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Watts CA, Smith J, Giacomino R, Walter D, Jang G, Malik A, Harvey N, Novak CM. Chemogenetic Excitation of Ventromedial Hypothalamic Steroidogenic Factor 1 (SF1) Neurons Increases Muscle Thermogenesis in Mice. Biomolecules 2024; 14:821. [PMID: 39062535 PMCID: PMC11274921 DOI: 10.3390/biom14070821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 07/03/2024] [Accepted: 07/04/2024] [Indexed: 07/28/2024] Open
Abstract
Allostatic adaptations to a perceived threat are crucial for survival and may tap into mechanisms serving the homeostatic control of energy balance. We previously established that exposure to predator odor (PO) in rats significantly increases skeletal muscle thermogenesis and energy expenditure (EE). Evidence highlights steroidogenic factor 1 (SF1) cells within the central and dorsomedial ventromedial hypothalamus (c/dmVMH) as a modulator of both energy homeostasis and defensive behavior. However, the brain mechanism driving elevated EE and muscle thermogenesis during PO exposure has yet to be elucidated. To assess the ability of SF1 neurons of the c/dmVMH to induce muscle thermogenesis, we used the combined technology of chemogenetics, transgenic mice, temperature transponders, and indirect calorimetry. Here, we evaluate EE and muscle thermogenesis in SF1-Cre mice exposed to PO (ferret odor) compared to transgenic and viral controls. We detected significant increases in muscle temperature, EE, and oxygen consumption following the chemogenetic stimulation of SF1 cells. However, there were no detectable changes in muscle temperature in response to PO in either the presence or absence of chemogenetic stimulation. While the specific role of the VMH SF1 cells in PO-induced thermogenesis remains uncertain, these data establish a supporting role for SF1 neurons in the induction of muscle thermogenesis and EE similar to what is seen after predator threats.
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Affiliation(s)
- Christina A. Watts
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA;
| | - Jordan Smith
- College of Public Health, Kent State University, Kent, OH 44242, USA
| | - Roman Giacomino
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Dinah Walter
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Guensu Jang
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Aalia Malik
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Nicholas Harvey
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Colleen M. Novak
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA;
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
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Shemery AM, Zendlo M, Kowalski J, Gorrell E, Everett S, Wagner JG, Davis AE, Koch LG, Britton SL, Mul JD, Novak CM. Reduced contextually induced muscle thermogenesis in rats with calorie restriction and lower aerobic fitness but not monogenic obesity. Temperature (Austin) 2023; 10:379-393. [PMID: 37554387 PMCID: PMC10405760 DOI: 10.1080/23328940.2023.2171669] [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: 12/01/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/29/2023] Open
Abstract
We have previously identified predator odor as a potent stimulus activating thermogenesis in skeletal muscle in rats. As this may prove relevant for energy balance and weight loss, the current study investigated whether skeletal muscle thermogenesis was altered with negative energy balance, obesity propensity seen in association with low intrinsic aerobic fitness, and monogenic obesity. First, weight loss subsequent to 3 wk of 50% calorie restriction suppressed the muscle thermogenic response to predator odor. Next, we compared rats bred based on artificial selection for intrinsic aerobic fitness - high- and low-capacity runners (HCR, LCR) - that display robust leanness and obesity propensity, respectively. Aerobically fit HCR showed enhanced predator odor-induced muscle thermogenesis relative to the less-fit LCR. This contrasted with the profound monogenic obesity displayed by rats homozygous for a loss of function mutation in Melanocortin 4 receptor (Mc4rK3a,4X/K314X rats), which showed no discernable deficit in thermogenesis. Taken together, these data imply that body size or obesity per se are not associated with deficient muscle thermogenesis. Rather, the physiological phenotype associated with polygenic obesity propensity may encompass pleiotropic mechanisms in the thermogenic pathway. Adaptive thermogenesis associated with weight loss also likely alters muscle thermogenic mechanisms.
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Affiliation(s)
- Ashley M Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Meredith Zendlo
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Jesse Kowalski
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Erin Gorrell
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Scott Everett
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Jacob G Wagner
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Ashley E Davis
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Lauren G Koch
- Department of Physiology and Pharmacology, the University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Steven L Britton
- Department of Anesthesiology, and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Joram D Mul
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, the Netherlands
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
- Department of Biological Sciences, Kent State University, Kent, OH, USA
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3
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Heemstra LA, Koch LG, Britton SL, Novak CM. Altered skeletal muscle sarco-endoplasmic reticulum Ca 2+-ATPase calcium transport efficiency after a thermogenic stimulus. Am J Physiol Regul Integr Comp Physiol 2022; 323:R628-R637. [PMID: 36094445 PMCID: PMC9602703 DOI: 10.1152/ajpregu.00173.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/01/2022] [Accepted: 09/01/2022] [Indexed: 01/22/2023]
Abstract
Exposure to predator threat induces a rapid and robust increase in skeletal muscle thermogenesis in rats. The central nervous system relays threat information to skeletal muscle through activation of the sympathetic nervous system, but muscle mechanisms mediating this thermogenesis remain unidentified. Given the relevance of sarcolipin-mediated futile calcium cycling through the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump to mammalian muscle nonshivering thermogenesis, we hypothesized that this plays a role in contextually induced muscle thermogenesis as well. This was assessed by measuring enzymatic activity of SERCA and sarcoplasmic reticulum Ca2+ transport, where the apparent coupling ratio (Ca2+ uptake rate divided by ATPase activity rate at a standard Ca2+ concentration) was predicted to decrease in association with muscle thermogenesis. Sprague-Dawley rats exposed to predator (ferret) odor (PO) showed a rapid decrease in the apparent coupling ratio in the soleus muscle, indicating SERCA uncoupling compared with control-odor-exposed rats. A rat model of high aerobic fitness and elevated muscle thermogenesis also demonstrated soleus muscle SERCA uncoupling relative to their obesity-prone, low-fitness counterparts. Both the high- and low-aerobic fitness rats showed soleus SERCA uncoupling with exposure to PO. Finally, no increase in sarcolipin expression in soleus muscle was detected with PO exposure. This dataset implicates muscle uncoupling of SERCA Ca2+ transport and ATP hydrolysis, likely through altered SERCA or sarcolipin function outside of translational regulation, as one contributor to the muscle thermogenesis provoked by exposure to predator threat. These data support the involvement of SERCA uncoupling in both muscle thermogenic induction and enhanced aerobic capacity.
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Affiliation(s)
- Lydia A Heemstra
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Colleen M Novak
- Department of Biological Sciences, Kent State University, Kent, Ohio
- School of Biomedical Sciences, Kent State University, Kent, Ohio
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4
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Peña-Villalobos I, Otárola FA, Casas BS, Sabat P, Palma V. Perinatal Food Deprivation Modifies the Caloric Restriction Response in Adult Mice Through Sirt1. Front Physiol 2021; 12:769444. [PMID: 34925065 PMCID: PMC8675943 DOI: 10.3389/fphys.2021.769444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/08/2021] [Indexed: 11/30/2022] Open
Abstract
Variations in the availability of nutritional resources in animals can trigger reversible adjustments, which in the short term are manifested as behavioral and physiological changes. Several of these responses are mediated by Sirt1, which acts as an energy status sensor governing a global genetic program to cope with changes in nutritional status. Growing evidence suggests a key role of the response of the perinatal environment to caloric restriction in the setup of physiological responses in adulthood. The existence of adaptive predictive responses has been proposed, which suggests that early nutrition could establish metabolic capacities suitable for future food-scarce environments. We evaluated how perinatal food deprivation and maternal gestational weight gain impact the transcriptional, physiological, and behavioral responses in mice, when acclimated to caloric restriction in adulthood. Our results show a strong predictive capacity of maternal weight and gestational weight gain, in the expression of Sirt1 and its downstream targets in the brain and liver, mitochondrial enzymatic activity in skeletal muscle, and exploratory behavior in offspring. We also observed differential responses of both lactation and gestational food restriction on gene expression, thermogenesis, organ masses, and behavior, in response to adult caloric restriction. We conclude that the early nutritional state could determine the magnitude of responses to food scarcity later in adulthood, mediated by the pivotal metabolic sensor Sirt1. Our results suggest that maternal gestational weight gain could be an important life history trait and could be used to predict features that improve the invasive capacity or adjustment to seasonal food scarcity of the offspring.
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Affiliation(s)
- Isaac Peña-Villalobos
- Department of Ecological Sciences, Faculty of Sciences, Universidad de Chile, Santiago, Chile.,Laboratory of Stem Cells and Developmental Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Fabiola A Otárola
- Laboratory of Stem Cells and Developmental Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Bárbara S Casas
- Laboratory of Stem Cells and Developmental Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Pablo Sabat
- Department of Ecological Sciences, Faculty of Sciences, Universidad de Chile, Santiago, Chile.,Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Verónica Palma
- Laboratory of Stem Cells and Developmental Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
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Pathak MP, Patowary P, Goyary D, Das A, Chattopadhyay P. β-caryophyllene ameliorated obesity-associated airway hyperresponsiveness through some non-conventional targets. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 89:153610. [PMID: 34175589 DOI: 10.1016/j.phymed.2021.153610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Obesity worsens airway hyperresponsiveness (AHR) in asthmatic subjects by up-regulating macrophage polarization that leads to excessive secretion of pro-inflammatory adipokines from white adipose tissue followed by generation of oxidative stress in the respiratory system. Treatment through conventional signaling pathways proved to be inadequate in obese asthmatics, so a therapeutical approach through a non-conventional pathway may prove to be effective. PURPOSE This study aimed to investigate the efficacy of a FDA-approved food additive, β-caryophyllene (BCP) in obesity-associated AHR. METHOD A repertoire of protein expression, cytokine and adiponectin estimation, oxidative stress assays, histopathology, and fluorescence immune-histochemistry were performed to assess the efficacy of BCP in C57BL/6 mice model of obesity-associated AHR. Additionally, human adipocyte was utilized to study the effect of BCP on macrophage polarization in Boyden chamber cell culture inserts. RESULTS Obesity-associated AHR is ameliorated by administration of BCP by inhibition of the macrophage polarization by activation of AMPKα, Nrf2/HO-1 and AdipoR1 and AdipoR2 signaling pathway, up-regulation of adiponectin, GLP-1, IFN-γ, SOD, catalase and down-regulation of NF-κB, leptin, IL-4, TNF, and IL-1β. Browning of eWAT by induction of thermogenesis and activation of melanocortin pathway also contributed to the amelioration of obesity-associated AHR. We conclude that BCP ameliorated the obesity-associated AHR via inhibition of macrophage polarization, activation of AMPKα, Nrf2/HO-1, and up-regulation of AdipoR1 and AdipoR2 expression and down-regulation of NFκB expression in lung of animal. CONCLUSION Being an FDA-approved food additive, BCP may prove to be a safe and potential agent against obesity-associated AHR.
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Affiliation(s)
- Manash Pratim Pathak
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur, 784001, India; Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, 786004, India
| | - Pompy Patowary
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur, 784001, India; Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, 786004, India
| | - Danswrang Goyary
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur, 784001, India
| | - Aparoop Das
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, 786004, India
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6
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Smyers ME, Koch LG, Britton SL, Wagner JG, Novak CM. Enhanced weight and fat loss from long-term intermittent fasting in obesity-prone, low-fitness rats. Physiol Behav 2020; 230:113280. [PMID: 33285179 DOI: 10.1016/j.physbeh.2020.113280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/10/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Intermittent fasting (IF) strategies have emerged as viable alternatives to traditional calorie-restricted diets. A key predictor of metabolic health and response to diet is cardiometabolic fitness, including intrinsic aerobic capacity. In a contrasting rat model of aerobic capacity-high- and low-capacity runners (HCR, LCR)-we found that the lean and physically active HCR were also more responsive to a standard calorie-restricted diet. Here, we assessed the ability of IF to induce weight loss on a background of high and low aerobic fitness accompanied by different levels of daily physical activity. METHODS Female HCR and LCR (8 per line) were subjected to IF (alternate-day fasting) for 14 weeks. Outcomes included changes in body weight, fat and lean mass, daily physical activity, and food and water intake. After initial measurements, IF was continued, and measurements were repeated after one year of IF. RESULTS All rats lost weight with IF, and LCR lost significantly more weight than HCR. This difference was primarily due to differential fat loss; loss of lean mass, on the other hand, was similar between HCR and LCR. Total food intake decreased with IF, and LCR showed lower intake than HCR only during the first 5 weeks of IF. Physical activity was suppressed by long-term IF. Physical activity increased on fed days compared to fasted days, and this pattern was more pronounced in HCR. The differential effects of IF in HCR and LCR persisted after one year of IF, with IF preventing the marked weight gain seen in ad libitum fed LCR during this time. CONCLUSION Weight and fat loss from IF was more pronounced in obesity-prone, low-aerobic capacity LCR, despite the low activity levels seen in these rats. The possibility that aerobic capacity modulates response to IF in human participants remains unexplored.
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Affiliation(s)
- Mark E Smyers
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, United States.
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614-2598, United States.
| | - Steven L Britton
- Department of Anesthesiology, and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-5622, United States.
| | - Jacob G Wagner
- Department of Biological Sciences, Kent State University, Kent, OH 44242, United States.
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, United States; Department of Biological Sciences, Kent State University, Kent, OH 44242, United States.
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7
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Xie WQ, Xiao WF, Tang K, Wu YX, Hu PW, Li YS, Duan Y, Lv S. Caloric restriction: implications for sarcopenia and potential mechanisms. Aging (Albany NY) 2020; 12:24441-24452. [PMID: 33226962 PMCID: PMC7762489 DOI: 10.18632/aging.103987] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/14/2020] [Indexed: 12/23/2022]
Abstract
Sarcopenia is a potential risk factor for weakness, disability and death in elderly individuals. Therefore, seeking effective methods to delay and treat sarcopenia and to improve the quality of life of elderly individuals is a trending topic in geriatrics. Caloric restriction (CR) is currently recognized as an effective means to extend the lifespan and delay the decline in organ function caused by aging. In this review, we describe the effects of CR on improving muscle protein synthesis, delaying muscle atrophy, regulating muscle mitochondrial function, maintaining muscle strength, promoting muscle stem cell (MuSC) regeneration and differentiation, and thus protecting against sarcopenia. We also summarize the possible cellular mechanisms by which CR delays sarcopenia. CR can delay sarcopenia by reducing the generation of oxygen free radicals, reducing oxidative stress damage, enhancing mitochondrial function, improving protein homeostasis, reducing iron overload, increasing autophagy and apoptosis, and reducing inflammation. However, the relationships between CR and genetics, sex, animal strain, regimen duration and energy intake level are complex. Therefore, further study of the proper timing and application method of CR to prevent sarcopenia is highly important for the aging population.
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Affiliation(s)
- Wen-Qing Xie
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Wen-Feng Xiao
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Kun Tang
- Discipline Construction Office, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yu-Xiang Wu
- School of Kinesiology, Jianghan University, Wuhan 430056, China
| | - Pei-Wu Hu
- Department of Scientific Research, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yu-Sheng Li
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yu Duan
- Department of Geriatric Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Shan Lv
- Department of Geriatric Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China
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8
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Carr KD. Modulatory Effects of Food Restriction on Brain and Behavioral Effects of Abused Drugs. Curr Pharm Des 2020; 26:2363-2371. [DOI: 10.2174/1381612826666200204141057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022]
Abstract
Energy homeostasis is achieved, in part, by metabolic signals that regulate the incentive motivating
effects of food and its cues, thereby driving or curtailing procurement and consumption. The neural underpinnings
of these regulated incentive effects have been identified as elements within the mesolimbic dopamine pathway.
A separate line of research has shown that most drugs with abuse liability increase dopamine transmission in
this same pathway and thereby reinforce self-administration. Consequently, one might expect shifts in energy
balance and metabolic signaling to impact drug abuse risk. Basic science studies have yielded numerous examples
of drug responses altered by diet manipulation. Considering the prevalence of weight loss dieting in Western
societies, and the anorexigenic effects of many abused drugs themselves, we have focused on the CNS and behavioral
effects of food restriction in rats. Food restriction has been shown to increase the reward magnitude of diverse
drugs of abuse, and these effects have been attributed to neuroadaptations in the dopamine-innervated nucleus
accumbens. The changes induced by food restriction include synaptic incorporation of calcium-permeable
AMPA receptors and increased signaling downstream of D1 dopamine receptor stimulation. Recent studies suggest
a mechanistic model in which concurrent stimulation of D1 and GluA2-lacking AMPA receptors enables
increased stimulus-induced trafficking of GluA1/GluA2 AMPARs into the postsynaptic density, thereby increasing
the incentive effects of food, drugs, and associated cues. In addition, the established role of AMPA receptor
trafficking in enduring synaptic plasticity prompts speculation that drug use during food restriction may more
strongly ingrain behavior relative to similar use under free-feeding conditions.
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Affiliation(s)
- Kenneth D. Carr
- Departments of Psychiatry, Biochemistry and Molecular Pharmacology, New York University School of Medicine, 435 East 30th Street, New York, NY 10016, United States
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9
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Carr KD. Homeostatic regulation of reward via synaptic insertion of calcium-permeable AMPA receptors in nucleus accumbens. Physiol Behav 2020; 219:112850. [PMID: 32092445 PMCID: PMC7108974 DOI: 10.1016/j.physbeh.2020.112850] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/23/2020] [Accepted: 02/18/2020] [Indexed: 10/25/2022]
Abstract
The incentive effects of food and related cues are determined by stimulus properties and the internal state of the organism. Enhanced hedonic reactivity and incentive motivation in energy deficient subjects have been demonstrated in animal models and humans. Defining the neurobiological underpinnings of these state-based modulatory effects could illuminate fundamental mechanisms of adaptive behavior, as well as provide insight into maladaptive consequences of weight loss dieting and the relationship between disturbed eating behavior and substance abuse. This article summarizes research of our laboratory aimed at identifying neuroadaptations induced by chronic food restriction (FR) that increase the reward magnitude of drugs and associated cues. The main findings are that FR decreases basal dopamine (DA) transmission, upregulates signaling downstream of the D1 DA receptor (D1R), and triggers synaptic incorporation of calcium-permeable AMPA receptors (CP-AMPARs) in the nucleus accumbens (NAc). Selective antagonism of CP-AMPARs decreases excitatory postsynaptic currents in NAc medium spiny neurons of FR rats and blocks the enhanced rewarding effects of d-amphetamine and a D1R, but not a D2R, agonist. These results suggest that FR drives CP-AMPARs into the synaptic membrane of D1R-expressing MSNs, possibly as a homeostatic response to reward loss. FR subjects also display diminished aversion for contexts associated with LiCl treatment and centrally infused cocaine. An encompassing, though speculative, hypothesis is that NAc synaptic incorporation of CP-AMPARs in response to food scarcity and other forms of sustained reward loss adaptively increases incentive effects of reward stimuli and, at the same time, diminishes responsiveness to aversive stimuli that have potential to interfere with goal pursuit.
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Affiliation(s)
- Kenneth D Carr
- Departments of Psychiatry and Biochemistry and Molecular Pharmacology, New York University School of Medicine, 435 East 30th Street, New York, NY 10016, United States.
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10
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Gorrell E, Shemery A, Kowalski J, Bodziony M, Mavundza N, Titus AR, Yoder M, Mull S, Heemstra LA, Wagner JG, Gibson M, Carey O, Daniel D, Harvey N, Zendlo M, Rich M, Everett S, Gavini CK, Almundarij TI, Lorton D, Novak CM. Skeletal muscle thermogenesis induction by exposure to predator odor. J Exp Biol 2020; 223:jeb218479. [PMID: 32165434 PMCID: PMC7174837 DOI: 10.1242/jeb.218479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/02/2020] [Indexed: 01/07/2023]
Abstract
Non-shivering thermogenesis can promote negative energy balance and weight loss. In this study, we identified a contextual stimulus that induces rapid and robust thermogenesis in skeletal muscle. Rats exposed to the odor of a natural predator (ferret) showed elevated skeletal muscle temperatures detectable as quickly as 2 min after exposure, reaching maximum thermogenesis of >1.5°C at 10-15 min. Mice exhibited a similar thermogenic response to the same odor. Ferret odor induced a significantly larger and qualitatively different response from that of novel or aversive odors, fox odor or moderate restraint stress. Exposure to predator odor increased energy expenditure, and both the thermogenic and energetic effects persisted when physical activity levels were controlled. Predator odor-induced muscle thermogenesis is subject to associative learning as exposure to a conditioned stimulus provoked a rise in muscle temperature in the absence of the odor. The ability of predator odor to induce thermogenesis is predominantly controlled by sympathetic nervous system activation of β-adrenergic receptors, as unilateral sympathetic lumbar denervation and a peripherally acting β-adrenergic antagonist significantly inhibited predator odor-induced muscle thermogenesis. The potential survival value of predator odor-induced changes in muscle physiology is reflected in an enhanced resistance to running fatigue. Lastly, predator odor-induced muscle thermogenesis imparts a meaningful impact on energy expenditure as daily predator odor exposure significantly enhanced weight loss with mild calorie restriction. This evidence signifies contextually provoked, centrally mediated muscle thermogenesis that meaningfully impacts energy balance.
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Affiliation(s)
- Erin Gorrell
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Ashley Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Jesse Kowalski
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Miranda Bodziony
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Nhlalala Mavundza
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Amber R Titus
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Mark Yoder
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Sarah Mull
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Lydia A Heemstra
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Jacob G Wagner
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Megan Gibson
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Olivia Carey
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Diamond Daniel
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Nicholas Harvey
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Meredith Zendlo
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Megan Rich
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Scott Everett
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Chaitanya K Gavini
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Tariq I Almundarij
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, PO Box 6622, Buraidah 51452, Saudi Arabia
| | - Diane Lorton
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
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11
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Calonne J, Arsenijevic D, Scerri I, Miles-Chan JL, Montani JP, Dulloo AG. Low 24-hour core body temperature as a thrifty metabolic trait driving catch-up fat during weight regain after caloric restriction. Am J Physiol Endocrinol Metab 2019; 317:E699-E709. [PMID: 31430205 DOI: 10.1152/ajpendo.00092.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The recovery of body weight after substantial weight loss or growth retardation is often characterized by a disproportionately higher rate of fat mass vs. lean mass recovery, with this phenomenon of "preferential catch-up fat" being contributed by energy conservation (thrifty) metabolism. To test the hypothesis that a low core body temperature (Tc) constitutes a thrifty metabolic trait underlying the high metabolic efficiency driving catch-up fat, the Anipill system, with telemetry capsules implanted in the peritoneal cavity, was used for continuous monitoring of Tc for several weeks in a validated rat model of semistarvation-refeeding in which catch-up fat is driven solely by suppressed thermogenesis. In animals housed at 22°C, 24-h Tc was reduced in response to semistarvation (-0.77°C, P < 0.001) and remained significantly lower than in control animals during the catch-up fat phase of refeeding (-0.27°C on average, P < 0.001), the lower Tc during refeeding being more pronounced during the light phase than during the dark phase of the 24-h cycle (-0.30°C vs. -0.23°C, P < 0.01) and with no between-group differences in locomotor activity. A lower 24-h Tc in animals showing catch-up fat was also observed when the housing temperature was raised to 29°C (i.e., at thermoneutrality). The reduced energy cost of homeothermy in response to caloric restriction persists during weight recovery and constitutes a thrifty metabolic trait that contributes to the high metabolic efficiency that underlies the rapid restoration of the body's fat stores during weight regain, with implications for obesity relapse after therapeutic slimming and the pathophysiology of catch-up growth.
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Affiliation(s)
- Julie Calonne
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Denis Arsenijevic
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Isabelle Scerri
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Jennifer L Miles-Chan
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Jean-Pierre Montani
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Abdul G Dulloo
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
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12
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Tonhajzerova I, Mestanikova A, Jurko A, Grendar M, Langer P, Ondrejka I, Jurko T, Hrtanek I, Cesnekova D, Mestanik M. Arterial stiffness and haemodynamic regulation in adolescent anorexia nervosa versus obesity. Appl Physiol Nutr Metab 2019; 45:81-90. [PMID: 31163115 DOI: 10.1139/apnm-2018-0867] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cardiovascular complications contribute to higher morbidity and mortality in patients with anorexia nervosa. We aimed to study biomarkers of cardiovascular risk in anorexic, normal-weight, and obese adolescents with focus on complex cardiovascular autonomic regulation and early arteriosclerotic damage. We examined 20 adolescent girls with anorexia nervosa, 20 obese girls, and 20 healthy normal-weight controls. Collected data: body composition analysis, 5 min recordings of R-R intervals and beat-to-beat blood pressure (BP), and arterial stiffness evaluated using cardio-ankle vascular index (CAVI). Evaluated parameters: beat-to-beat heart rate and BP variability, haemodynamic parameters (total peripheral resistance (TPR) cardiac output), CAVI, and anthropometric indices, including novel body roundness index (BRI). Adolescents with anorexia nervosa had increased CAVI associated with lower arterial constriction indexed by low-frequency band of BP variability compared with normal-weight peers (p = 0.03, p = 0.04, respectively) and obese adolescents (p < 0.01, p = 0.01, respectively). After normalization of CAVI and TPR by BRI, the relationship between CAVI and TPR was significant for all groups with the highest slope in the anorexia nervosa group (R2 = 0.724, p < 0.01). This is the first study revealing early arteriosclerotic damage in anorexic girls with increased CAVI. Complex analysis of cardiovascular autonomic regulation, and early arteriosclerotic, hemodynamic, and anthropometric changes in spectrum anorexia nervosa, normal weight, and obesity could help to understand the mechanisms of increased cardiovascular risk in malnutrition. Novelty Girls with anorexia nervosa showed signs of early arteriosclerotic damage indexed by CAVI. Insufficient sympathetic cardiovascular control was found already in adolescents with anorexia nervosa. The effect of body composition on CAVI was best predicted by novel body roundness index.
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Affiliation(s)
- Ingrid Tonhajzerova
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4C, 036 01 Martin, Slovak Republic.,Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, 036 01 Martin, Slovak Republic
| | - Andrea Mestanikova
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4C, 036 01 Martin, Slovak Republic.,Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, 036 01 Martin, Slovak Republic
| | - Alexander Jurko
- Pediatric Cardiology, Kollarova 13, 036 01 Martin, Slovak Republic
| | - Marian Grendar
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, 036 01 Martin, Slovak Republic
| | - Peter Langer
- Research Center, St. Anne's University Hospital Brno, 656 91 Brno, Czech Republic; Institute of Scientific Instruments of the ASCR, v.v.i., Kralovopolska 147, 612 64 Brno, Czech Republic
| | - Igor Ondrejka
- Psychiatric Clinic, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, University Hospital Martin, Kollarova 2, 036 59 Martin, Slovak Republic
| | - Tomas Jurko
- Department of Neonatology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, University Hospital Martin, Kollarova 2, 036 59 Martin, Slovak Republic
| | - Igor Hrtanek
- Psychiatric Clinic, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, University Hospital Martin, Kollarova 2, 036 59 Martin, Slovak Republic
| | - Dana Cesnekova
- Psychiatric Clinic, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, University Hospital Martin, Kollarova 2, 036 59 Martin, Slovak Republic
| | - Michal Mestanik
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4C, 036 01 Martin, Slovak Republic.,Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, 036 01 Martin, Slovak Republic
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13
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Gamu D, Juracic ES, Fajardo VA, Rietze BA, Tran K, Bombardier E, Tupling AR. Phospholamban deficiency does not alter skeletal muscle SERCA pumping efficiency or predispose mice to diet-induced obesity. Am J Physiol Endocrinol Metab 2019; 316:E432-E442. [PMID: 30601702 DOI: 10.1152/ajpendo.00288.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump is a major contributor to skeletal muscle Ca2+ homeostasis and metabolic rate. SERCA activity can become adaptively uncoupled by its regulator sarcolipin (SLN) to increase the energy demand of Ca2+ pumping, preventing excessive obesity and glucose intolerance in mice. Several other SERCA regulators bear structural and functional resemblance to SLN, including phospholamban (PLN). Here, we sought to examine whether endogenous levels of skeletal muscle PLN control SERCA Ca2+ pumping efficiency and whole body metabolism. Using PLN-null mice ( Pln-/-), we found that soleus (SOL) muscle's SERCA pumping efficiency (measured as an apparent coupling ratio: Ca2+ uptake/ATP hydrolysis) was unaffected by PLN. Expression of Ca2+-handling proteins within the SOL, including SLN, were comparable between Pln-/- and wild-type (WT) littermates, as were fiber-type characteristics. Not surprisingly then, Pln-/- mice developed a similar degree of diet-induced obesity and glucose intolerance as WT controls when given a "Western" high-fat diet. Lack of an excessively obesogenic phenotype of Pln-/- could not be explained by compensation from skeletal muscle SLN or brown adipose tissue uncoupling protein-1 content. In agreement with several other reports, our study lends support to the notion that PLN serves a functionally distinct role from that of SLN in skeletal muscle physiology.
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Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Emma Sara Juracic
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Val A Fajardo
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | | | - Khanh Tran
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
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14
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Clark KS, Coleman C, Shelton R, Heemstra LA, Novak CM. Caffeine enhances activity thermogenesis and energy expenditure in rats. Clin Exp Pharmacol Physiol 2019; 46:475-482. [PMID: 30620415 DOI: 10.1111/1440-1681.13065] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/06/2018] [Accepted: 12/27/2018] [Indexed: 10/27/2022]
Abstract
Caffeine and its derivatives have been used, alone and in combination with other phytochemicals, as weight-loss supplements. Caffeine affects several physiological and behavioural aspects of energy balance, including increasing locomotor activity. This study investigates the potential for caffeine to enhance activity thermogenesis and energy expenditure (EE) even when activity level is held constant. To do this, EE and muscle thermogenesis were measured in rats during treadmill walking regimens, with and without caffeine (25 mg/kg, ip). Activity-related EE was significantly increased throughout the treadmill walking protocol. Muscle heat dissipation, on the other hand, was significantly increased by caffeine only at the end of the 25-minute treadmill test. This study demonstrates that caffeine increases the caloric cost of physical activity, compared to the caloric cost of that same physical activity without caffeine, implicating decreased muscle work efficiency. Combined with the known ability of caffeine to increase locomotor activity, the decreased locomotor efficiency imparted by caffeine may further augment the potential for caffeine to enhance caloric expenditure.
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Affiliation(s)
| | - Claire Coleman
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Rhiannon Shelton
- Colorado School of Public Health, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Lydia A Heemstra
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Colleen M Novak
- Department of Biological Sciences, Kent State University, Kent, Ohio.,School of Biomedical Sciences, Kent State University, Kent, Ohio
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15
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Singh A, Zapata RC, Pezeshki A, Reidelberger RD, Chelikani PK. Inulin fiber dose-dependently modulates energy balance, glucose tolerance, gut microbiota, hormones and diet preference in high-fat-fed male rats. J Nutr Biochem 2018; 59:142-152. [PMID: 30005919 DOI: 10.1016/j.jnutbio.2018.05.017] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/17/2018] [Accepted: 05/31/2018] [Indexed: 12/19/2022]
Abstract
Inulin, a popular prebiotic fiber, has been reported to promote satiety and fat loss; however, the dose-response effects of inulin on energy balance and diet preference, and whether the metabolic effects are independent of calorie restriction are not well characterized. Therefore, we compared the effects of diets varying in inulin concentrations on food intake, energy expenditure, body composition, gut microbiota and hormones, and assessed whether inulin-induced hypophagia was due to reduced diet preference. In experiment 1, male rats were randomized to six high-fat diet groups: control (CON, 0% inulin), 2.5% inulin (2.5IN), 10% inulin (10IN), 25% inulin (25IN), 25% cellulose (25CE) or pair-fed to 25IN (25PF) for 21 days. We demonstrate that inulin dose-dependently decreased caloric intake and respiratory quotient; improved glucose tolerance; increased the abundance of Bacteroidetes and Bifidobacterium spp.; decreased Clostridium clusters I and IV; increased butyryl-CoA:acetate CoA-transferase in cecum; upregulated peptide YY, cholecystokinin and proglucagon transcripts in the cecum and colon; and increased plasma peptide YY and glucagon-like peptide-1 concentrations. Importantly, unlike 25PF, 25IN attenuated the reduction in energy expenditure associated with calorie restriction and decreased adiposity. In experiment 2, following four training periods, diet preferences were determined. Although 10IN and 25IN decreased caloric intake, and 25CE increased caloric intake, during training, all high-fiber diets were less preferred. Taken together, this work demonstrates that inulin dose-dependently decreased caloric intake, modulated gut microbiota and upregulated satiety hormones, with metabolic effects being largely independent of caloric restriction.
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Affiliation(s)
- Arashdeep Singh
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, AB, Canada T2N 4N1
| | - Rizaldy C Zapata
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, AB, Canada T2N 4N1
| | - Adel Pezeshki
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Roger D Reidelberger
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Prasanth K Chelikani
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, AB, Canada T2N 4N1; Gastrointestinal Research Group, Synder Institute for Chronic Diseases, University of Calgary, AB, Canada T2N 4N1.
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16
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Gavini CK, Britton SL, Koch LG, Novak CM. Inherently Lean Rats Have Enhanced Activity and Skeletal Muscle Response to Central Melanocortin Receptors. Obesity (Silver Spring) 2018; 26:885-894. [PMID: 29566460 PMCID: PMC5916025 DOI: 10.1002/oby.22166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Activity thermogenesis and energy expenditure (EE) are elevated in intrinsically lean rats (high-capacity runners [HCR]) and are also stimulated by melanocortin receptor activation in the ventromedial hypothalamus (VMH). This study determined whether HCR are more responsive to central modulation of activity EE compared with low-capacity runners (LCR). METHODS HCR and LCR rats received intra-VMH microinjections of melanotan II (MTII), a mixed melanocortin receptor agonist. Changes in EE, respiratory exchange ratio, activity EE, muscle heat, norepinephrine turnover, and muscle energetic modulators were compared. RESULTS HCR were significantly more responsive to intra-VMH MTII-induced changes in EE, activity EE, norepinephrine turnover to some muscle subgroups, and muscle mRNA expression of some energetic modulators. Though HCR had high muscle activity thermogenesis, limited MTII-induced modulation of muscle thermogenesis during activity was seen in LCR only. CONCLUSIONS An inherently lean, high-capacity rat phenotype showed elevated response to central melanocortin stimulation of activity EE and use of fat as fuel. This may be driven by sympathetic outflow to skeletal muscle, which was elevated after MTII. Central melanocortin receptor activation also altered skeletal muscle energetic modulators in a manner consistent with elevated EE and lowered respiratory exchange ratio.
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Affiliation(s)
- Chaitanya K. Gavini
- School of Biomedical Sciences, Kent State University, Kent, Ohio, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA
| | - Steven L. Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Lauren G. Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Physiology and Pharmacology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Colleen M. Novak
- School of Biomedical Sciences, Kent State University, Kent, Ohio, USA
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
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17
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Almundarij TI, Gavini CK, Novak CM. Suppressed sympathetic outflow to skeletal muscle, muscle thermogenesis, and activity energy expenditure with calorie restriction. Physiol Rep 2017; 5:5/4/e13171. [PMID: 28242830 PMCID: PMC5328781 DOI: 10.14814/phy2.13171] [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: 01/12/2017] [Accepted: 01/29/2017] [Indexed: 12/21/2022] Open
Abstract
During weight loss, adaptive thermogenesis occurs where energy expenditure (EE) is suppressed beyond that predicted for the smaller body size. Here, we investigated the contributions of resting and nonresting EE to the reduced total EE seen after 3 weeks of 50% calorie restriction (CR) in rats, focusing on activity‐associated EE, muscle thermogenesis, and sympathetic outflow. Prolonged food restriction resulted in a 42% reduction in daily EE, through a 40% decrease in resting EE, and a 48% decline in nonresting EE. These decreases in EE were significant even when the reductions in body weight and lean mass were taken into account. Along with a decreased caloric need for low‐to‐moderate‐intensity treadmill activity with 50% CR, baseline and activity‐related muscle thermogenesis were also suppressed, though the ability to increase muscle thermogenesis above baseline levels was not compromised. When sympathetic drive was measured by assessing norepinephrine turnover (NETO), 50% CR was found to decrease NETO in three of the four muscle groups examined, whereas elevated NETO was found in white adipose tissue of food‐restricted rats. Central activation of melanocortin 4 receptors in the ventromedial hypothalamus stimulated this pathway, enhancing activity EE; this was not compromised by 50% CR. These data suggest that suppressed activity EE contributes to adaptive thermogenesis during energy restriction. This may stem from decreased sympathetic drive to skeletal muscle, increasing locomotor efficiency and reducing skeletal muscle thermogenesis. The capacity to increase activity EE in response to central stimuli is retained, however, presenting a potential target for preventing weight regain.
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Affiliation(s)
- Tariq I Almundarij
- College of Agriculture and Veterinary Medicine, Al Qassim University, Buraydah, Al-Qassim Province, Saudi Arabia.,Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Chaitanya K Gavini
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois.,School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Colleen M Novak
- Department of Biological Sciences, Kent State University, Kent, Ohio .,School of Biomedical Sciences, Kent State University, Kent, Ohio
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