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Skiba D, Jaskuła K, Nawrocka A, Poznański P, Łazarczyk M, Szymański Ł, Żera T, Sacharczuk M, Cudnoch-Jędrzejewska A, Gaciong Z. The Role of Opioid Receptor Antagonists in Regulation of Blood Pressure and T-Cell Activation in Mice Selected for High Analgesia Induced by Swim Stress. Int J Mol Sci 2024; 25:2618. [PMID: 38473865 DOI: 10.3390/ijms25052618] [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: 01/17/2024] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 03/14/2024] Open
Abstract
Opioid peptides and their G protein-coupled receptors are important regulators within the cardiovascular system, implicated in the modulation of both heart and vascular functions. It is known that naloxone-an opioid antagonist-may exert a hypertensive effect. Recent experimental and clinical evidence supports the important role of inflammatory mechanisms in hypertension. Since opioids may play a role in the regulation of both blood pressure and immune response, we studied these two processes in our model. We aimed to evaluate the effect of selective and non-selective opioid receptor antagonists on blood pressure and T-cell activation in a mouse model of high swim stress-induced analgesia. Blood pressure was measured before and during the infusion of opioid receptor antagonists using a non-invasive tail-cuff measurement system. To assess the activation of T-cells, flow cytometry was used. We discovered that the non-selective antagonism of the opioid system by naloxone caused a significant elevation of blood pressure. The selective antagonism of μ and κ but not δ opioid receptors significantly increased systolic blood pressure. Subsequently, a brief characterization of T-cell subsets was performed. We found that the blockade of μ and δ receptors is associated with the increased expression of CD69 on CD4 T-cells. Moreover, we observed an increase in the central memory CD4 and central memory CD8 T-cell populations after the δ opioid receptor blockade. The antagonism of the μ opioid receptor increased the CD8 effector and central memory T-cell populations.
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Affiliation(s)
- Dominik Skiba
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Kinga Jaskuła
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Agata Nawrocka
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Piotr Poznański
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Marzena Łazarczyk
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Łukasz Szymański
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
| | - Tymoteusz Żera
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Banacha 1B Street, 02-097 Warsaw, Poland
| | - Mariusz Sacharczuk
- Department of Experimental Genomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Postepu 36A Street, Jastrzebiec, 05-552 Magdalenka, Poland
- Department of Pharmacodynamics, Medical University of Warsaw, Zwirki i Wigury 81 Street, 02-091 Warsaw, Poland
| | - Agnieszka Cudnoch-Jędrzejewska
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Banacha 1B Street, 02-097 Warsaw, Poland
| | - Zbigniew Gaciong
- Department and Clinic of Internal Diseases, Hypertension and Angiology, Medical University of Warsaw, Banacha 1A Street, 02-097 Warsaw, Poland
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Abstract
BACKGROUND The endogenous opioid system affects metabolism, including weight regulation. Evidence from preclinical and clinical studies provides a rationale for targeting this system to mitigate weight-related side effects of antipsychotics. This review describes the role of the opioid system in regulating weight and metabolism, examines the effects of opioid receptor antagonism on those functions, and explores the use of opioid antagonists to mitigate antipsychotic-associated weight gain and/or metabolic effects. METHODS A PubMed literature search was conducted to identify representative opioid antagonists and associated preclinical and clinical studies examining their potential for the regulation of weight and metabolism. RESULTS The mu opioid receptor (MOR), delta opioid receptor (DOR), and kappa opioid receptor (KOR) types have overlapping but distinct patterns of central and peripheral expression, and each contributes to the regulation of body weight and metabolism. Three representative opioid antagonists (eg, naltrexone, samidorphan, and LY255582) were identified for illustration. These opioid antagonists differed in their receptor binding and pharmacokinetic profiles, including oral bioavailability, systemic clearance, and half-life, and were associated with varying effects on food intake, energy utilization, and metabolic dysregulation. CONCLUSIONS Preclinical and clinical data suggest that antagonism of the endogenous opioid system is a mechanism to address antipsychotic-associated weight gain and metabolic dysregulation. However, evidence suggests that the differing roles of MOR, DOR, and KOR in metabolism, together with the differences in receptor binding, pharmacokinetic, and functional activity profiles of the opioid receptor antagonists discussed in this review, likely contribute to their differential pharmacodynamic effects and clinical outcomes observed regarding antipsychotic-associated weight gain.
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Bodnar RJ. Endogenous opioid modulation of food intake and body weight: Implications for opioid influences upon motivation and addiction. Peptides 2019; 116:42-62. [PMID: 31047940 DOI: 10.1016/j.peptides.2019.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 03/04/2019] [Accepted: 04/08/2019] [Indexed: 12/12/2022]
Abstract
This review is part of a special issue dedicated to Opioid addiction, and examines the influential role of opioid peptides, opioid receptors and opiate drugs in mediating food intake and body weight control in rodents. This review postulates that opioid mediation of food intake was an example of "positive addictive" properties that provide motivational drives to maintain opioid-seeking behavior and that are not subject to the "negative addictive" properties associated with tolerance, dependence and withdrawal. Data demonstrate that opiate and opioid peptide agonists stimulate food intake through homeostatic activation of sensory, metabolic and energy-related In contrast, general, and particularly mu-selective, opioid receptor antagonists typically block these homeostatically-driven ingestive behaviors. Intake of palatable and hedonic food stimuli is inhibited by general, and particularly mu-selective, opioid receptor antagonists. The selectivity of specific opioid agonists to elicit food intake was confirmed through the use of opioid receptor antagonists and molecular knockdown (antisense) techniques incapacitating specific exons of opioid receptor genes. Further extensive evidence demonstrated that homeostatic and hedonic ingestive situations correspondingly altered the levels and expression of opioid peptides and opioid receptors. Opioid mediation of food intake was controlled by a distributed brain network intimately related to both the appetitive-consummatory sites implicated in food intake as well as sites intimately involved in reward and reinforcement. This emergent system appears to sustain the "positive addictive" properties providing motivational drives to maintain opioid-seeking behavior.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology, Queens College, City University of New York, United States; Psychology Doctoral Program and CUNY Neuroscience Collaborative, The Graduate Center of the City University of New York, United States.
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Ujcikova H, Hlouskova M, Cechova K, Stolarova K, Roubalova L, Svoboda P. Determination of μ-, δ- and κ-opioid receptors in forebrain cortex of rats exposed to morphine for 10 days: Comparison with animals after 20 days of morphine withdrawal. PLoS One 2017; 12:e0186797. [PMID: 29053731 PMCID: PMC5650167 DOI: 10.1371/journal.pone.0186797] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/06/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Chronic exposure of mammalian organism to morphine results in adaption to persistent high opioid tone through homeostatic adjustments. Our previous results indicated that in the frontal brain cortex (FBC) of rats exposed to morphine for 10 days, such a compensatory adjustment was detected as large up-regulation of adenylylcyclases I (8-fold) and II (2.5-fold). The other isoforms of AC (III-IX) were unchanged. Importantly, the increase of ACI and ACII was reversible as it disappeared after 20 days of morphine withdrawal. Changes of down-stream signaling molecules such as G proteins and adenylylcyclases should respond to and be preceded by primary changes proceeding at receptor level. Therefore in our present work, we addressed the problem of reversibility of the long-term morphine effects on μ-, δ- and κ-OR protein levels in FBC. METHODS Rats were exposed to increasing doses of morphine (10-40 mg/kg) for 10 days and sacrificed either 24 h (group +M10) or 20 days (group +M10/-M20) after the last dose of morphine in parallel with control animals (groups -M10 and -M10/-M20). Post-nuclear supernatant (PNS) fraction was prepared from forebrain cortex, resolved by 1D-SDS-PAGE under non-dissociated (-DTT) and dissociated (+DTT) conditions, and analyzed for the content of μ-, δ- and κ-OR by immunoblotting with C- and N-terminus oriented antibodies. RESULTS Significant down-regulation of δ-OR form exhibiting Mw ≈ 60 kDa was detected in PNS prepared from both (+M10) and (+M10/-M20) rats. However, the total immunoblot signals of μ-, δ- and κ-OR, respectively, were unchanged. Plasma membrane marker Na, K-ATPase, actin and GAPDH were unaffected by morphine in both types of PNS. Membrane-domain marker caveolin-1 and cholesterol level increased in (+M10) rats and this increase was reversed back to control level in (+M10/-M20) rats. CONCLUSIONS In FBC, prolonged exposure of rats to morphine results in minor (δ-OR) or no change (μ- and κ-OR) of opioid receptor content. The reversible increases of caveolin-1 and cholesterol levels suggest participation of membrane domains in compensatory responses during opioid withdrawal. GENERAL SIGNIFICANCE Analysis of reversibility of morphine effect on mammalian brain.
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MESH Headings
- Animals
- Blotting, Western
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Male
- Morphine/administration & dosage
- Morphine/adverse effects
- Prosencephalon/metabolism
- Rats
- Rats, Wistar
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/metabolism
- Substance Withdrawal Syndrome
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Affiliation(s)
- Hana Ujcikova
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martina Hlouskova
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Kristina Cechova
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Katerina Stolarova
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lenka Roubalova
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Svoboda
- Department of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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Yan JB, Hu ZH. [µ-opioid receptors in the central nucleus of the amygdala mediate sodium intake in rats]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2017; 37:1195-1200. [PMID: 28951361 PMCID: PMC6765484 DOI: 10.3969/j.issn.1673-4254.2017.09.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the opioidergic mechanism of the central nucleus of the amygdala (CeA) for regulating sodium appetite in rats. METHDOS Using the elaborate invasive cerebral cannulation and brain microinjection method, we observed the effects of bilateral intra-CeA injections of DAMGO (a selective µ-opioid receptor agonist) and CTAP (a highly selective µ-opioid receptor antagonist), either alone or in combination, on NaCl solution (0.3 mol/L) and water intake by rats in different models of Na+ ingestion. RESULTS In the two-bottle tests, bilateral injections of DAMGO at 1, 2, and 4 nmol into the CeA induced a dose-related increase of NaCl and water intake in rats treated with water deprivation with partial rehydration (WD-PR), and pretreatment with 0.5, 1, and 2 nmol CTAP injected into the CeA significantly suppressed DAMGO-induced NaCl and water intake in a dose-dependent manner: in the one-bottle tests, bilateral injections of DAMGO (2 noml) into the CeA had no effect on water intake of the rats. In rats with subcutaneous injection of furosemide (FURO) combined with captopril (CAP) (FURO+CAP), bilateral intra-CeA injections of DAMGO (2 nmol) caused increased NaCl and water intake in the two-bottle tests, but such effects were suppressed by pretreatment with CTAP injection into the CeA; in the one-bottle tests, bilateral intra-CeA injections of DAMGO had no effect on water intake of the rats. CONCLUSION µ-opioid receptors in the CeA are involved in the excitatory regulation of sodium appetite to mediate sodium intake. µ-opioid receptor antagonists are expected to be targets for developing inhibitors of sodium appetite.
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Affiliation(s)
- Jun-Bao Yan
- Department of Physiology, Medical College of Henan University of Science and Technology, Luoyang 471023, China.E-mail:
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Oliva L, Aranda T, Caviola G, Fernández-Bernal A, Alemany M, Fernández-López JA, Remesar X. In rats fed high-energy diets, taste, rather than fat content, is the key factor increasing food intake: a comparison of a cafeteria and a lipid-supplemented standard diet. PeerJ 2017; 5:e3697. [PMID: 28929011 PMCID: PMC5600723 DOI: 10.7717/peerj.3697] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/26/2017] [Indexed: 11/20/2022] Open
Abstract
Background Food selection and ingestion both in humans and rodents, often is a critical factor in determining excess energy intake and its related disorders. Methods Two different concepts of high-fat diets were tested for their obesogenic effects in rats; in both cases, lipids constituted about 40% of their energy intake. The main difference with controls fed standard lab chow, was, precisely, the lipid content. Cafeteria diets (K) were self-selected diets devised to be desirable to the rats, mainly because of its diverse mix of tastes, particularly salty and sweet. This diet was compared with another, more classical high-fat (HF) diet, devised not to be as tasty as K, and prepared by supplementing standard chow pellets with fat. We also analysed the influence of sex on the effects of the diets. Results K rats grew faster because of a high lipid, sugar and protein intake, especially the males, while females showed lower weight but higher proportion of body lipid. In contrast, the weight of HF groups were not different from controls. Individual nutrient’s intake were analysed, and we found that K rats ingested large amounts of both disaccharides and salt, with scant differences of other nutrients’ proportion between the three groups. The results suggest that the key differential factor of the diet eliciting excess energy intake was the massive presence of sweet and salty tasting food. Conclusions The significant presence of sugar and salt appears as a powerful inducer of excess food intake, more effective than a simple (albeit large) increase in the diet’s lipid content. These effects appeared already after a relatively short treatment. The differential effects of sex agree with their different hedonic and obesogenic response to diet.
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Affiliation(s)
- Laia Oliva
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain
| | - Tània Aranda
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain
| | - Giada Caviola
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain
| | - Anna Fernández-Bernal
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain
| | - Marià Alemany
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain.,Institute of Biomedicine, University of Barcelona, Barcelona, Spain.,CIBER OBN, Centro de Investigaciones Biomédicas en Red, Barcelona, Spain
| | - José Antonio Fernández-López
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain.,Institute of Biomedicine, University of Barcelona, Barcelona, Spain.,CIBER OBN, Centro de Investigaciones Biomédicas en Red, Barcelona, Spain
| | - Xavier Remesar
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Faculty of Biology, Barcelona, Spain.,Institute of Biomedicine, University of Barcelona, Barcelona, Spain.,CIBER OBN, Centro de Investigaciones Biomédicas en Red, Barcelona, Spain
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Endogenous central amygdala mu-opioid receptor signaling promotes sodium appetite in mice. Proc Natl Acad Sci U S A 2016; 113:13893-13898. [PMID: 27849613 DOI: 10.1073/pnas.1616664113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Due to the importance of dietary sodium and its paucity within many inland environments, terrestrial animals have evolved an instinctive sodium appetite that is commensurate with sodium deficiency. Despite a well-established role for central opioid signaling in sodium appetite, the endogenous influence of specific opioid receptor subtypes within distinct brain regions remains to be elucidated. Using selective pharmacological antagonists of opioid receptor subtypes, we reveal that endogenous mu-opioid receptor (MOR) signaling strongly drives sodium appetite in sodium-depleted mice, whereas a role for kappa (KOR) and delta (DOR) opioid receptor signaling was not detected, at least in sodium-depleted mice. Fos immunohistochemistry revealed discrete regions of the mouse brain displaying an increased number of activated neurons during sodium gratification: the rostral portion of the nucleus of the solitary tract (rNTS), the lateral parabrachial nucleus (LPB), and the central amygdala (CeA). The CeA was subsequently targeted with bilateral infusions of the MOR antagonist naloxonazine, which significantly reduced sodium appetite in mice. The CeA is therefore identified as a key node in the circuit that contributes to sodium appetite. Moreover, endogenous opioids, acting via MOR, within the CeA promote this form of appetitive behavior.
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Crowley NA, Kash TL. Kappa opioid receptor signaling in the brain: Circuitry and implications for treatment. Prog Neuropsychopharmacol Biol Psychiatry 2015; 62:51-60. [PMID: 25592680 PMCID: PMC4465498 DOI: 10.1016/j.pnpbp.2015.01.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/20/2014] [Accepted: 01/04/2015] [Indexed: 12/15/2022]
Abstract
Kappa opioid receptors (KORs) in the central nervous system have been known to be important regulators of a variety of psychiatry illnesses, including anxiety and addiction, but their precise involvement in these disorders is complex and has yet to be fully elucidated. Here, we briefly review the pharmacology of KORs in the brain, including KOR's involvement in anxiety, depression, and drug addiction. We also review the known neuronal circuitry impacted by KOR signaling, and interactions with corticotrophin-releasing factor (CRF), another key peptide in anxiety-related illnesses, as well as the role of glucocorticoids. We suggest that KORs are a promising therapeutic target for a host of neuropsychiatric conditions.
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Affiliation(s)
- Nicole A. Crowley
- Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA,Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas L. Kash
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Bodnar RJ. Endogenous opioids and feeding behavior: A decade of further progress (2004-2014). A Festschrift to Dr. Abba Kastin. Peptides 2015; 72:20-33. [PMID: 25843025 DOI: 10.1016/j.peptides.2015.03.019] [Citation(s) in RCA: 18] [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: 03/03/2015] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 12/13/2022]
Abstract
Functional elucidation of the endogenous opioid system temporally paralleled the creation and growth of the journal, Peptides, under the leadership of its founding editor, Dr. Abba Kastin. He was prescient in publishing annual and uninterrupted reviews on Endogenous Opiates and Behavior that served as a microcosm for the journal under his stewardship. This author published a 2004 review, "Endogenous opioids and feeding behavior: a thirty-year historical perspective", summarizing research in this field between 1974 and 2003. The present review "closes the circle" by reviewing the last 10 years (2004-2014) of research examining the role of endogenous opioids and feeding behavior. The review summarizes effects upon ingestive behavior following administration of opioid receptor agonists, in opioid receptor knockout animals, following administration of general opioid receptor antagonists, following administration of selective mu, delta, kappa and ORL-1 receptor antagonists, and evaluating opioid peptide and opioid receptor changes in different food intake models.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Behavioral and Cognitive Neuroscience Doctoral Program Cluster, Queens College, City University of New York, Flushing, NY 11367, United States.
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Pavan CG, Roncari CF, Barbosa SP, De Paula PM, Colombari DS, De Luca LA, Colombari E, Menani JV. Activation of μ opioid receptors in the LPBN facilitates sodium intake in rats. Behav Brain Res 2015; 288:20-5. [DOI: 10.1016/j.bbr.2015.03.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/03/2015] [Accepted: 03/22/2015] [Indexed: 10/23/2022]
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Nascimento AIR, Ferreira HS, Cerqueira DR, Fregoneze JB. Blockade of central delta-opioid receptors inhibits salt appetite in sodium-depleted rats. Peptides 2014; 55:110-9. [PMID: 24602802 DOI: 10.1016/j.peptides.2014.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 01/06/2023]
Abstract
Various studies have investigated the role of central opioid peptides in feeding behavior; however, only a few have addressed the participation of opioids in the control of salt appetite. The present study investigated the effect of intracerebroventricular injections of the δ-opioid antagonist, naltrindole (5, 10 and 20 nmol/rat) and the agonist, deltorphin II (2.5, 5, 10 and 20 nmol/rat) on salt intake. Two protocols for inducing salt intake were used: sodium-depletion and the central injection of angiotensin II. In addition, the effect of a central δ-opioid receptor blockade on locomotor activity, on palatable solution intake (0.1% saccharin) and on blood pressure was also studied. The blockade of central δ-opioid receptors inhibits salt intake in sodium-depleted rats, while the pharmacological stimulation of these receptors increases salt intake in sodium-replete animals. Furthermore, the blockade of central δ-opioid receptors inhibits salt intake induced by central angiotensinergic stimulation. These data suggest that during sodium-depletion activation of the δ-opioid receptors regulates salt appetite to correct the sodium imbalance and it is possible that an interaction between opioidergic and angiotensinergic brain system participates in this control. Under normonatremic conditions, δ-opioid receptors may be necessary to modulate sodium intake, a response that could be mediated by angiotensin II. The decrease in salt intake following central δ-opioid receptors blockade does not appear to be due to a general inhibition of locomotor activity, changes in palatability or in blood pressure.
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Affiliation(s)
- A I R Nascimento
- Department of Biological Sciences, State University of Southwest Bahia, 45200-000 Jequié, Bahia, Brazil; Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil
| | - H S Ferreira
- Life Sciences Department, Bahia State University, 41195-001 Salvador, Bahia, Brazil
| | - D R Cerqueira
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil
| | - J B Fregoneze
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil.
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Abstract
This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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Silva ML, Silva JR, Prado WA. Analgesia induced by 2- or 100-Hz electroacupuncture in the rat tail-flick test depends on the anterior pretectal nucleus. Life Sci 2013; 93:742-54. [DOI: 10.1016/j.lfs.2013.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/14/2013] [Accepted: 09/11/2013] [Indexed: 12/27/2022]
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