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Cunningham C, Tapking C, Salter M, Seeton R, Kramer GC, Prough DS, Sheffield-Moore M, Kinsky MP. The physiologic responses to a fluid bolus administration in old and young healthy adults. Perioper Med (Lond) 2022; 11:30. [PMID: 35971161 PMCID: PMC9380305 DOI: 10.1186/s13741-022-00266-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/15/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Organ function is known to decline with age. Optimizing cardiac, pulmonary and renal function in older adults has led to significant improvements in perioperative care. However, when substantial blood loss and fluid shifts occur, perioperative outcomes still remains poor, especially in older adults. We suspect that this could be due to age-related changes in endothelial function-an organ controlling the transport of fluid and solutes. The capillary filtration coefficient (CFC) is an important determinant of fluid transport. The CFC can be measured in vivo, which provides a tool to estimate endothelial barrier function. We have previously shown that the CFC increases when giving a fluid bolus resulting in increased vascular and extravascular volume expansion, in young adults. This study aimed to compare the physiologic determinants of fluid distribution in young versus older adults so that clinicians can best optimize perioperative fluid therapy. METHODS Ten healthy young volunteers (ages 21-35) and nine healthy older volunteers (ages 60-75) received a 10 mL/kg fluid bolus over the course of twenty minutes. Hemodynamics, systolic and diastolic heart function, fluid volumetrics and microcirculatory determinants were measured before, during, and after the fluid bolus. RESULTS Diastolic function was reduced in older versus younger adults before and after fluid bolus (P < 0.01). Basal CFC and plasma oncotic pressure were lower in the older versus younger adults. Further, CFC did not increase in older adults following the fluid bolus, whereas it did in younger adults (p < 0.05). Cumulative urinary output, while lower in older adults, was not significantly different (p = 0.059). Mean arterial pressure and systemic vascular resistance were elevated in the older versus younger adults (p < 0.05). CONCLUSION Older adults show a less reactive CFC to a fluid bolus, which could reduce blood to tissue transport of fluid. Diastolic dysfunction likely contributes to fluid maldistribution in older adults.
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Affiliation(s)
- Cordell Cunningham
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Christian Tapking
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA
- Department of Hand, Plastic and Reconstructive Surgery, Microsurgery, Burn Trauma Center, BG Unfallklinik Ludwigshafen, University of Heidelberg, Heidelberg, Germany
| | - Michael Salter
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Roger Seeton
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - George C Kramer
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Donald S Prough
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | | | - Michael P Kinsky
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA.
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2
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Alavi P, Rathod AM, Jahroudi N. Age-Associated Increase in Thrombogenicity and Its Correlation with von Willebrand Factor. J Clin Med 2021; 10:4190. [PMID: 34575297 PMCID: PMC8472522 DOI: 10.3390/jcm10184190] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 02/07/2023] Open
Abstract
Endothelial cells that cover the lumen of all blood vessels have the inherent capacity to express both pro and anticoagulant molecules. However, under normal physiological condition, they generally function to maintain a non-thrombogenic surface for unobstructed blood flow. In response to injury, certain stimuli, or as a result of dysfunction, endothelial cells release a highly adhesive procoagulant protein, von Willebrand factor (VWF), which plays a central role in formation of platelet aggregates and thrombus generation. Since VWF expression is highly restricted to endothelial cells, regulation of its levels is among the most important functions of endothelial cells for maintaining hemostasis. However, with aging, there is a significant increase in VWF levels, which is concomitant with a significant rise in thrombotic events. It is not yet clear why and how aging results in increased VWF levels. In this review, we have aimed to discuss the age-related increase in VWF, its potential mechanisms, and associated coagulopathies as probable consequences.
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Affiliation(s)
| | | | - Nadia Jahroudi
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2S2, Canada; (P.A.); (A.M.R.)
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3
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Damiani AP, Strapazzon G, de Oliveira Sardinha TT, Rohr P, Gajski G, de Pinho RA, de Andrade VM. Melatonin supplementation over different time periods until ageing modulates genotoxic parameters in mice. Mutagenesis 2020; 35:465-478. [PMID: 32720686 DOI: 10.1093/mutage/geaa017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/19/2020] [Indexed: 12/17/2022] Open
Abstract
The ageing process is a multifactorial phenomenon, associated with decreased physiological and cellular functions and an increased propensity for various degenerative diseases. Studies on melatonin (N-acetyl-5-methoxytryptamine), a potent antioxidant, are gaining attention since melatonin production declines with advancing age. Hence, the aim of this study was to evaluate the effects of chronic melatonin consumption on genotoxic and mutagenic parameters of old Swiss mice. Herein, 3-month-old Swiss albino male mice (n = 240) were divided into eight groups and subdivided into two experiments: first (three groups): natural ageing experiment; second (five groups): animals that started water or melatonin supplementation at different ages (3, 6, 12 and 18 months) until 21 months. After 21 months, the animals from the second experiment were euthanized to perform the comet assay, micronucleus test and western blot analysis. The results demonstrated that melatonin prolonged the life span of the animals. Relative to genomic instability, melatonin was effective in reducing DNA damage caused by ageing, presenting antigenotoxic and antimutagenic activities, independently of initiation age. The group receiving melatonin for 18 months had high levels of APE1 and OGG1 repair enzymes. Conclusively, melatonin presents an efficient antioxidant mechanism aiding modulating genetic and physiological alterations due to ageing.
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Affiliation(s)
- Adriani Paganini Damiani
- Translational Biomedicine Laboratory, Graduate Programme of Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil
| | - Giulia Strapazzon
- Translational Biomedicine Laboratory, Graduate Programme of Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil
| | - Thanielly Thais de Oliveira Sardinha
- Translational Biomedicine Laboratory, Graduate Programme of Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil
| | - Paula Rohr
- Translational Biomedicine Laboratory, Graduate Programme of Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil
| | - Goran Gajski
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia, Croatia
| | - Ricardo Aurino de Pinho
- Laboratory of Exercise Biochemistry in Health, Graduate Program in Health Sciences, School of Medicine, Pontifícia Universidade Católica do Paraná, R. Imac. Conceição - Curitiba - PR, Brazil
| | - Vanessa Moraes de Andrade
- Translational Biomedicine Laboratory, Graduate Programme of Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil
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Stillhart C, Vučićević K, Augustijns P, Basit AW, Batchelor H, Flanagan TR, Gesquiere I, Greupink R, Keszthelyi D, Koskinen M, Madla CM, Matthys C, Miljuš G, Mooij MG, Parrott N, Ungell AL, de Wildt SN, Orlu M, Klein S, Müllertz A. Impact of gastrointestinal physiology on drug absorption in special populations––An UNGAP review. Eur J Pharm Sci 2020; 147:105280. [DOI: 10.1016/j.ejps.2020.105280] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 02/10/2020] [Accepted: 02/24/2020] [Indexed: 02/07/2023]
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Begg DP, Sinclair AJ, Weisinger RS. Impaired Fluid Intake, but Not Sodium Appetite, in Aged Rats Is Mediated by the Cyclooxygenase-Prostaglandin E 2 Pathway. Front Aging Neurosci 2020; 12:19. [PMID: 32184716 PMCID: PMC7059018 DOI: 10.3389/fnagi.2020.00019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/20/2020] [Indexed: 01/22/2023] Open
Abstract
Aging results in decreased fluid intake following dehydration and other dipsogenic stimuli; similar reductions in sodium intake have also been observed with aging. Given that cyclooxygenase (COX)-derived prostanoids are elevated in aged rats in the midbrain and proinflammatory prostanoids are known to decrease fluid intake in dehydrated rats, the aim of this study was to determine if the reductions of fluid intake and sodium intake in aging are mediated by proinflammatory eicosanoid signaling. Therefore, we examined the effect of acute COX inhibition in adult (4 months-old) and aged (30 months-old) rats prior to ingestive behavior challenges. COX inhibition, using acetylsalicylic acid (ASA), increased fluid intake in aged, but not adult, rats in response to 24-h dehydration. ASA had no effect on salt intake following sodium depletion and ASA did not change basal fluid or sodium consumption in either age group. Hypothalamic COX-1 and -2, prostaglandin E synthase (PGES) and inducible nitric oxide synthase (iNOS) mRNA expression were all elevated in aged animals, leading to elevated PGE2 levels. COX expression in the hypothalamus was reduced by ASA treatment in rats of both ages resulting in reduced PGE2 levels in aged ASA treated animals. These data indicate that the reduced fluid intake that occurs in aging is due to increased COX-PGE2-mediated inflammation. However, the reduced sodium intake in these animals appears to occur via an alternate mechanism.
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Affiliation(s)
- Denovan P Begg
- School of Psychology, UNSW Sydney, Sydney, NSW, Australia
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Quirós Cognuck S, Reis WL, Silva MS, Almeida-Pereira G, Debarba LK, Zorro SV, Mecawi AS, Franci CR, Elias LLK, Antunes-Rodrigues J. Sex- and age-dependent differences in the hormone and drinking responses to water deprivation. Am J Physiol Regul Integr Comp Physiol 2020; 318:R567-R578. [PMID: 31967852 DOI: 10.1152/ajpregu.00303.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maintenance of the volume and osmolality of body fluids is important, and the adaptive responses recruited to protect against osmotic stress are crucial for survival. The objective of this work was to compare the responses that occur in aging male and female rats during water deprivation. For this purpose, groups of male and female Wistar rats aged 3 mo (adults) or 18 mo (old) were submitted to water deprivation (WD) for 48 h. The water and sodium (0.15 M NaCl) intake, plasma concentrations of oxytocin (OT), arginine vasopressin (AVP), corticosterone (CORT), atrial natriuretic peptide (ANP), and angiotensin II (ANG II) were determined in hydrated and water-deprived animals. In response to WD, old male and female rats drank less water and saline than adults, and both adult and old females drank more water and saline than respective males. Dehydrated old animals displayed lower ANG II plasma concentration and CORT response compared with the respective normohydrated rats. Dehydrated adult males had higher plasma ANP and AVP as well as lower CORT concentrations than dehydrated adult females. Moreover, plasma OT and CORT levels of old female rats were higher than those in the dehydrated old male rats. Relative expression of ANG II type 1 receptor mRNA was decreased in the subfornical organ of adult and old male rats as well as adult female rats in response to WD. In conclusion, the study elucidated the effect of sex and age on responses induced by WD, altering the degree of dehydration induced by 48 h of WD.
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Affiliation(s)
- Susana Quirós Cognuck
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Wagner L Reis
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Marcia S Silva
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Gislaine Almeida-Pereira
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas K Debarba
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Sandra V Zorro
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - André S Mecawi
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Celso R Franci
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
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7
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Begg DP. Disturbances of thirst and fluid balance associated with aging. Physiol Behav 2017; 178:28-34. [DOI: 10.1016/j.physbeh.2017.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/22/2017] [Accepted: 03/02/2017] [Indexed: 01/25/2023]
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8
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Damiani AP, Garcez ML, Letieli de Abreu L, Tavares TH, Rodrigues Boeck C, Moraes de Andrade V. A reduction in DNA damage in neural tissue and peripheral blood of old mice treated with caffeine. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:621-629. [PMID: 28524728 DOI: 10.1080/15287394.2017.1286901] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Studies on caffeine consumption have shown a negative correlation with development of some diseases with subsequent beneficial manifestations. Our aim was to assess the effects of caffeine on peripheral blood and neural tissue DNA in young adult and aged mice. Male Swiss mice (age 2-3 or 16-18 months, respectively) were treated with a caffeine solution (0.3 g/l) for 4 weeks, while controls received water. After the treatments, blood and hippocampal cells (for a comet assay) and femurs (for a micronucleus [MN] test) were collected. The comet assay of peripheral blood and hippocampal cells demonstrated no significant differences between caffeine-treated and control young adult mice in terms of DNA damage index (DI) and frequency. In contrast, when comparing young adult with aged animals, significant differences were observed in DNA damage in blood and hippocampal cells. The differences between aged animals (with or without caffeine) consisted of a significant decrease in DNA DI in the group that received caffeine. In the MN test, an increase in frequency of micronucleated polychromatic (PCE) erythrocytes was noted in aged animals that received water compared to young adult mice. In addition, comparing treated with control aged murine groups, a decrease in frequency of MN was found in PCE erythrocytes of caffeine-treated mice. Chronic caffeine consumption was neither genotoxic nor mutagenic at the dose tested; however, it appears that caffeine actually protected mice from genotoxicity and mutagenicity, consequences attributed to aging.
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Affiliation(s)
- Adriani Paganini Damiani
- a Laboratório de Biologia Celular e Molecular, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde , Universidade do Extremo Sul Catarinense - UNESC , Criciúma , SC , Brazil
| | - Michelle Lima Garcez
- a Laboratório de Biologia Celular e Molecular, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde , Universidade do Extremo Sul Catarinense - UNESC , Criciúma , SC , Brazil
| | - Larissa Letieli de Abreu
- a Laboratório de Biologia Celular e Molecular, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde , Universidade do Extremo Sul Catarinense - UNESC , Criciúma , SC , Brazil
| | - Taís Helena Tavares
- a Laboratório de Biologia Celular e Molecular, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde , Universidade do Extremo Sul Catarinense - UNESC , Criciúma , SC , Brazil
| | - Carina Rodrigues Boeck
- b Programa de Pós-graduação em Nanociências , Centro Universitário Franciscano - UNIFRA , Santa Maria , RS , Brazil
| | - Vanessa Moraes de Andrade
- a Laboratório de Biologia Celular e Molecular, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde , Universidade do Extremo Sul Catarinense - UNESC , Criciúma , SC , Brazil
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9
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Abstract
The present study investigated whether salt appetite in the elderly is impaired similar to thirst because of the commonality of their physiological substrates and whether alterations in salt appetite are related to mood. Elderly (65–85 years, n 30) and middle-aged (45–58 years, n 30) men and women were compared in two test sessions. Thirst, psychophysical ratings of taste solutions, dietary Na and energy intakes, seasoning with salt and sugar, number of salty and sweet snacks consumed, preferred amounts of salt in soup and sugar in tea, and an overall measure of salt appetite and its relationship with mood, nocturia and sleep were measured. Elderly participants were found to be less thirsty and respond less to thirst. In contrast, no impairment of salt appetite was found in them, and although they had a reduced dietary Na intake, it dissipated when corrected for their reduced dietary energy intake. Diet composition and Na intake were found to be similar in middle-aged and elderly participants, despite the lesser intake in elderly participants. There were no age-related differences in the intensity of taste or hedonic profile of Na, in salting habits, in tests of salting soup, or number of salty snacks consumed. No relationship of any measure of salt appetite with mood measured by the Positive and Negative Affect Schedule, frequency of nocturia, or sleep duration was observed. The age-related impairment of the physiology of mineralofluid regulation, while compromising thirst and fluid intake, spares salt appetite, suggesting that salt appetite in humans is not regulated physiologically. Intact salt appetite in the elderly might be utilised judiciously to prevent hyponatraemia, increase thirst and improve appetite.
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Thunhorst RL, Beltz T, Johnson AK. Age-related declines in thirst and salt appetite responses in male Fischer 344×Brown Norway rats. Physiol Behav 2014; 135:180-8. [PMID: 24952266 DOI: 10.1016/j.physbeh.2014.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/28/2014] [Accepted: 06/11/2014] [Indexed: 12/14/2022]
Abstract
The F344×BN strain is the first generational cross between Fischer 344 (F344) and Brown Norway (BN) rats. The F344×BN strain is widely used in aging studies as it is regarded as a model of "healthy" aging (Sprott, 1991). In the present work, male F344×BN rats aged 4mo (young, n=6) and 20mo (old, n=9) received a series of experimental challenges to body fluid homeostasis to determine their thirst and salt appetite responses. Corresponding urinary responses were measured in some of the studies. Following sodium depletion, old rats ingested less saline solution (0.3M NaCl) than young rats on a body weight basis, but both ages drank enough saline solution to completely repair the accrued sodium deficits. Following intracellular dehydration, old rats drank less water than young rats, again on a body weight basis, and were less able than young rats to drink amounts of water proportionate to the osmotic challenge. Compared with young rats, old rats drank less of both water and saline solution after combined food and fluid restriction, and also were refractory to the stimulatory effects of low doses of captopril on water drinking and sodium ingestion. Age differences in urinary water and sodium excretion could not account for the age differences in accumulated water and sodium balances. These results extend observations of diminished behavioral responses of aging animals to the F344×BN rat strain and support the idea that impairments in behavior contribute more to the waning ability of aging animals to respond to body fluid challenges than do declines in kidney function. In addition, the results suggest that behavioral defense of sodium homeostasis is less diminished with age in the F344×BN strain compared to other strains so far studied.
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Affiliation(s)
- Robert L Thunhorst
- Department of Psychology, University of Iowa, Iowa City, IA 52242-1407, United States; The Cardiovascular Center, University of Iowa, Iowa City, IA 52242-1407, United States.
| | - Terry Beltz
- Department of Psychology, University of Iowa, Iowa City, IA 52242-1407, United States
| | - Alan Kim Johnson
- Department of Psychology, University of Iowa, Iowa City, IA 52242-1407, United States; Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242-1407, United States; Department of Pharmacology, University of Iowa, Iowa City, IA 52242-1407, United States; The Cardiovascular Center, University of Iowa, Iowa City, IA 52242-1407, United States
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Thunhorst RL, Beltz TG, Johnson AK. Effects of aging on mineralocorticoid-induced salt appetite in rats. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1498-505. [PMID: 24133100 DOI: 10.1152/ajpregu.00349.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This work examined the effects of age on salt appetite measured in the form of daily saline (i.e., 0.3 M NaCl) drinking in response to administration of deoxycorticosterone acetate (DOCA; 5 mg/kg body wt) using young (4 mo), "middle-aged" adult (12 mo), and old (30 mo) male Brown Norway rats. Water and sodium intakes, excretions, and balances were determined daily. The salt appetite response was age dependent with "middle-aged" rats ingesting the most saline solution followed in order by young and then old rats. While old rats drank the least saline solution, the amounts of saline ingested still were copious and comprise an unambiguous demonstration of salt appetite in old rats. Middle-aged rats had the highest saline preference ratios of the groups under baseline conditions and throughout testing consistent with an increased avidity for sodium taste. There were age differences in renal handling of water and sodium that were consistent with a renal contribution to the greater saline intakes by middle-aged rats. There was evidence of impaired renal function in old rats, but this did not account for the reduced saline intakes of the oldest rats.
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13
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Thirst deficits in aged rats are reversed by dietary omega-3 fatty acid supplementation. Neurobiol Aging 2012; 33:2422-30. [DOI: 10.1016/j.neurobiolaging.2011.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 11/11/2011] [Accepted: 12/01/2011] [Indexed: 02/05/2023]
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14
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Thunhorst RL, Grobe CL, Beltz TG, Johnson AK. Effects of β-adrenergic receptor agonists on drinking and arterial blood pressure in young and old rats. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1001-8. [PMID: 21307363 DOI: 10.1152/ajpregu.00737.2010] [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
These experiments examined water-drinking and arterial blood pressure responses to β-adrenergic receptor activation in young (4 mo), "middle-aged" adult (12 mo), and old (29 mo) male rats of the Brown-Norway strain. We used isoproterenol to simultaneously activate β(1)- and β(2)-adrenergic receptors, salbutamol to selectively activate β(2)-adrenergic receptors, and the combination of isoproterenol and the β(2)-adrenergic receptor antagonist ICI 118,551 to stimulate only β(1)-adrenergic receptors. Animals received one of the drug treatments, and water drinking was measured for 90 min. About 1 wk later, animals received the same drug treatment for measurement of arterial blood pressure responses for 90 min. In some rats, levels of renin and aldosterone secretion in response to isoproterenol or salbutamol were measured in additional tests. Old and middle-aged rats drank significantly less after isoproterenol than did young rats and also had greater reductions in arterial blood pressure. Old and middle-aged rats drank significantly less after salbutamol than did young rats, although reductions in arterial blood pressure were equivalent across the ages. The β(2)-adrenergic antagonist ICI 118,551 abolished drinking after isoproterenol and prevented most of the observed hypotension. Renin secretion after isoproterenol and salbutamol was greater in young rats than in middle-aged rats, and wholly absent in old rats. Aldosterone secretion was reduced in old rats compared with young and middle-aged rats after treatment with isoproterenol, but not after treatment with salbutamol. In conclusion, there are age-related differences in β-adrenergic receptor-mediated drinking that can be explained only in part by age-related differences in renin secretion after β-adrenergic receptor stimulation.
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Affiliation(s)
- Robert L Thunhorst
- Dept. of Psychology, Univ. of Iowa, 11 Seashore Hall E., Iowa City, IA 52242-1407, USA.
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Thunhorst RL, Beltz TG, Johnson AK. Drinking and arterial blood pressure responses to ANG II in young and old rats. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1135-41. [PMID: 20739604 DOI: 10.1152/ajpregu.00360.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated water drinking and arterial blood pressure responses to intravenous infusions of ANG II in young (4 mo), middle-aged adult (12 mo), and old (29 mo) male Brown Norway rats. Infusions of ANG II began with arterial blood pressure either at control levels or at reduced levels following injection of the vasodilator minoxidil. Under control conditions, mean arterial pressure (MAP) in response to ANG II rose to the same level for all groups, and middle-aged and old rats drank as much or more water in response to ANG II compared with young rats, depending on whether intakes were analyzed using absolute or body weight-adjusted values. When arterial blood pressure first was reduced with minoxidil, MAP in response to ANG II stabilized at significantly lower levels compared with control conditions for all groups. Young rats drank significantly more water under reduced pressure conditions compared with control conditions, while middle-aged and old rats did not. Urine volume in response to ANG II was lower, while water balance was higher, under conditions of reduced pressure compared with control conditions. Baroreflex control of heart rate was substantially reduced in old rats compared with young and middle-aged animals. In summary, young rats appear to be more sensitive to the inhibitory effects of increased arterial blood pressure on water drinking than are older animals.
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Affiliation(s)
- Robert L Thunhorst
- Dept. of Psychology, Univ. of Iowa, 11 Seashore Hall E., Iowa City, IA 52242-1407, USA.
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16
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Thunhorst RL, Beltz TG, Johnson AK. Hypotension- and osmotically induced thirst in old Brown Norway rats. Am J Physiol Regul Integr Comp Physiol 2009; 297:R149-57. [PMID: 19420291 DOI: 10.1152/ajpregu.00118.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Compared to young cohorts, old rats drink less water in response to several thirst-inducing stimuli. In these experiments, we characterized water drinking in response to hypotension and cellular dehydration in young (4 mo), middle-aged adult (12 mo) and old (29-30 mo) male Brown Norway rats. We injected the vasodilator, minoxidil as an intravenous bolus in a range of doses (0-20 mg/kg), so that drinking responses could be compared at equivalent reductions of arterial pressure. Old rats had greatly diminished reflex tachycardia and became significantly more hypotensive after minoxidil compared with young and middle-aged rats. When compared at equivalent reductions of arterial pressure, old rats drank one-third as much as middle-aged rats, and one-fifth as much as young rats. In addition, there were age-related deficits in drinking in response to a range of administered loads of sodium (0.15-2 M NaCl, 2 ml/100 g body wt). Urinary excretion of water and sodium in response to the loads was equivalent across ages. Both middle-aged and old rats were less able than young rats to repair their water deficits after sodium loading, attributable almost entirely to their reduced drinking responses compared with young rats. Lastly, age-related declines in drinking appeared to be more severe in response to hypotension than in response to cellular dehydration.
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Affiliation(s)
- Robert L Thunhorst
- Dept. of Psychology, Univ. of Iowa, 11 Seashore Hall E., Iowa City, IA 52242-1407, USA.
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Elmadfa I, Meyer AL. Body Composition, Changing Physiological Functions and Nutrient Requirements of the Elderly. ANNALS OF NUTRITION AND METABOLISM 2008; 52 Suppl 1:2-5. [DOI: 10.1159/000115339] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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