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Rodrigues AG, Campos HO, Drummond LR, Marubayashi U, Coimbra CC. Effects of Increased Central Cholinergic Activity on the Metabolic Challenge Induced by Submaximal Exercise in Rats: Adrenomedullary Secretion Influences. Pharmacology 2021; 107:46-53. [PMID: 34788751 DOI: 10.1159/000519807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 09/09/2021] [Indexed: 11/19/2022]
Abstract
AIM The aim of this study was to assess the influence of adrenomedullary secretion on the plasma glucose, lactate, and free fatty acids (FFAs) during running exercise in rats submitted to intracerebroventricular (i.c.v.) injection of physostigmine (PHY). PHY i.c.v. was used to activate the central cholinergic system. METHODS Wistar rats were divided into sham-saline (sham-SAL), sham-PHY, adrenal medullectomy-SAL, and ADM-PHY groups. The plasma concentrations of glucose, lactate, and FFAs were determined immediately before and after i.c.v. injection of 20 μL of SAL or PHY at rest and during running exercise on a treadmill. RESULTS The i.c.v. injection of PHY at rest increased plasma glucose in the sham group, but not in the ADM group. An increase in plasma glucose, lactate, and FFAs mobilization from adipose tissue was observed during physical exercise in the sham-SAL group; however, the increase in plasma glucose was greater with i.c.v. PHY. Moreover, the hyperglycemia induced by exercise and PHY in the ADM group were blunted by ADM, whereas FFA mobilization was unaffected. CONCLUSION These results indicate that there is a dual metabolic control by which activation of the central cholinergic pathway increases plasma glucose but not FFA during rest and exercise, and that this hyperglycemic response is dependent on adrenomedullary secretion.
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Affiliation(s)
| | - Helton Oliveira Campos
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Department of Biological Sciences, Minas Gerais State University-Carangola Unit, Carangola, Brazil
| | - Lucas Rios Drummond
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Umeko Marubayashi
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Cândido Celso Coimbra
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
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2
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Cavalcanti-de-Albuquerque JP, Donato J. Rolling out physical exercise and energy homeostasis: Focus on hypothalamic circuitries. Front Neuroendocrinol 2021; 63:100944. [PMID: 34425188 DOI: 10.1016/j.yfrne.2021.100944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 01/17/2023]
Abstract
Energy balance is the fine regulation of energy expenditure and energy intake. Negative energy balance causes body weight loss, while positive energy balance promotes weight gain. Modern societies offer a maladapted way of life, where easy access to palatable foods and the lack of opportunities to perform physical activity are considered the roots of the obesity pandemic. Physical exercise increases energy expenditure and, consequently, is supposed to promote weight loss. Paradoxically, physical exercise acutely drives anorexigenic-like effects, but the mechanisms are still poorly understood. Using an evolutionary background, this review aims to highlight the potential involvement of the melanocortin system and other hypothalamic neural circuitries regulating energy balance during and after physical exercise. The physiological significance of these changes will be explored, and possible signalling agents will be addressed. The knowledge discussed here might be important for clarifying obesity aetiology as well as new therapeutic approaches for body weight loss.
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Affiliation(s)
| | - José Donato
- Department of Physiology and Biophysics, University of São Paulo, São Paulo 05508-900, Brazil.
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3
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Pedroso JAB, Dos Santos LBP, Furigo IC, Spagnol AR, Wasinski F, List EO, Kopchick JJ, Donato J. Deletion of growth hormone receptor in hypothalamic neurons affects the adaptation capacity to aerobic exercise. Peptides 2021; 135:170426. [PMID: 33069692 PMCID: PMC7855886 DOI: 10.1016/j.peptides.2020.170426] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/08/2020] [Accepted: 10/10/2020] [Indexed: 12/12/2022]
Abstract
The hypothalamus mediates important exercise-induced metabolic adaptations, possibly via hormonal signals. Hypothalamic leptin receptor (LepR)- and steroidogenic factor 1 (SF1)-expressing neurons are directly responsive to growth hormone (GH) and deletion of GH receptor (GHR) in these cells impairs neuroendocrine responses during situations of metabolic stress. In the present study, we determined whether GHR ablation in LepR- or SF1-expressing cells modifies acute and chronic metabolic adaptations to exercise. Male mice carrying deletion of GHR in LepR- or SF1-expressing cells were submitted to 8 weeks of treadmill running training. Changes in aerobic performance and exercise-induced metabolic adaptations were determined. Mice carrying GHR deletion in LepR cells showed increased aerobic performance after 8 weeks of treadmill training, whereas GHR ablation in SF1 cells prevented improvement in running capacity. Trained mice carrying GHR ablation in SF1 cells exhibited increased fat mass and reduced cross-sectional area of the gastrocnemius muscle. In contrast, deletion of GHR in LepR cells reduced fat mass and increased gastrocnemius muscle hypertrophy, energy expenditure and voluntary locomotor activity in trained mice. Although glucose tolerance was not significantly affected by targeted deletions, glycemia before and immediately after maximum running tests was altered by GHR ablation. In conclusion, GHR signaling in hypothalamic neurons regulates the adaptation capacity to aerobic exercise in a cell-specific manner. These findings suggest that GH may represent a hormonal cue that informs specific hypothalamic neurons to produce exercise-induced acute and chronic metabolic adaptations.
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Affiliation(s)
- João A B Pedroso
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, 05508-000, Brazil
| | - Lucas B P Dos Santos
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, 05508-000, Brazil
| | - Isadora C Furigo
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, 05508-000, Brazil
| | - Alexandre R Spagnol
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Farmacologia, Sao Paulo, 05508-000, Brazil
| | - Frederick Wasinski
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, 05508-000, Brazil
| | - Edward O List
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701, USA
| | - John J Kopchick
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701, USA
| | - Jose Donato
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, 05508-000, Brazil.
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4
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Rabelo PCR, Cordeiro LMS, Aquino NSS, Fonseca BBB, Coimbra CC, Wanner SP, Szawka RE, Soares DD. Rats with higher intrinsic exercise capacities exhibit greater preoptic dopamine levels and greater mechanical and thermoregulatory efficiencies while running. J Appl Physiol (1985) 2019; 126:393-402. [DOI: 10.1152/japplphysiol.00092.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigated whether intrinsic exercise capacity affects the changes in thermoregulation, metabolism and central dopamine (DA) induced by treadmill running. Male Wistar rats were subjected to three incremental exercises and ranked as low-performance (LP), standard-performance (SP), and high-performance (HP) rats. In the first experiment, abdominal (TABD) and tail (TTAIL) temperatures were registered in these rats during submaximal exercise (SE) at 60% of maximal speed. Immediately after SE, rats were decapitated and concentrations of DA and 3,4-dihydroxyphenylacetic acid (DOPAC) were determined in the preoptic area (POA). In the second experiment, oxygen consumption was measured and mechanical efficiency (ME) was calculated in these rats during an incremental exercise. HP rats ran for longer periods and were fatigued with higher TABD values, with no difference in TTAIL. Nevertheless, thermoregulatory efficiency was higher in HP rats, compared with other groups. DA and DOPAC concentrations in the POA were increased by SE, with higher levels in HP compared with LP and SP rats. V̇o2 also differed between groups, with HP rats displaying a lower consumption throughout the incremental exercise but a higher V̇o2 at fatigue. ME, in turn, was consistently higher in HP than in LP and SP rats. Thus, our results show that HP rats have greater TABD values at fatigue, which seem to be related to a higher dopaminergic activity in the POA. Moreover, HP rats exhibited a greater thermoregulatory efficiency during exercise, which can be attributed to a lower V̇o2, but not to changes in tail heat loss mechanisms. NEW & NOTEWORTHY Our findings reveal that rats with higher intrinsic exercise capacities have greater thermoregulatory efficiencies and increased dopaminergic activity in the preoptic area, a key brain area in thermoregulatory control, while exercising. Moreover, higher intrinsic exercise capacities are associated with decreased oxygen consumption for a given exercise intensity, which indicates greater mechanical efficiencies. Collectively, these findings help to advance our knowledge of why some rats of a given strain can exercise for longer periods than others.
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Affiliation(s)
- Patrícia C. R. Rabelo
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Letícia M. S. Cordeiro
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Laboratório de Imunometabolismo, Departamento de Nutrição, Escola de Enfermagem, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Nayara S. S. Aquino
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Bruno B. B. Fonseca
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Cândido C. Coimbra
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Samuel P. Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Raphael E. Szawka
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Danusa D. Soares
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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5
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Wanner SP, Prímola-Gomes TN, Pires W, Guimarães JB, Hudson ASR, Kunstetter AC, Fonseca CG, Drummond LR, Damasceno WC, Teixeira-Coelho F. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology. Temperature (Austin) 2015; 2:457-75. [PMID: 27227066 PMCID: PMC4844073 DOI: 10.1080/23328940.2015.1119615] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/02/2015] [Accepted: 11/02/2015] [Indexed: 01/18/2023] Open
Abstract
Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.
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Affiliation(s)
- Samuel Penna Wanner
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Thales Nicolau Prímola-Gomes
- Laboratório de Biologia do Exercício; Departamento de Educação Física; Universidade Federal de Viçosa ; Viçosa (MG), Brazil
| | - Washington Pires
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Juliana Bohnen Guimarães
- Laboratório de Fisiologia do Exercício; Universidade Estadual de Minas Gerais ; Ibirité (MG), Brazil
| | - Alexandre Sérvulo Ribeiro Hudson
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Ana Cançado Kunstetter
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Cletiana Gonçalves Fonseca
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Lucas Rios Drummond
- Laboratório de Biologia do Exercício; Departamento de Educação Física; Universidade Federal de Viçosa ; Viçosa (MG), Brazil
| | - William Coutinho Damasceno
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais ; Belo Horizonte (MG), Brazil
| | - Francisco Teixeira-Coelho
- Laboratório de Fisiologia do Exercício; Departamento de Educação Física; Universidade Federal de Minas Gerais; Belo Horizonte (MG), Brazil; Centro de Formação de Professores; Universidade Federal do Recôncavo da Bahia; Amargosa (BA), Brazil
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6
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Zhou P, Zhu Q, Liu M, Li J, Wang Y, Zhang C, Hua T. Muscarinic acetylcholine receptor in cerebellar cortex participates in acetylcholine-mediated blood depressor response in rats. Neurosci Lett 2015; 593:129-33. [PMID: 25797185 DOI: 10.1016/j.neulet.2015.03.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/07/2015] [Accepted: 03/18/2015] [Indexed: 11/30/2022]
Abstract
Our previous investigations have revealed that cerebellar cholinergic innervation is involved in cardiovascular regulation. This study was performed to examine the effects of the muscarinic cholinergic receptor (mAChR) in the cerebellar cortex on blood pressure (BP) modulation in rats. Acetylcholine (ACh, 100mM), nonselective mAChR agonist (oxotremorine M; Oxo-M, 10, 30 and 100mM) and 100mM ACh mixed with nonselective mAChR antagonist atropine (1, 3 and 10mM) were microinjected into the cerebellar cortex of anesthetized rats. Mean arterial pressure (MAP), maximal decreased MAP (MDMAP), and reaction time (duration required for BP to return to basal values) were measured and analyzed. The results showed that Oxo-M dose-dependently decreased MAP, increased MDMAP, and prolonged reaction time, which displayed a homodromous effect of ACh-mediated blood depressor response; meanwhile, atropine concentration-dependently blocked the effect of ACh on the BP regulation. In conclusion, the present study showed for the first time that mAChRs in cerebellar cortex could modulate somatic BP by participation in ACh-mediated depressor response.
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Affiliation(s)
- Peiling Zhou
- School of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Qingfeng Zhu
- School of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Ming Liu
- School of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Jing Li
- School of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Yong Wang
- School of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Changzheng Zhang
- School of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China.
| | - Tianmiao Hua
- School of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
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7
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Rabelo P, Almeida T, Guimarães J, Barcellos L, Cordeiro L, Moraes M, Coimbra C, Szawka R, Soares D. Intrinsic exercise capacity is related to differential monoaminergic activity in the rat forebrain. Brain Res Bull 2015; 112:7-13. [DOI: 10.1016/j.brainresbull.2015.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 01/03/2015] [Accepted: 01/13/2015] [Indexed: 12/29/2022]
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8
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Damasceno WC, Pires W, Lima MRM, Lima NRV, Wanner SP. The dynamics of physical exercise-induced increases in thalamic and abdominal temperatures are modified by central cholinergic stimulation. Neurosci Lett 2015; 590:193-8. [PMID: 25655022 DOI: 10.1016/j.neulet.2015.01.082] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/14/2015] [Accepted: 01/30/2015] [Indexed: 10/24/2022]
Abstract
Evidence has shown that brain and abdominal (T abd) temperatures are regulated by distinct physiological mechanisms. Thus, the present study examined whether central cholinergic stimulation would change the dynamics of exercise-induced increases in T abd and thalamic temperature (T thal), an index of brain temperature. Adult male Wistar rats were used in all of the experiments. Two guide cannulae were implanted in the rats, one in the thalamus and the other in the right lateral cerebral ventricle, to measure T thal and to centrally inject a cholinergic agonist, respectively. Then, a temperature sensor was implanted in the abdominal cavity. On the day of the experiments, the rats received an intracerebroventricular injection of 2 μL of 10(-2)M physostigmine (Phy) or a vehicle solution (Veh) and were subjected to treadmill running until volitional fatigue occurred. T thal was measured using a thermistor connected to a multimeter, and T abd was recorded by telemetry. Phy injection delayed the exercise-induced increases in T thal (37.6 ± 0.2°C Phy vs 38.7 ± 0.1°C Veh at the 10th min of exercise) and in T abd. Despite the delayed hyperthermia, Phy did not change the rats' physical performance. In addition, the more rapid exercise-induced increase in T thal relative to Tabd in the rats treated with Veh was abolished by Phy. Collectively, our data indicate that central cholinergic stimulation affects the dynamics of exercise-induced increases in T thal and T abd. These results also provide evidence of the involvement of cholinoceptors in the modulation of brain heat loss during physical exercise.
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Affiliation(s)
- William Coutinho Damasceno
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Washington Pires
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Milene Rodrigues Malheiros Lima
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nilo Resende Viana Lima
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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9
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The time of day differently influences fatigue and locomotor activity: is body temperature a key factor? Physiol Behav 2014; 140:8-14. [PMID: 25479573 DOI: 10.1016/j.physbeh.2014.11.069] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 12/23/2022]
Abstract
The aim of this study was to verify the possible interactions between exercise capacity and spontaneous locomotor activity (SLA) during the oscillation of core body temperature (Tb) that occurs during the light/dark cycle. Wistar rats (n=11) were kept at an animal facility under a light/dark cycle of 14/10h at an ambient temperature of 23°C and water and food ad libitum. Initially, in order to characterize the daily oscillation in SLA and Tb of the rats, these parameters were continuously recorded for 24h using an implantable telemetric sensor (G2 E-Mitter). The animals were randomly assigned to two progressive exercise test protocols until fatigue during the beginning of light and dark-phases. Fatigue was defined as the moment rats could not keep pace with the treadmill. We assessed the time to fatigue, workload and Tb changes induced by exercise. Each test was separated by 3days. Our results showed that exercise capacity and heat storage were higher during the light-phase (p<0.05). In contrast, we observed that both SLA and Tb were higher during the dark-phase (p<0.01). Notably, the correlation analysis between the amount of SLA and the running capacity observed at each phase of the daily cycle revealed that, regardless of the time of the day, both types of locomotor physical activity have an important inherent component (r=0.864 and r=0.784, respectively, p<0.01) without a direct relationship between them. This finding provides further support for the existence of specific control mechanisms for each type of physical activity. In conclusion, our data indicate that the relationship between the body temperature and different types of physical activity might be affected by the light/dark cycle. These results mean that, although exercise performance and spontaneous locomotor activity are not directly associated, both are strongly influenced by daily cycles of light and dark.
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10
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Fonseca CG, Pires W, Lima MRM, Guimarães JB, Lima NRV, Wanner SP. Hypothalamic temperature of rats subjected to treadmill running in a cold environment. PLoS One 2014; 9:e111501. [PMID: 25365556 PMCID: PMC4218756 DOI: 10.1371/journal.pone.0111501] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 09/30/2014] [Indexed: 12/02/2022] Open
Abstract
Different strategies for cooling the body prior to or during physical exercise have been shown to improve prolonged performance. Because of ethical and methodological issues, no studies conducted in humans have evaluated the changes in brain temperature promoted by cooling strategies. Therefore, our first aim sought to measure the hypothalamic temperature (Thyp) of rats subjected to treadmill running in a cold environment. Moreover, evidence suggests that Thyp and abdominal temperature (Tabd) are regulated by different physiological mechanisms. Thus, this study also investigated the dynamics of exercise-induced changes in Thyp and Tabd at two ambient temperatures: 25°C (temperate environment) and 12°C (cold). Adult male Wistar rats were used in these experiments. The rats were implanted with a guide cannula in the hypothalamus and a temperature sensor in the abdominal cavity. After recovery from this surgery, the rats were familiarized with running on a treadmill and were then subjected to the two experimental trials: constant-speed running (20 m/min) at 12°C and 25°C. Both Thyp and Tabd increased during exercise at 25°C. In contrast, Thyp and Tabd remained unchanged during fatiguing exercise at 12°C. The temperature differential (i.e., Thyp - Tabd) increased during the initial min of running at 25°C and thereafter decreased toward pre-exercise values. Interestingly, external cooling prevented this early increase in the temperature differential from the 2nd to the 8th min of running. In addition, the time until volitional fatigue was higher during the constant exercise at 12°C compared with 25°C. Together, our results indicate that Thyp and Tabd are regulated by different mechanisms in running rats and that external cooling affected the relationship between both temperature indexes observed during exercise without environmental thermal stress. Our data also suggest that attenuated hypothalamic hyperthermia may contribute to improved performance in cold environments.
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Affiliation(s)
- Cletiana Gonçalves Fonseca
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Washington Pires
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Milene Rodrigues Malheiros Lima
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Juliana Bohnen Guimarães
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
- Instituto Superior de Educação Anísio Teixeira, Universidade Estadual de Minas Gerais, Ibirité (MG), Brazil
| | - Nilo Resende Viana Lima
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
- * E-mail:
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11
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Chan O, Sherwin R. Influence of VMH fuel sensing on hypoglycemic responses. Trends Endocrinol Metab 2013; 24:616-24. [PMID: 24063974 PMCID: PMC3909530 DOI: 10.1016/j.tem.2013.08.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/20/2013] [Accepted: 08/27/2013] [Indexed: 12/12/2022]
Abstract
Hypoglycemia produces complex neural and hormonal responses that restore glucose levels to normal. Glucose, metabolic substrates and their transporters, neuropeptides and neurotransmitters alter the firing rate of glucose-sensing neurons in the ventromedial hypothalamus (VMH); these monitor energy status and regulate the release of neurotransmitters that instigate a suitable counter-regulatory response. Under normal physiological conditions, these mechanisms maintain blood glucose concentrations within narrow margins. However, antecedent hypoglycemia and diabetes can lead to adaptations within the brain that impair counter-regulatory responses. Clearly, the mechanisms employed to detect and regulate the response to hypoglycemia, and the pathophysiology of defective counter-regulation in diabetes, are complex and need to be elucidated to permit the development of therapies that prevent or reduce the risk of hypoglycemia.
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Affiliation(s)
- Owen Chan
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
| | - Robert Sherwin
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
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Kucine N, Levine RL. JAK Inhibitors and other Novel Agents in Myeloproliferative Neoplasms: Are We Hitting the Target? Ther Adv Hematol 2013; 2:203-11. [PMID: 23556090 DOI: 10.1177/2040620711410095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The discovery of somatic mutations in the JAK-STAT signaling pathway was a major breakthrough in our understanding of the molecular pathogenesis of the myeloproliferative neoplasms (MPNs) polycythemia vera, essential thrombocytosis, and primary myelofibrosis. This finding led to the development of small molecule inhibitors targeting Janus kinase (JAK) 2 and other JAK family members. Currently, there are a number of research and clinical trials ongoing with JAK inhibitors. While the appeal of inhibiting JAK2 is clear, studies to date suggest that JAK2 inhibitor monotherapy might not be sufficient to cause reductions in disease allele burden in MPN patients. There is compelling evidence that JAK inhibitors are improving symptoms and therefore quality of life for patients. It will be important to investigate the efficacy of JAK inhibitors in preclinical and clinical studies to better understand their effects, while at the same time pursuing alternative therapies which might offer benefit to MPN patients alone and in combination with JAK inhibitors.
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Affiliation(s)
- Nicole Kucine
- Human Oncology and Pathogenesis Program and Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, New York, USA
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13
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Galetta F, Carpi A, Abraham N, Guidotti E, Russo MA, Camici M, Antonelli A, Franzoni F, Santoro G. Age related cardiovascular dysfunction and effects of physical activity. Front Biosci (Elite Ed) 2012; 4:2617-37. [PMID: 22652665 DOI: 10.2741/e570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The aim of the present article is to review the principal pathogenetic pathways of age-related cardiovascular changes and the positive effects of physical activity on these changes as well as on related cardiovascular dysfunction. The ageing mechanisms reviewed have been grouped into reduced tolerance of oxidative stress, loss of cardiac stem cells, cardiovascular remodeling and impairment of neurovegetative control. New pathogenetic conditions and their tests are described (sirtuines, telomere length, heart rate variability). Age related cardiovascular changes predispose the individual to arterial hypertension, heart failure and arrythmia. A broad spectrum of tests are available to indentify and monitor the emerging cardiovascular dysfunction. Physical activity influences all age related cardiovascular mechanisms, improves cardiovascular function and even, at moderate intensity can reduce mortality and heart attack risk. It is likely that the translation of laboratory studies to humans will improve understanding and stimulate the use of physical activity to benefit cardiovascular patients.
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Affiliation(s)
- Fabio Galetta
- Department of Internal Medicine, University of Pisa, Pisa, Italy
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14
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Guimarães JB, Wanner SP, Machado SC, Lima MRM, Cordeiro LMS, Pires W, La Guardia RB, Silami-Garcia E, Rodrigues LOC, Lima NRV. Fatigue is mediated by cholinoceptors within the ventromedial hypothalamus independent of changes in core temperature. Scand J Med Sci Sports 2011; 23:46-56. [DOI: 10.1111/j.1600-0838.2011.01350.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Muscarinic receptors within the ventromedial hypothalamic nuclei modulate metabolic rate during physical exercise. Neurosci Lett 2011; 488:210-4. [DOI: 10.1016/j.neulet.2010.11.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 11/01/2010] [Accepted: 11/11/2010] [Indexed: 11/23/2022]
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16
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Sinoaortic denervation prevents enhanced heat loss induced by central cholinergic stimulation during physical exercise. Brain Res 2010; 1366:120-8. [DOI: 10.1016/j.brainres.2010.09.110] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 11/20/2022]
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