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Cho BR, Kim WY, Jang JK, Lee JW, Kim JH. Glycogen Synthase Kinase 3β Is a Key Regulator in the Inhibitory Effects of Accumbal Cocaine- and Amphetamine-Regulated Transcript Peptide 55-102 on Amphetamine-Induced Locomotor Activity. Int J Mol Sci 2022; 23:ijms232415633. [PMID: 36555273 PMCID: PMC9779470 DOI: 10.3390/ijms232415633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Microinjection of cocaine- and amphetamine-regulated transcript (CART) peptide 55-102 into the nucleus accumbens (NAcc) core significantly attenuates psychostimulant-induced locomotor activity. However, the molecular mechanism remains poorly understood. We examined the phosphorylation levels of Akt, glycogen synthase kinase 3β (GSK3β), and glutamate receptor 1 (GluA1) in NAcc core tissues obtained 60 min after microinjection of CART peptide 55-102 into this site, followed by systemic injection of amphetamine (AMPH). Phosphorylation levels of Akt at Thr308 and GSK3β at Ser9 were decreased, while those of GluA1 at Ser845 were increased, by AMPH treatment. These effects returned to basal levels following treatment with CART peptide 55-102. Furthermore, the negative regulatory effects of the CART peptide on AMPH-induced changes in phosphorylation levels and locomotor activity were all abolished by pretreatment with the S9 peptide, an artificially synthesized indirect GSK3β activator. These results suggest that the CART peptide 55-102 in the NAcc core plays a negative regulatory role in AMPH-induced locomotor activity by normalizing the changes in phosphorylation levels of Akt-GSK3β, and subsequently GluA1 modified by AMPH at this site. The present findings are the first to reveal GSK3β as a key regulator of the inhibitory role of the CART peptide in psychomotor stimulant-induced locomotor activity.
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Affiliation(s)
- Bo Ram Cho
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA
| | - Wha Young Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ju Kyong Jang
- Department of Pharmacology, Bio-Pharm Solutions Co., Ltd., Suwon-si 16229, Gyeonggi-do, Republic of Korea
| | - Jung Won Lee
- Division of In Vitro Diagnostic Devices, National Institute of Food and Drug Safety Evaluation, Cheongju-si 28159, Chungcheongbuk-do, Republic of Korea
| | - Jeong-Hoon Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
- Department of Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
- Correspondence:
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Ong ZY, McNally GP. CART in energy balance and drug addiction: Current insights and mechanisms. Brain Res 2020; 1740:146852. [DOI: 10.1016/j.brainres.2020.146852] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022]
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Jayanthi S, Gonzalez B, McCoy MT, Ladenheim B, Bisagno V, Cadet JL. Methamphetamine Induces TET1- and TET3-Dependent DNA Hydroxymethylation of Crh and Avp Genes in the Rat Nucleus Accumbens. Mol Neurobiol 2018; 55:5154-5166. [PMID: 28842817 PMCID: PMC5948251 DOI: 10.1007/s12035-017-0750-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/15/2017] [Indexed: 12/30/2022]
Abstract
Methamphetamine (METH) addiction is a biopsychosocial disorder that is accompanied by multiple relapses even after prolonged abstinence, suggesting the possibilities of long-lasting maladaptive epigenetic changes in the brain. Here, we show that METH administration produced time-dependent increases in the expression of corticotropin-releasing hormone (Crh/Crf), arginine vasopressin (Avp), and cocaine- and amphetamine-regulated transcript prepropeptide (Cartpt) mRNAs in the rat nucleus accumbens (NAc). Chromatin immunoprecipitation (ChIP) assays revealed that METH increased the abundance of phosphorylated CREB (pCREB) at the promoter of Cartpt but not at Avp or Crh DNA sequences. In contrast, METH produced DNA hypomethylation at sites near the Crh transcription start site (TSS) and at intragenic Avp sequences. METH also increased DNA hydroxymethylation at the Crh TSS and at intragenic Avp sites. In addition, METH increased the protein expression of ten-eleven-translocation enzymes that catalyze DNA hydroxymethylation. Importantly, METH increased TET1 binding at the Crh promoter and increased TET3 binding at Avp intragenic regions. We further tested the role of TET enzymes in METH-induced changes in gene expression by using the TET inhibitor, 1,5-isoquinolinediol (IQD), and found that IQD blocked METH-induced increases in Crh and Avp mRNA expression. Together, these results indicate that METH produced changes in neuropeptide transcription by both activation of the cAMP/CREB pathway and stimulation of TET-dependent DNA hydroxymethylation. These results provide molecular evidence for epigenetic controls of METH-induced changes in the expression of neuropeptides.
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Affiliation(s)
- Subramaniam Jayanthi
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD, USA
| | - Betina Gonzalez
- Instituto de Investigaciones Farmacológicas (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Michael T McCoy
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD, USA
| | - Bruce Ladenheim
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD, USA
| | - Veronica Bisagno
- Instituto de Investigaciones Farmacológicas (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD, USA.
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA IRP, 251 Bayview Boulevard, Baltimore, MD, 21224, USA.
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Yoon HS, Hattori K, Sasayama D, Kunugi H. Low cocaine- and amphetamine-regulated transcript (CART) peptide levels in human cerebrospinal fluid of major depressive disorder (MDD) patients. J Affect Disord 2018; 232:134-138. [PMID: 29486339 DOI: 10.1016/j.jad.2018.02.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/18/2017] [Accepted: 02/16/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Cocaine- and amphetamine-regulated transcript (CART) peptide is a candidate neuropeptide as a biomarker for major depressive disorder (MDD) because of its effects on emotion and distribution covering brain areas involved in the pathophysiology of MDD symptoms. However, it is unknown whether CART peptide levels are altered in the cerebrospinal fluid (CSF) of patients with MDD patients and are correlated with MDD symptoms. METHODS Subjects were 24 patients with MDD and 25 healthy controls matched for age, gender and ethnicity (Japanese). We measured CSF CART levels by a commercially available immunoassay kit and analyzed the relationships of the levels with antidepressant dose and symptoms assessed with the 21 item Hamilton Depression Rating Scale (HAMD-21). RESULTS CSF CART levels were significantly decreased in the patients than in the controls (p < 0.05). In MDD patient group, the CART levels had a negative correlation with antidepressant dose (imipramine-equivalent dose) (ρ = -0.55, p < 0.01) and significantly decreased in antidepressant-treated group (AD-treated group) compared to controls (p < 0.05). CSF CART levels showed significant negative correlations with psychomotor retardation, somatic anxiety, and general somatic symptoms (all p < 0.05) and a positive correlation with obsessive and compulsive symptoms (p < 0.05). LIMITATIONS In our analysis, all classes of antidepressants were combined together and the effects of medication use in a longitudinal manner did not confirm. CONCLUSIONS We report for the first time that CSF CART peptide levels are reduced in patients with MDD compared with healthy controls. The CART levels showed negative correlations with antidepressant dose and some symptoms, supporting the possibility that CART peptide is involved in the development of depressive symptoms.
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Affiliation(s)
- Hyung Shin Yoon
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, OgawaHigashi, Kodaira, Tokyo 187-8502, Japan; Department of Physiology, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul 120-752, South Korea
| | - Kotaro Hattori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, OgawaHigashi, Kodaira, Tokyo 187-8502, Japan; Translational Medical Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Daimei Sasayama
- Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, OgawaHigashi, Kodaira, Tokyo 187-8502, Japan.
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Rakovska A, Baranyi M, Windisch K, Petkova-Kirova P, Gagov H, Kalfin R. Neurochemical evidence that cocaine- and amphetamine-regulated transcript (CART) 55-102 peptide modulates the dopaminergic reward system by decreasing the dopamine release in the mouse nucleus accumbens. Brain Res Bull 2017; 134:246-252. [PMID: 28802898 DOI: 10.1016/j.brainresbull.2017.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/05/2017] [Accepted: 08/07/2017] [Indexed: 01/11/2023]
Abstract
CART (Cocaine- and Amphetamine-Regulated Transcript) peptide is a neurotransmitter naturally occurring in the CNS and found mostly in nucleus accumbens, ventrotegmental area, ventral pallidum, amygdalae and striatum, brain regions associated with drug addiction. In the nucleus accumbens, known for its significant role in motivation, pleasure, reward and reinforcement learning, CART peptide inhibits cocaine and amphetamine-induced dopamine-mediated increases in locomotor activity and behavior, suggesting a CART peptide interaction with the dopaminergic system. Thus in the present study, we examined the effect of CART (55-102) peptide on the basal, electrical field stimulation-evoked (EFS-evoked) (30V, 2Hz, 120 shocks) and returning basal dopamine (DA) release and on the release of the DA metabolites 3,4-dihydroxyphenyl acetaldehyde (DOPAL), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3,4-dihydroxyphenylethanol (DOPET), 3-methoxytyramine (3-MT) as well as on norepinephrine (NE) and dopamine-o-quinone (Daq) in isolated mouse nucleus accumbens, in a preparation, in which any CART peptide effects on the dendrites or soma of ventral tegmental projection neurons have been excluded. We further extended our study to assess the effect of CART (55-102) peptide on basal cocaine-induced release of dopamine and its metabolites DOPAL, DOPAC, HVA, DOPET and 3-MT as well as on NE and Daq. To analyze the amount of [3H]dopamine, dopamine metabolites, Daq and NE in the nucleus accumbens superfusate, a high-pressure liquid chromatography (HPLC), coupled with electrochemical, UV and radiochemical detections was used. CART (55-102) peptide, 0.1μM, added alone, exerted: (i) a significant decrease in the basal and EFS-evoked levels of extracellular dopamine (ii) a significant increase in the EFS-evoked and returning basal levels of the dopamine metabolites DOPAC and HVA, major products of dopamine degradation and (iii) a significant decrease in the returning basal levels of DOPET. At the same concentration, 0.1μM, CART (55-102) peptide did not have any effect on the release of noradrenaline. In the presence of CART (55-102) peptide, 0.1μM, the effect of cocaine, 30μM, on the basal dopamine release was inhibited and the effect on the basal DOPAC release substantially increased. To our knowledge, our findings are the first to show direct neurochemical evidence that CART (55-102) peptide plays a neuromodulatory role on the dopaminergic reward system by decreasing dopamine in the mouse nucleus accumbens and by attenuating cocaine-induced effects on dopamine release.
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Affiliation(s)
- Angelina Rakovska
- Lab. "Neuropeptides", Institute of Neurobiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 23, 1113, Sofia, Bulgaria.
| | - Maria Baranyi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083, Budapest, Hungary
| | - Katalin Windisch
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083, Budapest, Hungary
| | - Polina Petkova-Kirova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
| | - Hristo Gagov
- Faculty of Biology, Sofia University St. Kliment Ohridski, Dragan Tsankov Str. 8, 1164, Sofia, Bulgaria
| | - Reni Kalfin
- Lab. "Neuropeptides", Institute of Neurobiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 23, 1113, Sofia, Bulgaria
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Bakhtazad A, Vousooghi N, Garmabi B, Zarrindast MR. Evaluation of the CART peptide expression in morphine sensitization in male rats. Eur J Pharmacol 2017; 802:52-59. [PMID: 28238767 DOI: 10.1016/j.ejphar.2017.02.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/20/2017] [Accepted: 02/22/2017] [Indexed: 11/24/2022]
Abstract
The importance of Cocaine- and amphetamine-regulated transcript (CART) peptide in reinforcing effects of addictive drugs specially alcohol and psychostimulants has been stablished. Involvement of CART peptide in rewarding effects of opioids in brain has recently been reported. Here we have studied the expression of CART mRNA and peptide in the reward pathway in morphine-induced sensitization phenomenon and also evaluated the peptide level fluctuations in CSF and plasma. Male Wistar rats received 7-day morphine injection (20mg/kg) and then after a 7-day washout period, a challenge dose of 10mg/kg morphine was administered and locomotor activity and oral stereotypical behaviors were recorded. Besides, the expression level of CART mRNA and peptide in four important areas of the mesocorticolimbic reward pathway including nucleus accumbens, striatum, prefrontal cortex, and hippocampus were measured by real-time PCR and western blotting, respectively. The level of the peptide in CSF and plasma was measured by Elisa method. The expression level of CART mRNA and protein in brain regions and also the peptide level in CSF and plasma were significantly down-regulated after 7-day morphine administration. These reduced levels returned to nearly normal rates after 7-day wash-out period. Administration of morphine challenge dose led to significant upregulation of CART gene expression (both mRNA and peptide) in the brain, and elevation of peptide level in CSF and plasma in morphine-sensitized rats. It can be concluded that CART is released in the framework of reward pathway and may serve as an important neurotransmitter in the process of morphine dependence and sensitization.
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Affiliation(s)
- Atefeh Bakhtazad
- Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Nasim Vousooghi
- Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; Genetics Laboratory, Iranian National Center for Addiction Studies (INCAS), Iranian Institute for Reduction of High-Risk Behaviors, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Cognitive and Behavioral Sciences, Tehran University of Medical Sciences, Tehran, Iran
| | - Behzad Garmabi
- Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Zarrindast
- Genetics Laboratory, Iranian National Center for Addiction Studies (INCAS), Iranian Institute for Reduction of High-Risk Behaviors, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Cognitive Neuroscience, Institute for Cognitive Science Studies, Tehran, Iran; Genomics Center, School of Advanced Sciences, Tehran Medical Branch, Islamic Azad University, Tehran, Iran; School of Cognitive Sciences, Institute for Studies in Theoretical Physics and Mathematics, Tehran, Iran.
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Kaya E, Gozen O, Ugur M, Koylu EO, Kanit L, Balkan B. Nicotine regulates cocaine-amphetamine-Regulated Transcript (Cart) in the mesocorticolimbic system. Synapse 2016; 70:283-92. [PMID: 26990424 DOI: 10.1002/syn.21903] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/03/2016] [Accepted: 03/10/2016] [Indexed: 12/21/2022]
Abstract
Cocaine-and-Amphetamine Regulated Transcript (CART) mRNA and peptides are intensely expressed in the brain regions comprising mesocorticolimbic system. Studies suggest that CART peptides may have a role in the regulation of reward circuitry. The present study aimed to examine the effect of nicotine on CART expression in the mesocorticolimbic system. Three different doses of nicotine (0.2, 0.4, 0.6 mg/kg free base) were injected subcutaneously for 5 days, and on day 6, rats were decapitated following a challenge dose. CART mRNA and peptide levels in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum (DST), amygdala (AMG), lateral hypothalamic area (LHA), and ventral tegmental area (VTA) were measured by quantitative real-time PCR (qPCR) and Western Blot analysis, respectively. In the mPFC, 0.4 and 0.6 mg/kg nicotine, decreased CART peptide levels whereas there was no effect on CART mRNA levels. In the VTA, a down-regulation of CART peptide expression was observed with 0.2 and 0.6 mg/kg nicotine. Conversely, 0.4 and 0.6 mg/kg nicotine increased CART mRNA levels in the AMG without affecting the CART peptide expression. Nicotine did not regulate CART mRNA or CART peptide expression in the NAc, DST, and LHA. We conclude that nicotine regulates CART expression in the mesocorticolimbic system and this regulation may play an important role in nicotine reward. Synapse 70:283-292, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Egemen Kaya
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey.,Center for Brain Research, Ege University, Izmir, Turkey
| | - Oguz Gozen
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey.,Center for Brain Research, Ege University, Izmir, Turkey
| | - Muzeyyen Ugur
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey
| | - Ersin O Koylu
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey.,Center for Brain Research, Ege University, Izmir, Turkey
| | - Lutfiye Kanit
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey.,Center for Brain Research, Ege University, Izmir, Turkey
| | - Burcu Balkan
- Department of Physiology, School of Medicine, Ege University, Izmir, Turkey.,Center for Brain Research, Ege University, Izmir, Turkey
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Burghardt PR, Krolewski DM, Dykhuis KE, Ching J, Pinawin AM, Britton SL, Koch LG, Watson SJ, Akil H. Nucleus accumbens cocaine-amphetamine regulated transcript mediates food intake during novelty conflict. Physiol Behav 2016; 158:76-84. [PMID: 26926827 DOI: 10.1016/j.physbeh.2016.02.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/24/2016] [Accepted: 02/24/2016] [Indexed: 02/09/2023]
Abstract
Obesity is a persistent and pervasive problem, particularly in industrialized nations. It has come to be appreciated that the metabolic health of an individual can influence brain function and subsequent behavioral patterns. To examine the relationship between metabolic phenotype and central systems that regulate behavior, we tested rats with divergent metabolic phenotypes (Low Capacity Runner: LCR vs. High Capacity Runner: HCR) for behavioral responses to the conflict between hunger and environmental novelty using the novelty suppressed feeding (NSF) paradigm. Additionally, we measured expression of mRNA, for peptides involved in energy management, in response to fasting. Following a 24-h fast, LCR rats showed lower latencies to begin eating in a novel environment compared to HCR rats. A 48-h fast equilibrated the latency to begin eating in the novel environment. A 24-h fast differentially affected expression of cocaine-amphetamine regulated transcript (CART) mRNA in the nucleus accumbens (NAc), where 24-h of fasting reduced CART mRNA in LCR rats. Bilateral microinjections of CART 55-102 peptide into the NAc increased the latency to begin eating in the NSF paradigm following a 24-h fast in LCR rats. These results indicate that metabolic phenotype influences how animals cope with the conflict between hunger and novelty, and that these differences are at least partially mediated by CART signaling in the NAc. For individuals with poor metabolic health who have to navigate food-rich and stressful environments, changes in central systems that mediate conflicting drives may feed into the rates of obesity and exacerbate the difficulty individuals have in maintaining weight loss.
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Affiliation(s)
- P R Burghardt
- Department of Psychiatry, University of Michigan, Ann Arbor, MI; Department of Nutrition and Food Science, Wayne State University, Detroit, MI.
| | - D M Krolewski
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - K E Dykhuis
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - J Ching
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - A M Pinawin
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - S L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - L G Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI
| | - S J Watson
- Department of Psychiatry, University of Michigan, Ann Arbor, MI; Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
| | - H Akil
- Department of Psychiatry, University of Michigan, Ann Arbor, MI; Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI
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Liu S, Borgland S. Regulation of the mesolimbic dopamine circuit by feeding peptides. Neuroscience 2015; 289:19-42. [DOI: 10.1016/j.neuroscience.2014.12.046] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/27/2014] [Accepted: 12/31/2014] [Indexed: 12/30/2022]
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Yoon HS, Adachi N, Kunugi H. Microinjection of cocaine- and amphetamine-regulated transcript 55-102 peptide into the nucleus accumbens could modulate anxiety-related behavior in rats. Neuropeptides 2014; 48:319-25. [PMID: 25256086 DOI: 10.1016/j.npep.2014.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/18/2014] [Accepted: 09/02/2014] [Indexed: 11/24/2022]
Abstract
Cocaine- and amphetamine-regulated transcript (CART) peptide is abundantly expressed in the nucleus accumbens (NAcc) and is involved in stress, anxiety and reward responses. To examine the role of CART peptide in anxiety-related behavior, naïve rats were bilaterally injected with CART 55-102 peptide (0.5, 1.0 or 2.5 µg/0.5 µl/side) or vehicle into the NAcc. Following this, their anxiety-related behavior was assessed using the elevated plus maze and the open field tests with a one-week interval between the tests. There was no difference in the time spent in open arms, or number of entries into open arms on the elevated plus maze in the CART-treated animals at any dose, when compared with the vehicle-treated group. However, there was a significant increase in the time spent in the center of the open field with administration of the low dose of CART peptide (0.5 µg/0.5 µl/side), although this effect disappeared at the high dose (2.5 µg/0.5 µl/side). None of the doses of CART peptide altered total locomotion in these tests. To further determine the possible anxiety-modulating effect of CART peptide at low dosages, the light and dark test was performed. Additional groups of rats given doses of 0.01 µg/0.5 µl/side or 0.5 µg/0.5 µl/side of CART peptide showed increased exploration time in the light side. These results suggest that accumbal-CART peptide reduces anxiety-like behavior in a dose-dependent manner.
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Affiliation(s)
- Hyung Shin Yoon
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Naoki Adachi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
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Differences in the structure of drinking, cart expression and dopamine turnover between polydipsic and non polydipsic rats in the quinpirole model of psychotic polydipsia. Psychopharmacology (Berl) 2014; 231:3889-97. [PMID: 24647922 DOI: 10.1007/s00213-014-3527-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 02/26/2014] [Indexed: 12/19/2022]
Abstract
RATIONALE Dopaminergic D2/D3 agonist quinpirole (QNP) elicits nonregulatory drinking in rats, a model of psychotic polydipsia. Why only a fraction of QNP-treated rats responds to the treatment becoming polydipsic is still unclear. OBJECTIVES To unveil possible factors contributing to such variability, we analyzed drinking microstructure in saline and QNP-treated rats, the hypothalamic expression of the cocaine and amphetamine regulated transcript (CART), and the monoaminergic turnover in selected brain areas. METHODS Rats were daily treated with saline or QNP 0.5 mg/kg, and their 5-h water intake was measured for five consecutive days. The number of bouts and episodes of licking, and their duration, were also measured. Brain CART expression was measured by in situ hybridization and monoamines turnover by HPLC analysis of tissue extracts. Based on the amount of water ingested during the 5-h session, QNP-treated rats were post hoc grouped in polydipsic (PD) and in nonpolydipsic (NPD) rats, and the results compared accordingly. RESULTS The number of drinking bouts and episodes increased in PD rats, while NPD rats behaved as the controls. CART expression decreased in the arcuate nucleus of the hypothalamus of the PD rats. In contrast, both PD and NPD rats showed a reduction of DA turnover in both ventral tegmental area (VTA) and nucleus accumbens (NAcc). No difference was detected in the turnover of 5HT and NA. CONCLUSIONS Microstructure analysis confirms that QNP acts on the appetitive component of drinking behavior, making it compulsive. CART expression reduction in response to dopaminergic hyperstimulation might sustain excessive drinking in PD rats.
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Enhanced upregulation of CRH mRNA expression in the nucleus accumbens of male rats after a second injection of methamphetamine given thirty days later. PLoS One 2014; 9:e84665. [PMID: 24475032 PMCID: PMC3903495 DOI: 10.1371/journal.pone.0084665] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 11/17/2013] [Indexed: 01/18/2023] Open
Abstract
Methamphetamine (METH) is a widely abused amphetamine analog. Few studies have investigated the molecular effects of METH exposure in adult animals. Herein, we determined the consequences of an injection of METH (10 mg/kg) on transcriptional effects of a second METH (2.5 mg/kg) injection given one month later. We thus measured gene expression by microarray analyses in the nucleus accumbens (NAc) of 4 groups of rats euthanized 2 hours after the second injection: saline-pretreated followed by saline-challenged (SS) or METH-challenged (SM); and METH-pretreated followed by saline-challenged (MS) or METH-challenged (MM). Microarray analyses revealed that METH (2.5 mg/kg) produced acute changes (1.8-fold; P<0.01) in the expression of 412 (352 upregulated, 60 down-regulated) transcripts including cocaine and amphetamine regulated transcript, corticotropin-releasing hormone (Crh), oxytocin (Oxt), and vasopressin (Avp) that were upregulated. Injection of METH (10 mg/kg) altered the expression of 503 (338 upregulated, 165 down-regulated) transcripts measured one month later (MS group). These genes also included Cart and Crh. The MM group showed altered expression of 766 (565 upregulated, 201 down-regulated) transcripts including Avp, Cart, and Crh. The METH-induced increased Crh expression was enhanced in the MM group in comparison to SM and MS groups. Quantitative PCR confirmed the METH-induced changes in mRNA levels. Therefore, a single injection of METH produced long-lasting changes in gene expression in the rodent NAc. The long-term increases in Crh, Cart, and Avp mRNA expression suggest that METH exposure produced prolonged activation of the endogenous stress system. The METH-induced changes in oxytocin expression also suggest the possibility that this neuropeptide might play a significant role in the neuroplastic and affiliative effects of this drug.
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Job MO, Licata J, Hubert GW, Kuhar MJ. Intra-accumbal administration of shRNAs against CART peptides cause increases in body weight and cocaine-induced locomotor activity in rats. Brain Res 2012; 1482:47-54. [PMID: 22975438 DOI: 10.1016/j.brainres.2012.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 08/13/2012] [Accepted: 09/04/2012] [Indexed: 12/29/2022]
Abstract
In order to examine the effect of cocaine and amphetamine regulated transcript (CART) peptide depletion in adult rats, CART shRNAs or scrambled control shRNAs were administered bilaterally into the nucleus accumbens (NAc). There was an increase in body weight of the shRNA injected rats compared with the rats injected with the scrambled RNA. This is compatible with the data showing a role for the peptide in body weight and food intake. Also at this time, there was about a two-and-a-half fold increase in cocaine-mediated locomotion in the shRNA injected rats compared to the control rats. This finding is critical support for the hypothesis that endogenous CART peptides in the NAc inhibit the actions of cocaine and other psychostimulants. In immunohistochemical experiments on these same animals, there was a decrease in the staining density of CART peptide in the NAc of the shRNA injected rats. These data show that shRNA can reduce CART peptides in the NAc and that endogenous CART peptides influence body weight and cocaine-induced locomotor activity (LMA).
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Affiliation(s)
- M O Job
- The Yerkes National Primate Research Center of Emory University, 954 Gatewood Road NE, Atlanta, GA 30329, USA
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Job MO, Kuhar MJ. Intraperitoneal Administration of CART 55-102 Inhibits Psychostimulant-Induced Locomotion. ACTA ACUST UNITED AC 2012; 1. [PMID: 23705073 DOI: 10.4303/jdar/235601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CART (cocaine and amphetamine regulated transcript) peptide functions as both a neurotransmitter and a hormone and is found both in the central nervous system (CNS) and in the periphery. CART peptide in the nucleus accumbens (NAc) has been implicated in the regulation of cocaine-dopamine-mediated locomotion and self-administration, and amphetamine-mediated locomotion and behavior. However, there are no studies on the effect of systemic administration of CART peptide on cocaine and amphetamine-mediated locomotion. In this study, we tested if the systemic administration of CART 55-102 by the intraperitoneal (ip) route has a functional effect on psychostimulant-mediated locomotion in rats as it does when given into the brain. We determined that ip CART 55-102 attenuates psychostimulant-mediated locomotion as it does when administered into the NAc and display a biphasic dose response curve.
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Affiliation(s)
- Martin O Job
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA 30329, USA
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15
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Single-chain variable fragments antibody of CART inhibits the expression of cocaine-induced behavioral sensitization. Neuroreport 2011; 22:433-6. [PMID: 21544003 DOI: 10.1097/wnr.0b013e328346f6f5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cocaine and amphetamine-regulated transcript (CART) peptides are neurotransmitters with important roles in drug abuse. The increase of CART expression in the brain induced by psychostimulants is associated with changes of behavior in addicted animals. We expressed and purified the single-chain variable fragments antibody (scFv) against CART55-102, and observed the effect of CART scFv on the expression of cocaine-induced behavior sensitization in mice. Results showed that the titer of CART scFv was 1.6 μg/ml. Single administration of CART scFv (intraperitoneal 0.04, 0.2, and 1 mg/kg) reduced the increasing locomotor activity induced by chronic cocaine intake in mice (P<0.05-0.01), but failed to affect the locomotor activity of naive mice. These results suggested that CART scFv may be a potential therapeutic tool to treat drug abuse.
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Hostetler CM, Kowalczyk AS, Griffin LL, Bales KL. CART peptide following social novelty in the prairie vole (Microtus ochrogaster). Brain Res 2011; 1414:32-40. [PMID: 21871610 DOI: 10.1016/j.brainres.2011.07.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/16/2011] [Accepted: 07/19/2011] [Indexed: 12/16/2022]
Abstract
Prairie voles (Microtus ochrogaster) are monogamous rodents that display high levels of affiliative behaviors, including pair-bonding, biparental care, and cooperative breeding. Species differences in basal cocaine- and amphetamine-regulated transcript (CART) mRNA and peptide expression have been found between prairie voles and polygamous meadow voles. Therefore, we hypothesized that the CART system may play a role in the regulation of social behavior in this species. Male and female adult prairie voles were placed in a cage either alone, or with a novel social partner of the same or opposite sex. After 45 min, subjects were sacrificed and CART peptide expression was examined using immunohistochemistry. We examined fifteen hypothalamic, limbic, and hindbrain regions of interest, focusing on areas that show species-specific patterns of expression. We found that subjects paired with a novel conspecific had lower levels of peptide in the bed nucleus of the stria terminalis (BNST) than isolated animals. This may reflect increased peptide release following increased dopaminergic activity in animals exposed to a novel conspecific. Additionally, CART peptide was higher in the nucleus accumbens (NAc) of subjects paired with an opposite sex partner compared to those paired with a same-sex conspecific, although there was no difference between isolated subjects and either socially housed group. These findings suggest that CART in the NAc is differentially responsive to the sex of adult conspecifics and that the social environment influences CART expression in the prairie vole in a region- and stimulus-specific manner.
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Han W, Takamatsu Y, Yamamoto H, Kasai S, Endo S, Shirao T, Kojima N, Ikeda K. Inhibitory role of inducible cAMP early repressor (ICER) in methamphetamine-induced locomotor sensitization. PLoS One 2011; 6:e21637. [PMID: 21738744 PMCID: PMC3125264 DOI: 10.1371/journal.pone.0021637] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 06/04/2011] [Indexed: 12/02/2022] Open
Abstract
Background The inducible cyclic adenosine monophosphate (cAMP) early repressor (ICER) is highly expressed in the central nervous system and functions as a repressor of cAMP response element-binding protein (CREB) transcription. The present study sought to clarify the role of ICER in the effects of methamphetamine (METH). Methods and Findings We tested METH-induced locomotor sensitization in wildtype mice, ICER knockout mice, and ICER I-overexpressing mice. Both ICER wildtype mice and knockout mice displayed increased locomotor activity after continuous injections of METH. However, ICER knockout mice displayed a tendency toward higher locomotor activity compared with wildtype mice, although no significant difference was observed between the two genotypes. Moreover, compared with wildtype mice, ICER I-overexpressing mice displayed a significant decrease in METH-induced locomotor sensitization. Furthermore, Western blot analysis and quantitative real-time reverse transcription polymerase chain reaction demonstrated that ICER overexpression abolished the METH-induced increase in CREB expression and repressed cocaine- and amphetamine-regulated transcript (CART) and prodynorphin (Pdyn) expression in mice. The decreased CART and Pdyn mRNA expression levels in vivo may underlie the inhibitory role of ICER in METH-induced locomotor sensitization. Conclusions Our data suggest that ICER plays an inhibitory role in METH-induced locomotor sensitization.
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Affiliation(s)
- Wenhua Han
- Research Project for Addictive Substances, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yukio Takamatsu
- Research Project for Addictive Substances, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hideko Yamamoto
- Research Project for Addictive Substances, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Shinya Kasai
- Research Project for Addictive Substances, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Shogo Endo
- Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Tomoaki Shirao
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Nobuhiko Kojima
- Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Japan
- Laboratory for Neurobiology of Emotion, RIKEN Brain Science Institute, Wako, Japan
- * E-mail:
| | - Kazutaka Ikeda
- Research Project for Addictive Substances, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Moffett MC, Song J, Kuhar MJ. CART peptide inhibits locomotor activity induced by simultaneous stimulation of D1 and D2 receptors, but not by stimulation of individual dopamine receptors. Synapse 2011; 65:1-7. [PMID: 20506412 DOI: 10.1002/syn.20815] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
CART (Cocaine- and amphetamine-regulated transcript) peptide has been implicated in playing a modulatory role in reward and reinforcement. Previously, our laboratory demonstrated that injections of CART peptide (CART 55-102) into the nucleus accumbens (NAc) attenuated both cocaine- and dopamine-induced increases in locomotor activity (LMA), and attenuated cocaine reward as well. In this study, the effects of CART peptide on LMA induced by dopamine receptor agonists were evaluated after intraaccumbal injections in male, Sprague-Dawley rats. Effects of the D1 receptor agonist SKF-81,297, saline, CART 55-102, or CART 55-102 and SKF-81,297 together were compared. The SKF-81,297-induced increase in LMA was potentiated by coadministration of CART, while injection of CART alone had no significant effect. Injection of the D2 agonist 7-OH-DPAT had no effect on LMA, and the combination of both 7-OH-DPAT and CART peptide also had no effect. Quinelorane, a D3 receptor agonist, did not alter LMA, nor did the combination of CART peptide and quinelorane. The next experiment examined the effects of CART peptide on LMA induced by coinjection of both the D1 agonist SKF-81,297 and the D2 agonist 7-OH-DPAT. The combination of SKF-81,297 and 7-OH-DPAT induced greater LMA than SKF-81,297 alone. Coadministration of CART peptide along with the D1 and D2 agonists reduced LMA. These results strongly suggest that CART peptide reduces the effects of psychostimulants by modulating the simultaneous activation of both D1 and D2 dopamine receptors rather than by affecting the action of any individual dopamine receptor.
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Affiliation(s)
- Mark C Moffett
- Division of Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
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Rogge GA, Shen LL, Kuhar MJ. Chromatin immunoprecipitation assays revealed CREB and serine 133 phospho-CREB binding to the CART gene proximal promoter. Brain Res 2010; 1344:1-12. [PMID: 20451507 DOI: 10.1016/j.brainres.2010.04.069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/14/2010] [Accepted: 04/26/2010] [Indexed: 02/07/2023]
Abstract
Both over expression of cyclic AMP response element binding protein (CREB) in the nucleus accumbens (NAc), and intra-accumbal injection of cocaine- and amphetamine-regulated transcript (CART) peptides, have been shown to decrease cocaine reward. Also, over expression of CREB in the rat NAc increased CART mRNA and peptide levels, but it is not known if this was due to a direct action of P-CREB on the CART gene promoter. The goal of this study was to test if CREB and P-CREB bound directly to the CRE site in the CART promoter, using chromatin immunoprecipitation (ChIP) assays. ChIP assay with anti-CREB antibodies showed an enrichment of the CART promoter fragment containing the CRE region over IgG precipitated material, a non-specific control. Forskolin, which was known to increase CART mRNA levels in GH3 cells, was utilized to show that the drug increased levels of P-CREB protein and P-CREB binding to the CART promoter CRE-containing region. A region of the c-Fos promoter containing a CRE cis-regulatory element was previously shown to bind P-CREB, and it was used here as a positive control. These data suggest that the effects of CREB over expression on blunting cocaine reward could be, at least in part, attributed to the increased expression of the CART gene by direct interaction of P-CREB with the CART promoter CRE site, rather than by some indirect action.
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Affiliation(s)
- George A Rogge
- Yerkes National Research Primate Center of Emory University, Atlanta, GA 30329, USA
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Regulation of CART peptide expression by CREB in the rat nucleus accumbens in vivo. Brain Res 2008; 1251:42-52. [PMID: 19046951 DOI: 10.1016/j.brainres.2008.11.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 10/22/2008] [Accepted: 11/01/2008] [Indexed: 11/20/2022]
Abstract
Production of mRNA from the cocaine- and amphetamine-regulated transcript (CART) gene is regulated by cocaine and other drugs of abuse in the nucleus accumbens (NAc), a brain reward region. Current hypotheses postulate that CART peptides there oppose the rewarding actions of cocaine by opposing the effects of dopaminergic transmission. Since over expression of CREB was shown to decrease cocaine-mediated reward, we hypothesized that CART could be a target gene for CREB in the NAc and that over expression of CREB would increase CART peptide levels. Transcription factor (TF) binding to DNA is influenced by sequences adjacent to consensus TF binding sites and other factors. We thus examined CREB binding to a 27mer oligonucleotide containing the CRE sequence from the CART gene proximal promoter. Using electrophoretic mobility shift assays and TF-antibody super shift assays, CREB was found to bind to the CRE sequence from the CART promoter. To test if over expression of CREB in the NAc affected CART peptide levels, Herpes simplex virus-1 vectors over expressing CREB (HSV-CREB), or a vector that expressed LacZ (HSV-LacZ) as a control, were injected into the NAc of rats. Western blotting and in situ hybridization showed that HSV-CREB injections increased CART mRNA and peptide levels. Injections of a dominant negative CREB mutant (HSV-mCREB) did not alter either CART mRNA or peptide levels. The finding that CREB can regulate the levels of CART mRNA and peptides in vivo in the NAc supports a role for CART peptides in psychostimulant-induced reward and reinforcement.
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Rogge G, Jones D, Hubert GW, Lin Y, Kuhar MJ. CART peptides: regulators of body weight, reward and other functions. Nat Rev Neurosci 2008; 9:747-58. [PMID: 18802445 PMCID: PMC4418456 DOI: 10.1038/nrn2493] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Over the past decade or so, CART (cocaine- and amphetamine-regulated transcript) peptides have emerged as major neurotransmitters and hormones. CART peptides are widely distributed in the CNS and are involved in regulating many processes, including food intake and the maintenance of body weight, reward and endocrine functions. Recent studies have produced a wealth of information about the location, regulation, processing and functions of CART peptides, but additional studies aimed at elucidating the physiological effects of the peptides and at characterizing the CART receptor(s) are needed to take advantage of possible therapeutic applications.
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Affiliation(s)
- G Rogge
- Neuroscience Division, Yerkes National Primate Research Center of Emory University, 954 Gatewood Road NE, Atlanta, Georgia 30329, USA
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Hubert GW, Kuhar MJ. Cocaine administration increases the fraction of CART cells in the rat nucleus accumbens that co-immunostain for c-Fos. Neuropeptides 2008; 42:339-43. [PMID: 18314190 PMCID: PMC2493299 DOI: 10.1016/j.npep.2008.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 12/14/2007] [Accepted: 01/12/2008] [Indexed: 11/29/2022]
Abstract
In order to further test whether or not psychostimulant drugs activate CART peptide-containing cells in the nucleus accumbens, we examined the fraction of CART positive cells that co-immunostained for c-Fos after administration of saline or cocaine (10 and 25 mg/kg i.p.). There was about a 45% increase in the fraction of cells that stained for both CART and c-Fos after administration of cocaine, but there was no change in the fraction after administration of saline. Moreover, the increase was not found 24h after injection and is therefore reversible. These results support the notion that psychostimulant drugs activate CART cells in the nucleus accumbens, even under conditions where it is difficult to show a change in CART levels.
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Affiliation(s)
- G W Hubert
- Division of Neuroscience, The National Yerkes Primate Research Center of Emory University, Atlanta, GA 30329, USA.
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