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Bischoff AR, Dalle Molle R, Mucellini AB, Pokhvisneva I, Levitan RD, Meaney MJ, Silveira PP. Accumbal μ-opioid receptors and salt taste-elicited hedonic responses in a rodent model of prenatal adversity, and their correlates using human functional genomics. Stress 2024; 27:2294954. [PMID: 38140734 DOI: 10.1080/10253890.2023.2294954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Prenatal adversity is associated with behavioral obesogenic features such as preference for palatable foods. Salt appetite may play a role in the development of adiposity and its consequences in individuals exposed to prenatal adversity, and sodium consumption involves individual differences in accumbal µ-opioid receptors function. We investigated the hedonic responses to salt and the levels of µ-opioid receptors and tyrosine hydroxylase in the nucleus accumbens (Nacc) of pups from an animal model of prenatal dietary restriction. In children, we evaluated the interaction between fetal growth and the genetic background associated with the accumbal µ-opioid receptor gene (OPRM1) expression on sodium consumption during a snack test. Sprague-Dawley dams were randomly allocated from pregnancy day 10 to receive an ad libitum (Adlib) or a 50% restricted (FR) diet. The pups' hedonic responses to a salt solution (NaCl 2%) or water were evaluated on the first day of life. FR and Adlib pups differ in their hedonic responses to salt, and there were decreased levels of accumbal µ-opioid and p-µ-opioid receptors in FR pups. In humans, a test meal and genotyping from buccal epithelial cells were performed in 270 children (38 intrauterine growth restricted-IUGR) at 4 years old from a Canadian prospective cohort (MAVAN). The OPRM1 genetic score predicted the sodium intake in IUGR children, but not in controls. The identification of mechanisms involved in the brain response to prenatal adversity and its consequences in behavioral phenotypes and risk for chronic diseases later in life is important for preventive and therapeutic purposes.
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Affiliation(s)
- Adrianne Rahde Bischoff
- Neonatal Hemodynamics, Stead Family Department of Pediatrics, Division of Neonatology, University of Iowa Stead Family Children's Hospital, Iowa City, IA, USA
| | - Roberta Dalle Molle
- Ludmer Centre for Neuroinformatics and Mental Health, McGill University, Montreal, Canada
- Douglas Mental Health University Institute, McGill University, Montreal, Canada
| | - Amanda Brondani Mucellini
- Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Irina Pokhvisneva
- Ludmer Centre for Neuroinformatics and Mental Health, McGill University, Montreal, Canada
- Douglas Mental Health University Institute, McGill University, Montreal, Canada
| | - Robert D Levitan
- Centre for Addition and Mental Health (CAMH) and Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Michael J Meaney
- Douglas Mental Health University Institute, McGill University, Montreal, Canada
- Department of Psychiatry, McGill University, Montreal, Canada
- Translational Neuroscience Program, Singapore Institute for Clinical Sciences and Brain - Body Initiative, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Patrícia P Silveira
- Ludmer Centre for Neuroinformatics and Mental Health, McGill University, Montreal, Canada
- Douglas Mental Health University Institute, McGill University, Montreal, Canada
- Department of Psychiatry, McGill University, Montreal, Canada
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Santollo J, Daniels D, Leshem M, Schulkin J. Sex Differences in Salt Appetite: Perspectives from Animal Models and Human Studies. Nutrients 2023; 15:208. [PMID: 36615865 PMCID: PMC9824138 DOI: 10.3390/nu15010208] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/26/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
Salt ingestion by animals and humans has been noted from prehistory. The search for salt is largely driven by a physiological need for sodium. There is a large body of literature on sodium intake in laboratory rats, but the vast majority of this work has used male rats. The limited work conducted in both male and female rats, however, reveals sex differences in sodium intake. Importantly, while humans ingest salt every day, with every meal and with many foods, we do not know how many of these findings from rodent studies can be generalized to men and women. This review provides a synthesis of the literature that examines sex differences in sodium intake and highlights open questions. Sodium serves many important physiological functions and is inextricably linked to the maintenance of body fluid homeostasis. Indeed, from a motivated behavior perspective, the drive to consume sodium has largely been studied in conjunction with the study of thirst. This review will describe the neuroendocrine controls of fluid balance, mechanisms underlying sex differences, sex differences in sodium intake, changes in sodium intake during pregnancy, and the possible neuronal mechanisms underlying these differences in behavior. Having reviewed the mechanisms that can only be studied in animal experiments, we address sex differences in human dietary sodium intake in reproduction, and with age.
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Affiliation(s)
- Jessica Santollo
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - Derek Daniels
- Department of Biology, University at Buffalo, Buffalo, NY 14260, USA
| | - Micah Leshem
- School of Psychological Sciences, The University of Haifa, Haifa 3498838, Israel
| | - Jay Schulkin
- School of Medicine, University of Washington, Seattle, WA 98195, USA
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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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Potential Use of Pharmacogenetics to Reduce Drug-Induced Syndrome of Inappropriate Antidiuretic Hormone (SIADH). J Pers Med 2021; 11:jpm11090853. [PMID: 34575630 PMCID: PMC8466173 DOI: 10.3390/jpm11090853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/21/2022] Open
Abstract
Syndrome of inappropriate antidiuretic hormone (SIADH) is a common cause of hyponatremia, and many cases represent adverse reactions to drugs that alter ion channel conductance within the peptidergic nerve terminals of the posterior pituitary. The frequency of drug-induced SIADH increases with age; as many as 20% of patients residing in nursing homes have serum sodium levels below 135 mEq/L. Mild hyponatremia is associated with cognitive changes, gait instability, and falls. Severe hyponatremia is associated with cerebral edema, seizures, permanent disability, and/or death. Although pharmacogenetic tests are now being deployed for some drugs capable of causing SIADH (e.g., antidepressants, antipsychotics, and opioid analgesics), the implementation of these tests has been based upon the prior known association of these drugs with other serious adverse drug reactions (e.g., electrocardiographic abnormalities). Work is needed in large observational cohorts to quantify the strength of association between pharmacogene variants and drug-induced SIADH so that decision support can be developed to identify patients at high risk.
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Bonfim THFD, Tavares RL, de Vasconcelos MHA, Gouveia M, Nunes PC, Soares NL, Alves RC, de Carvalho JLP, Alves AF, Pereira RDA, Cardoso GA, Silva AS, Aquino JDS. Potentially obesogenic diets alter metabolic and neurobehavioural parameters in Wistar rats: a comparison between two dietary models. J Affect Disord 2021; 279:451-461. [PMID: 33120246 DOI: 10.1016/j.jad.2020.10.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/28/2020] [Accepted: 10/13/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Clinical studies related to the obesity pandemic have intensified in recent years, being the animal studies are also considered of great relevance. However, despite the fact that many diets have been reported in the literature to induce obesity in animal models, there is still a gap regarding evidence of the efficacy of these models, considering not only changes in somatic parameters, but also the triggering of comorbidities associated with obesity. In this scenario, the aim of this study was to compare the effectiveness of western and cafeteria diets as obesity-inducing protocols, focusing on the evaluation of metabolic, somatic, oxidative, histological and behavioural parameters of Wistar rats. METHODS The rats were fed a control (CON), western (WTD) or cafeteria (CAF) diet for 16 weeks. RESULTS The CAF diet caused anxiogenic-like behaviour. Body mass (BMI), Lee and adiposity indices increased in the CAF group. CAF and WTD diets reduced glucose and insulin tolerance, caused dyslipidemia, increased lipid peroxidation and decrease antioxidant capacity in the liver, kidneys and brain. The WTD and CAF groups shows greater IL-6 protein expression in adipose tissue, developed hepatic steatosis and ischaemic neurons, whereas interstitial nephritis was observed only in the CAF group. CONCLUSION The CAF diet was most effective in inducing obesity, as shown both by the somatic parameters and by the greater number of obesity-related metabolic and neurobehavioural disorders in the evaluated rats.
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Affiliation(s)
| | - Renata Leite Tavares
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | | | - Mirela Gouveia
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Polyana Campos Nunes
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Naís Lira Soares
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Raquel Coutinho Alves
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Jader Luciano Pinto de Carvalho
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Adriano Francisco Alves
- Laboratory of Pathology, Department of Physiology and Pathology, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Ramon de Alencar Pereira
- Laboratory of Pathology, Department of Pathology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
| | - Glêbia Alexa Cardoso
- Associate Graduate Program in Physical Education - UPE / UFPB, Department of Physical Education, Federal University of Paraíba, João Pessoa, Brazil; Laboratory of Physical Training Applied to Performance and Health, Department of Physical Education, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Alexandre Sergio Silva
- Laboratory of Physical Training Applied to Performance and Health, Department of Physical Education, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil
| | - Jailane de Souza Aquino
- Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Paraíba (UFPB), João Pessoa, Paraíba, Brazil.
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Abstract
Expensive and extensive studies on the epidemiology of excessive Na intake and its pathology have been conducted over four decades. The resultant consensus that dietary Na is toxic, as well as the contention that it is less so, ignores the root cause of the attractiveness of salted food. The extant hypotheses are that most Na is infiltrated into our bodies via heavily salted industrialised food without our knowledge and that mere exposure early in life determines lifelong intake. However, these hypotheses are poorly evidenced and are meagre explanations for the comparable salt intake of people worldwide despite their markedly different diets. The love of salt begins at birth for some, vacillates in infancy, climaxes during adolescent growth, settles into separate patterns for men and women in adulthood and, with age, fades for some and persists for others. Salt adds flavour to food. It sustains and protects humans in exertion, may modulate their mood and contributes to their ailments. It may have as yet unknown benefits that may promote its delectability, and it generates controversy. An understanding of the predilection for salt should allow a more evidence-based and effective reduction of the health risks associated with Na surfeit and deficiency. The purpose of this brief review is to show the need for research into the determinants of salt intake by summarising the little we know.
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Affiliation(s)
- Micah Leshem
- School of Psychological Sciences, The University of Haifa, Haifa3498838, Israel
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The influence of opioid dependence on salt consumption and related psychological parameters in mice and humans. Drug Alcohol Depend 2019; 203:19-26. [PMID: 31400713 DOI: 10.1016/j.drugalcdep.2019.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/22/2019] [Accepted: 05/22/2019] [Indexed: 01/15/2023]
Abstract
BACKGROUND The consumption of dietary salt (NaCl) is controlled by neuronal pathways that are modulated by endogenous opioid signalling. The latter is disrupted by chronic use of exogenous opioid receptor agonists, such as morphine. Therefore, opioid dependence may influence salt consumption, which we investigated in two complimentary studies in humans and mice. METHODS Human study: three groups were recruited: i. Individuals who are currently opioid dependent and receiving opioid substitution treatment (OST); ii. Previously opioid dependent individuals, who are currently abstinent, and; iii. Healthy controls with no history of opioid dependence. Participants tasted solutions containing different salt concentrations and indicated levels of salt 'desire', salt 'liking', and perceptions of 'saltiness'. Mouse study: preference for 0.1 M versus 0.2 M NaCl and overall levels of salt consumption were recorded during and after chronic escalating morphine treatment. RESULTS Human study: Abstinent participants' 'desire' for and 'liking' of salt was shifted towards more highly concentrated salt solutions relative to control and OST individuals. Mouse study: Mice increased their total salt consumption during morphine treatment relative to vehicle controls, which persisted for 3 days after cessation of treatment. Preference for 'low' versus 'high' concentrations of salt were unchanged. CONCLUSION These findings suggest a possible common mechanistic cross-sensitization to salt that is present in both mice and humans and builds our understanding of how opioid dependence can influence dietary salt consumption. This research may help inform better strategies to improve the diet and overall wellbeing of the growing number of individuals who develop opioid dependence.
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Abstract
OBJECTIVE In Iran, there has been no national report on salt intake based on laboratory measurements so far. Therefore, this study was conducted to measure salt intake among Iranian population at the national level. METHODS In stepwise approach to conduct a surveillance survey 2016, 18 624 Iranian adults (25 years old and above), as a representative sample of Iranian adult population at national and subnational levels, underwent urine sodium measurement and were included in this study. The participants were recruited through a systematic random sampling from 30 provinces of Iran. For each individual, through a computer-assisted interview, a questionnaire on lifestyle risk factors was completed, all anthropometric indices were measured, and data on sodium of spot urine sample for all individuals and 24-h urine sample for a subsample were collected. To estimate the 24-h salt intake, common equations were used. RESULTS In total, 97.66% of the population consumed at least 5 g of salt per day. In addition, in 41.20% of the population, the level of salt intake was at least two times higher than the level recommended by the WHO for adults. The mean of salt intake among Iranian population was 9.52 g/day (95% confidence interval: 9.48-9.56). CONCLUSION The study showed that the consumption of salt among the Iranian population is higher than the level recommended by WHO. To reduce salt intake, it is necessary to adopt a combination of nationwide policies such as food reformulation and food labelling.
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9
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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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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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St John SJ. The Perceptual Characteristics of Sodium Chloride to Sodium-Depleted Rats. Chem Senses 2016; 42:93-103. [PMID: 27660150 DOI: 10.1093/chemse/bjw100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Three experiments assessed potential changes in the rat's perception of sodium chloride (NaCl) during a state of sodium appetite. In Experiment 1, sodium-sufficient rats licking a range of NaCl concentrations (0.028-0.89M) in 15s trials showed an inverted U-shaped concentration response function peaking at 0.281M. Depleted rats (furosemide) showed an identical function, merely elevated, suggesting altered qualitative or hedonic perception but no change in perceived intensity. In Experiment 2, sodium-depleted rats were tested with NaCl, sodium gluconate, and potassium chloride (KCl; 0.028-0.89M) similar to Experiment 1. KCl was licked at the same rate as water except for a slight elevation at 0.158; sodium gluconate and NaCl were treated similarly, but rats showed more licking for hypertonic sodium gluconate than hypertonic NaCl. Sodium-depleted rats were also tested with NaCl mixed in amiloride (10-300 μM). Amiloride reduced licking but did not alter the shape of the concentration-response function. Collectively, these results suggest that transduction of sodium by epithelial sodium channels (which are blocked by amiloride and are more dominant in sodium gluconate than NaCl transduction) is crucial for the perception of sodium during physiological sodium depletion. In Experiment 3, sodium-deplete rats were tested with NaCl as in Experiment 1 but after taste aversion conditioning to 0.3M NaCl or sucrose. Rats conditioned to avoid NaCl but not sucrose failed to express a sodium appetite, strongly suggesting that NaCl does not undergo a change in taste quality during sodium appetite-rats show no confusion between sucrose and NaCl in this paradigm.
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Affiliation(s)
- Steven J St John
- Department of Psychology, Rollins College, 1000 Holt Ave 2760, Winter Park, FL 32789, USA
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Zhang Y, Li F, Liu FQ, Chu C, Wang Y, Wang D, Guo TS, Wang JK, Guan GC, Ren KY, Mu JJ. Elevation of Fasting Ghrelin in Healthy Human Subjects Consuming a High-Salt Diet: A Novel Mechanism of Obesity? Nutrients 2016; 8:nu8060323. [PMID: 27240398 PMCID: PMC4924164 DOI: 10.3390/nu8060323] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 12/16/2022] Open
Abstract
Overweight/obesity is a chronic disease that carries an increased risk of hypertension, diabetes mellitus, and premature death. Several epidemiological studies have demonstrated a clear relationship between salt intake and obesity, but the pathophysiologic mechanisms remain unknown. We hypothesized that ghrelin, which regulates appetite, food intake, and fat deposition, becomes elevated when one consumes a high-salt diet, contributing to the progression of obesity. We, therefore, investigated fasting ghrelin concentrations during a high-salt diet. Thirty-eight non-obese and normotensive subjects (aged 25 to 50 years) were selected from a rural community in Northern China. They were sequentially maintained on a normal diet for three days at baseline, a low-salt diet for seven days (3 g/day, NaCl), then a high-salt diet for seven days (18 g/day). The concentration of plasma ghrelin was measured using an immunoenzyme method (ELISA). High-salt intake significantly increased fasting ghrelin levels, which were higher during the high-salt diet (320.7 ± 30.6 pg/mL) than during the low-salt diet (172.9 ± 8.9 pg/mL). The comparison of ghrelin levels between the different salt diets was statistically-significantly different (p < 0.01). A positive correlation between 24-h urinary sodium excretion and fasting ghrelin levels was demonstrated. Our data indicate that a high-salt diet elevates fasting ghrelin in healthy human subjects, which may be a novel underlying mechanism of obesity.
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Affiliation(s)
- Yong Zhang
- Cardiovascular Department, Shaanxi Provincial People's Hospital, Xi'an 710068, China.
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Fenxia Li
- Cardiovascular Department, Second Affiliated Hospital, Xi'an Medical University, Xi'an 710038, China.
| | - Fu-Qiang Liu
- Cardiovascular Department, Shaanxi Provincial People's Hospital, Xi'an 710068, China.
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Chao Chu
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Yang Wang
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Dan Wang
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Tong-Shuai Guo
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Jun-Kui Wang
- Cardiovascular Department, Shaanxi Provincial People's Hospital, Xi'an 710068, China.
| | - Gong-Chang Guan
- Cardiovascular Department, Shaanxi Provincial People's Hospital, Xi'an 710068, China.
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Ke-Yu Ren
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Jian-Jun Mu
- Cardiovascular Department, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, China.
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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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14
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Smith CM, Walker LL, Chua BE, McKinley MJ, Gundlach AL, Denton DA, Lawrence AJ. Involvement of central relaxin-3 signalling in sodium (salt) appetite. Exp Physiol 2015; 100:1064-72. [PMID: 26147879 DOI: 10.1113/ep085349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 06/30/2015] [Indexed: 01/21/2023]
Abstract
NEW FINDINGS What is the central question of this study? Sodium appetite is controlled by conserved neuronal transmitter-receptor systems. Here, we tested the contribution made by relaxin family peptide 3 receptor (RXFP3), the cognate G-protein-coupled receptor for the neuropeptide relaxin-3. What is the main finding and its importance? Intracerebroventricular infusion of an RXFP3 antagonist reduced in a dose-dependent manner the volume of 0.3 m NaCl consumed by sodium-depleted C57Bl/6J (wild-type) mice. This effect was absent in sodium-depleted Rxfp3 knockout mice, and RXFP3 antagonist infusion did not alter water consumption in wild-type mice subjected to multiple thirst tests, indicating both the pharmacological and the physiological specificity of observed effects. Our findings identify endogenous relaxin-3-RXFP3 signalling as a modulator of sodium appetite. Overconsumption of highly salted foods is common in Western diets and contributes significantly to metabolic disorders such as hypertension, renal dysfunction and diabetes. Sodium appetite, or the desire of terrestrial animals to seek and consume sodium-containing salts, is a behaviour mediated by a set of evolutionarily conserved neuronal systems. In these studies, we tested whether this instinctive behavioural drive is influenced by the G-protein-coupled relaxin family peptide 3 receptor (RXFP3), the cognate receptor for the neuropeptide relaxin-3, because relaxin-3-RXFP3 signalling can modulate arousal, motivation and ingestive behaviours. Intracerebroventricular (i.c.v.) infusion of the selective RXFP3 antagonist, R3(B1-22)R, reduced in a dose-dependent manner the volume of 0.3 m NaCl solution consumed when offered to sodium-depleted C57Bl/6J wild-type mice, relative to vehicle-treated control animals. Notably, i.c.v. R3(B1-22)R infusion did not alter 0.3 m NaCl consumption relative to vehicle in sodium-depleted Rxfp3 knockout mice, confirming the pharmacological specificity of this effect. Furthermore, i.c.v. R3(B1-22)R did not alter the volume of water consumed by wild-type mice in three tests where water drinking was the normal physiological response, suggesting that the ability of R3(B1-22)R to reduce activated salt appetite is specific and not due to a generalized reduction in drinking behaviour. These findings identify, for the first time, that endogenous relaxin-3-RXFP3 signalling is a powerful mediator of salt appetite in mice and further elucidate the functional role of the relaxin-3-RXFP3 system in the integrative control of motivated behaviours.
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Affiliation(s)
- Craig M Smith
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Lesley L Walker
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Berenice E Chua
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Michael J McKinley
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Physiology, The University of Melbourne, Victoria, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia
| | - Derek A Denton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Office of the Dean, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Victoria, Australia.,Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
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15
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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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16
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Hurley SW, Johnson AK. The biopsychology of salt hunger and sodium deficiency. Pflugers Arch 2015; 467:445-56. [PMID: 25572931 PMCID: PMC4433288 DOI: 10.1007/s00424-014-1676-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 12/14/2022]
Abstract
Sodium is a necessary dietary macromineral that tended to be sparsely distributed in mankind's environment in the past. Evolutionary selection pressure shaped physiological mechanisms including hormonal systems and neural circuits that serve to promote sodium ingestion. Sodium deficiency triggers the activation of these hormonal systems and neural circuits to engage motivational processes that elicit a craving for salty substances and a state of reward when salty foods are consumed. Sodium deficiency also appears to be associated with aversive psychological states including anhedonia, impaired cognition, and fatigue. Under certain circumstances the psychological processes that promote salt intake can become powerful enough to cause "salt gluttony," or salt intake far in excess of physiological need. The present review discusses three aspects of the biopsychology of salt hunger and sodium deficiency: (1) the psychological processes that promote salt intake during sodium deficiency, (2) the effects of sodium deficiency on mood and cognition, and (3) the sensitization of sodium appetite as a possible cause of salt gluttony.
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Affiliation(s)
- Seth W. Hurley
- Department of Psychology, University of Iowa, Iowa City, IA
| | - Alan Kim Johnson
- Department of Psychology, University of Iowa, Iowa City, IA
- Department of Pharmacology, University of Iowa, Iowa City, IA
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA
- Cardiovascular Center, University of Iowa, Iowa City, IA
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17
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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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