1
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Mishra S, Grewal J, Wal P, Bhivshet GU, Tripathi AK, Walia V. Therapeutic potential of vasopressin in the treatment of neurological disorders. Peptides 2024; 174:171166. [PMID: 38309582 DOI: 10.1016/j.peptides.2024.171166] [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: 10/19/2023] [Revised: 01/18/2024] [Accepted: 01/29/2024] [Indexed: 02/05/2024]
Abstract
Vasopressin (VP) is a nonapeptide made of nine amino acids synthesized by the hypothalamus and released by the pituitary gland. VP acts as a neurohormone, neuropeptide and neuromodulator and plays an important role in the regulation of water balance, osmolarity, blood pressure, body temperature, stress response, emotional challenges, etc. Traditionally VP is known to regulate the osmolarity and tonicity. VP and its receptors are widely expressed in the various region of the brain including cortex, hippocampus, basal forebrain, amygdala, etc. VP has been shown to modulate the behavior, stress response, circadian rhythm, cerebral blood flow, learning and memory, etc. The potential role of VP in the regulation of these neurological functions have suggested the therapeutic importance of VP and its analogues in the management of neurological disorders. Further, different VP analogues have been developed across the world with different pharmacotherapeutic potential. In the present work authors highlighted the therapeutic potential of VP and its analogues in the treatment and management of various neurological disorders.
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Affiliation(s)
- Shweta Mishra
- SGT College of Pharmacy, SGT University, Gurugram, India
| | - Jyoti Grewal
- Maharisi Markandeshwar University, Sadopur, India
| | - Pranay Wal
- Pranveer Singh Institute of Pharmacy, Kanpur, India
| | | | | | - Vaibhav Walia
- SGT College of Pharmacy, SGT University, Gurugram, India.
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2
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da Silva E Santos MR, Paes MH, Bento RCQS, Cardoso LM, de Oliveira LB. Reducing sugar intake through chronic swimming training: Exploring palatability changes and central vasopressin mechanisms. Pharmacol Biochem Behav 2024; 234:173691. [PMID: 38081330 DOI: 10.1016/j.pbb.2023.173691] [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: 09/18/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 01/01/2024]
Abstract
Excessive sugar intake has been associated with the onset of several non-communicable chronic diseases seen in humans. Physical activity could affect sweet taste perception which may affect sugar intake. Therefore, it was investigated the chronic effects of swimming training on sucrose intake/preference, reactivity to sucrose taste, self-care in neurobehavioral stress, and the possible involvement of the vasopressin type V1 receptor in sucrose solution intake. Male Wistar rats, of from different cohorts were used, subjected to a sedentary lifestyle (SED) or swimming training (TR - 1 h/day, 5×/week, for 8 weeks, with no added load). Weekly intake was verified in SED and TR rats after access to a sucrose solution 1×/week, 2 h/day, for eight weeks. Chronic effects of swimming and/or a sedentary lifestyle were carried out three days after the end of the physical exercise protocol. Swimming training reduced the intake of sucrose solution from the third week onwards in the two-bottle test measured once a week for 8 weeks. After the ending of the swimming protocol, sucrose intake was also reduced as per its preference. This reduced intake is probably correlated with the carbohydrate aspect of sucrose since saccharin intake was not affected. In addition, chronic swimming training was shown to reduce ingestive responses, increase neutral responses, without interfering with aversive, in the sucrose solution taste reactivity test. In addition, these results are not related to a depressive-like behavior, nor to neurobehavioral stress. Furthermore, treatment with vasopressin V1 receptor antagonist abolished the reduced sucrose intake in trained rats. The results suggest that swimming performed chronically is capable of reducing intake and preference for sucrose by decreasing the palatability of sucrose without causing depressive-type behavior or stress. In addition, the results also suggest that central V1 vasopressin receptors are part of the mechanisms activated to reduce sucrose intake in trained rats.
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Affiliation(s)
| | - Milede Hanner Paes
- Research Center in Biological Sciences - NUPEB, Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | - Leonardo Máximo Cardoso
- Research Center in Biological Sciences - NUPEB, Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | - Lisandra Brandino de Oliveira
- Department of Food and Medicine, Faculty of Pharmaceutical Sciences, Federal University of Alfenas, Alfenas, MG, Brazil.
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3
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Prilutski Y, Livneh Y. Physiological Needs: Sensations and Predictions in the Insular Cortex. Physiology (Bethesda) 2023; 38:0. [PMID: 36040864 DOI: 10.1152/physiol.00019.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Physiological needs create powerful motivations (e.g., thirst and hunger). Studies in humans and animal models have implicated the insular cortex in the neural regulation of physiological needs and need-driven behavior. We review prominent mechanistic models of how the insular cortex might achieve this regulation and present a conceptual and analytical framework for testing these models in healthy and pathological conditions.
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Affiliation(s)
- Yael Prilutski
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yoav Livneh
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
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4
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Sudbury JR, Zaelzer C, Trudel E, Bumagin A, Bourque CW. Synaptic control of rat magnocellular neurosecretory cells by warm-sensing neurons in the organum vasculosum lamina terminalis. J Neuroendocrinol 2022; 34:e13214. [PMID: 36426844 DOI: 10.1111/jne.13214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 10/07/2022] [Accepted: 10/27/2022] [Indexed: 11/11/2022]
Abstract
Increases in core body temperature cause secretion of vasopressin (vasopressin, antidiuretic hormone) to promote water reabsorption and blunt water losses incurred through homeostatic evaporative cooling. Subtypes of transient receptor potential vanilloid (Trpv) channels have been shown to contribute to the intrinsic regulation of vasopressin-releasing magnocellular neurosecretory cells (MNCs) in the supraoptic nucleus (SON) and paraventricular nucleus (PVN). However, MNCs in vivo can also be excited by local heating of the adjacent preoptic area, indicating they receive thermosensory information from other areas. Here, we investigated whether neurons in the organum vasculosum lamina terminalis (OVLT) contribute to this process using in vitro electrophysiological approaches in male rats. We found that the majority of OVLT neurons are thermosensitive in the physiological range (36-39°C) and that this property is retained under conditions blocking synaptic transmission. A subset of these neurons could be antidromically activated by electrical stimulation in the SON. Whole cell recordings from SON MNCs revealed that heating significantly increases the rate of spontaneous excitatory postsynaptic currents (sEPCSs), and that this response is abolished by lesions targeting the OVLT, but not by bilateral lesions placed in the adjacent preoptic area. Finally, local heating of the OVLT caused a significant excitation of MNCs in the absence of temperature changes in the SON, and this effect was blocked by inhibitors of ionotropic glutamate receptors. These findings indicate that the OVLT serves as an important thermosensory nucleus and contributes to the activation of MNCs during physiological heating.
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Affiliation(s)
- Jessica R Sudbury
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Cristian Zaelzer
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Eric Trudel
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Anna Bumagin
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Charles W Bourque
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
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5
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Park A, Croset V, Otto N, Agarwal D, Treiber CD, Meschi E, Sims D, Waddell S. Gliotransmission of D-serine promotes thirst-directed behaviors in Drosophila. Curr Biol 2022; 32:3952-3970.e8. [PMID: 35963239 PMCID: PMC9616736 DOI: 10.1016/j.cub.2022.07.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/04/2022] [Accepted: 07/15/2022] [Indexed: 12/13/2022]
Abstract
Thirst emerges from a range of cellular changes that ultimately motivate an animal to consume water. Although thirst-responsive neuronal signals have been reported, the full complement of brain responses is unclear. Here, we identify molecular and cellular adaptations in the brain using single-cell sequencing of water-deprived Drosophila. Water deficiency primarily altered the glial transcriptome. Screening the regulated genes revealed astrocytic expression of the astray-encoded phosphoserine phosphatase to bi-directionally regulate water consumption. Astray synthesizes the gliotransmitter D-serine, and vesicular release from astrocytes is required for drinking. Moreover, dietary D-serine rescues aay-dependent drinking deficits while facilitating water consumption and expression of water-seeking memory. D-serine action requires binding to neuronal NMDA-type glutamate receptors. Fly astrocytes contribute processes to tripartite synapses, and the proportion of astrocytes that are themselves activated by glutamate increases with water deprivation. We propose that thirst elevates astrocytic D-serine release, which awakens quiescent glutamatergic circuits to enhance water procurement.
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Affiliation(s)
- Annie Park
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Vincent Croset
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK; Department of Biosciences, Durham University, Durham DH1 3LE, UK.
| | - Nils Otto
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Devika Agarwal
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK; MRC Computational Genomics Analysis and Training Programme (CGAT), MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
| | - Christoph D Treiber
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Eleonora Meschi
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - David Sims
- MRC Computational Genomics Analysis and Training Programme (CGAT), MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
| | - Scott Waddell
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK.
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6
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Neural signalling of gut mechanosensation in ingestive and digestive processes. Nat Rev Neurosci 2022; 23:135-156. [PMID: 34983992 DOI: 10.1038/s41583-021-00544-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2021] [Indexed: 12/29/2022]
Abstract
Eating and drinking generate sequential mechanosensory signals along the digestive tract. These signals are communicated to the brain for the timely initiation and regulation of diverse ingestive and digestive processes - ranging from appetite control and tactile perception to gut motility, digestive fluid secretion and defecation - that are vital for the proper intake, breakdown and absorption of nutrients and water. Gut mechanosensation has been investigated for over a century as a common pillar of energy, fluid and gastrointestinal homeostasis, and recent discoveries of specific mechanoreceptors, contributing ion channels and the well-defined circuits underlying gut mechanosensation signalling and function have further expanded our understanding of ingestive and digestive processes at the molecular and cellular levels. In this Review, we discuss our current understanding of the generation of mechanosensory signals from the digestive periphery, the neural afferent pathways that relay these signals to the brain and the neural circuit mechanisms that control ingestive and digestive processes, focusing on the four major digestive tract parts: the oral and pharyngeal cavities, oesophagus, stomach and intestines. We also discuss the clinical implications of gut mechanosensation in ingestive and digestive disorders.
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7
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Livneh Y, Andermann ML. Cellular activity in insular cortex across seconds to hours: Sensations and predictions of bodily states. Neuron 2021; 109:3576-3593. [PMID: 34582784 PMCID: PMC8602715 DOI: 10.1016/j.neuron.2021.08.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 02/09/2023]
Abstract
Our wellness relies on continuous interactions between our brain and body: different organs relay their current state to the brain and are regulated, in turn, by descending visceromotor commands from our brain and by actions such as eating, drinking, thermotaxis, and predator escape. Human neuroimaging and theoretical studies suggest a key role for predictive processing by insular cortex in guiding these efforts to maintain bodily homeostasis. Here, we review recent studies recording and manipulating cellular activity in rodent insular cortex at timescales from seconds to hours. We argue that consideration of these findings in the context of predictive processing of future bodily states may reconcile several apparent discrepancies and offer a unifying, heuristic model for guiding future work.
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Affiliation(s)
- Yoav Livneh
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Mark L Andermann
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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8
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Kim A, Madara JC, Wu C, Andermann ML, Lowell BB. Neural basis for regulation of vasopressin secretion by anticipated disturbances in osmolality. eLife 2021; 10:66609. [PMID: 34585668 PMCID: PMC8601670 DOI: 10.7554/elife.66609] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 09/28/2021] [Indexed: 12/01/2022] Open
Abstract
Water balance, tracked by extracellular osmolality, is regulated by feedback and feedforward mechanisms. Feedback regulation is reactive, occurring as deviations in osmolality are detected. Feedforward or presystemic regulation is proactive, occurring when disturbances in osmolality are anticipated. Vasopressin (AVP) is a key hormone regulating water balance and is released during hyperosmolality to limit renal water excretion. AVP neurons are under feedback and feedforward regulation. Not only do they respond to disturbances in blood osmolality, but they are also rapidly suppressed and stimulated, respectively, by drinking and eating, which will ultimately decrease and increase osmolality. Here, we demonstrate that AVP neuron activity is regulated by multiple anatomically and functionally distinct neural circuits. Notably, presystemic regulation during drinking and eating are mediated by non-overlapping circuits that involve the lamina terminalis and hypothalamic arcuate nucleus, respectively. These findings reveal neural mechanisms that support differential regulation of AVP release by diverse behavioral and physiological stimuli. Fine-tuning the amount of water present in the body at any given time is a tight balancing act. The hormone vasopressin helps to ensure that organisms do not get too dehydrated by allowing water in the urine to be reabsorbed into the bloodstream. A group of vasopressin neurons in the brain trigger the release of the hormone if water levels get too low (as reflected by an increase in osmolality, the level of substances dissolved in a unit of blood). However, these cells also receive additional information that allows them to predict and respond to upcoming changes in water levels. For example, drinking water while dehydrated ‘switches off’ the neurons, even before osmolality is restored in the blood to normal levels. Eating, on the other hand, rapidly activates vasopressin neurons before the food is digested and blood osmolality increases as a result. How vasopressin neurons receive this ‘anticipatory’ information remains unclear. Kim et al. explored this question in mice by inhibiting different sets of brain cells one by one, and then examining whether the neurons could still exhibit anticipatory responses. This revealed a remarkable division of labor in the neural circuits that regulate vasopressin neurons: two completely different sets of neurons from distinct areas of the brain are dedicated to relaying anticipatory information about either water or food intake. These findings help to understand how healthy levels of water can be maintained in the body. Overall, they give a glimpse into the neural mechanisms that underlie anticipatory forms of regulation, which can also take place when hunger or thirst neurons ‘foresee’ that food or water will be consumed.
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Affiliation(s)
- Angela Kim
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States.,Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Joseph C Madara
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
| | - Chen Wu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
| | - Mark L Andermann
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States.,Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States.,Program in Neuroscience, Harvard Medical School, Boston, United States
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9
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Gamba M, Moreira P, Borges N, Santos A, Afonso C, Amaral TF, Padrão P. Are older adults with excessive sodium intake at increased risk of hypohydration? J Hum Nutr Diet 2021; 34:834-840. [PMID: 33513297 DOI: 10.1111/jhn.12859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Sodium intake is expected to affect water needs, although compensation mechanisms may not work efficiently particularly in older adults. The aim of this cross-sectional study was to quantify the association between sodium excretion and hydration status in a representative sample of Portuguese older adults. METHODS A cluster sampling approach was used, representing Portuguese older adults (≥65 years) according to sex, education level and region. From a sample size of 1500 participants, 1318 were eligible for the present analysis. A 24-h urine sample was collected, and volume, osmolality, creatinine and sodium were quantified. Free water reserve (FWR) was used to assess hydration status. Excessive sodium intake was defined as above 2000 mg day-1 as recommended by the World Health Organization. A multivariable binary logistic regression model was used to estimate the association between FWR and sodium excretion. Odds ratios (OR) and respective 95% confidence intervals (95% CI) were calculated. RESULTS Excessive sodium excretion was observed in 80.0% of women and 91.5% of men, whereas hypohydration affected 10.9% of women and 23.6% of men. After adjusting for confounders, excessive sodium excretion was associated with an increased risk of hypohydration among men (OR = 2.75; 95% CI = 1.06-7.15). CONCLUSIONS These results stress the positive association between excessive sodium intake and hypohydration in men and highlight the need for implementing strategies regarding the reduction of salt consumption and the promotion of water intake.
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Affiliation(s)
- Marta Gamba
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal
| | - Pedro Moreira
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal.,Centro de Atividade Física, Saúde e Lazer, Universidade do Porto, Porto, Portugal
| | - Nuno Borges
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,CINTESIS - Centre for Health Technology and Services Research, Porto, Portugal
| | - Alejandro Santos
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Porto, Portugal
| | - Cláudia Afonso
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
| | - Teresa F Amaral
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,UISPA-IDMEC, Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Patrícia Padrão
- Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal.,EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
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10
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Armstrong LE, Kavouras SA. Thirst and Drinking Paradigms: Evolution from Single Factor Effects to Brainwide Dynamic Networks. Nutrients 2019; 11:nu11122864. [PMID: 31766680 PMCID: PMC6950074 DOI: 10.3390/nu11122864] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 01/10/2023] Open
Abstract
The motivation to seek and consume water is an essential component of human fluid–electrolyte homeostasis, optimal function, and health. This review describes the evolution of concepts regarding thirst and drinking behavior, made possible by magnetic resonance imaging, animal models, and novel laboratory techniques. The earliest thirst paradigms focused on single factors such as dry mouth and loss of water from tissues. By the end of the 19th century, physiologists proposed a thirst center in the brain that was verified in animals 60 years later. During the early- and mid-1900s, the influences of gastric distention, neuroendocrine responses, circulatory properties (i.e., blood pressure, volume, concentration), and the distinct effects of intracellular dehydration and extracellular hypovolemia were recognized. The majority of these studies relied on animal models and laboratory methods such as microinjection or lesioning/oblation of specific brain loci. Following a quarter century (1994–2019) of human brain imaging, current research focuses on networks of networks, with thirst and satiety conceived as hemispheric waves of neuronal activations that traverse the brain in milliseconds. Novel technologies such as chemogenetics, optogenetics, and neuropixel microelectrode arrays reveal the dynamic complexity of human thirst, as well as the roles of motivation and learning in drinking behavior.
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Affiliation(s)
- Lawrence E. Armstrong
- Human Performance Laboratory and Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-1110, USA
- Correspondence:
| | - Stavros A. Kavouras
- Arizona State University, College of Health Solutions, Hydration Science Lab, Phoenix, AZ 85004, USA;
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11
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Leng G, Russell JA. The osmoresponsiveness of oxytocin and vasopressin neurones: Mechanisms, allostasis and evolution. J Neuroendocrinol 2019; 31:e12662. [PMID: 30451331 DOI: 10.1111/jne.12662] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/29/2018] [Accepted: 11/15/2018] [Indexed: 12/27/2022]
Abstract
In the rat supraoptic nucleus, every oxytocin cell projects to the posterior pituitary, and is involved both in reflex milk ejection during lactation and in regulating uterine contractions during parturition. All are also osmosensitive, regulating natriuresis. All are also regulated by signals that control appetite, including the neural and hormonal signals that arise from the gut after food intake and from the sites of energy storage. All are also involved in sexual behaviour, anxiety-related behaviours and social behaviours. The challenge is to understand how a single population of neurones can coherently regulate such a diverse set of functions and adapt to changing physiological states. Their multiple functions arise from complex intrinsic properties that confer sensitivity to a wide range of internal and environmental signals. Many of these properties have a distant evolutionary origin in multifunctional, multisensory neurones of Urbilateria, the hypothesised common ancestor of vertebrates, insects and worms. Their properties allow different patterns of oxytocin release into the circulation from their axon terminals in the posterior pituitary into other brain areas from axonal projections, as well as independent release from their dendrites.
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Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - John A Russell
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
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12
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13
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Augustine V, Gokce SK, Lee S, Wang B, Davidson TJ, Reimann F, Gribble F, Deisseroth K, Lois C, Oka Y. Hierarchical neural architecture underlying thirst regulation. Nature 2018; 555:204-209. [PMID: 29489747 PMCID: PMC6086126 DOI: 10.1038/nature25488] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 01/03/2018] [Indexed: 11/08/2022]
Abstract
Neural circuits for appetites are regulated by both homeostatic perturbations and ingestive behaviour. However, the circuit organization that integrates these internal and external stimuli is unclear. Here we show in mice that excitatory neural populations in the lamina terminalis form a hierarchical circuit architecture to regulate thirst. Among them, nitric oxide synthase-expressing neurons in the median preoptic nucleus (MnPO) are essential for the integration of signals from the thirst-driving neurons of the subfornical organ (SFO). Conversely, a distinct inhibitory circuit, involving MnPO GABAergic neurons that express glucagon-like peptide 1 receptor (GLP1R), is activated immediately upon drinking and monosynaptically inhibits SFO thirst neurons. These responses are induced by the ingestion of fluids but not solids, and are time-locked to the onset and offset of drinking. Furthermore, loss-of-function manipulations of GLP1R-expressing MnPO neurons lead to a polydipsic, overdrinking phenotype. These neurons therefore facilitate rapid satiety of thirst by monitoring real-time fluid ingestion. Our study reveals dynamic thirst circuits that integrate the homeostatic-instinctive requirement for fluids and the consequent drinking behaviour to maintain internal water balance.
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Affiliation(s)
- Vineet Augustine
- Computation and Neural Systems, California Institute of Technology, Pasadena, California, USA
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Sertan Kutal Gokce
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Sangjun Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Bo Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Thomas J Davidson
- Department of Physiology and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, California, USA
| | - Frank Reimann
- Department of Clinical Biochemistry, University of Cambridge, Cambridge, UK
| | - Fiona Gribble
- Department of Clinical Biochemistry, University of Cambridge, Cambridge, UK
| | - Karl Deisseroth
- Howard Hughes Medical Institute, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Carlos Lois
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Yuki Oka
- Computation and Neural Systems, California Institute of Technology, Pasadena, California, USA
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
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14
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Abstract
Our bodies are mostly water, and this water is constantly being lost through evaporative and other means. Thus the evolution of robust mechanisms for finding and consuming water has been critical for the survival of most animals. In this Primer, we discuss how the brain monitors the water content of the body and then transforms that physical information into the motivation to drink.
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Abstract
Water intake is one of the most basic physiological responses and is essential to sustain life. The perception of thirst has a critical role in controlling body fluid homeostasis and if neglected or dysregulated can lead to life-threatening pathologies. Clear evidence suggests that the perception of thirst occurs in higher-order centres, such as the anterior cingulate cortex (ACC) and insular cortex (IC), which receive information from midline thalamic relay nuclei. Multiple brain regions, notably circumventricular organs such as the organum vasculosum lamina terminalis (OVLT) and subfornical organ (SFO), monitor changes in blood osmolality, solute load and hormone circulation and are thought to orchestrate appropriate responses to maintain extracellular fluid near ideal set points by engaging the medial thalamic-ACC/IC network. Thirst has long been thought of as a negative homeostatic feedback response to increases in blood solute concentration or decreases in blood volume. However, emerging evidence suggests a clear role for thirst as a feedforward adaptive anticipatory response that precedes physiological challenges. These anticipatory responses are promoted by rises in core body temperature, food intake (prandial) and signals from the circadian clock. Feedforward signals are also important mediators of satiety, inhibiting thirst well before the physiological state is restored by fluid ingestion. In this Review, we discuss the importance of thirst for body fluid balance and outline our current understanding of the neural mechanisms that underlie the various types of homeostatic and anticipatory thirst.
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Affiliation(s)
- Claire Gizowski
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre and Montreal General Hospital, 1650 Cedar Avenue, Montreal H3G1A4, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre and Montreal General Hospital, 1650 Cedar Avenue, Montreal H3G1A4, Canada
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16
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Milano S, Carmosino M, Gerbino A, Svelto M, Procino G. Hereditary Nephrogenic Diabetes Insipidus: Pathophysiology and Possible Treatment. An Update. Int J Mol Sci 2017; 18:ijms18112385. [PMID: 29125546 PMCID: PMC5713354 DOI: 10.3390/ijms18112385] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 12/17/2022] Open
Abstract
Under physiological conditions, excessive loss of water through the urine is prevented by the release of the antidiuretic hormone arginine-vasopressin (AVP) from the posterior pituitary. In the kidney, AVP elicits a number of cellular responses, which converge on increasing the osmotic reabsorption of water in the collecting duct. One of the key events triggered by the binding of AVP to its type-2 receptor (AVPR2) is the exocytosis of the water channel aquaporin 2 (AQP2) at the apical membrane the principal cells of the collecting duct. Mutations of either AVPR2 or AQP2 result in a genetic disease known as nephrogenic diabetes insipidus, which is characterized by the lack of responsiveness of the collecting duct to the antidiuretic action of AVP. The affected subject, being incapable of concentrating the urine, presents marked polyuria and compensatory polydipsia and is constantly at risk of severe dehydration. The molecular bases of the disease are fully uncovered, as well as the genetic or clinical tests for a prompt diagnosis of the disease in newborns. A real cure for nephrogenic diabetes insipidus (NDI) is still missing, and the main symptoms of the disease are handled with s continuous supply of water, a restrictive diet, and nonspecific drugs. Unfortunately, the current therapeutic options are limited and only partially beneficial. Further investigation in vitro or using the available animal models of the disease, combined with clinical trials, will eventually lead to the identification of one or more targeted strategies that will improve or replace the current conventional therapy and grant NDI patients a better quality of life. Here we provide an updated overview of the genetic defects causing NDI, the most recent strategies under investigation for rescuing the activity of mutated AVPR2 or AQP2, or for bypassing defective AVPR2 signaling and restoring AQP2 plasma membrane expression.
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Affiliation(s)
- Serena Milano
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy.
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
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17
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Gizowski C, Bourque CW. Neurons that drive and quench thirst. Science 2017; 357:1092-1093. [PMID: 28912228 DOI: 10.1126/science.aao5574] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Claire Gizowski
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada.
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18
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Andermann ML, Lowell BB. Toward a Wiring Diagram Understanding of Appetite Control. Neuron 2017; 95:757-778. [PMID: 28817798 DOI: 10.1016/j.neuron.2017.06.014] [Citation(s) in RCA: 320] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/02/2017] [Accepted: 06/07/2017] [Indexed: 01/26/2023]
Abstract
Prior mouse genetic research has set the stage for a deep understanding of appetite regulation. This goal is now being realized through the use of recent technological advances, such as the ability to map connectivity between neurons, manipulate neural activity in real time, and measure neural activity during behavior. Indeed, major progress has been made with regard to meal-related gut control of appetite, arcuate nucleus-based hypothalamic circuits linking energy state to the motivational drive, hunger, and, finally, limbic and cognitive processes that bring about hunger-mediated increases in reward value and perception of food. Unexpected findings are also being made; for example, the rapid regulation of homeostatic neurons by cues that predict future food consumption. The aim of this review is to cover the major underpinnings of appetite regulation, describe recent advances resulting from new technologies, and synthesize these findings into an updated view of appetite regulation.
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Affiliation(s)
- Mark L Andermann
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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19
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Abstract
Due to the biological importance of sodium and its relative scarcity within many natural environments, 'salt appetite' has evolved whereby dietary salt is highly sought after and palatable when tasted. In addition to peripheral responses, salt depletion is detected within the brain via circumventricular organs and 11β-hydroxysteroid dehydrogenase type 2 (HSD2) neurons to increase salt appetite. Salt appetite is comprised of two main components. One component is the incentive salience or motivation for salt (i.e. how much salt is 'wanted'). Incentive salience is dynamic and largely depends on internal homeostatic conditions in combination with the detection of relevant cues. It involves the mesolimbic system and structures such as the central amygdala, and opioid signalling within these regions can increase salt intake in rodents. A second key feature is the hedonic palatability of salt (i.e. how much it is 'liked') when it is tasted. After detection on the tongue, gustatory information passes through the brainstem nucleus of the solitary tract and thalamus, before being consciously detected within the gustatory cerebral cortex. The positive or negative hedonic value of this stimulus is also dynamic, and is encoded by a network including the nucleus accumbens, ventral pallidum, and lateral parabrachial nucleus. Opioid signalling within these areas can alter salt intake, and 'liking'. The overconsumption of dietary salt likely contributes to hypertension and associated diseases, and hence further characterising the role played by opioid signalling has important implications for human health.
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Affiliation(s)
- Craig M Smith
- Faculty of Health, The School of Medicine, Deakin University, Geelong, VIC, 3220, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia. .,The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia.
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20
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Abstract
The metabolic syndrome is a cluster of risk factors (central obesity, hyperglycaemia, dyslipidaemia and arterial hypertension), indicating an increased risk of diabetes, cardiovascular disease and premature mortality. The gastrointestinal tract is seldom discussed as an organ system of principal importance for metabolic diseases. The present overview connects various metabolic research lines into an integrative physiological context in which the gastrointestinal tract is included. Strong evidence for the involvement of the gut in the metabolic syndrome derives from the powerful effects of weight-reducing (bariatric) gastrointestinal surgery. In fact, gastrointestinal surgery is now recommended as a standard treatment option for type 2 diabetes in obesity. Several gut-related mechanisms that potentially contribute to the metabolic syndrome will be presented. Obesity can be caused by hampered release of satiety-signalling gut hormones, reduced meal-associated energy expenditure and microbiota-assisted harvest of energy from nondigestible food ingredients. Adiposity per se is a well-established risk factor for hyperglycaemia. In addition, a leaky gut mucosa can trigger systemic inflammation mediating peripheral insulin resistance that together with a blunted incretin response aggravates the hyperglycaemic state. The intestinal microbiota is strongly associated with obesity and the related metabolic disease states, although the mechanisms involved remain unclear. Enterorenal signalling has been suggested to be involved in the pathophysiology of hypertension and postprandial triglyceride-rich chylomicrons; in addition, intestinal cholesterol metabolism probably contributes to atherosclerosis. It is likely that in the future, the metabolic syndrome will be treated according to novel pharmacological principles interfering with gastrointestinal functionality.
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Affiliation(s)
- L Fändriks
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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21
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Mandelblat-Cerf Y, Kim A, Burgess CR, Subramanian S, Tannous BA, Lowell BB, Andermann ML. Bidirectional Anticipation of Future Osmotic Challenges by Vasopressin Neurons. Neuron 2016; 93:57-65. [PMID: 27989461 DOI: 10.1016/j.neuron.2016.11.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 09/30/2016] [Accepted: 10/28/2016] [Indexed: 12/31/2022]
Abstract
Ingestion of water and food are major hypo- and hyperosmotic challenges. To protect the body from osmotic stress, posterior pituitary-projecting, vasopressin-secreting neurons (VPpp neurons) counter osmotic perturbations by altering their release of vasopressin, which controls renal water excretion. Vasopressin levels begin to fall within minutes of water consumption, even prior to changes in blood osmolality. To ascertain the precise temporal dynamics by which water or food ingestion affect VPpp neuron activity, we directly recorded the spiking and calcium activity of genetically defined VPpp neurons. In states of elevated osmolality, water availability rapidly decreased VPpp neuron activity within seconds, beginning prior to water ingestion, upon presentation of water-predicting cues. In contrast, food availability following food restriction rapidly increased VPpp neuron activity within seconds, but only following feeding onset. These rapid and distinct changes in activity during drinking and feeding suggest diverse neural mechanisms underlying anticipatory regulation of VPpp neurons.
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Affiliation(s)
- Yael Mandelblat-Cerf
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Angela Kim
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Christian R Burgess
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Siva Subramanian
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Bakhos A Tannous
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| | - Mark L Andermann
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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22
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Peyrot des Gachons C, Avrillier J, Gleason M, Algarra L, Zhang S, Mura E, Nagai H, Breslin PAS. Oral Cooling and Carbonation Increase the Perception of Drinking and Thirst Quenching in Thirsty Adults. PLoS One 2016; 11:e0162261. [PMID: 27685093 PMCID: PMC5042416 DOI: 10.1371/journal.pone.0162261] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 08/21/2016] [Indexed: 11/18/2022] Open
Abstract
Fluid ingestion is necessary for life, and thirst sensations are a prime motivator to drink. There is evidence of the influence of oropharyngeal stimulation on thirst and water intake in both animals and humans, but how those oral sensory cues impact thirst and ultimately the amount of liquid ingested is not well understood. We investigated which sensory trait(s) of a beverage influence the thirst quenching efficacy of ingested liquids and the perceived amount ingested. We deprived healthy individuals of liquid and food overnight (> 12 hours) to make them thirsty. After asking them to drink a fixed volume (400 mL) of an experimental beverage presenting one or two specific sensory traits, we determined the volume ingested of additional plain, 'still', room temperature water to assess their residual thirst and, by extension, the thirst-quenching properties of the experimental beverage. In a second study, participants were asked to drink the experimental beverages from an opaque container through a straw and estimate the volume ingested. We found that among several oro-sensory traits, the perceptions of coldness, induced either by cold water (thermally) or by l-menthol (chemically), and the feeling of oral carbonation, strongly enhance the thirst quenching properties of a beverage in water-deprived humans (additional water intake after the 400 ml experimental beverage was reduced by up to 50%). When blinded to the volume of liquid consumed, individual's estimation of ingested volume is increased (~22%) by perceived oral cold and carbonation, raising the idea that cold and perhaps CO2 induced-irritation sensations are included in how we normally encode water in the mouth and how we estimate the quantity of volume swallowed. These findings have implications for addressing inadequate hydration state in populations such as the elderly.
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Affiliation(s)
| | - Julie Avrillier
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
- AgroSup Dijon Institut National Superieur, Dijon, France
| | - Michael Gleason
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
| | - Laure Algarra
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
- AgroParisTech Paris, Paris, France
| | - Siyu Zhang
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
| | - Emi Mura
- Suntory Global Innovation Center Limited, Osaka, Japan
| | - Hajime Nagai
- Suntory Global Innovation Center Limited, Osaka, Japan
| | - Paul A. S. Breslin
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
- Rutgers University Department of Nutritional Sciences, New Brunswick, NJ, United States of America
- * E-mail:
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23
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Effects of interleukin-1 beta injections into the subfornical organ and median preoptic nucleus on sodium appetite, blood pressure and body temperature of sodium-depleted rats. Physiol Behav 2016; 163:149-160. [DOI: 10.1016/j.physbeh.2016.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/14/2016] [Accepted: 05/04/2016] [Indexed: 01/01/2023]
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24
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Thirst neurons anticipate the homeostatic consequences of eating and drinking. Nature 2016; 537:680-684. [PMID: 27487211 PMCID: PMC5161740 DOI: 10.1038/nature18950] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 06/17/2016] [Indexed: 12/19/2022]
Abstract
Thirst motivates animals to drink in order to maintain fluid balance. Thirst has conventionally been viewed as a homeostatic response to changes in blood volume or tonicity. However, most drinking behaviour is regulated too rapidly to be controlled by blood composition directly, and instead seems to anticipate homeostatic imbalances before they arise. How this is achieved remains unknown. Here we reveal an unexpected role for the subfornical organ (SFO) in the anticipatory regulation of thirst in mice. By monitoring deep-brain calcium dynamics, we show that thirst-promoting SFO neurons respond to inputs from the oral cavity during eating and drinking and then integrate these inputs with information about the composition of the blood. This integration allows SFO neurons to predict how ongoing food and water consumption will alter fluid balance in the future and then to adjust behaviour pre-emptively. Complementary optogenetic manipulations show that this anticipatory modulation is necessary for drinking in several contexts. These findings provide a neural mechanism to explain longstanding behavioural observations, including the prevalence of drinking during meals, the rapid satiation of thirst, and the fact that oral cooling is thirst-quenching.
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25
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Barney CC, Kuhrt DM. Intermittent heat exposure and thirst in rats. Physiol Rep 2016; 4:4/8/e12767. [PMID: 27095836 PMCID: PMC4848724 DOI: 10.14814/phy2.12767] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/24/2016] [Indexed: 11/24/2022] Open
Abstract
Adequate water intake, supporting both cardiovascular function and evaporative cooling, is a critical factor in mitigating the effects of heat waves, which are expected to increase with global warming. However, the regulation of water intake during periods of intermittent heat exposure is not well understood. In this study, the effects of access to water or no access during intermittent heat exposure were assessed using male Sprague-Dawley rats exposed to 37.5°C for 4 h/day. After 7 days of intermittent heat exposure, reductions in evaporative water loss were observed in all animals and reductions in water intake following heat exposure occurred as the days of heat exposure increased. Rats that were not allowed water during the 7 days of exposure had decreased rehydration levels, however, rats allowed access to water increased water intake during exposure and exhibited higher overall rehydration levels over the same time period. Peripheral administration of angiotensinII, mimicking activation of volemic thirst, or hypertonic saline solution, activating intracellular thirst, did not result in alteration of water intake in rats exposed to heat with access to water compared to control rats. In contrast, rats exposed to heat without access to water had reduced water intake after administration of hypertonic saline and increased water intake after administration of angiotensinIIcompared to control rats. These experiments demonstrate that thirst responses to intermittent heat exposure are altered by providing water during heat exposure and that intermittent heat exposure without access to water alters drinking responses to both intracellular and extracellular thirst challenges.
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Affiliation(s)
| | - David M Kuhrt
- Department of Biology, Hope College, Holland, Michigan
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26
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Abstract
AgRP and POMC neurons are two key cell types that regulate feeding in response to hormones and nutrients. Recently, it was discovered that these neurons are also rapidly modulated by the mere sight and smell of food. This rapid sensory regulation "resets" the activity of AgRP and POMC neurons before a single bite of food has been consumed. This surprising and counterintuitive discovery challenges longstanding assumptions about the function and regulation of these cells. Here we review these recent findings and discuss their implications for our understanding of feeding behavior. We propose several alternative hypotheses for how these new observations might be integrated into a revised model of the feeding circuit, and also highlight some of the key questions that remain to be answered.
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Affiliation(s)
- Yiming Chen
- Department of Physiology, University of California, San Francisco, CA, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, CA, USA
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27
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Barney CC, Schanhals EM, Grobe JL, Andresen BT, Traver M. Heat acclimation and thirst in rats. Physiol Rep 2015; 3:e12642. [PMID: 26702076 PMCID: PMC4760436 DOI: 10.14814/phy2.12642] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022] Open
Abstract
The effects of heat acclimation on water intake and urine output responses to thermal dehydration and other thirst stimuli were studied in male Sprague-Dawley rats. Rats were heat acclimated by continuous exposure to a 34°C environment for at least 6 weeks. Thermal dehydration-induced thirst was brought about by exposing the heat-acclimated rats and control rats housed at 24°C to a 37.5°C environment for 4 h without access to food or water. Heat acclimation reduced evaporative and urinary water losses and the increases in plasma sodium and osmolality during thermal dehydration, which led to a reduction in thermal dehydration-induced thirst. Heat acclimation reduced the rate of rehydration following thermal dehydration but did not alter the final rehydration level, indicating that heat acclimation does not alter the primary control of thermal dehydration-induced thirst. Heat acclimation did not alter water intake or urine output following administration of hypertonic saline, which selectively stimulates intracellular thirst, but led to greater water intake following administration of angiotensin II, which plays an important role in extracellular/volemic thirst, and following water deprivation, which activates both thirst pathways. Cardiovascular responses to angiotensin II were not altered by heat acclimation. Heat acclimation thus reduces water loss during heat exposure in rats, but does not have major effects on thermal dehydration-induced or extracellular thirst but does appear to alter volemic thirst.
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28
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Association between sodium excretion and hydration status by Free Water Reserve: a cross-sectional analysis in adolescents. BMC Nutr 2015. [DOI: 10.1186/s40795-015-0013-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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29
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Mandelblat-Cerf Y, Ramesh RN, Burgess CR, Patella P, Yang Z, Lowell BB, Andermann ML. Arcuate hypothalamic AgRP and putative POMC neurons show opposite changes in spiking across multiple timescales. eLife 2015; 4. [PMID: 26159614 PMCID: PMC4498165 DOI: 10.7554/elife.07122] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/19/2015] [Indexed: 12/18/2022] Open
Abstract
Agouti-related-peptide (AgRP) neurons—interoceptive neurons in the arcuate nucleus of the hypothalamus (ARC)—are both necessary and sufficient for driving feeding behavior. To better understand the functional roles of AgRP neurons, we performed optetrode electrophysiological recordings from AgRP neurons in awake, behaving AgRP-IRES-Cre mice. In free-feeding mice, we observed a fivefold increase in AgRP neuron firing with mounting caloric deficit in afternoon vs morning recordings. In food-restricted mice, as food became available, AgRP neuron firing dropped, yet remained elevated as compared to firing in sated mice. The rapid drop in spiking activity of AgRP neurons at meal onset may reflect a termination of the drive to find food, while residual, persistent spiking may reflect a sustained drive to consume food. Moreover, nearby neurons inhibited by AgRP neuron photostimulation, likely including satiety-promoting pro-opiomelanocortin (POMC) neurons, demonstrated opposite changes in spiking. Finally, firing of ARC neurons was also rapidly modulated within seconds of individual licks for liquid food. These findings suggest novel roles for antagonistic AgRP and POMC neurons in the regulation of feeding behaviors across multiple timescales. DOI:http://dx.doi.org/10.7554/eLife.07122.001 Appetite is controlled in part by the opposing actions of the ‘hunger hormone’ (called ghrelin) and the ‘satiety hormone’ (called leptin). Ghrelin is released by the stomach when empty and stimulates appetite, whereas leptin is released by fat stores and induces feelings of fullness. Both hormones travel via the bloodstream and are detected by a region of the brain called the hypothalamus. Ghrelin and leptin act specifically on a group of cells in the hypothalamus that contains at least two major cell types: AgRP neurons and POMC neurons. Electrode recordings from slices of mouse brain show that AgRP neurons fire more rapidly at night—when mice normally feed—than during the day, whereas POMC neurons do the opposite. This suggests that the activity of AgRP neurons drives food-seeking behavior, whereas POMC firing inhibits it. However, the absence of circulating hormones such as leptin and ghrelin in brain slices makes it difficult to draw firm conclusions about the role of these cells in controlling appetite. Mandelblat-Cerf, Ramesh, Burgess et al. have addressed this issue by performing the first recordings of spiking activity in individual AgRP neurons and other cells that are likely to be POMC neurons in awake mice. Consistent with the results of slice experiments, the firing rate of AgRP neurons increased steadily over the course of the day, suggesting that their activity signals an increasing need for food. Furthermore, as soon as food became available, the firing rate of the AgRP neurons suddenly dropped—even though the animals' energy reserves would still have been low. These results are consistent with the findings of two recent studies reported earlier this year that used different methods to indirectly measure neuronal activity in awake mice. Notably, even after the drop in activity, the firing rates of AgRP neurons remained above those recorded in fully sated mice—which possibly reflects the fact that the animals' energy reserves were still low. The putative POMC neurons generally showed opposite effects to the AgRP neurons. The results of these electrode recordings in awake mice thus suggest that AgRP and POMC neurons together maintain a drive to seek out food sources as energy reserves fall, and to refrain from doing so when energy reserves are plentiful. Moreover, the seemingly paradoxical drop in AgRP firing and increase in POMC firing upon receiving food may act as a signal to temporarily stop searching for food, so that feeding itself can begin. Alternatively, since the release of satiety hormones after eating a meal is slow, these rapid changes in firing may provide more immediate feedback to the neuronal circuits that regulate the drives to seek and consume food. DOI:http://dx.doi.org/10.7554/eLife.07122.002
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Affiliation(s)
- Yael Mandelblat-Cerf
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Rohan N Ramesh
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Christian R Burgess
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Paola Patella
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Zongfang Yang
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Bradford B Lowell
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
| | - Mark L Andermann
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, United States
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30
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De Luca LA, Almeida RL, David RB, de Paula PM, Andrade CAF, Menani JV. Participation of α2 -adrenoceptors in sodium appetite inhibition during sickness behaviour following administration of lipopolysaccharide. J Physiol 2015; 594:1607-16. [PMID: 26036817 DOI: 10.1113/jp270377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/26/2015] [Indexed: 11/08/2022] Open
Abstract
Sickness behaviour, a syndrome characterized by a general reduction in animal activity, is part of the active-phase response to fight infection. Lipopolysaccharide (LPS), an effective endotoxin to model sickness behaviour, reduces thirst and sodium excretion, and increases neurohypophysial secretion. Here we review the effects of LPS on thirst and sodium appetite. Altered renal function and hydromineral fluid intake in response to LPS occur in the context of behavioural reorganization, which manifests itself as part of the syndrome. Recent data show that, in addition to its classical effect on thirst, non-septic doses of LPS injected intraperitoneally produce a preferential inhibition of intracellular thirst versus extracellular thirst. Moreover, LPS also reduced hypertonic NaCl intake in sodium-depleted rats that entered a sodium appetite test. Antagonism of α2 -adrenoceptors abolished the effect of LPS on sodium appetite. LPS and cytokine transduction potentially recruit brain noradrenaline and α2 -adrenoceptors to control sodium appetite and sickness behaviour.
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Affiliation(s)
- Laurival A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Roberto L Almeida
- Department of Physiology, ABC Medical School, Santo André, São Paulo, Brazil
| | - Richard B David
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Patricia M de Paula
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Carina A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - José V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
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de Souza Mecawi A, Ruginsk SG, Elias LLK, Varanda WA, Antunes‐Rodrigues J. Neuroendocrine Regulation of Hydromineral Homeostasis. Compr Physiol 2015; 5:1465-516. [DOI: 10.1002/cphy.c140031] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Opposite effects of oxytocin on water intake induced by hypertonic NaCl or polyethylene glycol administration. Physiol Behav 2015; 141:135-42. [PMID: 25617595 DOI: 10.1016/j.physbeh.2015.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/20/2014] [Accepted: 01/20/2015] [Indexed: 11/21/2022]
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Marshall A, Santollo J, Corteville C, Lutz TA, Daniels D. Roux-en-Y gastric bypass does not affect daily water intake or the drinking response to dipsogenic stimuli in rats. Am J Physiol Regul Integr Comp Physiol 2014; 307:R114-20. [PMID: 24898844 DOI: 10.1152/ajpregu.00135.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bariatric surgery is currently the most effective treatment for severe obesity, and Roux-en-Y gastric bypass (RYGB) is the most common approach in the United States and worldwide. Many studies have documented the changes in body weight, food intake, and glycemic control associated with the procedure. Although dehydration is commonly listed as a postoperative complication, little focus has been directed to testing the response to dipsogenic treatments after RYGB. Accordingly, we used a rat model of RYGB to test for procedure-induced changes in daily water intake and in the response to three dipsogenic treatments: central administration of ANG II, peripheral injection of hypertonic saline, and overnight water deprivation. We did not find any systematic differences in daily water intake of sham-operated and RYGB rats, nor did we find any differences in the response to the dipsogenic treatments. The results of these experiments suggest that RYGB does not impair thirst responses and does not enhance any satiating effect of water intake. Furthermore, these data support the current view that feedback from the stomach is unnecessary for the termination of drinking behavior and are consistent with a role of orosensory or postgastric feedback.
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Khegai II, Mel'nikova VI, Popova NA, Zakharova LA, Ivanova LN. The effect of vasopressin on the Zajdela hepatocellular carcinoma growth rate. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2014; 457:222-224. [PMID: 25172586 DOI: 10.1134/s0012496614040061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Indexed: 06/03/2023]
Affiliation(s)
- I I Khegai
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia,
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Arai SR, Butzlaff A, Stotts NA, Puntillo KA. Quench the thirst: lessons from clinical thirst trials. Biol Res Nurs 2013; 16:456-66. [PMID: 24136996 DOI: 10.1177/1099800413505900] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Thirst, as a symptom, has long been considered the most prevalent clinical complaint patients voice in healthcare settings. Yet, rarely have researchers examined thirst by its correlation with physiologic factors. This review was undertaken to examine the relationships between thirst ratings and factors mediating its primary physiologic correlates: plasma osmolality (pOsm) and arginine vasopressin peptide (AVP). A literature search was undertaken to identify clinical studies in human subjects that investigated the relationship of thirst to specific physiologic thirst-related correlates and associated thirst mediators. Thirst was induced in 17 selected clinical studies by hyperosmolar infusion, through water deprivation or exercise weight-loss regimens. Positive linear relationships between the subjects' thirst ratings and rising serum pOsm levels confirmed the presence of intact osmotic thirst drives. However, there were significant variations in normal compensatory rises in AVP levels that followed the rises in plasma osmolality after the subjects were exposed to cold, physical pre-conditioning and water immersion tests. Notably, older adults in the studies reported diminished thirst ratings. Weak correlations suggest that angiotensin II may play only a minor role in thirst mediation. Atrial natriuretic hormone's inhibitory effect on thirst was inconsistent. Findings indicated that older adults are at higher risk for profound dehydration due to sensory deficits along with failure to correct volume losses. The thirst trials results support the close correlation between serum pOsm values and patients' thirst ratings, with the exception of the older adult.
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Affiliation(s)
- Shoshana R Arai
- Department of Physiological Nursing, San Francisco School of Nursing, University of California, San Francisco, CA, USA
| | - Alice Butzlaff
- Department of Physiological Nursing, San Francisco School of Nursing, University of California, San Francisco, CA, USA
| | - Nancy A Stotts
- Department of Physiological Nursing, San Francisco School of Nursing, University of California, San Francisco, CA, USA
| | - Kathleen A Puntillo
- Department of Physiological Nursing, San Francisco School of Nursing, University of California, San Francisco, CA, USA
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Sensory-specific appetition: Postingestive detection of glucose rapidly promotes continued consumption of a recently encountered flavor. Physiol Behav 2013; 121:125-33. [DOI: 10.1016/j.physbeh.2013.03.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/15/2013] [Accepted: 03/06/2013] [Indexed: 01/02/2023]
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Arai S, Stotts N, Puntillo K. Thirst in critically ill patients: from physiology to sensation. Am J Crit Care 2013; 22:328-35. [PMID: 23817822 DOI: 10.4037/ajcc2013533] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Critically ill patients often report distressful episodes of severe thirst, but the complex biochemical, neurohormonal mechanisms that regulate this primal sensation still elude clinicians. The most potent stimuli for thirst are subtle increases in plasma osmolality. These minute changes in osmolality stimulate central osmoreceptors to release vasopressin (also known as antidiuretic hormone). Vasopressin in turn acts on the kidneys to promote the reabsorption of water to correct the increased osmolality. If this compensatory mechanism fails to decrease osmolality, then thirst is triggered to motivate drinking. In contrast, thirst induced by marked volume loss, or hypovolemic thirst, is subject to the tight osmoregulation of the renin-angiotensin aldosterone system and accompanying adrenergic agonists. Understanding the essential role that thirst plays in salt and water regulation can provide clinicians with a better appreciation for the complex physiology that underlies this intense sensation.
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Affiliation(s)
- Shoshana Arai
- Shoshana Arai is an assistant adjunct professor in physiological nursing, Nancy Stotts and Kathleen Puntillo are professors at University of California San Francisco, School of Nursing, San Francisco, California
| | - Nancy Stotts
- Shoshana Arai is an assistant adjunct professor in physiological nursing, Nancy Stotts and Kathleen Puntillo are professors at University of California San Francisco, School of Nursing, San Francisco, California
| | - Kathleen Puntillo
- Shoshana Arai is an assistant adjunct professor in physiological nursing, Nancy Stotts and Kathleen Puntillo are professors at University of California San Francisco, School of Nursing, San Francisco, California
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Stricker EM, Grigson PS, Norgren R. Variable effects of parabrachial nucleus lesions on salt appetite in rats depending upon experimental paradigm and saline concentration. Behav Neurosci 2013; 127:275-84. [PMID: 23398436 DOI: 10.1037/a0031716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies have demonstrated that bilateral lesions of the gustatory (medial) zone of the parabrachial nucleus (PBN) in the pons eliminate the salt (sodium chloride; NaCl) appetite induced in rats by treatment with the diuretic drug, furosemide. The present studies reexamined NaCl intake of rats with PBN lesions induced by ibotenic acid, using multiple models of salt appetite. The impairment of a conditioned taste aversion, an established consequence of PBN damage, was used as an initial screen with which to assess the effectiveness of the lesions. Rats with PBN lesions did not drink either 0.3 of a molar (M) solution of NaCl or 0.5 M NaCl in response to daily treatment with desoxycorticosterone acetate. These findings suggest that the excitatory stimulus of salt appetite mediated by mineralocorticoids is abolished by PBN lesions. In contrast, rats with PBN lesions drank some 0.5 M NaCl and more 0.3 M NaCl, in addition to water, in response to hypovolemia induced by subcutaneous injection of 30% polyethylene glycol solution. Those findings suggest that an excitatory stimulus of salt appetite, presumably mediated by Angiotensin II, is not abolished by PBN lesions. These and other observations indicate that lesions of the gustatory PBN in rats may or may not eliminate salt appetite, depending on which model is used and which concentration of NaCl solution is available.
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Affiliation(s)
- Edward M Stricker
- Department of Neuroscience, 210 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Hallersund P, Sjöström L, Olbers T, Lönroth H, Jacobson P, Wallenius V, Näslund I, Carlsson LM, Fändriks L. Gastric bypass surgery is followed by lowered blood pressure and increased diuresis - long term results from the Swedish Obese Subjects (SOS) study. PLoS One 2012; 7:e49696. [PMID: 23209592 PMCID: PMC3510228 DOI: 10.1371/journal.pone.0049696] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/15/2012] [Indexed: 01/14/2023] Open
Abstract
Objective To compare two bariatric surgical principles with regard to effects on blood pressure and salt intake. Background In most patients bariatric surgery induces a sustained weight loss and a reduced cardiovascular risk profile but the long-term effect on blood pressure is uncertain. Methods Cohort study with data from the prospective, controlled Swedish Obese Subjects (SOS) study involving 480 primary health care centres and 25 surgical departments in Sweden. Obese patients treated with non-surgical methods (Controls, n = 1636 and n = 1132 at 2 y and 10 y follow up, respectively) were compared to patients treated with gastric bypass (GBP, n = 245 and n = 277, respectively) or purely restrictive procedures (vertical banded gastroplasty or gastric banding; VBG/B, n = 1534 and n = 1064, respectively). Results At long-term follow-up (median 10 y) GBP was associated with lowered systolic (mean: −5.1 mm Hg) and diastolic pressure (−5.6 mmHg) differing significantly from both VBG/B (−1.5 and −2.1 mmHg, respectively; p<0.001) and Controls (+1.2 and −3.8 mmHg, respectively; p<0.01). Diurnal urinary output was +100 ml (P<0.05) and +170 ml (P<0.001) higher in GBP subjects than in weight-loss matched VBG/B subjects at the 2 y and 10 y follow-ups, respectively. Urinary output was linearly associated with blood pressure only after GBP and these patients consumed approximately 1 g salt per day more at the follow-ups than did VBG/B (P<0.01). Conclusions The purely restrictive techniques VBG/B exerted a transient blood pressure lowering effect, whereas gastric bypass was associated with a sustained blood pressure reduction and an increased diuresis. The daily salt consumption was higher after gastric bypass than after restrictive bariatric surgery.
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Affiliation(s)
- Peter Hallersund
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lars Sjöström
- Department of Molecular and Clinical Medicine and Center for Cardiovascular and Metabolic Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Torsten Olbers
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Hans Lönroth
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Peter Jacobson
- Department of Molecular and Clinical Medicine and Center for Cardiovascular and Metabolic Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ville Wallenius
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ingmar Näslund
- Department of Molecular and Clinical Medicine and Center for Cardiovascular and Metabolic Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lena M. Carlsson
- Department of Molecular and Clinical Medicine and Center for Cardiovascular and Metabolic Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lars Fändriks
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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Seale AP, Watanabe S, Grau EG. Osmoreception: perspectives on signal transduction and environmental modulation. Gen Comp Endocrinol 2012; 176:354-60. [PMID: 22036842 DOI: 10.1016/j.ygcen.2011.10.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/05/2011] [Accepted: 10/12/2011] [Indexed: 01/16/2023]
Abstract
Osmoregulation is essential to life in vertebrates and osmoreception is a fundamental element in osmoregulation. Progress in characterizing the mechanisms that mediate osmoreception has been made possible by using a uniquely accessible cell model, the prolactin (PRL) cell of the euryhaline tilapia, Oreochromis mossambicus. In addition to a brief historical overview, we offer a summary of our recent progress on signal transduction and osmosensitivity in the tilapia PRL cell model. Prolactin is a central regulator of hydromineral balance in teleosts in freshwater (FW). Consistent with its essential role in FW osmoregulation, PRL release in tilapia is inversely related to extracellular osmolality, both in vivo and in vitro. Osmotically-driven changes in PRL cell volume control PRL release. A decrease in extracellular osmolality increases cell volume, leading to a rapid influx of Ca(2+) through stretch-activated channels followed by a sharp rise in PRL release. Our recent studies also suggest that cAMP is involved in the osmotic signal transduction, and that acclimation salinity can modulate PRL cell osmosensitivity. Prolactin cells from FW tilapia show a larger rise in PRL release after a reduction in medium osmolality than those from SW fish. Paradoxically, hyposmotically-induced increase in PRL mRNA was observed only in cells from SW fish. Our studies have revealed differences in the abundance of the water channel, aquaporin 3 (AQP3), and the stretch activated Ca(2+) channel, transient receptor potential vanilloid 4 (TRPV4) in PRL cells of FW and SW fish that may explain their differing osmosensitivity and osmoreceptive output in differing acclimation salinities.
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Affiliation(s)
- A P Seale
- Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
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41
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Acute arrhythmogenesis after myocardial infarction in normotensive rats: Influence of high salt intake. Food Chem Toxicol 2012; 50:473-7. [DOI: 10.1016/j.fct.2011.11.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 12/22/2022]
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Morrison CD, Reed SD, Henagan TM. Homeostatic regulation of protein intake: in search of a mechanism. Am J Physiol Regul Integr Comp Physiol 2012; 302:R917-28. [PMID: 22319049 DOI: 10.1152/ajpregu.00609.2011] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Free-living organisms must procure adequate nutrition by negotiating an environment in which both the quality and quantity of food vary markedly. Recent decades have seen marked progress in our understanding of neural regulation of feeding behavior. However, this progress has occurred largely in the context of energy intake, despite the fact that food intake is influenced by more than just the energy content of the diet. A large number of behavioral studies indicate that both the quantity and quality of dietary protein can markedly influence food intake. High-protein diets tend to reduce intake, low-protein diets tend to increase intake, and rodent models seem to self-select between diets in order to meet protein requirements and avoid diets that are imbalanced in amino acids. Recent work suggests that the amino acid leucine regulates food intake by altering mTOR and AMPK signaling in the hypothalamus, while activation of GCN2 within the anterior piriform cortex contributes to the detection and avoidance of amino acid-imbalanced diets. This review focuses on the role that these and other signaling systems may play in mediating the homeostatic regulation of protein balance, and in doing so, highlights our lack of knowledge regarding the physiological and neurobiological mechanisms that might underpin such a regulatory phenomenon.
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Abstract
PURPOSE OF REVIEW To highlight recent developments relating perioperative fluid therapy to gastrointestinal function by reviewing clinically pertinent English language articles mainly from January 2010 to March 2011. RECENT FINDINGS The control of fluid and electrolyte balance involves multiple processes in which the gastrointestinal tract plays an integral role. Diseases affecting the gastrointestinal tract commonly cause fluid and electrolyte disturbance. Similarly, intravenous fluid therapy in the perioperative period can affect gastrointestinal function and have a bearing on postoperative outcome. Striking a balance, in terms of both fluid composition and volume, is likely to reduce the morbidity associated with interstitial edema, a frequently observed occurrence with contemporary perioperative fluid regimens. This balance may be best achieved using individualized and goal-directed approaches to fluid therapy, in order to provide fluid when it is needed and in the correct quantities. SUMMARY In planning strategies of fluid therapy, the possibility of adverse effects on the gastrointestinal tract should be considered, as this is likely to have an impact on fluid and electrolyte balance and postoperative outcome.
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Affiliation(s)
- Abeed H Chowdhury
- Division of Gastrointestinal Surgery, Nottingham Digestive Diseases Centre, NIHR Biomedical Research Unit, Nottingham University Hospitals, Queen's Medical Centre, Nottingham, UK
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44
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Pedersen SF, Kapus A, Hoffmann EK. Osmosensory mechanisms in cellular and systemic volume regulation. J Am Soc Nephrol 2011; 22:1587-97. [PMID: 21852585 DOI: 10.1681/asn.2010121284] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Perturbations of cellular and systemic osmolarity severely challenge the function of all organisms and are consequently regulated very tightly. Here we outline current evidence on how cells sense volume perturbations, with particular focus on mechanisms relevant to the kidneys and to extracellular osmolarity and whole body volume homeostasis. There are a variety of molecular signals that respond to perturbations in cell volume and osmosensors or volume sensors responding to these signals. The early signals of volume perturbation include integrins, the cytoskeleton, receptor tyrosine kinases, and transient receptor potential channels. We also present current evidence on the localization and function of central and peripheral systemic osmosensors and conclude with a brief look at the still limited evidence on pathophysiological conditions associated with deranged sensing of cell volume.
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Affiliation(s)
- Stine Falsig Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
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Role of superior laryngeal nerve and Fos staining following dehydration and rehydration in the rat. Physiol Behav 2011; 104:1053-8. [PMID: 21781979 DOI: 10.1016/j.physbeh.2011.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
Immunohistochemistry for Fos was used to determine the role of the superior laryngeal nerve in conscious rats following water deprivation and rehydration. Adult male rats were subjected to either unilateral superior laryngeal nerve section (SLNX) or sham surgery. Two weeks later rats from each surgical group were water deprived for 48 h or water deprived for 46 h and given access to water for 2 h prior to perfusion. Controls were allowed ad libitum access to water. Brains were processed for Fos using a commercially available antibody. Changes in plasma osmolality and hematocrit were not significantly different between SLNX and sham following any of the treatments. Water intake in rats was not significantly affected by SLNX. In the supraoptic nucleus (SON) of sham rats, water deprivation significantly increased Fos staining while water intake following dehydration prevented this increase. Water deprivation significantly increased Fos staining in the SON of SLNX rats. Following water intake after 46 h water deprivation in SLNX rats, Fos staining in the ipsilateral SON was significantly greater than the contralateral SON and significantly lower than 48 h water deprivation. In the nucleus of the solitary tract (NTS) of sham rats, both water deprivation and water intake produced significant increases in Fos staining bilaterally compared to euhydrated controls. In SLNX rats, water deprivation significantly increased Fos in both ipsilateral and contralateral NTS that was not different from sham rats. SLNX significantly decreased Fos staining in the ipsilateral NTS of rats given access to water after dehydration compared to the corresponding sham treated rats. Fos staining was not affected in the contralateral NTS of SLNX rats given access to water after dehydration. This suggests that the superior laryngeal nerve contributes to changes in Fos staining in the NTS and SON following water intake in dehydrated rats.
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Almeida RL, David RB, Constancio J, Fracasso JF, Menani JV, De Luca LA. Inhibition of sodium appetite by lipopolysaccharide: involvement of alpha2-adrenoceptors. Am J Physiol Regul Integr Comp Physiol 2011; 301:R185-92. [PMID: 21474430 DOI: 10.1152/ajpregu.00555.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lipopolysaccharide (LPS), an endotoxin from the wall of Escherichia coli, produces a general behavioral inhibition and affects several aspects of fluid-electrolyte balance. LPS inhibits thirst; however, it is not clear if it also inhibits sodium appetite. The present results show that LPS (0.3-2.5 mg/kg body wt) injected intraperitoneally produces a dose-dependent reduction of sodium appetite expressed as 0.3 M NaCl intake induced by sodium depletion (furosemide plus removal of ambient sodium for 24 h). The high doses of LPS (1.2-2.5 mg/kg) also produced transient hypothermia at the beginning of the sodium appetite test; however, no dose produced hyperthermia. LPS also increased the stomach liquid content (an index of gastric emptying) after a load of 0.3 M NaCl given intragastrically by gavage to sodium-depleted rats. The α(2)-adrenoceptor antagonist yohimbine (5 mg/kg ip) abolished the effect of LPS on 0.3 M NaCl intake, without changing the effect of LPS on gastric emptying. Injection of RX-821002 (160 nmol), another α(2)-adrenoceptor antagonist, in the lateral cerebral ventricle (LV) also reversed the inhibition of sodium appetite produced by LPS. Yohimbine intraperitoneally or RX-821002 in the LV alone had no effect on sodium intake. Although yohimbine plus LPS produced a slight hypotension, RX-821002 plus LPS produced no change in arterial pressure, suggesting that the blockade of the effects of LPS on sodium intake by the α(2)-adrenoceptor antagonists is independent from changes in arterial pressure. The results suggest an inhibitory role for LPS in sodium appetite that is mediated by central α(2)-adrenoceptors.
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Affiliation(s)
- R L Almeida
- Dept. of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Rua Humaitá, 1680, Araraquara, São Paulo, 14801-903, Brazil
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47
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Pre-systemic controls of fluid intake and vasopressin secretion. Physiol Behav 2011; 103:86-8. [DOI: 10.1016/j.physbeh.2010.11.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Accepted: 11/16/2010] [Indexed: 11/18/2022]
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Abstract
Water drinking elicits profound pressor responses in patients with impaired baroreflex function and in sinoaortic-denervated mice. Healthy subjects show more subtle changes in heart rate and blood pressure with water drinking. The water-induced pressor response appears to be mediated through sympathetic nervous system activation at the spinal level. Indeed, water drinking raises resting energy expenditure in normal weight and obese subjects. The stimulus setting off the response is hypoosmolarity rather than water temperature or gastrointestinal stretch. Studies in mice suggest that this osmopressor response may involve transient receptor potential vanniloid 4 (Trpv4) receptors. However, the (nerve) cell population serving as peripheral osmosensors and the exact transduction mechanisms are still unknown. The osmopressor response can be exploited in the treatment of orthostatic and postprandial hypotension in patients with severe autonomic failure. Furthermore, the osmopressor response acutely improves orthostatic tolerance in healthy subjects and in patients with neurally mediated syncope. The phenomenon should be recognized as an important confounder in cardiovascular and metabolic studies.
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Affiliation(s)
- Marcus May
- Institute of Clinical Pharmacology, Hannover, Germany
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49
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Bernal A, Mahía J, García Del Rio C, Puerto A. Oxytocin polyuria and polydipsia is blocked by NaCl administration in food-deprived male rats. J Neuroendocrinol 2010; 22:1043-51. [PMID: 20649851 DOI: 10.1111/j.1365-2826.2010.02050.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined the effects of NaCl injections on the polydipsia and polyuria induced by subcutaneous oxytocin (OT) administration in food-deprived male rats. During the first 12 h of the treatment day, both food deprivation and OT administration increased urine excretion but reduced water intake, water balance (fluid intake minus urine volume) and body weight. OT treatment enhanced urine excretion and the reduction in water balance and body weight without reducing the water intake of food-deprived animals. Analysis of the physiological effects of OT administration showed increases in urinary sodium concentration, sodium excretion and a reduced plasma sodium concentration. During the second 12 h, OT increased both urine excretion and water intake in food-deprived but not in ad lib.-fed rats. However, hypertonic NaCl administration at the start of this second 12-h period blocked the polyuric and polydipsic responses observed in the OT/deprived group but increased the water intake of the ad lib. groups. After the whole 24-h period, animals treated with OT showed a water balance and body weight change matching those observed in Control animals. Although the recording time period is a critical factor to demonstrate the effect of peripheral OT administration on water intake, the results obtained suggest that the polyuric and polydipsic responses observed in food-deprived animals depend on the negative sodium and water balance induced by the natriuretic effect of OT and the unavailability of sodium. These OT-induced deficits can be counteracted by the administration of hypertonic NaCl solutions or simply by the intake of standard food.
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Affiliation(s)
- A Bernal
- Psychobiology, University of Granada, Granada, Spain. Department of Physiology, School of Medicine, University of Granada, Granada, Spain.
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50
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Knight WD, Ji LL, Little JT, Cunningham JT. Dehydration followed by sham rehydration contributes to reduced neuronal activation in vasopressinergic supraoptic neurons after water deprivation. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1232-40. [PMID: 20844266 DOI: 10.1152/ajpregu.00066.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This experiment tested the role of oropharyngeal and gastric afferents on hypothalamic activation in dehydrated rats instrumented with gastric fistulas and allowed to drink water or isotonic saline compared with euhydrated controls (CON). Rats were water-deprived for 48 h (48 WD) or 46 h WD with 2 h rehydration with water (46+W) or isotonic saline (46+S). 46+W and 46+S rats were given water with fistulas open (46+WO/46+SO, sham) or closed (46+WC/46+SC). Compared with CON, water deprivation increased and water rehydration decreased plasma osmolality, while sham rehydration had no effect. Water deprivation increased c-Fos staining in the lamina terminalis. However, none of the sham or rehydration treatments normalized c-Fos staining in the lamina terminalis. Analysis of AVP and c-Fos-positive neurons in the supraoptic nucleus (SON) revealed reduced colocalization in 46+WO and 46+SC rats compared with 48 WD and 46+SO rats. However, 46+WO and 46+SC rats had higher c-Fos staining in the SON than 46+WC or CON rats. Examination of c-Fos in the perinuclear zone (PNZ) revealed that sham and rehydrated rats had increased c-Fos staining to CON, while 48 WD and 46+SO rats had little or no c-Fos staining in this region. Thus, preabsorptive reflexes contribute to the regulation of AVP neurons in a manner independent of c-Fos expression in the lamina terminalis. Further, this reflex pathway may include inhibitory interneurons in the PNZ region surrounding the SON.
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Affiliation(s)
- W David Knight
- Department of Integrative Physiology and Cardiovascular Research Instittute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas 76107, USA.
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