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Łupina M, Wąsik A, Baranowska-Bosiacka I, Tarnowski M, Słowik T, Listos P, Kotlińska J, Kosik-Bogacka D, Gutowska I, Listos J. Acute and Chronic Exposure to Linagliptin, a Selective Inhibitor of Dipeptidyl Peptidase-4 (DPP-4), Has an Effect on Dopamine, Serotonin and Noradrenaline Level in the Striatum and Hippocampus of Rats. Int J Mol Sci 2024; 25:3008. [PMID: 38474255 DOI: 10.3390/ijms25053008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
Linagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor that indirectly elevates the glucagon-like peptide-1 (GLP-1) level. The aim of the present study was to check whether linagliptin has an influence on neurotransmission in rat brain. Rats were acutely and chronically exposed to linagliptin (10 and 20 mg/kg, intraperitoneally (i.p.)). Twenty-four hours later, the striatum and hippocampus were selected for further studies. In neurochemical experiments, using high-performance liquid chromatography with electrochemical detection (HPLC-ED), the concentrations of three major neurotransmitters-dopamine, serotonin and noradrenaline-and their metabolites were measured. The analysis of mRNA expression of dopamine (D1 and D2), serotonin (5-HT-1 and 5-HT-2) and noradrenaline (α1 and α2a) receptors was also investigated using real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in the same brain areas. Linagliptin has the ability to influence the dopaminergic system. In the striatum, the elevation of dopamine and its metabolites was observed after repeated administration of that linagliptin, and in the hippocampus, a reduction in dopamine metabolism was demonstrated. Acute linagliptin exposure increases the serotonin level in both areas, while after chronic linagliptin administration a tendency for the mRNA expression of serotoninergic receptors (5-HT1A and 5-HT2A) to increase was observed. A single instance of exposure to linagliptin significantly modified the noradrenaline level in the striatum and intensified noradrenaline turnover in the hippocampus. The recognition of the interactions in the brain between DPP-4 inhibitors and neurotransmitters and/or receptors is a crucial step for finding novel discoveries in the pharmacology of DPP-4 inhibitors and raises hope for further applications of DPP-4 inhibitors in clinical practices.
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Affiliation(s)
- Małgorzata Łupina
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b St., 20-090 Lublin, Poland
| | - Agnieszka Wąsik
- Department of Neurochemistry, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111 Szczecin, Poland
| | - Maciej Tarnowski
- Department of Physiology in Health Sciences, Pomeranian Medical University, Żołnierska 54, 70-210 Szczecin, Poland
| | - Tymoteusz Słowik
- Experimental Medicine Center, Medical University of Lublin, Jaczewskiego 8d St., 20-090 Lublin, Poland
| | - Piotr Listos
- Department of Pathological Anatomy, Faculty of Veterinary Medicine, University of Life Sciences, Głęboka 30, 20-612 Lublin, Poland
| | - Jolanta Kotlińska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093 Lublin, Poland
| | - Danuta Kosik-Bogacka
- Independent Laboratory of Pharmaceutical Botany, Department of Biology and Medical Parasitology, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24, 71-460 Szczecin, Poland
| | - Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093 Lublin, Poland
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Linagliptin, a Selective Dipeptidyl Peptidase-4 Inhibitor, Reduces Physical and Behavioral Effects of Morphine Withdrawal. Molecules 2022; 27:molecules27082478. [PMID: 35458676 PMCID: PMC9028142 DOI: 10.3390/molecules27082478] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/18/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
(1) Background: Recent data indicate that receptors for GLP-1 peptide are involved in the activity of the mesolimbic system. Thus, the purpose of the present study was to examine the effect of the selective dipeptidyl peptidase-4 (DPP-4) inhibitor, linagliptin, on morphine dependence in mice. (2) Methods: Morphine dependence in mice was obtained by administration of increasing doses of morphine for eight consecutive days, twice a day. On the 9th day of the experiment, the naloxone-induced (2 mg/kg, ip) morphine withdrawal signs (jumping) were assessed. Moreover, behavioral effects of short-term (60 h after morphine discontinuation) and long-term (14 days after morphine discontinuation) morphine withdrawal were observed. In terms of behavioral effects, the depressive effect in the forced swim test and anxiety in the elevated plus maze test were investigated. Locomotor activity of mice was also studied. (3) Results: The administration of linagliptin (10 and 20 mg/kg, ip) for 8 consecutive days before morphine injections significantly diminished the number of naloxone-induced morphine withdrawal signs (jumping) in mice. In addition, the cessation of morphine administration induced depressive behavior in mice which were observed during short- and long-term morphine withdrawal. Linagliptin administered during morphine withdrawal significantly reduced the depressive behavior in studied mice. Furthermore, the short-term morphine withdrawal evoked anxiety which also was reduced by linagliptin in mice. (4) Conclusions: The present study reveals that GLP-1 receptors are involved in morphine dependence. What is more, linagliptin might be a valuable drug in attenuating the physical symptoms of morphine dependence. It might be also a useful drug in reducing emotional disturbances which may develop during the morphine withdrawal period.
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Eacret D, Noreck J, Blendy J. Adenosine Monophosphate-activated Protein Kinase (AMPK) in serotonin neurons mediates select behaviors during protracted withdrawal from morphine in mice. Behav Brain Res 2022; 419:113688. [PMID: 34843742 PMCID: PMC8688336 DOI: 10.1016/j.bbr.2021.113688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/11/2021] [Accepted: 11/23/2021] [Indexed: 01/02/2023]
Abstract
Serotonin neurotransmission has been implicated in behavior deficits that occur during protracted withdrawal from opioids. In addition, studies have highlighted multiple pathways whereby serotonin (5-HT) modulates energy homeostasis, however the underlying metabolic effects of opioid withdrawal have not been investigated. A key metabolic regulator that senses the energy status of the cell and regulates fuel availability is Adenosine Monophosphate-activated Protein Kinase (AMPK). To investigate the interaction between cellular metabolism and serotonin in modulating protracted abstinence from morphine, we depleted AMPK in serotonin neurons. Morphine exposure via drinking water generates dependence in these mice, and both wildtype and serotonergic AMPK knockout mice consume similar amounts of morphine with no changes in body weight. Serotonergic AMPK contributes to baseline differences in open field and social interaction behaviors and blocks abstinence induced reductions in immobility following morphine withdrawal in the tail suspension test. Lastly, morphine locomotor sensitization is blunted in mice lacking AMPK in serotonin neurons. Taken together, our results suggest serotonergic AMPK mediates both baseline and protracted morphine withdrawal-induced behaviors.
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Affiliation(s)
- D. Eacret
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - J. Noreck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - J.A. Blendy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Corresponding author , Phone: (215) 898-0730, Fax: (215) 573-2236
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Chivite M, Naderi F, Conde-Sieira M, Soengas JL, Lopez-Patiño MA, Míguez JM. Central serotonin participates in the anorexigenic effect of GLP-1 in rainbow trout (Oncorhynchus mykiss). Gen Comp Endocrinol 2021; 304:113716. [PMID: 33484717 DOI: 10.1016/j.ygcen.2021.113716] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/03/2021] [Accepted: 01/12/2021] [Indexed: 12/20/2022]
Abstract
The incretin, glucagon-like peptide-1 (GLP-1) is a major player in the gut-brain axis regulation of energy balance and in fish it seems to exert a negative influence on food intake. In this study, we investigated the role of the brain serotonergic system in the effects promoted by a peripheral GLP-1 injection on food intake in rainbow trout (Oncorhynchus mykiss). For this, in a first experiment the incretin was intraperitoneally injected (100 ng/g body weight) alone or in combination with a 5HT2C receptor antagonist (SB 242084, 1 µg/g body weight) and food intake was measured 30, 90, and 180 min later. In a second experiment, we studied the effect of these treatments on mRNA abundance of hypothalamic neuropeptides that control food intake. In addition, the effect of GLP-1 on serotonin metabolism was assessed in hindbrain and hypothalamus. Our results show that GLP-1 induced a significant food intake inhibition, which agreed with the increased expression of anorexigenic neuropeptides pomc and cart in the hypothalamus. Furthermore, GLP-1 stimulated the synthesis of serotonin in the hypothalamus, which might be indicative of a higher use of the neurotransmitter. The effects of GLP-1 on food intake were partially reversed when a serotonin receptor antagonist, SB 242084, was previously administered to trout. This antagonist also reversed the stimulatory effect of the hormone in hypothalamic pomca1 mRNA abundance. We conclude that hypothalamic serotonergic pathways are essential for mediating the effects of GLP-1 on food intake in rainbow trout. In addition, the 5HT2C receptor subtype seems to have a prominent role in the inhibition of food intake induced by GLP-1 in this species.
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Affiliation(s)
- Mauro Chivite
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain
| | - Fatemeh Naderi
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain
| | - Marta Conde-Sieira
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain
| | - José Luis Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain
| | - Marcos A Lopez-Patiño
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain
| | - Jesús M Míguez
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, E-36310 Vigo, Spain.
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Essmat N, Soliman E, Mahmoud MF, Mahmoud AAA. Antidepressant activity of anti-hyperglycemic agents in experimental models: A review. Diabetes Metab Syndr 2020; 14:1179-1186. [PMID: 32673838 DOI: 10.1016/j.dsx.2020.06.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND AIMS Diabetes Mellitus (DM) and depression occur comorbidly and share some pathophysiological mechanisms. The course of depression in patients with the two conditions is severe. Treatment of depression in diabetic patients requires special attention because most of psychopharmacological agents can worsen glycemic control. This article aims to review studies evaluating the antidepressant effect of anti-hyperglycemic agents from preclinical perspective. METHODS A literature search was performed with PubMed and Google Scholar using relevant keywords (antidiabetic; diabetes; depression; antidepressant; animals) to extract relevant studies evaluating the antidepressant activity of anti-hyperglycemic agents in experimental models. RESULTS Several studies have reported that some traditional anti-hyperglycemic agents reduce depression-like behavior in the absence or presence of diabetes. These drugs include insulin, glyburide, metformin, pioglitazone, vildagliptin, liraglutide, and exenatide. The antidepressant activity of anti-hyperglycemic agents may be mediated by reducing the blood glucose level, ameliorating the central oxidative stress and inflammation, and regulating the hypothalamic-pituitary-adrenal axis (HPAA). CONCLUSIONS Drugs which have both antidiabetic and antidepressant activities can provide better treatment strategy for patients with diabetes-associated depression. However, further research studies are still required in human subjects.
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Affiliation(s)
- Nariman Essmat
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Eman Soliman
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
| | - Mona F Mahmoud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Amr A A Mahmoud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt; Department of Pharmacology, Pharmacy Program, Oman College of Health Sciences, Muscat, 114, Oman
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Association between GLP-1 receptor gene polymorphisms with reward learning, anhedonia and depression diagnosis. Acta Neuropsychiatr 2020; 32:218-225. [PMID: 32213216 PMCID: PMC7351594 DOI: 10.1017/neu.2020.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Glucagon-like peptide-1 receptors (GLP-1Rs) are widely expressed in the brain. Evidence suggests that they may play a role in reward responses and neuroprotection. However, the association of GLP-1R with anhedonia and depression diagnosis has not been studied. Here, we examined the association of GLP-1R polymorphisms with objective and subjective measures of anhedonia, as well as depression diagnosis. METHODS Objective [response bias assessed by the probabilistic reward task (PRT)] and subjective [Snaith-Hamilton Pleasure Scale (SHAPS)] measures of anhedonia, clinical variables and DNA samples were collected from 100 controls and 164 patients at McLean Hospital. An independent sample genotyped as part of the Psychiatric Genomics Consortium (PGC) was used to study the effect of putative GLP-1R polymorphisms linked to response bias in PRT on depression diagnosis. RESULTS The C allele in rs1042044 was significantly associated with increased PRT response bias, when controlling for age, sex, case-control status and PRT discriminability. AA genotype of rs1042044 showed higher anhedonia phenotype based on SHAPS scores. However, analysis of PGC major depressive disorder data showed no association between rs1042044 and depression diagnosis. CONCLUSION Findings suggest a possible association of rs1042044 with anhedonia but no association with depression diagnosis.
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Neuroprotective and Neuromodulatory Effects Induced by Cannabidiol and Cannabigerol in Rat Hypo-E22 cells and Isolated Hypothalamus. Antioxidants (Basel) 2020; 9:antiox9010071. [PMID: 31941059 PMCID: PMC7022242 DOI: 10.3390/antiox9010071] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/23/2019] [Accepted: 01/10/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cannabidiol (CBD) and cannabigerol (CBG) are non-psychotropic terpenophenols isolated from Cannabis sativa, which, besides their anti-inflammatory/antioxidant effects, are able to inhibit, the first, and to stimulate, the second, the appetite although there are no studies elucidating their role in the hypothalamic appetite-regulating network. Consequently, the aim of the present research is to investigate the role of CBD and CBG in regulating hypothalamic neuromodulators. Comparative evaluations between oxidative stress and food intake-modulating mediators were also performed. METHODS Rat hypothalamic Hypo-E22 cells and isolated tissues were exposed to either CBD or CBG, and the gene expressions of neuropeptide (NP)Y, pro-opiomelanocortin (POMC) and fatty acid amide hydrolase were assessed. In parallel, the influence of CBD on the synthesis and release of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) was evaluated. The 3-hydroxykinurenine/kinurenic acid (3-HK/KA) ratio was also determined. RESULTS Both CBD and CBG inhibited NPY and POMC gene expression and decreased the 3-HK/KA ratio in the hypothalamus. The same compounds also reduced hypothalamic NE synthesis and DA release, whereas the sole CBD inhibited 5-HT synthesis. CONCLUSION The CBD modulates hypothalamic neuromodulators consistently with its anorexigenic role, whereas the CBG effect on the same mediators suggests alternative mechanisms, possibly involving peripheral pathways.
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Hypophagia induced by hindbrain serotonin is mediated through central GLP-1 signaling and involves 5-HT2C and 5-HT3 receptor activation. Neuropsychopharmacology 2019; 44:1742-1751. [PMID: 30959513 PMCID: PMC6784912 DOI: 10.1038/s41386-019-0384-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/01/2019] [Accepted: 03/30/2019] [Indexed: 02/06/2023]
Abstract
The overlap in neurobiological circuitry mediating the physiological and behavioral response to satiation and noxious/stressful stimuli are not well understood. The interaction between serotonin (5-HT) and glucagon-like peptide-1 (GLP-1) could play a role as upstream effectors involved in mediating associations between anorectic and noxious/stressful stimuli. We hypothesize that 5-HT acts as an endogenous modulator of the central GLP-1 system to mediate satiation and malaise in rats. Here, we investigate whether interactions between central 5-HT and GLP-1 signaling are behaviorally and physiologically relevant for the control of food intake and pica (i.e., behavioral measure of malaise). Results show that the anorexia and body weight changes induced by administration of exogenous hindbrain 5-HT are dependent on central GLP-1 receptor signaling. Furthermore, anatomical evidence shows mRNA expression of 5-HT2C and 5-HT3 receptors on GLP-1-producing preproglucagon (PPG) neurons in the medial nucleus tractus solitarius by fluorescent in situ hybridization, suggesting that PPG neurons are likely to express both of these receptors. Behaviorally, the hypophagia induced by the pharmacological activation of both of these receptors is also dependent on GLP-1 signaling. Finally, 5-HT3, but not 5-HT2C receptors, are required for the anorectic effects of the interoceptive stressor LiCl, suggesting the hypophagia induced by these 5-HT receptors may be driven by different mechanisms. Our findings highlight 5-HT as a novel endogenous modulator of the central GLP-1 system and suggest that the central interaction between 5-HT and GLP-1 is involved in the control of food intake in rats.
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Rebosio C, Balbi M, Passalacqua M, Ricciarelli R, Fedele E. Presynaptic GLP-1 receptors enhance the depolarization-evoked release of glutamate and GABA in the mouse cortex and hippocampus. Biofactors 2018; 44:148-157. [PMID: 29265673 DOI: 10.1002/biof.1406] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/13/2017] [Accepted: 11/28/2017] [Indexed: 12/27/2022]
Abstract
Glucagon-like peptide-1 receptors (GLP-1Rs) have been shown to mediate cognitive-enhancing and neuroprotective effects in the central nervous system. However, little is known about their physiological roles on central neurotransmission, especially at the presynaptic level. Using purified synaptosomal preparations and immunofluorescence techniques, here we show for the first time that GLP-1Rs are localized on mouse cortical and hippocampal synaptic boutons, in particular on glutamatergic and GABAergic nerve terminals. Their activation by the selective agonist exendin-4 (1-100 nM) was able to increase the release of either [3 H]d-aspartate or [3 H]GABA. These effects were abolished by 10 nM of the selective GLP1-R antagonist exendin-3 (9-39) and were prevented by the selective adenylyl cyclase inhibitor 2',5'-dideoxyadenosine (10 µM), indicating the involvement of classic GLP-1Rs coupled to Gs protein stimulating cAMP synthesis. Our data demonstrate the existence and activity of presynaptic receptors for GLP-1 that could represent additional mechanisms by which this neurohormone exerts its effects in the CNS. © 2017 BioFactors, 44(2):148-157, 2018.
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Affiliation(s)
- Claudia Rebosio
- Department of Pharmacy, Section of Pharmacology and Toxicology, University of Genova, Italy
| | - Matilde Balbi
- Department of Pharmacy, Section of Pharmacology and Toxicology, University of Genova, Italy
| | - Mario Passalacqua
- Department of Experimental Medicine, Section of Biochemistry and Italian Institute of Biostructures and Biosystems, University of Genova, Italy
| | - Roberta Ricciarelli
- Department of Experimental Medicine, Section of General Pathology, University of Genova, Italy
| | - Ernesto Fedele
- Department of Pharmacy, Section of Pharmacology and Toxicology, University of Genova, Italy
- Centre of Excellence for Biomedical Research, Pharmacology and Toxicology Unit, University of Genova, Italy
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Anderberg RH, Richard JE, Eerola K, López-Ferreras L, Banke E, Hansson C, Nissbrandt H, Berqquist F, Gribble FM, Reimann F, Wernstedt Asterholm I, Lamy CM, Skibicka KP. Glucagon-Like Peptide 1 and Its Analogs Act in the Dorsal Raphe and Modulate Central Serotonin to Reduce Appetite and Body Weight. Diabetes 2017; 66:1062-1073. [PMID: 28057699 PMCID: PMC6237271 DOI: 10.2337/db16-0755] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 01/02/2017] [Indexed: 12/13/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) and serotonin play critical roles in energy balance regulation. Both systems are exploited clinically as antiobesity strategies. Surprisingly, whether they interact in order to regulate energy balance is poorly understood. Here we investigated mechanisms by which GLP-1 and serotonin interact at the level of the central nervous system. Serotonin depletion impaired the ability of exendin-4, a clinically used GLP-1 analog, to reduce body weight in rats, suggesting that serotonin is a critical mediator of the energy balance impact of GLP-1 receptor (GLP-1R) activation. Serotonin turnover and expression of 5-hydroxytryptamine (5-HT) 2A (5-HT2A) and 5-HT2C serotonin receptors in the hypothalamus were altered by GLP-1R activation. We demonstrate that the 5-HT2A, but surprisingly not the 5-HT2C, receptor is critical for weight loss, anorexia, and fat mass reduction induced by central GLP-1R activation. Importantly, central 5-HT2A receptors are also required for peripherally injected liraglutide to reduce feeding and weight. Dorsal raphe (DR) harbors cell bodies of serotonin-producing neurons that supply serotonin to the hypothalamic nuclei. We show that GLP-1R stimulation in DR is sufficient to induce hypophagia and increase the electrical activity of the DR serotonin neurons. Finally, our results disassociate brain metabolic and emotionality pathways impacted by GLP-1R activation. This study identifies serotonin as a new critical neural substrate for GLP-1 impact on energy homeostasis and expands the current map of brain areas impacted by GLP-1R activation.
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Affiliation(s)
- Rozita H Anderberg
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Jennifer E Richard
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Kim Eerola
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Lorena López-Ferreras
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Elin Banke
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Caroline Hansson
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Hans Nissbrandt
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Filip Berqquist
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Fiona M Gribble
- MRC Metabolic Diseases Unit and Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Frank Reimann
- MRC Metabolic Diseases Unit and Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Ingrid Wernstedt Asterholm
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Christophe M Lamy
- Laboratory of Neurometabolic Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Karolina P Skibicka
- Department of Physiology/Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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Palleria C, Leo A, Andreozzi F, Citraro R, Iannone M, Spiga R, Sesti G, Constanti A, De Sarro G, Arturi F, Russo E. Liraglutide prevents cognitive decline in a rat model of streptozotocin-induced diabetes independently from its peripheral metabolic effects. Behav Brain Res 2017; 321:157-169. [PMID: 28062257 DOI: 10.1016/j.bbr.2017.01.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/23/2016] [Accepted: 01/01/2017] [Indexed: 12/13/2022]
Abstract
Diabetes has been identified as a risk factor for cognitive dysfunctions. Glucagone like peptide 1 (GLP-1) receptor agonists have neuroprotective effects in preclinical animal models. We evaluated the effects of GLP-1 receptor agonist, liraglutide (LIR), on cognitive decline associated with diabetes. Furthermore, we studied LIR effects against hippocampal neurodegeneration induced by streptozotocin (STZ), a well-validated animal model of diabetes and neurodegeneration associated with cognitive decline. Diabetes and/or cognitive decline were induced in Wistar rats by intraperitoneal or intracerebroventricular injection of STZ and then rats were treated with LIR (300μg/kg daily subcutaneously) for 6 weeks. Rats underwent behavioral tests: Morris water maze, passive avoidance, forced swimming (FST), open field, elevated plus maze, rotarod tests. Furthermore, LIR effects on hippocampal neurodegeneration and mTOR pathway (AKT, AMPK, ERK and p70S6K) were assessed. LIR improved learning and memory only in STZ-treated animals. Anxiolytic effects were observed in all LIR-treated groups but pro-depressant effects in CTRL rats were observed. At a cellular/molecular level, intracerebroventricular STZ induced hippocampal neurodegeneration accompanied by decreased phosphorylation of AMPK, AKT, ERK and p70S6K. LIR reduced hippocampal neuronal death and prevented the decreased phosphorylation of AKT and p70S6K; AMPK was hyper-phosphorylated in comparison to CTRL group, while LIR had no effects on ERK. LIR reduced animal endurance in the rotarod test and this effect might be also linked to a reduction in locomotor activity during only the last two minutes of the FST. LIR had protective effects on cognitive functions in addition to its effects on blood glucose levels. LIR effects in the brain also comprised anxiolytic and pro-depressant actions (although influenced by reduced endurance). Finally, LIR protected from diabetes-dependent hippocampal neurodegeneration likely through an effect on mTOR pathway.
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Affiliation(s)
- Caterina Palleria
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Antonio Leo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Michelangelo Iannone
- CNR, Institute of Neurological Sciences, Pharmacology Section, Roccelletta di Borgia, Catanzaro, Italy
| | - Rosangela Spiga
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Giorgio Sesti
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Andrew Constanti
- Department of Pharmacology, UCL School of Pharmacy, 29/39 Brunswick Square, London, UK
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Franco Arturi
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy.
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12
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Dwarkasing JT, Witkamp RF, Boekschoten MV, Ter Laak MC, Heins MS, van Norren K. Increased hypothalamic serotonin turnover in inflammation-induced anorexia. BMC Neurosci 2016; 17:26. [PMID: 27207102 PMCID: PMC4875640 DOI: 10.1186/s12868-016-0260-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 05/11/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Anorexia can occur as a serious complication of disease. Increasing evidence suggests that inflammation plays a major role, along with a hypothalamic dysregulation characterized by locally elevated serotonin levels. The present study was undertaken to further explore the connections between peripheral inflammation, anorexia and hypothalamic serotonin metabolism and signaling pathways. First, we investigated the response of two hypothalamic neuronal cell lines to TNFα, IL-6 and LPS. Next, we studied transcriptomic changes and serotonergic activity in the hypothalamus of mice after intraperitoneal injection with TNFα, IL-6 or a combination of TNFα and IL-6. RESULTS In vitro, we showed that hypothalamic neurons responded to inflammatory mediators by releasing cytokines. This inflammatory response was associated with an increased serotonin release. Mice injected with TNFα and IL-6 showed decreased food intake, associated with altered expression of inflammation-related genes in the hypothalamus. In addition, hypothalamic serotonin turnover showed to be elevated in treated mice. CONCLUSIONS Overall, our results underline that peripheral inflammation reaches the hypothalamus where it affects hypothalamic serotoninergic metabolism. These hypothalamic changes in serotonin pathways are associated with decreased food intake, providing evidence for a role of serotonin in inflammation-induced anorexia.
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Affiliation(s)
- J T Dwarkasing
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD, Wageningen, The Netherlands.
| | - R F Witkamp
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD, Wageningen, The Netherlands
| | - M V Boekschoten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD, Wageningen, The Netherlands
| | - M C Ter Laak
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD, Wageningen, The Netherlands
| | - M S Heins
- Brains On-line, P.O. Box 4030, 9701 EA, Groningen, The Netherlands
| | - K van Norren
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD, Wageningen, The Netherlands
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13
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The glucagon-like peptide 1 (GLP) receptor as a therapeutic target in Parkinson's disease: mechanisms of action. Drug Discov Today 2016; 21:802-18. [DOI: 10.1016/j.drudis.2016.01.013] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/03/2015] [Accepted: 01/25/2016] [Indexed: 02/06/2023]
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14
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Koshal P, Kumar P. Effect of Liraglutide on Corneal Kindling Epilepsy Induced Depression and Cognitive Impairment in Mice. Neurochem Res 2016; 41:1741-50. [PMID: 27017512 DOI: 10.1007/s11064-016-1890-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 03/14/2016] [Accepted: 03/17/2016] [Indexed: 12/13/2022]
Abstract
GLP-1 play important role in neuroprotection and GLP-1 receptor deficit mice showed decreased seizure threshold and increased cognitive impairment. Therefore, study was premeditated to investigate the effect of liraglutide (GLP-1 analogue) on cornel kindling epilepsy induced co-morbidities in mice. Corneal kindling was induced by electrical stimulation (6 mA, 50 Hz, 3 s); twice daily for 13 days. Liraglutide (75 and 150 µg/kg) and phenytoin (20 mg/kg) were administered in corneal kindled groups. On day 14, elevated plus maze, passive shock avoidance paradigms were performed, and on day 15, retention was taken. On day 16 tail suspension test were performed. On 20th day challenge test was performed with same electrical stimulation and retention was observed on elevated plus maze and passive avoidance paradigm. Animal were sacrificed on 21st day for biochemical (LPO, GSH, and nitrite) and neurochemical (GABA, glutamate, DA, NE, 5-HT and their metabolites) estimation. Electrical stimulation by corneal electrode for 13 days developed generalized clonic seizures, increased cognitive impairment, oxidative stress and neurochemical alteration in mice brain. Co-treatment with liraglutide (75 and 150 μg/kg) significantly prevented the seizure severity, restored behavioural activity, oxidative stress and restored the altered level of neurotransmitters observed in corneal kindled mouse.
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Affiliation(s)
- Prashant Koshal
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Ferozepur Road, Ghal Kalan, Moga, Punjab, 142001, India
| | - Puneet Kumar
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Ferozepur Road, Ghal Kalan, Moga, Punjab, 142001, India.
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15
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Koshal P, Kumar P. Neurochemical modulation involved in the beneficial effect of liraglutide, GLP-1 agonist on PTZ kindling epilepsy-induced comorbidities in mice. Mol Cell Biochem 2016; 415:77-87. [PMID: 26965494 DOI: 10.1007/s11010-016-2678-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 03/04/2016] [Indexed: 12/15/2022]
Abstract
Epilepsy is a neurological disorder which occurs due to excessive firing of excitatory neurons in specific region of brain and associated with cognitive impairment and depression. GLP-1 has been reported to maintain hyperexcitability of neurons. Therefore, this study was designed to investigate the neuroprotective effect of liraglutide, GLP-1 analogue in PTZ kindling epilepsy-induced comorbidities and neurochemical alteration in mice. Male albino mice were administered PTZ (35 mg/kg) on every alternate day up to 29th days and challenge test was performed on 33rd day. From 1st day liraglutide (75 and 150 µg/kg) and diazepam (3 mg/kg) were administered up to 33rd day, 30 min prior to PTZ treatment. On 30th day animals were trained on elevated plus maze and passive shock avoidance paradigm and retention was recorded on 31st and 33rd day. On 32nd day tail suspension test was performed. Animals were sacrificed on 34th day for biochemical (LPO, GSH, and nitrite) and neurotransmitters (GABA, glutamate, DA, NE, 5-HT and their metabolites) estimation. Chronic treatment with PTZ developed generalized tonic-clonic seizures, reduced cognitive skills, increased oxidative stress and alteration in the level of neurotransmitters. Pre-treatment with liraglutide (75 and 150 μg/kg) significantly prevented the seizure severity, restored behavioural activity, oxidative defence enzymes, and altered level of neurochemicals in mice brain. The protective effect of liraglutide is attributed to restoration of altered level of GABA, glutamate, DA, NE, and 5-HT by the up-regulation of GLP-1Rs in mice brain.
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Affiliation(s)
- Prashant Koshal
- Department of Pharmacology, ISF College of Pharmacy, Ferozepur Road, Ghal Kalan, Moga, Punjab, 142001, India
| | - Puneet Kumar
- Department of Pharmacology, ISF College of Pharmacy, Ferozepur Road, Ghal Kalan, Moga, Punjab, 142001, India.
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16
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Dwarkasing JT, Marks DL, Witkamp RF, van Norren K. Hypothalamic inflammation and food intake regulation during chronic illness. Peptides 2016; 77:60-6. [PMID: 26158772 DOI: 10.1016/j.peptides.2015.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/14/2015] [Accepted: 06/22/2015] [Indexed: 02/08/2023]
Abstract
Anorexia is a common symptom in chronic illness. It contributes to malnutrition and strongly affects survival and quality of life. A common denominator of many chronic diseases is an elevated inflammatory status, which is considered to play a pivotal role in the failure of food-intake regulating systems in the hypothalamus. In this review, we summarize findings on the role of hypothalamic inflammation on food intake regulation involving hypothalamic neuropeptide Y (NPY) and pro-opiomelanocortin (POMC). Furthermore, we outline the role of serotonin in the inability of these peptide based food-intake regulating systems to respond and adapt to changes in energy metabolism during chronic disease.
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Affiliation(s)
- J T Dwarkasing
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
| | - D L Marks
- Department of Pediatric Endocrinology, Oregon Health & Sciences University, Portland, OR 97201, USA
| | - R F Witkamp
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - K van Norren
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; Nutricia Research, Utrecht, The Netherlands
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17
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Hasni Ebou M, Singh-Estivalet A, Launay JM, Callebert J, Tronche F, Ferré P, Gautier JF, Guillemain G, Bréant B, Blondeau B, Riveline JP. Glucocorticoids Inhibit Basal and Hormone-Induced Serotonin Synthesis in Pancreatic Beta Cells. PLoS One 2016; 11:e0149343. [PMID: 26901633 PMCID: PMC4763453 DOI: 10.1371/journal.pone.0149343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/29/2016] [Indexed: 12/31/2022] Open
Abstract
Diabetes is a major complication of chronic Glucocorticoids (GCs) treatment. GCs induce insulin resistance and also inhibit insulin secretion from pancreatic beta cells. Yet, a full understanding of this negative regulation remains to be deciphered. In the present study, we investigated whether GCs could inhibit serotonin synthesis in beta cell since this neurotransmitter has been shown to be involved in the regulation of insulin secretion. To this aim, serotonin synthesis was evaluated in vitro after treatment with GCs of either islets from CD1 mice or MIN6 cells, a beta-cell line. We also explored the effect of GCs on the stimulation of serotonin synthesis by several hormones such as prolactin and GLP 1. We finally studied this regulation in islet in two in vivo models: mice treated with GCs and with liraglutide, a GLP1 analog, and mice deleted for the glucocorticoid receptor in the pancreas. We showed in isolated islets and MIN6 cells that GCs decreased expression and activity of the two key enzymes of serotonin synthesis, Tryptophan Hydroxylase 1 (Tph1) and 2 (Tph2), leading to reduced serotonin contents. GCs also blocked the induction of serotonin synthesis by prolactin or by a previously unknown serotonin activator, the GLP-1 analog exendin-4. In vivo, activation of the Glucagon-like-Peptide-1 receptor with liraglutide during 4 weeks increased islet serotonin contents and GCs treatment prevented this increase. Finally, islets from mice deleted for the GR in the pancreas displayed an increased expression of Tph1 and Tph2 and a strong increased serotonin content per islet. In conclusion, our results demonstrate an original inhibition of serotonin synthesis by GCs, both in basal condition and after stimulation by prolactin or activators of the GLP-1 receptor. This regulation may contribute to the deleterious effects of GCs on beta cells.
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Affiliation(s)
- Moina Hasni Ebou
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Amrit Singh-Estivalet
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Jean-Marie Launay
- INSERM U942, Assistance Publique–Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Service de Biochimie, Paris, France
| | - Jacques Callebert
- INSERM U942, Assistance Publique–Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Service de Biochimie, Paris, France
| | - François Tronche
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- CNRS UMR INSERM 952-CNRS 7224, Paris, France
| | - Pascal Ferré
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Jean-François Gautier
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Department of Diabetes and Endocrinology, Hôpital Lariboisière, AP-HP, Paris, France
- Université Paris Diderot, Paris, France
| | - Ghislaine Guillemain
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Bernadette Bréant
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Bertrand Blondeau
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- * E-mail:
| | - Jean-Pierre Riveline
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Department of Diabetes and Endocrinology, Hôpital Lariboisière, AP-HP, Paris, France
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Sharma AN, Ligade SS, Sharma JN, Shukla P, Elased KM, Lucot JB. GLP-1 receptor agonist liraglutide reverses long-term atypical antipsychotic treatment associated behavioral depression and metabolic abnormalities in rats. Metab Brain Dis 2015; 30:519-27. [PMID: 25023888 DOI: 10.1007/s11011-014-9591-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
Mood disorder patients that are on long-term atypical antipsychotics treatment frequently experience metabolic dysfunctions. In addition to this, accumulating evidences points to increased risk of structural abnormalities, brain volume changes, altered neuroplasticity and behavioral depression with long-term antipsychotics use. However, there is paucity of preclinical evidences for long-term antipsychotic associated depression-like behavior. The objectives of the present study were: (1) to evaluate influence of long-term antipsychotic (olanzapine) treatment on rat behavior in forced swim test (FST) as a model for depression and; (2) to examine impact of glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide - an antidiabetic medication for type II diabetes, on long-term olanzapine associated metabolic and behavioral changes in rats. Daily olanzapine treatment (0.5 mg/kg; p.o.) for 8-9 weeks significantly increased body weights, food and water intake, plasma cholesterol and triglycerides and immobility time in FST with parallel reduction in plasma HDL cholesterol levels. These results points to development of metabolic abnormalities and depression-like behavior with long-term olanzapine treatment. Acute liraglutide (50 μg/kg; i.p.) and imipramine (10 mg/kg, i. p.) treatment per se significantly decreased duration of immobility in FST compared to vehicle treated rats. Additionally, 3-week liraglutide treatment (50 μg/kg; i.p., daily) partially reversed metabolic abnormalities and depression-like behavior with long-term olanzapine-treatment in rats. None of these treatment regimens affected locomotor behavior of rats. In summary, add-on GLP-1 receptor agonists promise novel alternatives to counteract long-term antipsychotics associated behavioral and metabolic complications.
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Affiliation(s)
- Ajaykumar N Sharma
- Department of Pharmacology, S.T.E.S.s Smt. Kashibai Navale College of Pharmacy, Kondhwa (Bk), Pune, MS, 411048, India,
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19
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Voigt JP, Fink H. Serotonin controlling feeding and satiety. Behav Brain Res 2015; 277:14-31. [DOI: 10.1016/j.bbr.2014.08.065] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 02/06/2023]
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20
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Ramsey T, Brennan MD. Glucagon-like peptide 1 receptor (GLP1R) haplotypes correlate with altered response to multiple antipsychotics in the CATIE trial. Schizophr Res 2014; 160:73-9. [PMID: 25449714 PMCID: PMC4258179 DOI: 10.1016/j.schres.2014.09.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/23/2014] [Accepted: 09/25/2014] [Indexed: 11/29/2022]
Abstract
Glucagon-like peptide 1 receptor (GLP1R) signaling has been shown to have antipsychotic properties in animal models and to impact glucose-dependent insulin release, satiety, memory, and learning in man. Previous work has shown that two coding mutations (rs6923761 and rs1042044) are associated with altered insulin release and cortisol levels. We identified four frequently occurring haplotypes in Caucasians, haplotype 1 through haplotype 4, spanning exons 4-7 and containing the two coding variants. We analyzed response to antipsychotics, defined as predicted change in PANSS-Total (dPANSS) at 18 months, in Caucasian subjects from the Clinical Antipsychotic Trial of Intervention Effectiveness treated with olanzapine (n=139), perphenazine (n=78), quetiapine (n=14), risperidone (n=143), and ziprasidone (n=90). Haplotype trend regression analysis revealed significant associations with dPANSS for olanzapine (best p=0.002), perphenazine (best p=0.01), quetiapine (best p=0.008), risperidone (best p=0.02), and ziprasidone (best p=0.007). We also evaluated genetic models for the two most common haplotypes. Haplotype 1 (uniquely including the rs1042044 [Leu(260)] allele) was associated with better response to olanzapine (p=0.002), and risperidone (p=0.006), and worse response to perphenazine (p=.03), and ziprasidone (p=0.003), with a recessive genetic model providing the best fit. Haplotype 2 (uniquely including the rs6923761 [Ser(168)] allele) was associated with better response to perphenazine (p=0.001) and worse response to olanzapine (p=.02), with a dominant genetic model providing the best fit. However, GLP1R haplotypes were not associated with antipsychotic-induced weight gain. These results link functional genetic variants in GLP1R to antipsychotic response.
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21
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Patel KN, Joharapurkar AA, Patel V, Kshirsagar SG, Bahekar R, Srivastava BK, Jain MR. Cannabinoid receptor 1 antagonist treatment induces glucagon release and shows an additive therapeutic effect with GLP-1 agonist in diet-induced obese mice. Can J Physiol Pharmacol 2014; 92:975-83. [PMID: 25361428 DOI: 10.1139/cjpp-2014-0310] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cannabinoid 1 (CB1) receptor antagonists reduce body weight and improve insulin sensitivity. Preclinical data indicates that an acute dose of CB1 antagonist rimonabant causes an increase in blood glucose. A stable analog of glucagon-like peptide 1 (GLP-1), exendin-4 improves glucose-stimulated insulin secretion in pancreas, and reduces appetite through activation of GLP-1 receptors in the central nervous system and liver. We hypothesized that the insulin secretagogue effect of GLP-1 agonist exendin-4 may synergize with the insulin-sensitizing action of rimonabant. Intraperitoneal as well as intracerebroventricular administration of rimonabant increased serum glucose upon glucose challenge in overnight fasted, diet-induced obese C57 mice, with concomitant rise in serum glucagon levels. Exendin-4 reversed the acute hyperglycemia induced by rimonabant. The combination of exendin-4 and rimonabant showed an additive effect in the food intake, and sustained body weight reduction upon repeated dosing. The acute efficacy of both the compounds was additive for inducing nausea-like symptoms in conditioned aversion test in mice, whereas exendin-4 treatment antagonized the effect of rimonabant on forced swim test upon chronic dosing. Thus, the addition of exendin-4 to rimonabant produces greater reduction in food intake owing to increased aversion, but reduces the other central nervous system side effects of rimonabant. The hyperglucagonemia induced by rimonabant is partially responsible for enhancing the antiobesity effect of exendin-4.
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Affiliation(s)
- Kartikkumar Navinchandra Patel
- a Department of Pharmacology and Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Sarkhej-Bavla N.H. No. 8A, Moraiya, Ahmedabad 382210, India
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22
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Brunetti L, Orlando G, Ferrante C, Recinella L, Leone S, Chiavaroli A, Di Nisio C, Shohreh R, Manippa F, Ricciuti A, Vacca M. Peripheral chemerin administration modulates hypothalamic control of feeding. Peptides 2014; 51:115-21. [PMID: 24269538 DOI: 10.1016/j.peptides.2013.11.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 11/22/2022]
Abstract
Chemerin is a recently identified adipokine that is involved in the regulation of adipogenesis, energy metabolism, and inflammation. The aim of the present study was to investigate the role of chemerin on food intake, body weight and hypothalamic peptidergic and aminergic modulators which play a pivotal role in feeding regulation in rats. Male adult Wistar rats were intraperitoneally injected, daily for 17 days at 9.00am, with either vehicle (saline; N=12) or chemerin (8μg/kg; N=12) and (16μg/kg; N=12). Food intake was recorded 24h after each administration. Animals were sacrificed 24h after the last injection. Total RNA was extracted from hypothalami and reverse transcribed to evaluate gene expression of agouti-related peptide (AgRP), neuropeptide Y (NPY), orexin-A, corticotrophin releasing hormone (CRH), pro-opiomelanocortin (POMC) and cocaine and amphetamine-regulated transcript (CART). Furthermore, we evaluated the effect of chemerin on dopamine, norepinephrine and serotonin steady state concentrations in rat hypothalamus homogenate, and monoamine release from rat hypothalamic synaptosomes. Chemerin administration (8 and 16μg/kg) decreased both food intake and body weight compared to vehicle, possibly associated with a significant increase in serotonin synthesis and release, in the hypothalamus. On the other hand, the pattern of gene expression following chemerin administration indicates a minor role played by chemerin as a peripheral appetite-regulating signal.
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Affiliation(s)
- Luigi Brunetti
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Giustino Orlando
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Claudio Ferrante
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Lucia Recinella
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Sheila Leone
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Annalisa Chiavaroli
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Chiara Di Nisio
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Rugia Shohreh
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Fabio Manippa
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Adriana Ricciuti
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
| | - Michele Vacca
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
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Brunetti L, Orlando G, Ferrante C, Recinella L, Leone S, Chiavaroli A, Di Nisio C, Shohreh R, Manippa F, Ricciuti A, Vacca M. Orexigenic effects of omentin-1 related to decreased CART and CRH gene expression and increased norepinephrine synthesis and release in the hypothalamus. Peptides 2013; 44:66-74. [PMID: 23538212 DOI: 10.1016/j.peptides.2013.03.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/01/2013] [Accepted: 03/01/2013] [Indexed: 12/21/2022]
Abstract
Omentin-1, a visceral fat depot-specific secretory protein, is inversely correlated with obesity and insulin resistance. We investigated, in rats, the effects of chronic omentin-1 administration (8 μg/kg, intraperitoneally, once daily for 14-days) on feeding behavior and related hypothalamic peptides and neurotransmitters. Food intake and body weight were recorded daily throughout the study. We found a significantly increased food intake compared to controls, but only in days 10-14, while body weight significantly increased since day 12 (P<0.05). Compared with vehicle, omentin-1 treatment led to a significant reduction in both cocaine and amphetamine-regulated transcript (CART) (P<0.05) and corticotrophin releasing hormone (CRH) (P<0.05) gene expression, while pro-opiomelanocortin (POMC), agouti-related peptide (AgRP), neuropeptide Y (NPY) and orexin-A gene expression were not modified with respect to vehicle-treated rats. We also found an increase in hypothalamic levodopa (l-dopa) (P<0.05) and norepinephrine (NE) (P<0.01) synthesis, without any effect on dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) metabolism. Furthermore, in hypothalamic synaptosomes, omentin-1 (10-100 ng/ml) stimulated basal NE release (ANOVA, P<0.0001; post hoc, P<0.001 vs. vehicle), in a dose-dependent manner, leaving unaffected both basal and depolarization-induced DA and 5-HT release. Finally, when synaptosomes were co-perfused with leptin and omentin-1, we observed that leptin was able to reverse omentin-1-induced stimulation of NE. In conclusion, the orexigenic effects of omentin-1 could be related, at least in part, to decreased CART and CRH gene expression and increased NE synthesis and release in the hypothalamus.
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Affiliation(s)
- Luigi Brunetti
- Department of Pharmacy, "G. d'Annunzio" University, via dei Vestini 31, 66013 Chieti, Italy.
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Dixit TS, Sharma AN, Lucot JB, Elased KM. Antipsychotic-like effect of GLP-1 agonist liraglutide but not DPP-IV inhibitor sitagliptin in mouse model for psychosis. Physiol Behav 2013; 114-115:38-41. [PMID: 23523479 DOI: 10.1016/j.physbeh.2013.03.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/09/2013] [Accepted: 03/11/2013] [Indexed: 01/07/2023]
Abstract
Recent studies indicate a high comorbidity between type-2 diabetes mellitus (T2DM) and neurological disorders. Many are associated with abnormalities in dopamine neurotransmission such as schizophrenia. Because most of the antipsychotic drugs aggravate pre-existing insulin resistance in type-2 diabetics, there is a need to search for alternative antipsychotics. Glucagon like peptide-1 (GLP-1) is a gut hormone primarily involved in glucose homeostasis. GLP-1 agonist (liraglutide) and dipeptidyl peptidase-IV (DPP-IV) inhibitor (sitagliptin) are the US-FDA approved medications for the management of T2DM. However, little is known about their role in dopamine mediated neurological disorders like schizophrenia. To address this, we used apomorphine-induced cage climbing behavior as a murine model for psychosis and examined for potential antipsychotic-like effect of liraglutide and sitagliptin. While acute liraglutide treatment (50 μg/kg; i.p.) significantly attenuated apomorphine (3 mg/kg, s.c.) induced cage climbing, sitagliptin (50mg/kg; i.p.) failed to elicit such effect. This is the first preclinical evidence for antipsychotic-like effect of GLP-1 receptor agonist. These results open an opportunity to explore GLP-1 analogs for their potential to modulate spectrum of dopamine-mediated neurological disorders.
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Affiliation(s)
- Tejashree S Dixit
- Department of Pharmacology, S.T.E.S.s Smt. Kashibai Navale College of Pharmacy, Kondhwa (Bk), Pune, MS 411048, India
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Repeated administration of exendin-4 reduces focal cerebral ischemia-induced infarction in rats. Brain Res 2011; 1427:23-34. [PMID: 22055454 DOI: 10.1016/j.brainres.2011.10.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 09/23/2011] [Accepted: 10/14/2011] [Indexed: 12/20/2022]
Abstract
Exendin-4 is a GLP-1 agonist that is clinically used for the treatment of diabetes mellitus and may also have neuroprotective effect. We explored the effect of repeated administration of exendin-4 (0.5 μg/kg, intraperitoneal twice a day for 7 days) on infarct volume, neurological deficit (neurological score, grip test, foot fault and rota rod tests), oxidative stress parameters (malondialdehyde, reduced glutathione, and superoxide dismutase) and expression of endothelin (ET) ET(A) and ET(B) receptors following cerebral ischemia produced in rats by permanent middle cerebral artery occlusion (MCAO). Since ET(A) receptors in the central nervous system (CNS) are involved in cerebral ischemia, we determined the effect of a specific ET(A) receptor antagonist, BQ123 (1mg/kg, intravenously administered thrice: 30 min, 2h and 4h after MCAO for a total dose of 3 mg/kg) on cerebral ischemia in control and exendin-4 treated rats. Results indicate that exendin-4 treated rats had significant protection following MCAO induced cerebral ischemia. The infarct volume was 27% less compared to vehicle treated rats. The neurological deficit following MCAO was lower and oxidative stress parameters were improved in exendin-4 treated rats compared to control. BQ123 significantly improved infarct volume, oxidative stress parameters and neurological deficit in ischemic rats treated with vehicle or exendin-4. BQ123 induced protection from cerebral ischemia was similar in vehicle or exendin-4 treated rats. Expression of ET(A) receptors was significantly increased following cerebral ischemia which was not affected by exendin-4 treatment or by BQ123 administration. No change in expression of ET(B) receptors was observed following cerebral ischemia or any treatment. It is concluded that exendin-4 protects the CNS from damage due to cerebral ischemia by reducing oxidative stress and is independent of ET receptor involvement.
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Grant P, Lipscomb D, Quin J. Psychological and quality of life changes in patients using GLP-1 analogues. J Diabetes Complications 2011; 25:244-6. [PMID: 21601480 DOI: 10.1016/j.jdiacomp.2011.03.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/28/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
AIMS Using psychological and quality of life assessment tools, we prospectively studied changes in health-related quality of life and emotional well-being in patients who had commenced GLP-1 analogue therapy (exenatide) and compared them with new insulin starters. METHODS Two matched groups of patients with type 2 diabetes who had suboptimal glycaemic control on oral medication were assessed using a battery of well-validated psychological and quality of life tests at baseline, prior to commencement of treatment and then again after 6 months of continuous therapy, along with body mass index (BMI) and hemoglobin A1c (HbA1c) measurements. RESULTS In the exenatide-treated patient group (n=71), treatment satisfaction was greater (P<.05), as was the well-being score, at 6 months (P<.05), and the Hospital Anxiety and Depression Scale scores were significantly reduced (P<.05) when compared with the insulin-treated group (n=67). This was also found to be independent of changes in BMI in an analysis of covariance calculation. The effect size (using Cohen's d) of these changes was however relatively small. CONCLUSIONS Although exenatide and insulin appear to have similar efficacy for the treatment of type 2 diabetes mellitus, there are several differences between them that could influence outcomes from a patient's perspective. Exenatide affects both physiological and psychological parameters. 'Well-being' generally tends to improve in exenatide-treated patients and could be used as an adjunctive therapy for depression in the context of diabetes. A larger study is required to confirm these interesting findings.
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Affiliation(s)
- Paul Grant
- Royal Sussex County Hospital, Eastern Road, Brighton, 01273 696955 BN2 5BE, United Kingdom.
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Abstract
There is a rising worldwide prevalence of diabetes, especially type 2 diabetes mellitus (T2DM), which is one of the most challenging health problems in the 21st century. The associated complications of diabetes, such as cardiovascular disease, peripheral vascular disease, stroke, diabetic neuropathy, amputations, renal failure, and blindness result in increasing disability, reduced life expectancy, and enormous health costs. T2DM is a polygenic disease characterized by multiple defects in insulin action in tissues and defects in pancreatic insulin secretion, which eventually leads to loss of pancreatic insulin-secreting cells. The treatment goals for T2DM patients are effective control of blood glucose, blood pressure, and lipids (if elevated) and, ultimately, to avert the serious complications associated with sustained tissue exposure to excessively high glucose concentrations. Prevention and control of diabetes with diet, weight control, and physical activity has been difficult. Treatment of T2DM has centered on increasing insulin levels, either by direct insulin administration or oral agents that promote insulin secretion, improving sensitivity to insulin in tissues, or reducing the rate of carbohydrate absorption from the gastrointestinal tract. This review presents comprehensive and up-to-date information on the mechanism(s) of action, efficacy, pharmacokinetics, pleiotropic effects, drug interactions, and adverse effects of the newer antidiabetic drugs, including (1) peroxisome proliferator-activated-receptor-γ agonists (thiazolidinediones, pioglitazone, and rosiglitazone); (2) the incretin, glucagon-like peptide-) receptor agonists (incretin-mimetics, exenatide. and liraglutide), (3) inhibitors of dipeptidyl-peptidase-4 (incretin enhancers, sitagliptin, and vildagliptin), (4) short-acting, nonsulfonylurea secretagogue, meglitinides (repaglinide and nateglinide), (5) amylin anlog-pramlintide, (6) α-glucosidase inhibitors (miglitol and voglibose), and (7) colesevelam (a bile acid sequestrant). In addition, information is presented on drug candidates in clinical trials, experimental compounds, and some plants used in the traditional treatment of diabetes based on experimental evidence. In the opinion of this reviewer, therapy based on orally active incretins and incretin mimetics with long duration of action that will be efficacious, preserve the β-cell number/function, and block the progression of diabetes will be highly desirable. However, major changes in lifestyle factors such as diet and, especially, exercise will also be needed if the growing burden of diabetes is to be contained.
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Isacson R, Nielsen E, Dannaeus K, Bertilsson G, Patrone C, Zachrisson O, Wikström L. The glucagon-like peptide 1 receptor agonist exendin-4 improves reference memory performance and decreases immobility in the forced swim test. Eur J Pharmacol 2011; 650:249-55. [DOI: 10.1016/j.ejphar.2010.10.008] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/16/2010] [Accepted: 10/03/2010] [Indexed: 12/11/2022]
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Brunetti L, Di Nisio C, Recinella L, Orlando G, Ferrante C, Chiavaroli A, Leone S, Di Michele P, Shohreh R, Vacca M. Obestatin inhibits dopamine release in rat hypothalamus. Eur J Pharmacol 2010; 641:142-7. [PMID: 20553917 DOI: 10.1016/j.ejphar.2010.05.059] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 04/14/2010] [Accepted: 05/31/2010] [Indexed: 10/19/2022]
Abstract
We have investigated the effects of the gastric peptide obestatin injected into the arcuate nucleus of the rat hypothalamus on the hypothalamic mRNA expression of peptides which play master roles as feeding behavior modulators. We have also evaluated the effects of obestatin on dopamine, norepinephrine and serotonin release from rat hypothalamic synaptosomes in vitro. After 4 daily intrahypothalamic injections of obestatin (1 nmol/kg), we recorded a significant reduction of daily caloric intake and body weight gain. Gene expressions of either anorexigenic (cocaine- and amphetamine-regulated transcript, corticotropin releasing hormone, proopiomelanocortin) or orexigenic (agouti-related peptide, neuropeptide Y, orexin-A) peptide mRNAs in the hypothalamus, as evaluated by real-time quantitative PCR, were not different in respect to vehicle treated rats. Moreover, ghrelin/obestatin prepropeptide gene expression in the hypothalamus was not affected by obestatin treatment. In hypothalamic synaptosomes perfused with obestatin (1-100 nM), we found a dose-dependent inhibition of depolarization-induced dopamine release, while norepinephrine and serotonin releases were not modified by obestatin treatment. When ghrelin (1 nM) and obestatin (1 nM) were co-perfused, we observed that ghrelin reversed obestatin-induced inhibition of dopamine release, and obestatin was able to block ghrelin-induced inhibition of serotonin release. We can conclude that obestatin plays an anorectic role in the hypothalamus which could be partially mediated by the acute inhibition of dopamine release, with the possible involvement of antagonism of the hypothalamic serotonin inhibitory effects of ghrelin.
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Affiliation(s)
- Luigi Brunetti
- Department of Drug Sciences, School of Pharmacy, G. d'Annunzio University, via dei Vestini, Chieti, Italy
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