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Shin Y, Kim S, Sohn JW. Serotonergic regulation of appetite and sodium appetite. J Neuroendocrinol 2023; 35:e13328. [PMID: 37525500 DOI: 10.1111/jne.13328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/27/2023] [Accepted: 07/15/2023] [Indexed: 08/02/2023]
Abstract
Serotonin is a neurotransmitter that is synthesized and released from the brainstem raphe nuclei to affect many brain functions. It is well known that the activity of raphe serotonergic neurons is changed in response to the changes in feeding status to regulate appetite via the serotonin receptors. Likewise, changes in volume status are known to alter the activity of raphe serotonergic neurons and drugs targeting serotonin receptors were shown to affect sodium appetite. Therefore, the central serotonin system appears to regulate ingestion of both food and salt, although neural mechanisms that induce appetite in response to hunger and sodium appetite in response to volume depletion are largely distinct from each other. In this review, we discuss our current knowledge regarding the regulation of ingestion - appetite and sodium appetite - by the central serotonin system.
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Affiliation(s)
- Yurim Shin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seungjik Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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Reich N, Hölscher C. Beyond Appetite: Acylated Ghrelin As A Learning, Memory and Fear Behavior-modulating Hormone. Neurosci Biobehav Rev 2022; 143:104952. [DOI: 10.1016/j.neubiorev.2022.104952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 04/27/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022]
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Reed CH, Bauer EE, Shoeman A, Buhr TJ, Clark PJ. Acute Stress Exposure Alters Food-Related Brain Monoaminergic Profiles in a Rat Model of Anorexia. J Nutr 2021; 151:3617-3627. [PMID: 34522956 PMCID: PMC8643607 DOI: 10.1093/jn/nxab298] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/02/2021] [Accepted: 08/12/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Adverse life experiences are a major risk factor for anorexia nervosa (AN). Eating-provoked anxiousness associated with AN is postulated to be due to food-related exaggerated serotonin activity in the brain and imbalances of monoamine neurotransmitters. OBJECTIVES Using a rodent model of stress-induced hypophagia, we investigated if stress exposure augments food-related serotonin turnover and imbalances in measures of brain serotonin and dopamine activity in manners consistent with anxiousness toward food and restricted eating. METHODS Adult male F344 rats were conditioned to associate an audio cue with daily food over 2 weeks, after which half of the rats were exposed to a single episode of tail shocks (stress) or left undisturbed (nonstressed). All rats were killed 48 h later, during a control period, the food-associated cue, or a period of food access. Serotonin, dopamine, and norepinephrine, as well as metabolite concentrations, were assessed across brain regions comprising reward, emotion, and feeding circuits relevant to AN in acutely stressed and nonstressed rats using HPLC. Statistical significance level was 5%. RESULTS Stress-induced rat hypophagia paralleled an augmented serotonin turnover in response to the food-associated cue in the hypothalamus and hippocampus, as well as food access in the hypothalamus and cortical areas (all P < 0.05). Stress exposure increased the ratio of serotonin to dopamine metabolites across several brain areas, but the magnitude of this imbalance was further augmented during the food-associated cue and food access in the brainstem, hippocampus, and cortical areas (all P < 0.05). Finally, stress lowered norepinephrine concentrations by 18% in the hypothalamus (P < 0.05). CONCLUSIONS The observed stress-induced changes to monoamine profiles in rats could have key implications for physiological states that contribute to restricted eating and may hold relevance for the development of AN precipitated by adverse life experiences.
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Affiliation(s)
- Carter H Reed
- Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA,Department of Kinesiology, Iowa State University, Ames, IA, USA
| | - Ella E Bauer
- Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA,Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA,Neuroscience Program, Iowa State University, Ames, IA, USA
| | - Allyse Shoeman
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA
| | - Trevor J Buhr
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA,Neuroscience Program, Iowa State University, Ames, IA, USA
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van Galen KA, Ter Horst KW, Serlie MJ. Serotonin, food intake, and obesity. Obes Rev 2021; 22:e13210. [PMID: 33559362 PMCID: PMC8243944 DOI: 10.1111/obr.13210] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/16/2022]
Abstract
The role of serotonin in food intake has been studied for decades. Food intake is mainly regulated by two brain circuitries: (i) the homeostatic circuitry, which matches energy intake to energy expenditure, and (ii) the hedonic circuitry, which is involved in rewarding and motivational aspects of energy consumption. In the homeostatic circuitry, serotonergic signaling contributes to the integration of metabolic signals that convey the body's energy status and facilitates the ability to suppress food intake when homeostatic needs have been met. In the hedonic circuitry, serotonergic signaling may reduce reward-related, motivational food consumption. In contrast, peripherally acting serotonin promotes energy absorption and storage. Disturbed serotonergic signaling is associated with obesity, emphasizing the importance to understand the role of serotonergic signaling in food intake. However, unraveling the serotonin-mediated regulation of food intake is complex, as the effects of serotonergic signaling in different brain regions depend on the regional expression of serotonin receptor subtypes and downstream effects via connections to other brain regions. We therefore provide an overview of the effects of serotonergic signaling in brain regions of the homeostatic and hedonic regulatory systems on food intake. Furthermore, we discuss the disturbances in serotonergic signaling in obesity and its potential therapeutic implications.
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Affiliation(s)
- Katy A van Galen
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Kasper W Ter Horst
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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Kirsch M, Mertens W. On the Drive Specificity of Freudian Drives for the Generation of SEEKING Activities: The Importance of the Underestimated Imperative Motor Factor. Front Psychol 2018; 9:616. [PMID: 29774002 PMCID: PMC5943553 DOI: 10.3389/fpsyg.2018.00616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 04/12/2018] [Indexed: 12/19/2022] Open
Abstract
Doubters of Freud's theory of drives frequently mentioned that his approach is outdated and therefore cannot be useful for solving current problems in patients with mental disorders. At present, many scientists believe that affects rather than drives are of utmost importance for the emotional life and the theoretical framework of affective neuroscience, developed by Panksepp, strongly underpinned this view. Panksepp evaluated seven so-called command systems and the SEEKING system is therein of central importance. Panksepp used Pankseppian drives as inputs for the SEEKING system but noted the missing explanation of drive-specific generation of SEEKING activities in his description. Drive specificity requires dual action of the drive: the activation of a drive-specific brain area and the release of the neurotransmitter dopamine. Noticeably, as Freud claimed drive specificity too, it was here analyzed whether a Freudian drive can evoke the generation of drive-specific SEEKING activities. Special importance was addressed to the imperative motor factor in Freud's drive theory because Panksepp's formulations focused on neural pathways without specifying underlying neurotransmitter/endocrine factors impelling motor activity. As Panksepp claimed sleep as a Pankseppian drive, we firstly had to classified sleep as a Freudian drive by using three evaluated criteria for a Freudian drive. After that it was possible to identify the imperative motor factors of hunger, thirst, sex, and sleep. Most importantly, all of these imperative motor factors can both activate a drive-specific brain area and release dopamine from dopaminergic neurons, i.e., they can achieve the so-called drive specificity. Surprisingly, an impaired Freudian drive can alter via endocrinological pathways the concentration of the imperative motor factor of a second Freudian drive, obviously in some independence to the level of the metabolic deficit, thereby offering the possibility to modulate the generation of SEEKING activities of this second Freudian drive. This novel possibility might help to refine the general understanding of the action of Freudian drives. As only imperative motor factors of Freudian drives can guarantee drive specificity for the generation of SEEKING activities, the impact of Freud's construct Eros (with its constituents hunger, thirst, sex, and sleep) should be revisited.
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Affiliation(s)
- Michael Kirsch
- Institute of Physiological Chemistry, University Hospital Essen, Essen, Germany
| | - Wolfgang Mertens
- Division of Clinical Psychology and Psychotherapy, Department of Psychology, Faculty of Psychology and Educational Sciences, Ludwig Maximilian University of Munich, Munich, Germany
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Restoring Serotonergic Homeostasis in the Lateral Hypothalamus Rescues Sleep Disturbances Induced by Early-Life Obesity. J Neurosci 2017; 38:441-451. [PMID: 29196316 DOI: 10.1523/jneurosci.1333-17.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/13/2017] [Accepted: 10/12/2017] [Indexed: 01/09/2023] Open
Abstract
Early-life obesity predisposes to obesity in adulthood, a condition with broad medical implications including sleep disorders, which can exacerbate metabolic disturbances and disrupt cognitive and affective behaviors. In this study, we examined the long-term impact of transient peripubertal diet-induced obesity (ppDIO, induced between 4 and 10 weeks of age) on sleep-wake behavior in male mice. EEG and EMG recordings revealed that ppDIO increases sleep during the active phase but reduces resting-phase sleep quality. This impaired sleep phenotype persisted for up to 1 year, although animals were returned to a non-obesiogenic diet from postnatal week 11 onwards. To better understand the mechanisms responsible for the ppDIO-induced alterations in sleep, we focused on the lateral hypothalamus (LH). Mice exposed to ppDIO did not show altered mRNA expression levels of orexin and melanin-concentrating hormone, two peptides that are important for sleep-wake behavior and food intake. Conversely, the LH of ppDIO-exposed mice had reduced contents of serotonin (5-hydroxytryptamine, 5-HT), a neurotransmitter involved in both sleep-wake and satiety regulation. Interestingly, an acute peripheral injection of the satiety-signaling peptide YY 3-36 increased 5-HT turnover in the LH and ameliorated the ppDIO-induced sleep disturbances, suggesting the therapeutic potential of this peptide. These findings provide new insights into how sleep-wake behavior is programmed during early life and how peripheral and central signals are integrated to coordinate sleep.SIGNIFICANCE STATEMENT Adult physiology and behavior are strongly influenced by dynamic reorganization of the brain during puberty. The present work shows that obesity during puberty leads to persistently dysregulated patterns of sleep and wakefulness by blunting serotonergic signaling in the lateral hypothalamus. It also shows that pharmacological mimicry of satiety with peptide YY3-36 can reverse this neurochemical imbalance and acutely restore sleep composition. These findings add insight into how innate behaviors such as feeding and sleep are integrated and suggest a novel mechanism through which diet-induced obesity during puberty imposes its long-lasting effects on sleep-wake behavior.
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Ge T, Zhang Z, Lv J, Song Y, Fan J, Liu W, Wang X, Hall FS, Li B, Cui R. The role of 5-HT 2c receptor on corticosterone-mediated food intake. J Biochem Mol Toxicol 2017; 31. [PMID: 28186389 DOI: 10.1002/jbt.21890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 11/07/2022]
Abstract
Corticosterone plays an important role in feeding behavior. However, its mechanism remains unclear. Therefore, the present study aimed to investigate the effect of corticosterone on feeding behavior. In this study, cumulative food intake was increased by acute corticosterone administration in a dose-dependent manner. Administration of the 5-HT2c receptor agonist m-chlorophenylpiperazin (mCPP) reversed the effect of corticosterone on food intake. The anorectic effects of mCPP were also blocked by the 5-HT2c receptor antagonist RS102221 in corticosterone-treated mice. Both corticosterone and mCPP increased c-Fos expression in hypothalamic nuclei, but not the nucleus of the solitary tract. RS102221 inhibited c-Fos expression induced by mCPP, but not corticosterone. In addition, mCPP had little effect on TH and POMC levels in the hypothalamus. Furthermore, mCPP antagonized decreasing effect of the leptin produced by corticosterone. Taken together, our findings suggest that 5-HT2c receptors and leptin may be involved in the effects of corticosterone-induced hyperphagia.
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Affiliation(s)
- Tongtong Ge
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - Zhuo Zhang
- Department of Orthopedics, China-Japan Union Hospital of Jilin University 126 Xiantai Street, Nanguan District, Changchun, 13033, People's Republic of China
| | - Jiayin Lv
- Department of Orthopedics, China-Japan Union Hospital of Jilin University 126 Xiantai Street, Nanguan District, Changchun, 13033, People's Republic of China
| | - Yunong Song
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - Jie Fan
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - Wei Liu
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - Xuefeng Wang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - F Scott Hall
- Department of Pharmacology and Experimental Therapeutics, University of Toledo College of Pharmacy and Pharmaceutical Sciences, Toledo, OH, USA
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
| | - Ranji Cui
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China
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Sestan-Pesa M, Horvath TL. Metabolism and Mental Illness. Trends Mol Med 2016; 22:174-183. [PMID: 26776095 DOI: 10.1016/j.molmed.2015.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 01/23/2023]
Abstract
Over the past century, overwhelming evidence has emerged pointing to the hypothalamus of the central nervous system (CNS) as a crucial regulator of systemic control of metabolism, including appetite and feeding behavior. Appetite (or hunger) is a fundamental driver of survival, involving complex behaviors governed by various parts of the brain, including the cerebral cortex. Here, we provide an overview of basic metabolic principles affecting the CNS and discuss their relevance to physiological and pathological conditions of higher brain functions. These novel perspectives may well provide new insights into future research strategies to facilitate the development of novel therapies for treating mental illness.
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Affiliation(s)
- Matija Sestan-Pesa
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
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Interacting Neural Processes of Feeding, Hyperactivity, Stress, Reward, and the Utility of the Activity-Based Anorexia Model of Anorexia Nervosa. Harv Rev Psychiatry 2016; 24:416-436. [PMID: 27824637 PMCID: PMC5485261 DOI: 10.1097/hrp.0000000000000111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Anorexia nervosa (AN) is a psychiatric illness with minimal effective treatments and a very high rate of mortality. Understanding the neurobiological underpinnings of the disease is imperative for improving outcomes and can be aided by the study of animal models. The activity-based anorexia rodent model (ABA) is the current best parallel for the study of AN. This review describes the basic neurobiology of feeding and hyperactivity seen in both ABA and AN, and compiles the research on the role that stress-response and reward pathways play in modulating the homeostatic drive to eat and to expend energy, which become dysfunctional in ABA and AN.
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10
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Voigt JP, Fink H. Serotonin controlling feeding and satiety. Behav Brain Res 2015; 277:14-31. [DOI: 10.1016/j.bbr.2014.08.065] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 02/06/2023]
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12
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Donovan MH, Tecott LH. Serotonin and the regulation of mammalian energy balance. Front Neurosci 2013; 7:36. [PMID: 23543912 PMCID: PMC3608917 DOI: 10.3389/fnins.2013.00036] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/03/2013] [Indexed: 01/17/2023] Open
Abstract
Maintenance of energy balance requires regulation of the amount and timing of food intake. Decades of experiments utilizing pharmacological and later genetic manipulations have demonstrated the importance of serotonin signaling in this regulation. Much progress has been made in recent years in understanding how central nervous system (CNS) serotonin systems acting through a diverse array of serotonin receptors impact feeding behavior and metabolism. Particular attention has been paid to mechanisms through which serotonin impacts energy balance pathways within the hypothalamus. How upstream factors relevant to energy balance regulate the release of hypothalamic serotonin is less clear, but work addressing this issue is underway. Generally, investigation into the central serotonergic regulation of energy balance has had a predominantly “hypothalamocentric” focus, yet non-hypothalamic structures that have been implicated in energy balance regulation also receive serotonergic innervation and express multiple subtypes of serotonin receptors. Moreover, there is a growing appreciation of the diverse mechanisms through which peripheral serotonin impacts energy balance regulation. Clearly, the serotonergic regulation of energy balance is a field characterized by both rapid advances and by an extensive and diverse set of central and peripheral mechanisms yet to be delineated.
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Affiliation(s)
- Michael H Donovan
- Department of Psychiatry, University of California San Francisco CA, USA
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Rivera HM, Santollo J, Nikonova LV, Eckel LA. Estradiol increases the anorexia associated with increased 5-HT(2C) receptor activation in ovariectomized rats. Physiol Behav 2011; 105:188-94. [PMID: 21889523 DOI: 10.1016/j.physbeh.2011.08.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 07/20/2011] [Accepted: 08/17/2011] [Indexed: 11/24/2022]
Abstract
Estradiol's inhibitory effect on food intake is mediated, in part, by its ability to increase the activity of meal-related signals, including serotonin (5-HT), which hastens satiation. The important role that postsynaptic 5-HT(2C) receptors play in mediating 5-HT's anorexigenic effect prompted us to investigate whether a regimen of acute estradiol treatment increases the anorexia associated with increased 5-HT(2C) receptor activation in ovariectomized (OVX) rats. We demonstrated that intraperitoneal and intracerebroventricular (i.c.v.) administration of low doses of the 5-HT(2C) receptor agonist meta-chlorophenylpiperazine (mCPP) decreased 1-h dark-phase food intake in estradiol-treated, but not oil-treated, OVX rats. During a longer feeding test, we demonstrated that i.c.v. administration of mCPP decreased 22-h food intake in oil-treated and, to a greater extent, estradiol-treated OVX rats. In a second study, we demonstrated that estradiol increased 5-HT(2C) receptor protein content in the caudal brainstem, but not hypothalamus, of OVX rats. We conclude that a physiologically-relevant regimen of acute estradiol treatment increases sensitivity to mCPP's anorexigenic effect. Our demonstration that this same regimen of estradiol treatment increases 5-HT(2C) receptor protein content in the caudal hindbrain of OVX rats provides a possible mechanism to explain our behavioral findings.
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Affiliation(s)
- Heidi M Rivera
- Department of Psychology and program in Neuroscience, The Florida State University, Tallahassee, FL 32306-4301, USA
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Hull EM. Sex, drugs and gluttony: how the brain controls motivated behaviors. Physiol Behav 2011; 104:173-7. [PMID: 21554895 PMCID: PMC3107928 DOI: 10.1016/j.physbeh.2011.04.057] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
Bart Hoebel has forged a view of an integrated neural network that mediates both natural rewards and drug use. He pioneered the use of microdialysis, and also effectively used electrical stimulation, lesions, microinjections, and immunohistochemistry. He found that feeding, stimulant drug administration, and electrical stimulation of the lateral hypothalamus (LH) all increased dopamine (DA) release in the nucleus accumbens (NAc). However, whereas DA in the NAc enhanced motivation, DA in the LH inhibited motivated behaviors. The Hull lab has pursued some of those ideas. We have suggested that serotonin (5-HT) in the perifornical LH inhibits sexual behavior by inhibiting orexin/hypocretin neurons (OX/HCRT), which would otherwise excite neurons in the mesocorticolimbic DA tract. We have shown that DA release in the medial preoptic area (MPOA) is very important for male sexual behavior, and that testosterone, glutamate, nitric oxide (NO) and previous sexual experience promote MPOA DA release and mating. Future research should follow Bart Hoebel's emphasis on neural systems and interactions among brain areas and neurotransmitters.
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Affiliation(s)
- Elaine M Hull
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL 32306-4301, United States.
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Hernández L, Paredes D, Rada P. Feeding behavior as seen through the prism of brain microdialysis. Physiol Behav 2011; 104:47-56. [PMID: 21549733 DOI: 10.1016/j.physbeh.2011.04.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/28/2022]
Abstract
The knowledge of feeding behavior mechanisms gained through brain microdialysis is reviewed. Most of the chemical changes so far reported concern to the limbic system in rodents. A picture showing increases and decreases of extracellular neurotransmitters correlating to different aspects of feeding behavior is gradually emerging. Depending on the region, the same neurotransmitter may signal opposite aspects of feeding. Dopamine (DA) in the nucleus accumbens (NAC) correlates with food reward, stimulus saliency, and goal directed hyperlocomotion but in the ventromedial hypothalamus DA correlates with satiety and hypolocomotion. The findings accumulated in the last 25 years suggest that the control of a particular function relies on the interaction of several neurotransmitters rather than on a single neurotransmitter. The poor sensitivity of most analytical techniques hinders time and spatial resolution of microdialysis. Therefore, neurochemical correlates of short lasting behaviors are hard to figure out. As new and more sensitive analytical techniques are applied, new neurochemical correlates of feeding show up. Sometimes the proper analytical techniques are simply not available. As a consequence, critical signals such as neuropeptides are not yet completely placed in the puzzle. Despite such limitations, brain microdialysis has yielded a great deal of knowledge on the neurochemical basis of feeding.
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Affiliation(s)
- Luis Hernández
- Laboratory of Behavioral Physiology, School of Medicine, Universidad de los Andes, Mérida, Venezuela
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Avraham Y, Saidian M, Burston JJ, Mevorach R, Vorobiev L, Magen I, Kunkes E, Borges B, Lichtman AH, Berry EM. Fish oil promotes survival and protects against cognitive decline in severely undernourished mice by normalizing satiety signals. J Nutr Biochem 2010; 22:766-76. [PMID: 21109417 DOI: 10.1016/j.jnutbio.2010.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 05/24/2010] [Accepted: 07/22/2010] [Indexed: 12/15/2022]
Abstract
Severe malnutrition resulting from anorexia nervosa or involuntary starvation leads to low weight, cognitive deficits and increased mortality rates. In the present study, we examined whether fish oil supplementation, compared with that of canola oil, would ameliorate the morbidity and mortality associated with these conditions by normalizing endocannabinoid and monoaminergic systems as well as other systems involved in satiety and cognitive function within the hypothalamus and hippocampus. Female Sabra mice restricted to 40% of their daily food intake exhibited decreased body weight, were sickly in appearance, displayed cognitive deficits and had increased mortality rates. Strikingly, fish oil supplementation that contains high omega-3 fatty acids levels decreased mortality and morbidity, and normalized the expression of genes and neurotransmitters in the hippocampus and hypothalamus. Fish oil supplementation, but not canola oil, increased survival rates, improved general appearance and prevented cognitive decline, despite the facts that both diets contained an equivalent number of calories and that there were no differences in weight between mice maintained on the two diets in 100% but decrease in the 40%. In the hypothalamus, the beneficial effects of fish oil supplementation were related to normalization of the endocannabinoid 2-arachidonylglycerol, serotonin (5-HT) (P<.056), dopamine, neuropeptide Y (NPY) and Ca(2+)/calmodulin (CaM)-dependent protein kinase (Camkk2). In the hippocampus, fish oil supplementation normalized 5-HT, Camkk2, silent mating type information regulation 1 and brain-derived neurotrophic factor. In conclusion, dietary supplements of fish oil, as source of omega-3 fatty acids, may alleviate cognitive impairments associated with severe diet restriction and prolong survival independently of weight gain by normalizing neurochemical systems.
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Affiliation(s)
- Yosefa Avraham
- Department of Human Nutrition and Metabolism and School of Public Health, Hebrew University Hadassah Medical School, Jerusalem 91120, Israel.
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Fletcher PJ, Sinyard J, Higgins GA. Genetic and pharmacological evidence that 5-HT2C receptor activation, but not inhibition, affects motivation to feed under a progressive ratio schedule of reinforcement. Pharmacol Biochem Behav 2010; 97:170-8. [PMID: 20624416 DOI: 10.1016/j.pbb.2010.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 06/25/2010] [Accepted: 07/05/2010] [Indexed: 12/27/2022]
Abstract
Previous work showed that 5-HT(2C) receptor agonists reduce cocaine self-administration on a progressive ratio (PR) schedule of reinforcement, whereas a 5-HT(2C) receptor antagonist enhances responding for cocaine. The present experiments examined the effects of Ro60-0175 (5-HT(2C) agonist) and SB242084 (5-HT(2C) receptor antagonist) in rats on responding for food on a PR schedule; responding was also determined in mice lacking functional 5-HT(2C) receptors. In food-restricted rats, lever pressing reinforced by regular food pellets or sucrose pellets was reduced by Ro60-0175. This effect was blocked by SB242084, and was absent in mice lacking functional 5-HT(2C) receptors. A number of studies examined the effects of SB242084 on responding for food under a variety of conditions. These included manipulation of food type (regular pellets versus sucrose pellets), nutritional status of the animals (food restriction versus no restriction), and rate of progression of the increase in ratio requirements on the PR schedule. In all cases there was no evidence of enhanced responding for food by SB242084. Mice lacking functional 5-HT(2C) receptors did not differ from wildtype mice in responding for food in either food-restricted or non-restricted states. The effects of Ro60-0175 are consistent with its effects on food consumption and motivation to self-administer cocaine. Unlike their effects on cocaine self-administration, pharmacological blockade of 5-HT(2C) receptors, and genetic disruption of 5-HT(2C) receptor function do not alter the motivation to respond for food. Because the 5-HT(2C) receptor exerts a modulatory effect on dopamine function, the differential effects of reduced 5-HT(2C) receptor mediated transmission on responding for food versus cocaine may relate to a differential role of this neurotransmitter in mediating these two behaviours.
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Affiliation(s)
- Paul J Fletcher
- Section of Biopsychology, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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Quarta D, Di Francesco C, Melotto S, Mangiarini L, Heidbreder C, Hedou G. Systemic administration of ghrelin increases extracellular dopamine in the shell but not the core subdivision of the nucleus accumbens. Neurochem Int 2009; 54:89-94. [DOI: 10.1016/j.neuint.2008.12.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 11/14/2008] [Accepted: 12/02/2008] [Indexed: 11/25/2022]
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Steffens SM, da Cunha IC, Beckman D, Lopes APF, Faria MS, Marino-Neto J, Paschoalini MA. The effects of metergoline and 8-OH-DPAT injections into arcuate nucleus and lateral hypothalamic area on feeding in female rats during the estrous cycle. Physiol Behav 2008; 95:484-91. [PMID: 18694771 DOI: 10.1016/j.physbeh.2008.07.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 07/10/2008] [Accepted: 07/17/2008] [Indexed: 01/15/2023]
Abstract
The present study examined the effects of local injections of metergoline (MET, an antagonist of 5-HT1/2 receptors, 2 and 20 nmol) and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, selective 5-HT1A receptor agonist, 0.6 and 6 nmol) into the arcuate nucleus (ARC) and the lateral hypothalamus (LH), on ingestive and non-ingestive behaviors of female rats. These effects were examined during the diurnal periods of diestrus and estrus in rats adapted to eat a wet mash diet (enriched with 10% sucrose) during 1h for 3 consecutive days at the recording chamber. The results showed that 8-OH-DPAT injected into the LH significantly reduced food intake at all doses and both cycle stages, while in the ARC these treatments evoked hypophagia only at the highest 8-OH-DPAT dose and only at the estrous phase. MET administered into the ARC (at all doses) failed to affect food intake during both estrous stages. On the other hand, food intake decreased after injection of both doses of MET into the LH of rats during estrous and diestrus phases. In estrus stage, injections of the higher dose of 8-OH-DPAT into the ARC and into the LH decreased the duration of feeding. Latency to start feeding, drinking, and non-ingestive behaviors were not affected by 8-OH-DPAT or MET treatments in the ARC or the LH in both cycle phases. These results indicated that 5-HT1A receptors participate in the serotonergic control of feeding-related mechanisms located at the ARC and the LH. These feeding-related serotonergic circuits in both areas are possibly affected by ovarian hormones that could increase sensitivity of ARC neurons to the hypophagic effects of 8-OH-DPAT or increase the efficacy of satiety signals that terminate feeding. In addition, the present data indicated that serotonergic inputs do not exert a tonic inhibitory activity on the ARC and the LH feeding-related circuits.
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Affiliation(s)
- Sérgio Murilo Steffens
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), Florianópolis, SC, Brazil
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20
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Centeno ML, Henderson JA, Pau KYF, Bethea CL. Estradiol increases alpha7 nicotinic receptor in serotonergic dorsal raphe and noradrenergic locus coeruleus neurons of macaques. J Comp Neurol 2006; 497:489-501. [PMID: 16736471 PMCID: PMC2601699 DOI: 10.1002/cne.21026] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Acetylcholine, acting on presynaptic nicotinic receptors (nAChRs), modulates the release of neurotransmitters in the brain. The rat dorsal raphe nucleus (DR) and the locus coeruleus (LC) receive cholinergic input and express the alpha7nAChR. In previous reports, we demonstrated that estradiol (E) administration stimulates DR serotonergic and LC noradrenergic function in the macaque. In addition, it has been reported that E induces the expression of the alpha7nAChR in rats. We questioned whether E increased the expression of the alpha7nAChR in the macaque DR and LC. We utilized double immunostaining to study the effect of a simulated preovulatory surge of E on the expression of the alpha7nAChR in the DR and the LC and to determine whether alpha7nAChR colocalizes with serotonin and tyrosine hydroxylase (TH) in macaques. There was no difference in the number of alpha7nAChR-positive neurons between ovariectomized (OVX) controls and OVX animals treated with a silastic capsule containing E (Ecap). However, supplemental infusion of E for 5-30 hours to Ecap animals (Ecap + inf) significantly increased the number of alpha7nAChR-positive neurons in DR and LC. In addition, supplemental E infusion significantly increased the number of neurons in which alpha7nAChR colocalized with serotonin and TH. These results constitute an important antecedent for study of the effects of nicotine and ovarian steroid hormones in the physiological functions regulated by the DR and the LC in women.
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Affiliation(s)
- Maria Luisa Centeno
- Division of Reproductive Sciences, Oregon National Primate Research Center, Beaverton, Oregon 97006, USA.
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21
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Fraga IC, Fregoneze JB, Carvalho FLQ, Dantas KB, Azevedo CS, Pinho CB, de Castro E Silva E. Acute fluoxetine administration differentially affects brain C-Fos expression in fasted and refed rats. Neuroscience 2005; 134:327-34. [PMID: 15953686 DOI: 10.1016/j.neuroscience.2005.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Revised: 02/22/2005] [Accepted: 03/11/2005] [Indexed: 11/30/2022]
Abstract
In the present study we investigated the effect of acute fluoxetine administration on the expression of c-Fos in the rat brain under two different metabolic conditions: fed and fasting states. Wistar male rats, weighing 220+/-30g, received i.p. injections of saline solution or fluoxetine (10mg/kg), and were killed 2 h later. The brains were removed after transcardiac perfusion with phosphate-buffered saline followed by paraformaldehyde, and were then processed for immunohistochemistry. Fos-like immunoreactivity was quantified by a computerized system. Fasted animals faced an 18-h suppression of food intake, while fed groups were submitted to an initial 14-h period of fast followed by a 4-h period in which food was freely available. Both in fasting and fed states, fluoxetine-treated animals presented a significant increase in c-Fos expression in hypothalamic areas, limbic structures, circumventricular areas, and in mesencephalic and rhomboencephalic regions, as compared with saline-treated controls. The quantitative comparison of data obtained from fasted and fed animals showed that fasted rats treated with fluoxetine presented a higher c-Fos expression in the ventromedial hypothalamus and the paraventricular nuclei compared with the fed group, while in fluoxetine-treated fed rats c-Fos expression was higher in the arcuate nuclei, medial amygdala, locus coeruleus and dorsal raphe nuclei, as compared with fasted, fluoxetine-treated animals. These data indicate that the metabolic condition of the animals significantly modifies fluoxetine-induced brain c-Fos expression, suggesting that visceral and behavioral fluoxetine effects may be influenced by the metabolic state of the individual.
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Affiliation(s)
- I C Fraga
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil
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22
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Blevins JE, Teh PS, Wang CX, Gietzen DW. Effects of amino acid deficiency on monoamines in the lateral hypothalamus (LH) in rats. Nutr Neurosci 2003; 6:291-9. [PMID: 14609315 DOI: 10.1080/10284150310001622248] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Animals decrease intake of an indispensable amino acid deficient diet, due in part to decreased dietary limiting amino acid concentrations within the anterior piriform cortex (APC). In addition to studies supporting a primary role for the APC in this phenomenon, recent studies have shown that the lateral hypothalamus (LH), which receives projections from the APC, also mediates the anorectic response to amino acid deficiency. The neurochemical changes within the LH that accompany the anorexia to amino acid deficiency are unclear. We hypothesized that norepinephrine (NE), dopamine (DA) and serotonin, whose levels are altered in response to amino acid deficiency within the APC, also act within the LH to mediate amino acid deficiency-induced anorexia. We determined that ingestion of an amino acid devoid diet increased concentrations of NE and the serotonin metabolite, 5-hydroxyindoleacetic acid in the LH. The 5-hydroxytryptamine metabolite was increased overall, according to analysis by area under the curve. Individual points reached significance at 130 min; NE was elevated at 170 min. These results suggest that the sustained anorectic response following ingestion of an amino acid devoid diet may be associated with increased activity of the NE and 5-hydroxytryptamine systems in the LH.
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Affiliation(s)
- J Ernie Blevins
- Division of Endocrinology/Metabolism, Department of Veterans Affairs Medical Center, University of Washington, Seattle, WA 91808, USA.
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23
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Helm KA, Rada P, Hoebel BG. Cholecystokinin combined with serotonin in the hypothalamus limits accumbens dopamine release while increasing acetylcholine: a possible satiation mechanism. Brain Res 2003; 963:290-7. [PMID: 12560135 DOI: 10.1016/s0006-8993(02)04051-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serotonin (5-HT) or cholecystokinin (CCK) injected in the hypothalamic paraventricular nucleus (PVN) inhibits feeding, but the mechanism is unknown. Prior research suggests that dopamine (DA) input to the nucleus accumbens (NAc) motivates behavior, and a component of that motivation circuit includes hypothalamic feeding systems. Acetylcholine (ACh) in the NAc, on the other hand, may act in part to inhibit feeding and generate satiety. If so, 5-HT and/or CCK in the PVN should lower extracellular DA or release ACh in the NAc. Rats were prepared with microdialysis probes in the NAc and injectors in the PVN. Serotonin (7.75 microg) or CCK-8 (0.12 microg) injected in the PVN significantly decreased ipsilateral accumbens DA (63 and 73% of baseline, respectively, without effect on ACh). However, 5-HT plus CCK injected in combination decreased DA to 72% (P<0.001) and simultaneously increased extracellular ACh to 128% of baseline (P<0.001). In later tests with the same doses and the same animals, unilateral PVN injections of 5-HT, CCK, or both combined, significantly inhibited food intake in the early dark period. The results suggest that 5-HT in the PVN acts as a neural modulator that primes a hypothalamic satiation system to respond to CCK when the gastrointestinal tract contains food to be digested. The synergistic action of 5-HT plus phasic CCK may then activate a circuit that simultaneously limits DA and releases ACh in the accumbens as part of the satiation process.
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Affiliation(s)
- Katherine A Helm
- Department of Psychology, Princeton University, Princeton, NJ 08544-1010, USA
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Jo YH, Talmage DA, Role LW. Nicotinic receptor-mediated effects on appetite and food intake. JOURNAL OF NEUROBIOLOGY 2002; 53:618-32. [PMID: 12436425 PMCID: PMC2367209 DOI: 10.1002/neu.10147] [Citation(s) in RCA: 220] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It is well known, although not well understood, that smoking and eating just do not go together. Smoking is associated with decreased food intake and lower body weight. Nicotine, administered either by smoking or by smokeless routes, is considered the major appetite-suppressing component of tobacco. Perhaps the most renowned example of nicotine's influence on appetite and feeding behavior is the significant weight gain associated with smoking cessation. This article presents an overview of the literature at, or near, the interface of nicotinic receptors and appetite regulation. We first consider some of the possible sites of nicotine's action along the complex network of neural and non-neural regulators of feeding. We then present the hypothesis that the lateral hypothalamus is a particularly important locus of the anorectic effects of nicotine. Finally, we discuss the potential role of endogenous cholinergic systems in motivational feeding, focusing on cholinergic pathways in the lateral hypothalamus.
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Affiliation(s)
- Young-Hwan Jo
- Department of Anatomy and Cell Biology, in the Center for Neurobiology and Behavior, Columbia, University, New York, NY 10032, USA
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25
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Guimarães RB, Telles MM, Coelho VBO, Mori RCT, Nascimento CMO, Ribeiro EB. Adrenalectomy abolishes the food-induced hypothalamic serotonin release in both normal and monosodium glutamate-obese rats. Brain Res Bull 2002; 58:363-9. [PMID: 12183012 DOI: 10.1016/s0361-9230(02)00799-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Corticosteroids influence energy homeostasis through centrally-mediated stimulation of energy intake and inhibition of expenditure, while central serotonin (5-HT) has opposite effects. Both serotonergic dysfunction and high glucocorticoid levels may be relevant in obesity. The neurotoxin monosodium glutamate (MSG) induces a non-hyperphagic and hypometabolic obesity with hypercorticosteronemia. We investigated the influence of corticosterone levels on the serotonergic system of MSG-obese and control rats. Applying microdialysis, we found a similar feeding-induced stimulation of serotonin release in the lateral hypothalamus (LH) in sham-adrenalectomized control and MSG rats. The concomitant serum corticosterone variations were markedly distinct between them, in that an increase occurred in the control group, while the initially high levels of the MSG rats decreased with feeding. It is suggested that this lowering of corticosterone prevented a higher serotonergic activation, which would lead to a higher meal-induced thermogenesis and a better adequation of the caloric intake to a low metabolism. Adrenalectomy completely abolished the feeding-evoked serotonergic stimulation in both groups. This observation demonstrates that glucocorticoids are necessary for food intake to acutely stimulate 5-HT release and indicates that serotonergic activity in the LH is not likely to participate in the adrenalectomy-induced attenuation of the MSG-obesity.
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Affiliation(s)
- Regina B Guimarães
- Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
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26
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Sullivan SD, Howard LC, Clayton AH, Moenter SM. Serotonergic activation rescues reproductive function in fasted mice: does serotonin mediate the metabolic effects of leptin on reproduction? Biol Reprod 2002; 66:1702-6. [PMID: 12021050 DOI: 10.1095/biolreprod66.6.1702] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Negative energy balance inhibits reproduction by restraining GnRH secretion. Leptin is a permissive metabolic signal for reproduction, but GnRH neurons do not appear to express leptin receptors, suggesting that interneurons transmit leptin signals to these cells. Serotonin (5HT) has satiety effects similar to those of leptin and alters LH release, and serotonergic neurons, which have been shown to express leptin receptors, terminate on GnRH neurons. We hypothesized that serotonergic neurons convey leptin signals to the reproductive neuroendocrine axis. To test this, mice were fasted for 48 h beginning on Diestrous Day 1. While fasting, mice received saline or leptin every 12 h or the 5HT-selective reuptake-inhibitor fluoxetine once at the start of the fast. Estrous cycles of fasted mice were longer (mean +/- SEM, 10.2 +/- 0.5 days; P < 0.0001) than those of fed mice (4.5 +/- 0.2 days). As previously reported, leptin prevented fasting-induced cycle lengthening (4.6 +/- 0.7 days). Fluoxetine also rescued estrous cycles in fasted mice (4.7 +/- 0.6 days), suggesting that 5HT and leptin have similar positive effects on reproduction. Coadministration of the 5HT 1/2/7 receptor-antagonist metergoline blocked rescue of cycle length by fluoxetine and by leptin. Treating leptin-deficient ob/ob and leptin receptor-deficient db/db mice with fluoxetine did not normalize body weight or rescue fertility, perhaps due to altered serotonergic tone in these animals. Together, these data demonstrate a permissive role for serotonergic systems in the metabolic control of reproduction and are consistent with the hypothesis that serotonergic neurons convey leptin signals to GnRH neurons.
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Affiliation(s)
- Shannon D Sullivan
- Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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27
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Zippel U, Heidel E, Plagemann A, Davidowa H. Action of CCK and 5-HT on lateral hypothalamic neurons depends on early postnatal nutrition. Nutr Neurosci 2002; 4:143-52. [PMID: 11842882 DOI: 10.1080/1028415x.2001.11747358] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Wistar rats grown up during the early postnatal life (3-21 days after birth) in artificially built normal, small or large lifters developed a significantly different body weight. This difference persisted also during adulthood when they had free access to food and water. The influence of iontophoretically administered cholecystokinin (CCK8S), serotonin (5-HT) or co-ejection of both on firing of lateral hypothalamic neurons was investigated in adult, urethane anesthetized rats of the three groups. The responsiveness to CCK8S was significantly higher in large- and small-litter rats than in the normal control group. The differences were greater in males than in females. They resulted in the male large-litter group from an increase of excitatory responses, whereas in the male small-litter group the proportion of inhibitory responses was augmented. Co-administration of 5-HT generally reduced the neuronal responsiveness. Especially in the large-litter group excitatory responses were significantly reduced. It may be speculated that the availability of food in the early postnatal life influences the development of the hypothalamic regulatory network in such a way that it stabilizes the high or low food ingestion all the life. At least in males, a changed responsiveness and type of response to cholecystokinin of lateral hypothalamic neurons might be involved in this altered regulation.
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Affiliation(s)
- U Zippel
- Johannes-Mueller-Institute of Physiology, Faculty of Medicine, Charité, Humboldt University Berlin, Germany.
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28
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Duva MA, Tomkins EM, Moranda LM, Kaplan R, Sukhaseum A, Jimenez A, Stanley BG. Reverse microdialysis of N-methyl-D-aspartic acid into the lateral hypothalamus of rats: effects on feeding and other behaviors. Brain Res 2001; 921:122-32. [PMID: 11720718 DOI: 10.1016/s0006-8993(01)03108-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of reverse microdialysis of N-methyl-D-aspartic acid (NMDA) into the lateral hypothalamus (LH) on feeding and other behaviors were examined. Consistent with similar studies utilizing central microinjections, NMDA reverse microdialysed into the rat LH rapidly elicited a strong concentration-dependent stimulation of feeding. The minimum perfusate concentration of NMDA needed to elicit feeding with reverse microdialysis was 660 microM, a concentration 1/50 of that needed with pressure injections. Further, eating responses could be consistently elicited in sequential tests separated by 2-4 h in the same subject, and the magnitude of the eating in the first and second tests was highly correlated (r=0.87). Behavioral analysis revealed that the main response to NMDA consisted of eating without the concomitant hyperactivity produced by central microinjections of this agonist. The other behaviors exhibited during NMDA administration were those that normally occur during spontaneous feeding in rats. Also, rats precisely compensated for the increased food intake elicited by NMDA by reducing spontaneous feeding during the subsequent nocturnal phase, so as to maintain normal daily intakes. In contrast, N-methyl-L-aspartate (NMLA) reverse microdialysed in to the LH (660 microM) did not elicit feeding nor affect any other behaviors we examined. These data support a role for LH glutamate and NMDA receptors in the control of feeding.
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Affiliation(s)
- M A Duva
- Department of Psychology, University of California-Riverside, Riverside, CA 92521, USA
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29
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Tachibana T, Tazawa M, Sugahara K. Feeding increases 5-hydroxytryptamine and norepinephrine within the hypothalamus of chicks. Comp Biochem Physiol A Mol Integr Physiol 2001; 130:715-22. [PMID: 11691607 DOI: 10.1016/s1095-6433(01)00403-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
It is thought that hypothalamic 5-hydroxytryptamine (5HT) and norepinephrine (NE) are involved in the regulation of feeding in chicks. The present study was conducted to elucidate changes in the levels of extracellular 5HT and NE in the hypothalamus during feeding of chicks. In order to measure 5HT, NE and 4-hydroxy-3-methoxyphenylglycol (MHPG), which is a major metabolite of NE, we used brain microdialysis and high-pressure liquid chromatography with an electrochemical detector. After collecting samples to determine the basal levels of 5HT, NE and MHPG, food-deprived birds were given access to food. 5HT levels in the medial hypothalamus (MH) and lateral hypothalamus (LH) increased during the first 30 min of feeding, and then returned to basal levels. NE and MHPG in the LH increased during feeding, and remained elevated throughout the experiment. This study supports an idea that hypothalamic monoamines in the chick brain are involved in the regulation of feeding.
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Affiliation(s)
- T Tachibana
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
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30
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Meguid MM, Fetissov SO, Varma M, Sato T, Zhang L, Laviano A, Rossi-Fanelli F. Hypothalamic dopamine and serotonin in the regulation of food intake. Nutrition 2000; 16:843-57. [PMID: 11054589 DOI: 10.1016/s0899-9007(00)00449-4] [Citation(s) in RCA: 318] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Because daily food intake is the product of the size of a meal and the frequency of meals ingested, the characteristic of meal size to meal number during a 24-h light-dark cycle constitutes an identifiable pattern specific to normal states and obesity and that occurs during early cancer anorexia. An understanding of simultaneous changes in meal size and meal number (constituting a change in feeding patterns) as opposed to an understanding of only food intake provides a more insightful dynamic picture reflecting integrated behavior. We have correlated this to simultaneous changes in dopamine and serotonin concentrations and to their postsynaptic receptors, focusing simultaneously on two discrete hypothalamic food-intake-related nuclei, in response to the ingestion of food. The relation between concentrations of dopamine and serotonin limited to the lateral hypothalamic area (LHA) and the ventromedial nucleus (VMN) as they relate to the influence of meal size and meal number during the hyperphagia of obesity and anorexia of cancer as measured in our experiments are discussed. Based on these data, conceptual models are proposed concerning: 1) an "afferent-efferent neurotransmitter unit," with facilitatory or inhibitory neuropeptide properties to generate an appropriate neuroendocrine and neuronal response that ultimately modifies food intake; 2) initiation and termination of a meal, thereby determining the number and size of a meal under normal conditions; and 3) a schema integrating the onset mechanism of cancer anorexia. Nicotine is used as a tool to further explore the relation of meal size to meal number, with a focus on simultaneous changes in dopamine and serotonin concentrations in the LHA and VMN with the onset of acute anorexia of nicotine infusion and acute hyperphagia of nicotine cessation. Data concerning the role of sex-related hormones on dopamine and serotonin with regard to the LHA and VMN in relation to the modulation of food intake are also presented.
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Affiliation(s)
- M M Meguid
- Neuroscience Program, Surgical Metabolism and Nutrition Laboratory, Department of Surgery, University Hospital, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
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31
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Abstract
Although numerous epidemiological studies have provided convincing evidence for the inverse association between tobacco smoking and body weight, the molecular mechanisms underlying this relationship are not well-understood. Nicotine, as a potent secretagogue, could be expected to influence the levels and expression of many classes of neurotransmitters, as well as of cell-membrane constituents linked to neurotransmission, including signal transducers and related effectors. A potentially major group of candidate molecules that could be involved in feeding-related actions of nicotine are the numerous neuropeptides and peptide hormones shown in the past two decades to regulate food intake and energy expenditure. These could include neuropeptide Y (NPY), orexins, leptins, and uncoupling proteins (UCPs). Some of these peptides were already shown to respond to nicotine treatment in terms of regulation of levels and of activity at the level of cell-membrane receptors. The primary objective of this review is to summarize our current understanding of the regulatory effects of nicotine on the food intake and energy expenditure as related to the expression levels of leptin, NPY, orexin, uncoupling proteins, and of NPY and orexin receptors.
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Affiliation(s)
- M D Li
- Department of Pharmacology, University of Tennessee College of Medicine, Memphis 38163, USA.
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32
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Voigt JP, Kienzle F, Sohr R, Rex A, Fink H. Feeding and 8-OH-DPAT-related release of serotonin in the rat lateral hypothalamus. Pharmacol Biochem Behav 2000; 65:183-9. [PMID: 10638652 DOI: 10.1016/s0091-3057(99)00172-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Based on the different effects of somatodendritic 5-HT1A agonist 8-OH-DPAT on food intake whether given to food-deprived rats or freely feeding rats, we hypothesized that the effects of 8-OH-DPAT on extracellular serotonin (5-HT) in the lateral hypothalamus (LH) will interfere with different feeding states, eventually resulting in different patterns of 5-HT release. In a microdialysis study we measured extracellular 5-HT in the LH after 8-OH-DPAT under four experimental conditions, i.e., in freely feeding rats with no food available, freely feeding rats with access to food, in food-deprived rats with no food available, and in food-deprived rats with good available after treatment. The results show a significant decrease of 5-HT release after 300 microg/kg 8-OH-DPAT (i.p.) in freely feeding rats. This effect is not seen when food is provided after drug treatment. In contrast, the same dose of 8-OH-DPAT has no effect on 5-HT release in food-deprived rats. In addition, providing food after drug treatment does not change the release pattern significantly in food-deprived rats, suggesting more complexity in the underlying mechanisms. The present study describes the effects of 8-OH-DPAT on 5-HT release in the LH, depending on feeding conditions and feeding-related behavioral states.
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Affiliation(s)
- J P Voigt
- Institute of Pharmacology and Toxicology, Medical Faculty (Charité), Humboldt University, Berlin, Germany
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Abstract
Dopamine (DA) is released in several brain areas, including the nucleus accumbens (NAcc), before and during copulation in male rats. DA agonists administered into this area facilitate, and DA antagonists inhibit, numerous motivated behaviors, including male sexual behavior. Serotonin (5-HT) is generally inhibitory to male sexual behavior. We reported previously that 5-HT is released in the anterior lateral hypothalamic area (LHA(A)) and that a selective serotonin reuptake inhibitor microinjected into that area delayed and slowed copulation. Our present results, using high temporal resolution microdialysis, (1) confirm previous electrochemical evidence that extracellular levels of DA increase in the NAcc during copulation and decrease during the postejaculatory interval (PEI) and (2) reveal that LHA(A) 5-HT can inhibit both basal and female-elicited DA release in the NAcc. These findings suggest that the neural circuit promoting sexual quiescence during the PEI includes serotonergic input to the LHA(A), which in turn inhibits DA release in the NAcc. These findings may also provide insights concerning the inhibitory control of other motivated behaviors activated by the NAcc and may have relevance for understanding the sexual side effects common to antidepressant medications.
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Yang ZJ, Blaha V, Meguid MM, Oler A, Miyata G. Infusion of nicotine into the LHA enhances dopamine and 5-HT release and suppresses food intake. Pharmacol Biochem Behav 1999; 64:155-9. [PMID: 10495010 DOI: 10.1016/s0091-3057(99)00111-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nicotine administration induces hypophagia. Because of the involvement of hypothalamic neurotransmitters in food intake control, we hypothesized that increased activity of the lateral hypothalamic dopamine (LHA-DA) and/or serotonin (LHA-5-HT) may be responsible for nicotine-induced hypophagia. Either 4 mM nicotine or vehicle was administered via reverse microdialysis technique into the LHA of overnight food-deprived rats for 60 min; then food was provided for 40 min. The LHA-DA, 5-HT and their intermediate metabolites, DOPAC and 5-HIAA, were continuously measured during 20-min intervals before, during, and after nicotine administration. Continuous nicotine administration for 60 min increased LHA-DA and DOPAC concentrations during the first 40 min, and induced a long-lasting increase in LHA-5-HT release, until 120 min after the start nicotine administration, even when nicotine administration was stopped. The food intake during the 40-min refeeding period was significantly lower when rats received nicotine. Eating induced a significant and short-lasting increase in the LHA-DA and a long-lasting increase in the LHA-5-HT. These findings indicate that nicotine enhances dopaminergic and serotonergic activity in the LHA, and that the enhanced LHA-5-HT activity may contribute to nicotine-induced hypophagia.
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Affiliation(s)
- Z J Yang
- Department of Surgery, University Hospital SUNY Health Science Center at Syracuse, 13210, USA
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35
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Zippel U, Heidel E, Davidowa H. Action of cholecystokinin and serotonin on lateral hypothalamic neurons of rats. Eur J Pharmacol 1999; 379:135-40. [PMID: 10497899 DOI: 10.1016/s0014-2999(99)00502-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Discharges of spontaneously active lateral hypothalamic neurons were extracellularly recorded during iontophoretic administration of cholecystokinin (CCK-8S) or/and serotonin (5-HT) in anesthetized rats. The main results are the following. (1) The proportion of neurons responsive to CCK-8S was 62% (61/99) and that responsive to 5-HT 42% (33/78). (2) Out of the neuronal sample, 36% were influenced by both transmitters, allowing an interaction between the two systems. (3) Co-ejection of CCK and 5-HT elicited a response in 40% of the tested neurons, which was a significantly smaller responsiveness than with separate ejection of CCK-8S. The effect resulted from a reduced number of excited neurons whereas the number of inhibitions did not change. The results show that effects of 5-HT and CCK can converge on the same neuron within the lateral hypothalamus. This might be of relevance in the regulation of feeding behavior.
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Affiliation(s)
- U Zippel
- Institute of Physiology (Charité), Berlin, Germany.
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36
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Affiliation(s)
- M J Bickerdike
- Cerebrus plc, Oakdene Court, 613 Reading Road, Winnersh, Wokingham RG41 5UA, UK
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37
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Chai JK, Blaha V, Meguid MM, Laviano A, Yang ZJ, Varma M. Use of orchiectomy and testosterone replacement to explore meal number-to-meal size relationship in male rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:R1366-73. [PMID: 10233029 DOI: 10.1152/ajpregu.1999.276.5.r1366] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because food intake is a function of meal number and meal size and because gender-related hormones are involved in feeding regulation, we explored effects of orchiectomy and testosterone replacement on the relationship between meal number and size and changes in resulting feeding patterns in adult male rats, randomized into orchiectomy and sham-operation groups. A rat eater meter measured feeding indexes for 1 wk before and 2 wk after castration and during 8 days of testosterone replacement. Orchiectomy leads to an immediate change in the meal number-to-size relationship, resulting in 1) change in pattern of feeding; 2) a significant decrease in dark-phase meal number; 3) a significant increase in dark-phase meal size, but insufficient to offset decrease in meal number, so total food intake significantly decreased during dark phase; 4) no significant change in light-phase meal number; and 5) an increase in meal size leading to an increased food intake during light phase, which offset decreased food intake in dark cycle and resulted in no net significant change in food intake after orchiectomy. Testosterone replacement acutely reversed effects of orchiectomy on meal number-to-meal size relationship, restoring feeding pattern. Data suggest that androgens immediately influence the meal number-to-meal size relationship. The speed of onset seen after orchiectomy suggests that the influence of testosterone on food intake may also occur partially via a nongenomic effect.
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Affiliation(s)
- J K Chai
- Neuroscience Program, Surgical Metabolism and Nutrition Laboratory, Department of Surgery, University Hospital, State University of New York Health Science Center, Syracuse, New York 13210, USA
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38
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Mori RCT, Guimarães RB, Nascimento CMO, Ribeiro EB. Lateral hypothalamic serotonergic responsiveness to food intake in rat obesity as measured by microdialysis. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-024] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hypothalamic serotonergic system is involved in the regulation of food ingestion and energy metabolism. Since disturbances of both energy intake and expenditure can contribute to obesity, the objective of the present study was to evaluate the serotonergic response stimulated by food ingestion in two different models of obesity: the hyperphagic Zucker and the hypophagic and hypometabolic, monosodium glutamate (MSG) obese Wistar rat. For this we used microdialysis to examine the release of 5-hydroxytryptamine (serotonin, 5HT) and 5-hydroxyindoleacetic acid (5HIAA) in the lateral hypothalamus. Daily intake of MSG-obese rats was 40% lower while that of Zucker obese rats was 60% higher than that of the respective lean controls. In overnight-fasted animals, 20-min microdialysate samples were collected before (basal release) and during a 2-h period of access to a balanced palatable food mash. The animals began to eat during the first 20 min of food access, and food consumption was similar among the four groups in all six individual 20-min periods recorded. Ingestion of food increased 5HT release in all groups. In MSG-obese and lean Wistar rats, 5HT levels were similarly elevated during the whole experimental period. In the Zucker strain, 5HT increments of basal release tended to be higher in obese than in lean rats at 20 and 40 min, and a significantly higher increment was observed at 60 min after food access (40 and 135% for lean and obese, respectively). The area under the curve relating serotonin levels to the 120 min of food availability was significantly higher in Zucker obese (246.7 ± 23.3) than MSG-obese (152.7 ± 13.4), lean Wistar (151.9 ± 11.1), and lean Zucker (173.5 ± 24.0) rats. The present observation, of a food-induced serotonin release in the lateral hypothalamus of lean Wistar and Zucker rats, evidences that 5HT in the lateral hypothalamus is important in the normal response to feeding. In obese animals, the serotonin response was similar to (in the hypophagic-hypometabolic MSG model) or even higher than (in the hyperphagic Zucker model) that seen in the respective lean controls. This result indicates that the energy homeostasis disturbances of both these obesity models may not be ascribed to an impairment of the acute lateral hypothalamic serotonin response to a dietary stimulus.Key words: serotonin, food intake, brain microdialysis, lateral hypothalamus, monosodium glutamate obesity, Zucker obesity.
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Varma M, Torelli GF, Meguid MM, Chai JK, Blaha V, Laviano A, Kim HJ. Potential strategies for ameliorating early cancer anorexia. J Surg Res 1999; 81:69-76. [PMID: 9889061 DOI: 10.1006/jsre.1998.5460] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Normally the lateral hypothalamic area (LHA) and the ventromedial nucleus (VMN) interact to regulate food intake (FI), the product of meal number (MN) and meal size (MZ), by changes in neurotransmitters, mainly dopamine and serotonin. Change in LHA dopamine influences meal size; while in VMN, decreasing dopamine and increasing serotonin levels influence meal number. Whether this situation exists in early cancer anorexia was tested in a series of studies to examine the role of the hypothalamus in the pathogenesis of early cancer anorexia. MATERIALS AND METHODS In experiment 1, male Fischer tumor-bearing (TB) rats and weight-matched controls had FI, MN, and MZ measured continuously via a computerized rat eater meter. At onset of anorexia, feeding patterns were measured. In experiment 2, the VMN was temporarily blocked with 0.32 microgram of colchicine in TB rats, while TB controls had an equal volume of intra-VMN saline, and changes in feeding patterns were measured. In experiment 3, changes in VMN dopamine and serotonin were measured via microdialysis at anorexia and after tumor resection. RESULTS In experiment 1, with the onset of anorexia, food intake decreased significantly in TB rats, initially by a decrease in MN and then by a decrease in both MN and MZ. No change occurred in controls, suggesting that VMN versus LHA played a more significant role in mediation of cancer anorexia. In experiment 2, following VMN block, FI increased significantly in anorectic TB rats, achieved by an almost exclusive increase in MN with minimal change in MZ, thus supporting the role of the VMN in anorexia. In experiment 3, at the onset of anorexia, FI decreased significantly in TB rats versus controls. TB rats had a significant increase in VMN serotonin and a significant decrease in VMN dopamine. After tumor resection, food intake improved and high levels of serotonin normalized with no change in dopamine. CONCLUSION Serotoninergic and dopaminergic systems are involved in the etiology of cancer anorexia. The changes in food intake are mediated via the VMN by a decrease in meal number.
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Affiliation(s)
- M Varma
- Surgical Metabolism and Nutrition Laboratory, Department of Surgery, University Hospital and V. A. Medical Center, State University of New York Health Science Center, New York, Syracuse, 13210, USA
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40
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Affiliation(s)
- M M Meguid
- Neuroscience Program, Department of Surgery, SUNY Health Science Center at Syracuse, NY 13210, USA
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41
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Abstract
Serotonin (5-HT) has been strongly implicated in the regulation of the mammalian circadian clock located in the suprachiasmatic nuclei (SCN). However, little is known of the pattern of neuronal 5-HT release in the SCN or of the factors involved in regulating its release. Using in vivo microdialysis, we demonstrated the existence of a daily rhythm in the output of 5-HT in the SCN of freely behaving hamsters. This rhythm was characterized by a sharp increase in release from a nadir during late midday to peak levels at the light/dark transition. Output declined to basal levels throughout the remainder of the night. A similar pattern also was evident under constant darkness, with increased 5-HT output occurring at the onset of subjective night. Locomotor activity induced by exposure to a novel running wheel had a pronounced phase-dependent effect on 5-HT release in the SCN, with stimulation during the light phase and suppression during the late dark phase. Systemic application of the somatodendritic 5-HT1A agonist BMY 7378 had a significantly greater suppressive effect on 5-HT release in the SCN during the late dark phase compared with mid light phase, indicating that a variation in raphe autoreceptor response may underlie the time-dependent effects of wheel running on 5-HT release. Collectively, these results show that the daily rhythm in output of 5-HT in the SCN is generated endogenously, and that behavioral state can strongly influence serotonergic activity in the circadian clock in a phase-dependent manner.
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Extracellular serotonin in the lateral hypothalamic area is increased during the postejaculatory interval and impairs copulation in male rats. J Neurosci 1997. [PMID: 9364081 DOI: 10.1523/jneurosci.17-23-09361.1997] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Serotonin (5-HT) is generally inhibitory to masculine sexual behavior. It has been suggested that 5-HT released after ejaculation may promote the sexual quiescence of the postejaculatory interval (PEI). The following experiments were conducted to test (1) whether extracellular 5-HT increases in either the anterior lateral hypothalamic area (LHAA) or the medial preoptic area (MPOA) of male rats after ejaculation; (2) whether increasing 5-HT in these sites, by microinjecting the selective serotonin reuptake inhibitor alaproclate, could inhibit copulatory abilities; and (3) whether copulation deficits produced by alaproclate were attributable to locomotor impairments. The effects of local application of alaproclate on extracellular 5-HT levels in the LHAA and the MPOA were also tested. Extracellular serotonin was measured in all experiments using in vivo microdialysis. Ejaculation was correlated with enhanced 5-HT release from the LHAA; no 5-HT increases were observed before ejaculation, and levels were decreased toward basal values during a subsequent copulatory series. Elevating 5-HT in the LHAA by microinjecting alaproclate inhibited copulation by increasing the latency to mount, intromit, and ejaculate. This inhibition did not result from nonspecific locomotor impairments. In the MPOA, 5-HT release remained stable throughout copulation, and microinjecting alaproclate into this site did not significantly alter sexual behavior. These data support the large body of evidence suggesting that 5-HT is inhibitory to masculine sexual behavior. Furthermore, the LHAA, but not the MPOA, may be one site responsible for serotonergic inhibition of copulation during the PEI.
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43
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Routh VH, Stern JS, Horwitz BA. Physiological Responses of Mammals to Overnutrition. Compr Physiol 1996. [DOI: 10.1002/cphy.cp040262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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44
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Møller SE, Mortensen EL, Breum L, Alling C, Larsen OG, Bøge-Rasmussen T, Jensen C, Bennicke K. Aggression and personality: association with amino acids and monoamine metabolites. Psychol Med 1996; 26:323-331. [PMID: 8685288 DOI: 10.1017/s0033291700034711] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Associations in 52 normal individuals were examined between plasma and cerebrospinal fluid (CSF) concentrations of tryptophan (Trp) and tyrosine, and concentrations of monoamine metabolites in the CSF, and scores on an aggression questionnaire, the Kinsey Institute Reaction List II, and the Eysenck Personality Questionnaire. There was a significantly positive correlation between CSF 5-hydroxyindoleacetic acid (5-HIAA) levels and extroverted aggression scores, and a significantly negative correlation between CSF 5-HIAA levels and introverted aggression scores. Males showed higher plasma Trp concentrations than females, and significantly positive correlations between plasma Trp concentrations and scores on extroverted aggression and the Eysenck E scale. Males, furthermore, showed a significantly negative correlation between CSF Trp levels and scores on the Eysenck P scale, and a significantly positive correlation between concentrations of 3-methoxy-4-hydroxy-phenylglycol in CSF and scores on moral aggression. These results suggest that central serotonin influences aggression in normal individuals through effects on personality.
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Affiliation(s)
- S E Møller
- Research Institute of Biological Psychiatry, St Hans Hospital, Roskilde, Denmark
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45
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Abstract
This article discusses the role of the lateral hypothalamic area (LHA) in feeding and drinking and draws on data obtained from lesion and stimulation studies and neurochemical and electrophysiological manipulations of the area. The LHA is involved in catecholaminergic and serotonergic feeding systems and plays a role in circadian feeding, sex differences in feeding and spontaneous activity. This article discusses the LHA regarding dietary self-selection, responses to high-protein diets, amino acid imbalances, liquid and cafeteria diets, placentophagia, "stress eating," finickiness, diet texture, consistency and taste, aversion learning, olfaction and the effects of post-operative period manipulations by hormonal and other means. Glucose-sensitive neurons have been identified in the LHA and their manipulation by insulin and 2-deoxy-D-glucose is discussed. The effects on feeding of numerous transmitters, hormones and appetite depressants are described, as is the role of the LHA in salivation, lacrimation, gastric motility and secretion, and sensorimotor deficits. The LHA is also illuminated as regards temperature and feeding, circumventricular organs and thirst and electrolyte dynamics. A discussion of its role in the ischymetric hypothesis as an integrative Gestalt concept concludes the review.
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Affiliation(s)
- L L Bernardis
- Neurovisceral-Neuroendocrine Laboratory, Veterans Administration Medical Center Buffalo, NY, USA
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46
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McMahon LR, Wellman PJ. Effects of systemic phenylpropanolamine and fenfluramine on serotonin activity within rat paraventricular hypothalamus. Physiol Behav 1996; 59:63-9. [PMID: 8848492 DOI: 10.1016/0031-9384(95)02032-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Phenylpropanolamine (PPA) anorexia has been linked to activation of alpha 1-adrenergic receptors within rat paraventricular hypothalamus (PVN) by studies documenting that intra-PVN injection of PPA and other alpha 1-adrenergic agonists suppress food intake. The present experiments examine the hypothesis that PPA may suppress appetite indirectly via release of serotonin (5-HT) within the PVN. In Experiment 1, we compare the effects of PPA (20 mg/kg, IP) and of d,l-fenfluramine (FEN: 7.5 mg/kg, IP), relative to a vehicle treatment, on extracellular levels of 5-HT and the 5-HT metabolite 5-HIAA in adult male rats prepared with concentric microdialysis probes aimed at either the PVN or the perifornical hypothalamus (PFH). Injection of either vehicle or 20 mg/kg PPA had no significant effect on extracellular 5-HT within the PFH or the PVN. In contrast, a subsequent injection of 7.5 mg/kg FEN produced significant increases in 5-HT and significant decreases in 5-HIAA within the PVN and the PFH. In Experiment 2, the 5-HT1a autoreceptor agonist 8-OH-DPAT (0.25 mg/kg, SC) was used to suppress presynaptic release of 5-HT prior to systemic injection of either fenfluramine (5 mg/kg, IP) or PPA (5, 10, 20, and 30 mg/kg, IP). The anorexic action of FEN, but not PPA, was reduced by pretreatment with 8-OH-DPAT. These results suggest that the anorexic action of PPA is not mediated by an indirect effect of PPA on presynaptic release of 5-HT.
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Affiliation(s)
- L R McMahon
- Department of Psychology, Texas A&M University 77843, USA.
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47
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Pijl H, Cohen AF, Verkes RJ, Koppeschaar HP, Iestra JA, Schoemaker HC, Frölich M, Onkenhout W, Meinders AE. Plasma amino acid ratios related to brain serotonin synthesis in response to food intake in bulimia nervosa. Biol Psychiatry 1995; 38:659-68. [PMID: 8555377 DOI: 10.1016/0006-3223(95)00043-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fifteen bulimic women (BN) and 19 healthy female controls (CO) were studied. The subjects were cross-over treated with either fluoxetine (FXT) or placebo during 4 days. They received, in randomized order, a breakfast containing pure carbohydrate (CHO) or a protein-rich (PROT) breakfast following day 3 and 4 of each treatment period. Twenty-nine different food items were offered for lunch. The fasting serum glucose and insulin concentrations and the fasting plasma tryptophan (Trp)/large neutral amino acid (LNAA) ratio were slightly higher in BN. The changes of these metabolic parameters in response to a CHO or PROT breakfast were similar in both groups. Across breakfast type, the plasma (Trp)/(LNAA) ratio at 120 min after breakfast was higher in BN. Total caloric intake at lunchtime was less in BN. In CO, less carbohydrate was selected at lunchtime following the CHO breakfast, an effect that was abolished by FXT. Breakfast type or FXT did not have any apparent effect on food intake at lunchtime in BN. This might indicate that bulimic subjects are less sensitive to serotoninergic stimuli than control subjects.
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Affiliation(s)
- H Pijl
- Department of General Internal Medicine, University Hospital Leiden, The Netherlands
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48
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Pothos EN, Hernandez L, Hoebel BG. Chronic food deprivation decreases extracellular dopamine in the nucleus accumbens: implications for a possible neurochemical link between weight loss and drug abuse. OBESITY RESEARCH 1995; 3 Suppl 4:525S-529S. [PMID: 8697053 DOI: 10.1002/j.1550-8528.1995.tb00222.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In rats reduced to 80% of normal body weight (n = 9), the basal levels of extracellular dopamine (DA) in the nucleus accumbens (NAC), as determined by microdialysis, decreased significantly to 33% (mean +/- SEM) of their normal baseline (p < 01). Basal extracellular DA did not change significantly over a matching 3-week period in controls (n = 7). No changes were observed in NAC serotonin after weight reduction. These results indicate that parts of the mesolimbic DA system are depressed in underweight rats. The observed decrease in basal DA may be responsible for a variety of behavioral changes observed in undernourished humans and animals including the tendency to eat and gain weight when food becomes available. Given that DA can be released in the NAC when rats self-inject drugs of abuse, the present findings may help explain why animals increase drug intake when they are underweight.
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Affiliation(s)
- E N Pothos
- Department of Psychology, Princeton University, NJ 08544-1010, USA
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49
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Abstract
Microdialysis is a sampling method that is used to determine the extracellular concentration of neurotransmitters in the brain. The method can be applied to conscious and unrestrained animals and is very suitable for the study of the chemistry of endogenous behaviour. This article reviews the contribution that microdialysis made to our understanding of the chemistry of behaviour. Methodological and practical considerations such as the implantation time and the use of guide cannulas are reviewed. The question whether neurotransmitters and related metabolites in dialysates reflect true synaptic release is critically discussed. There is much evidence that dopamine, noradrenaline, acetylcholine and serotonin in dialysates are related to neurotransmission, but there is serious doubt whether this is the case with amino acid transmitters such as GABA, glutamate and aspartate. Until now far over 100 papers appeared that used microdialysis in behavioural studies. Behavioural activation, the sleep-awake cycle and diurnal rhythms were subject of several of these studies. Various workers have described neurochemical changes in the brain that are related to feeding. Other studies were concerned with sexual behaviour and the sexual cycle in females. Parturition, maternal behaviour and offspring recognition have been studied in a series of microdialysis studies carried out in sheep. An overview is given of the microdialysis studies that were carried out to understand the biochemistry of stress. In this respect dopamine and noradrenaline have received much attention. A great number of microdialysis studies dealt with the role of dopamine in self-stimulation, reward and aversive emotions. It is concluded that microdialysis is at presently the most versatile and practical method to study the chemistry of behaviour and it is to be expected that it will soon be a routine methodology in behavioural research. Finally, perspectives and possible future developments of the methods are discussed.
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Affiliation(s)
- B H Westerink
- University centre for Pharmacy, Department of Medicinal Chemistry, University of Groningen, The Netherlands
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50
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Abstract
There is evidence that central infusion of brain-derived neurotrophic factor (BDNF) induces weight loss in rats. We have begun to investigate the physiological basis for BDNF-induced weight loss by assessing its relationship to (a) appetite, (b) serum indices of metabolic and renal toxicity, and (c) brain monoamine activity in areas associated with feeding or motor function. BDNF (0-6 microgram/day) was infused into the lateral ventricle (LV) of male Long-Evans rats for 14 days. Body weight and food intake were monitored throughout infusion and recovery periods. BDNF induced severe, dose-dependent appetite suppression and weight loss. Although appetite began to recover after the 10th infusion day, body weight had not returned to control values at the end of the recovery period. The weight loss observed in BDNF-infused rats was related to appetite suppression, since uninfused rats that were pair-fed to high dose BDNF-treated rats showed comparable weight loss. Despite severe weight loss, serum BUN, creatinine, thyroxine, glucose, and total protein were not affected by BDNF infusion. Striatal DO-PAC/DA was similarly unaffected by BDNF. In contrast, BDNF-infused rats showed a dose-dependent increase in hypothalamic 5-HIAA/5-HT that was not observed in pair-fed rats, suggesting that the observed increase in hypothalamic 5-HIAA/5-HT was a direct effect of BDNF infusion rather than a secondary effect of food restriction. These data suggest that BDNF may induce appetite suppression and weight loss through a central mechanism.
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Affiliation(s)
- M A Pelleymounter
- Department of Neurobiology, Amgen Center, Thousand Oaks, California 91320, USA
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