receptors, Kainic Acid/genetics
- Receptors, N-Methyl-D-Aspartate/biosynthesis
- Receptors, N-Methyl-D-Aspartate/genetics
- Substance P/biosynthesis
- Synaptic Transmission/drug effects
- GluK2 Kainate Receptor
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Affiliation(s)
- R Izawa
- Institut National de la Santé et de la Recherche Scientifique U588, Laboratoire de Psychobiologie des Comportements Adaptatifs, Domaine de Carreire, rue Camille St Saëns, 33077 Bordeaux Cedex, France
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13
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Ziółkowska B, Stefański R, Mierzejewski P, Zapart G, Kostowski W, Przewłocki R. Contingency does not contribute to the effects of cocaine self-administration on prodynorphin and proenkephalin gene expression in the rat forebrain. Brain Res 2006; 1069:1-9. [PMID: 16412997 DOI: 10.1016/j.brainres.2005.11.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 11/14/2005] [Accepted: 11/16/2005] [Indexed: 11/28/2022]
Abstract
Neuroadaptations in the brain opioid systems produced by chronic exposure to drugs of abuse may contribute to the drug dependence and addiction. Although regulation of the gene expression of the opioid propeptides proenkephalin (PENK) and prodynorphin (PDYN) by psychostimulants has previously been described, little attention has been paid to dissociating effects of pharmacological actions of the drugs from those produced by motivational processes driving active drug intake in self-administration paradigms. In the present study, effects of response-dependent (contingent) and response-independent (noncontingent) cocaine administration on the PENK and PDYN gene expression in the rat forebrain have been directly compared using the "yoked" self-administration procedure. The i.v. cocaine treatment lasted for 5 weeks, and rats were sacrificed 24 h after the last self-administration session. In situ hybridization analysis revealed that levels of the PDYN mRNA were significantly increased in the caudate/putamen, to the same extent in rats self-administering cocaine as in animals receiving noncontingent injections of the drug at the same frequency and dosage. No changes in the expression of the PDYN gene were detected in the nucleus accumbens or in the central nucleus of amygdala. Levels of the PENK mRNA remained unaltered in all the above-mentioned forebrain regions of rats receiving contingent or noncontingent cocaine injections. The obtained data indicate that up-regulation of the PDYN gene expression in the caudate/putamen results from direct pharmacological actions of cocaine rather than from the motivational and cognitive processes underlying active self-administration of the drug.
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Affiliation(s)
- Barbara Ziółkowska
- Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
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Chiu CT, Ma T, Ho IK. Attenuation of methamphetamine-induced behavioral sensitization in mice by systemic administration of naltrexone. Brain Res Bull 2005; 67:100-9. [PMID: 16140168 PMCID: PMC3138078 DOI: 10.1016/j.brainresbull.2005.05.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 05/31/2005] [Accepted: 05/31/2005] [Indexed: 01/01/2023]
Abstract
Repeated intermittent exposure to psychostimulants was found to produce behavioral sensitization. The present study was designed to establish a mouse model and by which to investigate whether opioidergic system plays a role in methamphetamine-induced behavioral sensitization. Mice injected with 2.5 mg/kg of methamphetamine once a day for 7 consecutive days showed behavioral sensitization after challenge with 0.3125 mg/kg of the drug on day 11, whereas mice injected with a lower daily dose (1.25 mg/kg) did not. Mice received daily injections with either 1.25 or 2.5 mg/kg of methamphetamine showed behavioral sensitization after challenge with 1.25 mg/kg of the drug on days 11, 21, and 28. To investigate the role of opioidergic system in the induction and expression of behavioral sensitization, long-acting but non-selective opioid antagonist naltrexone was administrated prior to the daily injections of and challenge with methamphetamine, respectively. Our results show that the expressions of behavioral sensitization were attenuated by pretreatment with 10 or 20 mg/kg of naltrexone either during the induction period or before methamphetamine challenge when they were tested on days 11 and 21. These results indicate that repeated injection with methamphetamine dose-dependently induced behavioral sensitization in mice, and suggest the involvement of opioid receptors in the induction and expression of methamphetamine-induced behavioral sensitization.
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Affiliation(s)
| | | | - Ing K. Ho
- Corresponding author. Tel.: +1 601 984 1600; fax: +1 601 984 1637. (I.K. Ho)
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15
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Di Benedetto M, D'addario C, Candeletti S, Romualdi P. Chronic and acute effects of 3,4-methylenedioxy-N-methylamphetamine ('Ecstasy') administration on the dynorphinergic system in the rat brain. Neuroscience 2005; 137:187-96. [PMID: 16289352 DOI: 10.1016/j.neuroscience.2005.09.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 07/14/2005] [Accepted: 09/13/2005] [Indexed: 11/22/2022]
Abstract
The prodynorphin system is implicated in the neurochemical mechanism of psychostimulants. Exposure to different drugs of abuse can induce neuroadaptations in the brain and affect opioid gene expression. The present study aims to examine the possibility of a common neurobiological substrate in drug addiction processes. We studied the effects of single and repeated 3,4-methylenedioxy-N-methylamphetamine ('Ecstasy') on the gene expression of the opioid precursor prodynorphin, and on the levels of peptide dynorphin A in the rat brain. Acute (8 mg/kg, intraperitoneally) 3,4-methylenedioxy-N-methylamphetamine markedly raised, two hours later, prodynorphin mRNA levels in the prefrontal cortex, and in the caudate putamen, whereas it decreased gene expression in the ventral tegmental area. Chronic (8 mg/kg, intraperitoneally, twice a day for 7 days) 3,4-methylenedioxy-N-methylamphetamine increased prodynorphin mRNA in the nucleus accumbens, hypothalamus and caudate putamen and decreased it in the ventral tegmental area. Dynorphin A levels increased after chronic treatment in the ventral tegmental area and decreased after acute treatment in the nucleus accumbens, prefrontal cortex and hypothalamus. These findings confirm the role of the dynorphinergic system in mediating the effects of drugs of abuse, such as 3,4-methylenedioxy-N-methylamphetamine, in various regions of the rat brain, which may be important sites for the opioidergic mechanisms activated by addictive drugs.
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Affiliation(s)
- M Di Benedetto
- Department of Pharmacology, University of Bologna, Irnerio 48, 40126 Bologna, Italy
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16
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Chakravarty S, Herkenham M. Toll-like receptor 4 on nonhematopoietic cells sustains CNS inflammation during endotoxemia, independent of systemic cytokines. J Neurosci 2005; 25:1788-96. [PMID: 15716415 PMCID: PMC6725921 DOI: 10.1523/jneurosci.4268-04.2005] [Citation(s) in RCA: 306] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inflammatory agonists such as lipopolysaccharide (LPS) induce robust systemic as well as CNS responses after peripheral administration. Responses in the innate immune system require triggering of toll-like receptor 4 (TLR4), but the origin of CNS sequelas has been controversial. We demonstrate expression of TLR4 transcripts in mouse brain in the meninges, ventricular ependyma, circumventricular organs, along the vasculature, and in parenchymal microglia. The contribution of TLR4 expressed in CNS resident versus hematopoietic cells to the development of CNS inflammation was examined using chimeric mice. Reciprocal bone marrow chimeras between wild-type and TLR4 mutant mice show that TLR4 on CNS resident cells is critically required for sustained inflammation in the brain after systemic LPS administration. Hematopoietic TLR4 alone supported the systemic release of acute phase cytokines, but transcription of proinflammatory genes in the CNS was reduced in duration. In contrast, TLR4 function in radiation-resistant cells was sufficient for inflammatory progression in the brains of chimeric mice, despite the striking absence of cytokine elevations in serum. Surprisingly, a temporal rise in serum corticosterone was also dependent on TLR4 signaling in nonhematopoietic cells. Our findings demonstrate a requirement for TLR4 function in CNS-resident cells, independent of systemic cytokine effects, for sustained CNS-specific inflammation and corticosterone rise during endotoxemia.
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MESH Headings
- Animals
- Bone Marrow Transplantation
- Brain/metabolism
- CX3C Chemokine Receptor 1
- Cell Lineage
- Choroid Plexus/metabolism
- Corticosterone/blood
- Cytokines/physiology
- Encephalitis/etiology
- Encephalitis/metabolism
- Encephalitis/pathology
- Endotoxemia/complications
- Endotoxemia/metabolism
- Endotoxemia/pathology
- Gene Expression Regulation
- Hypothalamo-Hypophyseal System/physiopathology
- I-kappa B Proteins/biosynthesis
- I-kappa B Proteins/genetics
- Lipopolysaccharides/toxicity
- Male
- Meninges/metabolism
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- NF-KappaB Inhibitor alpha
- Pituitary-Adrenal System/physiopathology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Radiation Chimera
- Receptors, Chemokine/biosynthesis
- Receptors, Chemokine/genetics
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Spleen/metabolism
- Toll-Like Receptor 4
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Affiliation(s)
- Sumana Chakravarty
- Section on Functional Neuroanatomy, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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17
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Crocker A, España RA, Papadopoulou M, Saper CB, Faraco J, Sakurai T, Honda M, Mignot E, Scammell TE. Concomitant loss of dynorphin, NARP, and orexin in narcolepsy. Neurology 2005; 65:1184-8. [PMID: 16247044 PMCID: PMC2254145 DOI: 10.1212/01.wnl.0000168173.71940.ab] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Narcolepsy with cataplexy is associated with a loss of orexin/hypocretin. It is speculated that an autoimmune process kills the orexin-producing neurons, but these cells may survive yet fail to produce orexin. OBJECTIVE To examine whether other markers of the orexin neurons are lost in narcolepsy with cataplexy. METHODS We used immunohistochemistry and in situ hybridization to examine the expression of orexin, neuronal activity-regulated pentraxin (NARP), and prodynorphin in hypothalami from five control and two narcoleptic individuals. RESULTS In the control hypothalami, at least 80% of the orexin-producing neurons also contained prodynorphin mRNA and NARP. In the patients with narcolepsy, the number of cells producing these markers was reduced to about 5 to 10% of normal. CONCLUSIONS Narcolepsy with cataplexy is likely caused by a loss of the orexin-producing neurons. In addition, loss of dynorphin and neuronal activity-regulated pentraxin may contribute to the symptoms of narcolepsy.
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Affiliation(s)
- A Crocker
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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18
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Adams DH, Hanson GR, Keefe KA. 3,4-Methylenedioxymethamphetamine increases neuropeptide messenger RNA expression in rat striatum. ACTA ACUST UNITED AC 2005; 133:131-42. [PMID: 15661373 DOI: 10.1016/j.molbrainres.2004.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2004] [Indexed: 11/25/2022]
Abstract
The amphetamine analog 3,4-methylenedioxymethamphetamine (MDMA) is also known as the recreational drug of abuse, Ecstasy. Several neuropeptides are found in striatal neurons postsynaptic to dopamine and serotonin nerve terminals, and changes in neuropeptide neurotransmission may be important for behavioral effects of 3,4-methylenedioxymethamphetamine. This study used in situ hybridization to characterize the effects of 3,4-methylenedioxymethamphetamine on four neuropeptide mRNAs: preprodynorphin, preprotachykinin, neurotensin/neuromedin N, and preproenkephalin. Male, Sprague-Dawley rats received a single administration of 10 mg/kg 3,4-methylenedioxymethamphetamine and were sacrificed 30 min or 3 h later. Three hours after administration, 3,4-methylenedioxymethamphetamine increased preprodynorphin, preprotachykinin, and neurotensin/neuromedin N mRNAs. These increases were most prominent in ventral and medial aspects of the rostral-middle striatum, and then became more dorsally restricted in the caudal striatum. At the 30-minute time point, MDMA significantly decreased the signal for preproenkephalin mRNA in a general manner but did not affect the signal for the other neuropeptide precursors. These data suggest that 3,4-methylenedioxymethamphetamine has a generalized, transient, inhibitory effect on striatopallidal neuron gene expression, and then preferentially influences striatonigral neuropeptide systems at the later time point in a regionally selective manner.
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Affiliation(s)
- David H Adams
- Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Rm. 201, Salt Lake City, UT 84112-5820, USA
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19
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Abstract
The transcription factor cAMP response element binding protein (CREB) has been implicated in the long-term neuronal plasticity associated with addiction. While CREB is expressed in many cells throughout the brain, very little is known about the relative concentrations of CREB protein in various brain regions. Studies in which CREB levels have been altered, either constitutively throughout the brain via gene targeting or transiently in specific brain regions, demonstrate variable roles for this protein in mediating reinforcing properties of drugs of abuse. To investigate the complex nature of CREB function in addiction, we examined the distribution of CREB protein in the nucleus accumbens (NAc) and ventral tegmental area (VTA), two brain regions that are part of the well-defined mesolimbic dopamine pathway involved in reward processing. Our data demonstrate significantly more CRE binding activity and CREB protein in the NAc compared to levels present in the VTA of wild-type mice. Phospho-CREB levels are increased in the NAc of both wild-type and CREBalphaDelta mutant animals after cocaine. However, morphine-induced increases of phospho-CREB levels are seen in the VTA of wild-type mice but not CREBalphaDelta mutant mice. Consequently, the 90% reduction of CREB in CREBalphaDelta mutant mice differentially affects CREB phosphorylation and induction of downstream targets of CREB in the NAc and VTA.
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Affiliation(s)
- Carrie L Walters
- Department of Pharmacology, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, PA 19104-6084, USA
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20
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LaForge KS, Yuferov V, Zhou Y, Ho A, Nyberg F, Jeanne Kreek M. "Binge" cocaine differentially alters preproenkephalin mRNA levels in guinea pig brain. Brain Res Bull 2003; 59:353-7. [PMID: 12507685 DOI: 10.1016/s0361-9230(02)00927-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Male Hartley guinea pigs were administered i.p. injections of cocaine or saline for 2 or 7 days in a "binge" paradigm. RNA was isolated from dissected brain regions and levels of preproenkephalin mRNA and total RNA were quantified by RNase protection assays. Following 2 days of "binge" cocaine administration, no significant alterations in preproenkephalin mRNA levels were detected in six brain regions. Following 7 days of cocaine administration, however, lower levels of preproenkephalin mRNA were observed in the nucleus accumbens and hypothalamus of cocaine-treated animals and higher levels in the frontal cortex and amygdala. These findings differed from previous studies in the rat, so an additional experiment was performed with animals treated at the 7 day time point. For increased statistical power, data from the two experiments were combined and examined by two-way ANOVAs; in this combined analysis, increases in preproenkephalin mRNA were observed in frontal cortex, amygdala, and hippocampus, decreases were found in the nucleus accumbens and hypothalamus, with no change in thalamus, caudate putamen, or cerebellum. These observed differences between guinea pigs and rats make this species an interesting model for neurobiological studies of cocaine-induced alterations in neuropeptide gene expression in the mammalian brain.
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Affiliation(s)
- K Steven LaForge
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY 10021, USA.
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21
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Adams DH, Hanson GR, Keefe KA. Distinct effects of methamphetamine and cocaine on preprodynorphin messenger RNA in rat striatal patch and matrix. J Neurochem 2003; 84:87-93. [PMID: 12485404 DOI: 10.1046/j.1471-4159.2003.01507.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We and others previously reported that equimolar doses of methamphetamine and cocaine differentially increase preprodynorphin mRNA in striatum: methamphetamine causes a patchy increase, whereas cocaine produces a more homogenous one. The current study directly examined whether this effect reflects differential induction in the patch-matrix division of striatum, as identified by micro opioid receptor immunohistochemistry. In addition, we determined whether doses of cocaine (30 mg/kg) and methamphetamine (2 mg/kg) that produced equivalent increases in extracellular dopamine differentially affected preprodynorphin mRNA expression in striatum of male, Sprague-Dawley rats. In both experiments, methamphetamine and cocaine differentially affected preprodynorphin mRNA in striatum after 3 h. The high, equimolar dose of methamphetamine selectively increased preprodynorphin mRNA in the patch division of rostral striatum, whereas cocaine increased preprodynorphin mRNA throughout patch and matrix divisions of striatum. In contrast, a dose of methamphetamine (2.0 mg/kg) that caused an increase in extracellular dopamine similar to that produced by 30 mg/kg cocaine did not significantly affect preprodynorphin mRNA in any region of striatum. These data provide further evidence that cocaine and amphetamines exert distinct effects on the patch-matrix division of striatum and suggest further that the post-synaptic consequences of elevated extracellular dopamine produced by methamphetamine and cocaine are distinct.
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Affiliation(s)
- David H Adams
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, USA
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22
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Pillot C, Héron A, Schwartz JC, Arrang JM. Ciproxifan, a histamine H3-receptor antagonist/inverse agonist, modulates the effects of methamphetamine on neuropeptide mRNA expression in rat striatum. Eur J Neurosci 2003; 17:307-14. [PMID: 12542667 DOI: 10.1046/j.1460-9568.2003.02422.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have explored the effect of histamine H3-receptor ligands on the regulation of neuropeptide mRNA expression in the striatum by using in situ hybridization performed with proenkephalin, prodynorphin, substance P and proneurotensin riboprobes. Acute administration of ciproxifan, an H3-receptor antagonist/inverse agonist, or (R)-alpha-methylhistamine, an H3-receptor agonist, did not modify the striatal expression of the neuropeptides by itself. However, ciproxifan strongly and differentially modulated the effect of a single administration of 3 mg/kg methamphetamine on neuropeptide mRNA expression. This modulation was suppressed by the administration of (R)-alpha-methylhistamine and occurred in both the caudate-putamen and nucleus accumbens. Ciproxifan strongly potentiated the decrease of proenkephalin mRNA expression induced by methamphetamine. In contrast, it suppressed the increase in prodynorphin and substance P mRNA expression induced by methamphetamine. Methamphetamine alone or with ciproxifan did not modify proneurotensin mRNA expression. These neurochemical findings indicate that ciproxifan differentially regulates the effect of methamphetamine on the neuropeptides contained in striatonigral and striatopallidal neurons. They suggest that endogenous histamine and dopamine cooperate to modulate the activity of striatal projection neurons and strengthen the interest of H3-receptors as new targets for the treatment of psychotic disorders and drug abuse.
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Affiliation(s)
- Catherine Pillot
- Laboratoire de Physiologie, Faculté des Sciences Pharmaceutiques et Biologiques, 75006 Paris, France
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23
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Johnson-Davis KL, Hanson GR, Keefe KA. Long-term post-synaptic consequences of methamphetamine on preprotachykinin mRNA expression. J Neurochem 2002; 82:1472-9. [PMID: 12354295 DOI: 10.1046/j.1471-4159.2002.01095.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Exposure to repeated high doses of methamphetamine produces long-term toxicity to central monoamine systems and alters striatonigral pathway function 3 weeks after exposure. To determine whether these changes in the striatonigral pathway persist for longer we examined neuropeptide mRNA expression in the striatum and cytochrome oxidase activity in the output nuclei of the basal ganglia after treatment with multiple high doses of methamphetamine. Rats exposed to multiple high doses of methamphetamine had significant depletion in dopamine and serotonin content, decreases in tyrosine hydroxylase immunoreactivity, and decreases in preprotachykinin mRNA expression, 6 and 12 weeks after methamphetamine treatment. Preprotachykinin mRNA expression was significantly reduced by approximately 20% in the middle striatum and approximately 32% in the caudal striatum, 6 weeks after treatment. Twelve weeks after treatment, preprotachykinin mRNA expression continued to be significantly reduced by approximately 20% in the middle striatum and approximately 14% in the caudal striatum. Cytochrome oxidase histochemical staining in the entopeduncular nucleus and substantia nigra pars reticulata was not significantly different from that in controls at either time point. These data suggest that neurotoxic regimens of methamphetamine induce changes in striatonigral neurons that persist for up to 3 months, although there is some recovery.
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Affiliation(s)
- Kamisha L Johnson-Davis
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, USA
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24
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Collins S, D'Addario C, Romualdi P, Candeletti S, Izenwasser S. Regulation of dynorphin gene expression by kappa-opioid agonist treatment. Neuroreport 2002; 13:107-9. [PMID: 11924869 DOI: 10.1097/00001756-200201210-00025] [Citation(s) in RCA: 11] [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
The effects of K-opioid agonist treatment on prodynorphin mRNA expression in the rat brain were studied. Rats were treated with the selective kappa-opioid agonist U-69593 or vehicle for 5 days and prodynorphin mRNA was measured on day 8 (3 days after the last injection) or 22 (17 days after the last injection). On day 8 prodynorphin mRNA was increased in the hypothalamus and decreased in the striatum, frontal cortex, and hippocampus of rats treated with U-69593. On day 22, prodynorphin mRNA was increased in the hypothalamus, frontal cortex and striatum of U-69593 treated rats. These findings suggests that kappa-opioid receptor agonist treatment has long-term, continually changing effects on prodynorphin mRNA expression.
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Affiliation(s)
- Stephanie Collins
- Department of Psychiatry and Behavioral Sciences, University of Miami School of Medicine, FL 33136, USA
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25
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Abstract
This paper is the twenty-third installment of the annual review of research concerning the opiate system. It summarizes papers published during 2000 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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26
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Cowen MS, Lawrence AJ. Alterations in Central Preproenkephalin mRNA Expression After Chronic Free-Choice Ethanol Consumption by Fawn-Hooded Rats. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02326.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Alburges ME, Keefe KA, Hanson GR. Unique responses of limbic met-enkephalin systems to low and high doses of methamphetamine. Brain Res 2001; 905:120-6. [PMID: 11423086 DOI: 10.1016/s0006-8993(01)02514-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A single administration of a low (0.5 mg/kg) or high (10 mg/kg) dose of methamphetamine (METH) significantly altered the met-enkephalin (M-Enk) systems associated with some, but not all, limbic structures examined. Neither treatment influenced M-Enk levels 3 h after drug exposure in any limbic region studied; however, 12 h after drug administration, 0.5 mg/kg of METH reduced the tissue content of this peptide in both the nucleus accumbens shell (NAs) and the frontal cortex (FrCx). This was similar to the effect of this treatment on the anterior striatal region. In contrast, the high dose of METH increased M-Enk content in the frontal cortex and anterior striatum (AS), but had no effect in the nucleus accumbens shell. By 24 h, the effects of METH in the anterior striatum subsided, but decreases in M-Enk levels were still observed after both the low- and the high-dose METH treatments in the nucleus accumbens shell. The levels of M-Enk were not changed at any of the time points examined in the core of the nucleus accumbens (NAc). In general, treatment with a low or high dose of METH causes distinct and regional selective changes in the tissue levels of M-Enk in the limbic system. These changes appear to be mediated by dopamine (DA) D(2) and D(1) receptor activation.
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Affiliation(s)
- M E Alburges
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, 30 So. 2000 E., Room 201, Salt Lake City, UT 84112-5820, USA.
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