1
|
McIlvain G, Magoon EM, Clements RG, Merritt A, Hiscox LV, Schwarb H, Johnson CL. Acute effects of high-intensity exercise on brain mechanical properties and cognitive function. Brain Imaging Behav 2024:10.1007/s11682-024-00873-y. [PMID: 38538876 DOI: 10.1007/s11682-024-00873-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 04/26/2024]
Abstract
Previous studies have shown that engagement in even a single session of exercise can improve cognitive performance in the short term. However, the underlying physiological mechanisms contributing to this effect are still being studied. Recently, with improvements to advanced quantitative neuroimaging techniques, brain tissue mechanical properties can be sensitively and noninvasively measured with magnetic resonance elastography (MRE) and regional brain mechanical properties have been shown to reflect individual cognitive performance. Here we assess brain mechanical properties before and immediately after engagement in a high-intensity interval training (HIIT) regimen, as well as one-hour post-exercise. We find that immediately after exercise, subjects in the HIIT group had an average global brain stiffness decrease of 4.2% (p < 0.001), and an average brain damping ratio increase of 3.1% (p = 0.002). In contrast, control participants who did not engage in exercise showed no significant change over time in either stiffness or damping ratio. Changes in brain mechanical properties with exercise appeared to be regionally dependent, with the hippocampus decreasing in stiffness by 10.4%. We also found that one-hour after exercise, brain mechanical properties returned to initial baseline values. The magnitude of changes to brain mechanical properties also correlated with improvements in reaction time on executive control tasks (Eriksen Flanker and Stroop) with exercise. Understanding the neural changes that arise in response to exercise may inform potential mechanisms behind improvements to cognitive performance with acute exercise.
Collapse
Affiliation(s)
- Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Emily M Magoon
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Rebecca G Clements
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Alexis Merritt
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Lucy V Hiscox
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Hillary Schwarb
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA.
| |
Collapse
|
2
|
Andrade MT, Barbosa NHS, Souza-Junior RCS, Fonseca CG, Damasceno WC, Regina-Oliveira K, Drummond LR, Bittencourt MA, Kunstetter AC, Andrade PVR, Hudson ASR, Paula PH, Teixeira-Coelho F, Coimbra CC, Pires W, Wanner SP. Determinants of body core temperatures at fatigue in rats subjected to incremental-speed exercise: The prominent roles of ambient temperature, distance traveled, initial core temperature, and measurement site. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023; 67:761-775. [PMID: 36935415 DOI: 10.1007/s00484-023-02453-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 02/06/2023] [Accepted: 03/08/2023] [Indexed: 05/09/2023]
Abstract
Understanding the factors that underlie the physical exercise-induced increase in body core temperature (TCORE) is essential to developing strategies to counteract hyperthermic fatigue and reduce the risk of exertional heatstroke. This study analyzed the contribution of six factors to TCORE attained at fatigue in Wistar rats (n = 218) subjected to incremental-speed treadmill running: ambient temperature (TAMB), distance traveled, initial TCORE, body mass, measurement site, and heat loss index (HLI). First, we ran hierarchical multiple linear regression analyses with data from different studies conducted in our laboratory (n = 353 recordings). We observed that TAMB, distance traveled, initial TCORE, and measurement site were the variables with predictive power. Next, regression analyses were conducted with data for each of the following TCORE indices: abdominal (TABD), brain cortex (TBRAIN), or colonic (TCOL) temperature. Our findings indicated that TAMB, distance traveled (i.e., an exercise performance-related variable), initial TCORE, and HLI predicted the three TCORE indices at fatigue. Most intriguingly, HLI was inversely related to TABD and TBRAIN but positively associated with TCOL. Lastly, we compared the temperature values at fatigue among these TCORE indices, and the following descendent order was noticed - TCOL, TABD, and TBRAIN - irrespective of TAMB where experiments were conducted. In conclusion, TCORE in rats exercised to fatigue depends primarily on environmental conditions, performance, pre-exercise TCORE, and measurement site. Moreover, the influence of cutaneous heat loss on TCOL is qualitatively different from the influence on TABD and TBRAIN, and the temperature values at fatigue are not homogenous within the body core.
Collapse
Affiliation(s)
- Marcelo T Andrade
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Nicolas H S Barbosa
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Roberto C S Souza-Junior
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Cletiana G Fonseca
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - William C Damasceno
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Kássya Regina-Oliveira
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Lucas R Drummond
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
- Department of Physical Education, Universidade do Estado de Minas Gerais, Unidade Divinópolis, MG, Divinópolis, Brazil
| | - Myla A Bittencourt
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Ana C Kunstetter
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Pedro V R Andrade
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Alexandre S R Hudson
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Pedro H Paula
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
| | - Francisco Teixeira-Coelho
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
- Department of Sport Sciences, Institute of Health Sciences, Universidade Federal do Triângulo Mineiro, MG, Uberaba, Brazil
| | - Cândido C Coimbra
- Laboratory of Endocrinology and Metabolism, Institute of Biological Sciences, 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, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil
- Physical Activity Laboratory, School of Physical Education, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Samuel P Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, MG, 31.270-901, Belo Horizonte, Brazil.
| |
Collapse
|
3
|
Reis TO, Noronha SISR, Lima PMA, De Abreu ARR, Mesquita LBT, Ferreira FI, Silva FC, Chianca-Jr DA, De Menezes RC. Abdominal TRPV1 channel desensitization enhances stress-induced hyperthermia during social stress in rats. Auton Neurosci 2023; 246:103073. [PMID: 36736078 DOI: 10.1016/j.autneu.2023.103073] [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: 05/18/2022] [Revised: 12/22/2022] [Accepted: 01/24/2023] [Indexed: 01/28/2023]
Abstract
AIMS In rats, stress-induced hyperthermia caused by social interaction depends on brown adipose tissue (BAT) thermogenesis and peripheral vasoconstriction. However, the peripheral mechanisms responsible for regulating the level of hyperthermia during social stress are still unknown. The transient receptor potential vanilloid 1 (TRPV1) subfamily, expressed in sensory and visceral neurons, can serve as a thermoreceptor. Here, we tested the hypothesis that the abdominal TRPV1 is essential in regulating stress-induced hyperthermia during social stress. MAIN METHODS Male Wistar rats received an intraperitoneal injection of Resiniferatoxin (RTX) - an ultra-potent capsaicin analog, (i.e., to desensitize the TRPV1 channels) or vehicle. Seven days later, we evaluated the effects of abdominal TRPV1 channels desensitization on core body temperature (CBT), brown adipose tissue (BAT) temperature, tail skin temperature, and heart rate (HR) of rats subjected to a social stress protocol. KEY FINDINGS We found abdominal TRPV1 desensitization increased CBT and BAT temperature but did not change tail skin temperature and HR during rest. However, under social stress, we found that abdominal TRPV1 desensitization heightened the increase in CBT and BAT caused by stress. Also, it abolished the increase in tail skin temperature that occurs during and after social stress. TRPV1 desensitization also delayed the HR recovery after the exposure to the social stress. SIGNIFICANCE These results show that abdominal TRPV1 channels desensitization heightens stress-induced hyperthermia, causing heat dissipation during and after social stress, enabling optimal thermal control during social encounters.
Collapse
Affiliation(s)
- T O Reis
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - S I S R Noronha
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - P M A Lima
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - A R R De Abreu
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - L B T Mesquita
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - F I Ferreira
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil
| | - F C Silva
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil..
| | - D A Chianca-Jr
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil..
| | - R C De Menezes
- Department of Biological Science, Laboratory of Cardiovascular Physiology, University of Ouro Preto, Ouro Preto, MG 35400-000, Brazil..
| |
Collapse
|
4
|
Andrade MT, Goulart KNO, Barbosa NHS, Soares DD, Andrade AGP, Gonçalves DAP, Mendes TT, Coimbra CC, Wanner SP. Core body temperatures of rats subjected to treadmill exercise to fatigue or exhaustion: The journal Temperature toolbox. Temperature (Austin) 2022; 10:287-312. [PMID: 37554383 PMCID: PMC10405761 DOI: 10.1080/23328940.2022.2115274] [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: 06/29/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 10/14/2022] Open
Abstract
This study systematically reviewed the literature reporting the changes in rats' core body temperature (TCORE) induced by either incremental- or constant-speed running to fatigue or exhaustion. In addition, multiple linear regression analyses were used to determine the factors contributing to the TCORE values attained when exercise was interrupted. Four databases (EMBASE, PubMed, SPORTDiscus, and Web of Science) were searched in October 2021, and this search was updated in August 2022. Seventy-two studies (n = 1,538 rats) were included in the systematic review. These studies described heterogeneous experimental conditions; for example, the ambient temperature ranged from 5 to 40°C. The rats quit exercising with TCORE values varying more than 8°C among studies, with the lowest and highest values corresponding to 34.9°C and 43.4°C, respectively. Multiple linear regression analyses indicated that the ambient temperature (p < 0.001), initial TCORE (p < 0.001), distance traveled (p < 0.001; only incremental exercises), and running speed and duration (p < 0.001; only constant exercises) contributed significantly to explaining the variance in the TCORE at the end of the exercise. In conclusion, rats subjected to treadmill running exhibit heterogeneous TCORE when fatigued or exhausted. Moreover, it is not possible to determine a narrow range of TCORE associated with exercise cessation in hyperthermic rats. Ambient temperature, initial TCORE, and physical performance-related variables are the best predictors of TCORE at fatigue or exhaustion. From a broader perspective, this systematic review provides relevant information for selecting appropriate methods in future studies designed to investigate exercise thermoregulation in rats.
Collapse
Affiliation(s)
- Marcelo T. Andrade
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Karine N. O. Goulart
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Nicolas H. S. Barbosa
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Danusa D. Soares
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - André G. P. Andrade
- Biomechanics Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Dawit A. P. Gonçalves
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Thiago T. Mendes
- Department of Physical Education, Faculty of Education, Universidade Federal da Bahia, Salvador, Brazil
| | - Cândido C. Coimbra
- Laboratory of Endocrinology and Metabolism, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Samuel P. Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
5
|
Reliability of physical performance and thermoregulatory parameters in rats subjected to incremental treadmill running. J Therm Biol 2022; 108:103270. [DOI: 10.1016/j.jtherbio.2022.103270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 04/02/2022] [Accepted: 05/27/2022] [Indexed: 11/24/2022]
|
6
|
Teixeira-Coelho F, Fonseca CG, Vaz FF, Barbosa NHS, Soares DD, Pires W, Wanner SP. Physical exercise-induced thermoregulatory responses in trained rats: Effects of manipulating the duration and intensity of aerobic training sessions. J Therm Biol 2021; 97:102878. [PMID: 33863441 DOI: 10.1016/j.jtherbio.2021.102878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/05/2021] [Accepted: 02/13/2021] [Indexed: 11/25/2022]
Abstract
This study investigated the effects of increasing the intensity and/or duration of aerobic training sessions on thermoregulatory responses in rats subjected to exercises in temperate and warm environments. Thirty-two adult male Wistar rats were divided into four groups: a control (CON) group and three groups that were subjected to an 8-week aerobic training, during which the physical overload was achieved by predominantly increasing the exercise intensity (INT), duration (DUR) or by increasing both in an alternate manner (ID). During the last week of training, the rats received an abdominal sensor implant to measure their core body temperature (TCORE) by telemetry. After the training protocol, the 32 rats were subjected to incremental speed-exercises in temperate (23 °C) and warm (32 °C) environments. The rats had their TCORE recorded while running on a treadmill, and the ratio between the increase in TCORE and distance traveled was calculated to estimate thermoregulatory efficiency. All training protocols increased the rats' thermoregulatory efficiency during the incremental-speed exercise at 23 °C; i.e., trained rats attained faster running speeds but unchanged TCORE at fatigue compared to CON rats. However, none of the load components of training sessions - intensity or duration - was more effective than the other in improving this efficiency. At 32 °C, the aerobic training protocols did not influence the exercise-induced thermoregulatory responses. Our data indicate that different progressions in aerobic training performed at temperate conditions improved thermoregulatory efficiency during incremental exercise in the same environment; this training-induced adaptation was not clearly observed when running in warmer conditions.
Collapse
Affiliation(s)
- Francisco Teixeira-Coelho
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Department of Sport Sciences, Institute of Health Science. Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brazil
| | - Cletiana Gonçalves Fonseca
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Filipe Ferreira Vaz
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nicolas Henrique Santos Barbosa
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Danusa Dias Soares
- 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; Physical Activity Laboratory, School of Physical Education, Universidade Federal de Ouro Preto, Ouro Preto, 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.
| |
Collapse
|
7
|
Sela Y, Hoekstra MM, Franken P. Sub-minute prediction of brain temperature based on sleep-wake state in the mouse. eLife 2021; 10:62073. [PMID: 33683202 PMCID: PMC7939547 DOI: 10.7554/elife.62073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Although brain temperature has neurobiological and clinical importance, it remains unclear which factors contribute to its daily dynamics and to what extent. Using a statistical approach, we previously demonstrated that hourly brain temperature values co-varied strongly with time spent awake (Hoekstra et al., 2019). Here we develop and make available a mathematical tool to simulate and predict cortical temperature in mice based on a 4-s sleep-wake sequence. Our model estimated cortical temperature with remarkable precision and accounted for 91% of the variance based on three factors: sleep-wake sequence, time-of-day ('circadian'), and a novel 'prior wake prevalence' factor, contributing with 74%, 9%, and 43%, respectively (including shared variance). We applied these optimized parameters to an independent cohort of mice and predicted cortical temperature with similar accuracy. This model confirms the profound influence of sleep-wake state on brain temperature, and can be harnessed to differentiate between thermoregulatory and sleep-wake-driven effects in experiments affecting both.
Collapse
Affiliation(s)
- Yaniv Sela
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Marieke Mb Hoekstra
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
8
|
Gibbons TD, Ainslie PN, Thomas KN, Wilson LC, Akerman AP, Donnelly J, Campbell HA, Cotter JD. Influence of the mode of heating on cerebral blood flow, non-invasive intracranial pressure and thermal tolerance in humans. J Physiol 2021; 599:1977-1996. [PMID: 33586133 DOI: 10.1113/jp280970] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/01/2021] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS The human brain is particularly vulnerable to heat stress; this manifests as impaired cognition, orthostatic tolerance, work capacity and eventually, brain death. The brain's limitation in the heat is often ascribed to inadequate cerebral blood flow (CBF), but elevated intracranial pressure is commonly observed in mammalian models of heat stroke and can on its own cause functional impairment. The CBF response to incremental heat strain was dependent on the mode of heating, decreasing by 30% when exposed passively to hot, humid air (sauna), while remaining unchanged or increasing with passive hot-water immersion (spa) and exercising in a hot environment. Non-invasive intracranial pressure estimates (nICP) were increased universally by 18% at volitional thermal tolerance across all modes of heat stress, and therefore may play a contributing role in eliciting thermal tolerance. The sauna, more so than the spa or exercise, poses a greater challenge to the brain under mild to severe heating due to lower blood flow but similarly increased nICP. ABSTRACT The human brain is particularly vulnerable to heat stress; this manifests as impaired cognitive function, orthostatic tolerance, work capacity, and eventually, brain death. This vulnerability is often ascribed to inadequate cerebral blood flow (CBF); however, elevated intracranial pressure (ICP) is also observed in mammalian models of heat stroke. We investigated the changes in CBF with incremental heat strain under three fundamentally different modes of heating, and assessed whether heating per se increased ICP. Fourteen fit participants (seven female) were heated to thermal tolerance or 40°C core temperature (Tc ; oesophageal) via passive hot-water immersion (spa), passive hot, humid air exposure (sauna), cycling exercise, and cycling exercise with CO2 inhalation to prevent heat-induced hypocapnia. CBF was measured with duplex ultrasound at each 0.5°C increment in Tc and ICP was estimated non-invasively (nICP) from optic nerve sheath diameter at thermal tolerance. At thermal tolerance, CBF was decreased by 30% in the sauna (P < 0.001), but was unchanged in the spa or with exercise (P ≥ 0.140). CBF increased by 17% when end-tidal P C O 2 was clamped at eupnoeic pressure (P < 0.001). On the contrary, nICP increased universally by 18% with all modes of heating (P < 0.001). The maximum Tc was achieved with passive heating, and preventing hypocapnia during exercise did not improve exercise or thermal tolerance (P ≥ 0.146). Therefore, the regulation of CBF is dramatically different depending on the mode and dose of heating, whereas nICP responses are not. The sauna, more so than the spa or exercise, poses a greater challenge to the brain under equivalent heat strain.
Collapse
Affiliation(s)
- Travis D Gibbons
- University of Otago, 55/47 Union St. W, Dunedin, Otago, 9016, New Zealand
| | - Philip N Ainslie
- University of British Columbia, Okangan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Kate N Thomas
- University of Otago, 55/47 Union St. W, Dunedin, Otago, 9016, New Zealand
| | - Luke C Wilson
- University of Otago, 55/47 Union St. W, Dunedin, Otago, 9016, New Zealand
| | | | | | - Holly A Campbell
- University of Otago, 55/47 Union St. W, Dunedin, Otago, 9016, New Zealand
| | - Jim D Cotter
- University of Otago, 55/47 Union St. W, Dunedin, Otago, 9016, New Zealand
| |
Collapse
|
9
|
Shang FLT, Wanner SP, Damasceno WC, Martins YAT, Silva A, Prado LS. Independent effects of rapid eye movement sleep deprivation and exposure to environmental heat stress on aerobic performance and thermoregulatory responses in exercising rats. Temperature (Austin) 2020; 8:188-201. [PMID: 33997117 DOI: 10.1080/23328940.2020.1829939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Evidence indicates that aerobic performance is degraded either by environmental heat stress or sleep deprivation. However, whether these conditions interact to produce more significant performance impairment deserves further investigation. Therefore, this study investigated the effects of experimental sleep deprivation (24 h or 96 h) on aerobic performance and thermoregulatory responses in rats exercised on a treadmill at different environmental conditions. Adult male Wistar rats were subjected to rapid eye movement sleep deprivation (RSD) using the modified multiple platform method and were then subjected to an incremental-speed exercise until they were fatigued. Treadmill running was performed in a temperate (24°C) or warm (31°C) environment, and the colonic temperature (an index of core body temperature; TCORE) and the tail-skin temperature (TSKIN; an index of cutaneous heat loss) were recorded. 24-h and 96-h RSD produced small magnitude reductions in aerobic performance (Cohen's d = 0.47-0.58) and minor changes in thermoregulation. Relative to control rats, sleep-deprived rats showed a higher TCORE at the exercise initiation and a higher threshold for activating cutaneous heat loss, but unchanged TCORE and TSKIN at fatigue. Exercise at 31°C induced large reductions in performance (d = 0.82-1.29) and marked changes in thermoregulation, as evidenced by higher TCORE and TSKIN at fatigue, compared to exercise at 24°C. Interestingly, none of the effects induced by RSD were exacerbated by environmental heat stress and vice-versa, indicating that both conditions did not interact. We conclude that RSD and heat stress modulate aerobic performance and thermoregulatory responses by acting independently.
Collapse
Affiliation(s)
- Felipe Lioe Teh Shang
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - William Coutinho Damasceno
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ygor Antônio Tinoco Martins
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Andressa Silva
- Psychobiology and Exercise Studies Centre, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Luciano Sales Prado
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
10
|
Tsai YJ, Jhong YC, Ching SH, Liao YC, Ching CH, Chuang JI. Cold Exposure After Exercise Impedes the Neuroprotective Effects of Exercise on Thermoregulation and UCP4 Expression in an MPTP-Induced Parkinsonian Mouse Model. Front Neurosci 2020; 14:573509. [PMID: 33041765 PMCID: PMC7522410 DOI: 10.3389/fnins.2020.573509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/17/2020] [Indexed: 11/26/2022] Open
Abstract
Moderate exercise and mild hypothermia have protective effects against brain injury and neurodegeneration. Running in a cold environment alters exercise-induced hyperthermia and outcomes; however, evaluations of post-exercise cold exposure related to exercise benefits for the brain are relatively rare. We investigated the effects of 4°C cold exposure after exercise on exercise-induced thermal responses and neuroprotection in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced Parkinsonian mouse model. Male C57BL/6J mice were pretreated with MPTP for five consecutive days and follow-up treadmill exercise for 4 weeks. After 1-h running at a 22°C temperature, the mice were exposed to a 4°C environment for 2 h. An MPTP injection induced a transient drop in body and brain temperatures, while mild brain hypothermia was found to last for 4 weeks after MPTP treatment. Preventing brain hypothermia by exercise or 4°C exposure was associated with an improvement in MPTP-induced striatal uncoupling protein 4 (UCP4) downregulation and nigrostriatal dopaminergic neurodegeneration. However, 4°C exposure after exercise abrogated the exercise-induced beneficial effects and thermal responses in MPTP-treated mice, including a low amplitude of exercise-induced brain hyperthermia and body temperature while at rest after exercise. Our findings elucidate that post-exercise thermoregulation and UCP4 expression are important in the neuroprotective effects of exercise against MPTP toxicity.
Collapse
Affiliation(s)
- Yi-Ju Tsai
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yue-Cih Jhong
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Hong Ching
- The Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ching Liao
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Hsin Ching
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jih-Ing Chuang
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,The Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| |
Collapse
|
11
|
Drummond LR, Campos HO, de Andrade Lima PM, da Fonseca CG, Kunstetter AC, Rodrigues QT, Szawka RE, Natali AJ, Prímola-Gomes TN, Wanner SP, Coimbra CC. Impaired thermoregulation in spontaneously hypertensive rats during physical exercise is related to reduced hypothalamic neuronal activation. Pflugers Arch 2020; 472:1757-1768. [PMID: 33040159 DOI: 10.1007/s00424-020-02474-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/05/2020] [Accepted: 10/06/2020] [Indexed: 12/25/2022]
Abstract
This study aimed to evaluate the physical exercise-induced neuronal activation in brain nuclei controlling thermoregulatory responses in hypertensive and normotensive rats. Sixteen-week-old male normotensive Wistar rats (NWRs) and spontaneously hypertensive rats (SHRs) were implanted with an abdominal temperature sensor. After recovery, the animals were subjected to a constant-speed treadmill running (at 60% of the maximum aerobic speed) for 30 min at 25 °C. Core (Tcore) and tail-skin (Tskin) temperatures were measured every minute during exercise. Ninety minutes after the exercise, the rats were euthanized, and their brains were collected to determine the c-Fos protein expression in the following areas that modulate thermoregulatory responses: medial preoptic area (mPOA), paraventricular hypothalamic nucleus (PVN), and supraoptic nucleus (SON). During treadmill running, the SHR group exhibited a greater increase in Tcore and an augmented threshold for cutaneous heat loss relative to the NWR group. In addition, the SHRs showed reduced neuronal activation in the mPOA (< 49.7%) and PVN (< 44.2%), but not in the SON. The lower exercise-induced activation in the mPOA and PVN in hypertensive rats was strongly related to the delayed onset of cutaneous heat loss. We conclude that the enhanced exercise-induced hyperthermia in hypertensive rats can be partially explained by a delayed cutaneous heat loss, which is, in turn, associated with reduced activation of brain areas modulating thermoregulatory responses.
Collapse
Affiliation(s)
- Lucas Rios Drummond
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil.
| | - Helton Oliveira Campos
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Paulo Marcelo de Andrade Lima
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Cletiana Gonçalves da Fonseca
- 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
| | - Quezia Teixeira Rodrigues
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Raphael Escorsim Szawka
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Antônio José Natali
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Thales Nicolau Prímola-Gomes
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Samuel Penna Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cândido Celso Coimbra
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| |
Collapse
|
12
|
Bittencourt MA, Wanner SP, Kunstetter AC, Barbosa NHS, Walker PCL, Andrade PVR, Turnes T, Guglielmo LGA. Comparative effects of two heat acclimation protocols consisting of high-intensity interval training in the heat on aerobic performance and thermoregulatory responses in exercising rats. PLoS One 2020; 15:e0229335. [PMID: 32084208 PMCID: PMC7034902 DOI: 10.1371/journal.pone.0229335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 02/04/2020] [Indexed: 01/15/2023] Open
Abstract
Acclimation resulting from low- to moderate-intensity physical exertion in the heat induces several thermoregulatory adaptations, including slower exercise-induced increases in core body temperature. However, few studies have investigated the thermoregulatory adaptations induced by high-intensity interval training (HIIT) protocols. Thus, the present study aimed to compare the adaptations in rats’ thermoregulatory parameters and aerobic performance observed after two different heat acclimation regimens consisting of HIIT protocols performed in a hot environment. Twenty-three adult male Wistar rats were initially subjected to an incremental-speed exercise at 32°C until they were fatigued and then randomly assigned to one of the following three heat acclimation strategies: passive heat exposure without any exercise (untrained controls–UN; n = 7), HIIT performed at the maximal aerobic speed (HIIT100%; n = 8) and HIIT performed at a high but submaximal speed (HIIT85%; n = 8). Following the two weeks of interventions, the rats were again subjected to a fatiguing incremental exercise at 32°C, while their colonic temperature (TCOL) was recorded. The workload performed by the rats and their thermoregulatory efficiency were calculated. After the intervention period, rats subjected to both HIIT protocols attained greater workloads (HIIT100%: 313.7 ± 21.9 J vs. HIIT85%: 318.1 ± 32.6 J vs. UN: 250.8 ± 32.4 J; p < 0.01) and presented a lower ratio between the change in TCOL and the distance travelled (HIIT100%: 4.95 ± 0.42°C/km vs. HIIT85%: 4.33 ± 0.59°C/km vs. UN: 6.14 ± 1.03°C/km; p < 0.001) when compared to UN rats. The latter finding indicates better thermoregulatory efficiency in trained animals. No differences were observed between rats subjected to the two HIIT regimens. In conclusion, the two HIIT protocols induce greater thermoregulatory adaptations and performance improvements than passive heat exposure. These adaptations do not differ between the two training protocols investigated in the present study.
Collapse
Affiliation(s)
- Myla Aguiar Bittencourt
- Physical Effort Laboratory, Graduate Program in Physical Education, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
| | - Ana Cançado Kunstetter
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Nicolas Henrique Santos Barbosa
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Paula Carolina Leite Walker
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pedro Victor Ribeiro Andrade
- Exercise Physiology Laboratory, Graduate Program in Sport Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Tiago Turnes
- Physical Effort Laboratory, Graduate Program in Physical Education, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Luiz Guilherme Antonacci Guglielmo
- Physical Effort Laboratory, Graduate Program in Physical Education, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| |
Collapse
|
13
|
Soares ADN, Wanner SP, Morais ESS, Hudson ASR, Martins FS, Cardoso VN. Supplementation with Saccharomyces boulardii Increases the Maximal Oxygen Consumption and Maximal Aerobic Speed Attained by Rats Subjected to an Incremental-Speed Exercise. Nutrients 2019; 11:nu11102352. [PMID: 31581750 PMCID: PMC6835599 DOI: 10.3390/nu11102352] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023] Open
Abstract
Benefits to the host metabolism resulting from Saccharomyces boulardii (Sb) supplementation have been described; however, no study has investigated the effects of this supplementation on aerobic metabolism and performance during physical exercise. Thus, in the present study, we addressed the effects of Sb supplementation on the rate of oxygen consumption (VO2), mechanical efficiency (external work divided by VO2), and aerobic performance of rats subjected to fatiguing, incremental-speed exercise. Twenty-six male Wistar rats were randomly divided into two groups: (1) non-supplemented, in which rats received 0.1 mL of a saline solution, and (2) Sb-supplemented, in which rats received 0.1 mL of a suspension containing 8.0 log10 colony-forming units. The rats received the treatments by gavage for 10 consecutive days; they were then subjected to fatiguing treadmill running. Sb supplementation did not change the VO2 values or mechanical efficiency during submaximal exercise intensities. In contrast, at fatigue, VO2MAX was increased by 12.7% in supplemented rats compared with controls (p = 0.01). Moreover, Sb improved aerobic performance, as evidenced by a 12.4% increase in maximal running speed attained by the supplemented rats (p < 0.05). We conclude that Sb supplementation for 10 days increases VO2MAX and aerobic performance in rats.
Collapse
Affiliation(s)
- Anne Danieli Nascimento Soares
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
- Instituto Federal de Educação, Ciência e Tecnologia do Sudeste de Minas Gerais, Barbacena, MG, 36205-018, Brazil.
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| | - Elissa Stefane Silva Morais
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| | - Alexandre Sérvulo Ribeiro Hudson
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| | - Flaviano Santos Martins
- Department of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| | - Valbert Nascimento Cardoso
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
| |
Collapse
|
14
|
Drummond LR, Kunstetter AC, Campos HO, Vaz FF, Drummond FR, Andrade AG, Coimbra CC, Natali AJ, Wanner SP, Prímola-Gomes TN. Spontaneously hypertensive rats have greater impairments in regulating abdominal temperature than brain cortex temperature following physical exercise. J Therm Biol 2019; 83:30-36. [DOI: 10.1016/j.jtherbio.2019.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 12/11/2022]
|
15
|
Park HJ, Kang H, Jo J, Chung E, Kim S. Planar coil-based contact-mode magnetic stimulation: synaptic responses in hippocampal slices and thermal considerations. Sci Rep 2018; 8:13423. [PMID: 30194395 PMCID: PMC6128857 DOI: 10.1038/s41598-018-31536-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 08/16/2018] [Indexed: 12/30/2022] Open
Abstract
Implantable magnetic stimulation is an emerging type of neuromodulation using coils that are small enough to be implanted in the brain. A major advantage of this method is that stimulation performance could be sustained even though the coil is encapsulated by gliosis due to foreign body reactions. Magnetic fields can induce indirect electric fields and currents in neurons. Compared to transcranial magnetic stimulation, the coil size used in implantable magnetic stimulation can be greatly reduced. However, the size reduction is accompanied by an increase in coil resistance. Hence, the coil could potentially damage neurons from the excess heat generated. Therefore, it is necessary to study the stimulation performance and possible thermal damage by implantable magnetic stimulation. Here, we devised contact-mode magnetic stimulation (CMS), wherein magnetic stimulation was applied to hippocampal slices through a customized planar-type coil underneath the slice in the contact mode. With acute hippocampal slices, we investigated the synaptic responses to examine the field excitatory postsynaptic responses of CMS and the temperature rise during CMS. A long-lasting synaptic depression was exhibited in the CA1 stratum radiatum after CMS, while the temperature remained in a safe range so as not to seriously affect the neural responses.
Collapse
Affiliation(s)
- Hee-Jin Park
- School of Mechanical Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Heekyung Kang
- Department of Biomedical Science and Neurology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Jihoon Jo
- Biomedical Research Institute, Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Euiheon Chung
- School of Mechanical Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea.
- Department of Biomedical Science and Engineering, Institute of Integrated Technology, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea.
| | - Sohee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.
| |
Collapse
|
16
|
Kunstetter AC, Barbosa NHS, Moraes MM, Pinto VA, Soares DD, Pires W, Wanner SP. Pre-exercise exposure to the treadmill setup changes the cardiovascular and thermoregulatory responses induced by subsequent treadmill running in rats. Temperature (Austin) 2017; 5:109-122. [PMID: 30377632 DOI: 10.1080/23328940.2017.1388343] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 10/18/2022] Open
Abstract
Different methodological approaches have been used to conduct experiments with rats subjected to treadmill running. Some experimenters have exposed rats to the treadmill setup before initiating exercise to minimize the influences of handling and being placed in an anxiety-inducing environment on the physiological responses to subsequent running. Other experimenters have subjected rats to exercise immediately after placing them on the treadmill. Thus, the present study aimed to evaluate the effects of pre-exercise exposure to the treadmill on physical performance and cardiovascular and thermoregulatory responses during subsequent exercise. Male Wistar rats were subjected to fatiguing incremental-speed exercise at 24°C immediately after being placed on the treadmill or after being exposed to the treadmill for 70 min following removal from their home cages. Core body temperature (TCORE), tail-skin temperature (TSKIN), heart rate (HR) and mean arterial pressure (MAP) were recorded throughout the experiments. Rats exposed to the treadmill started exercise with higher TCORE, lower HR and MAP, and unaltered TSKIN. This exposure did not influence performance, but it markedly affected the exercise-induced increases in the four physiological parameters evaluated; for example, the TSKIN increased earlier and at a higher TCORE. Moreover, previous treadmill exposure notably allowed expected exercise-induced changes in cardiovascular parameters to be observed. Collectively, these data indicate that pre-exercise exposure to the treadmill induces important effects on physiological responses during subsequent treadmill running. The present data are particularly relevant for researchers planning experiments involving physical exercise and the recording of physiological parameters in rats.
Collapse
Affiliation(s)
- Ana C Kunstetter
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Nicolas H S Barbosa
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Michele M Moraes
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Valéria A Pinto
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Danusa D Soares
- 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.,Department of Physical Education, Institute of Life Sciences, Universidade Federal de Juiz de Fora, Governador Valadares (MG), Brazil
| | - Samuel P Wanner
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| |
Collapse
|
17
|
Teixeira-Coelho F, Fonseca CG, Barbosa NHS, Vaz FF, Cordeiro LMDS, Coimbra CC, Pires W, Soares DD, Wanner SP. Effects of manipulating the duration and intensity of aerobic training sessions on the physical performance of rats. PLoS One 2017; 12:e0183763. [PMID: 28841706 PMCID: PMC5571967 DOI: 10.1371/journal.pone.0183763] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 08/10/2017] [Indexed: 11/18/2022] Open
Abstract
This study investigated the effects of manipulating the load components of aerobic training sessions on the physical performance of rats. To achieve this purpose, adult male Wistar rats were divided into four groups: an untrained control (CON) group and training groups with a predominant overload in intensity (INT) or duration (DUR) or alternating and similar overloads in intensity and duration (ID). Prior to, during, and after 8 weeks of the control or training protocols, the performance of the rats (evaluated by their workload) was determined during fatiguing, incremental-speed treadmill running. Two additional incremental running tests were performed prior to and at the end of the protocols to measure the peak rate of oxygen consumption (VO2peak). As expected, the rats in the trained groups exhibited increased performance, whereas the untrained rats showed stable performance throughout the 8 weeks. Notably, the performance gain exhibited by the DUR rats reached a plateau after the 4th week. This plateau was not present in the INT or ID rats, which exhibited increased performance at the end of training protocol compared with the DUR rats. None of the training protocols changed the VO2peak values; however, these values were attained at faster speeds, which indicated increased running economy. In conclusion, our findings demonstrate that the training protocols improved the physical performance of rats, likely resulting from enhanced running economy. Furthermore, compared with overload in duration, overload in the intensity of training sessions was more effective at inducing performance improvements across the 8 weeks of the study.
Collapse
Affiliation(s)
- Francisco Teixeira-Coelho
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
- Teacher Formation Center; Universidade Federal do Recôncavo da Bahia, Amargosa (BA), Brazil
| | - Cletiana Gonçalves Fonseca
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Nicolas Henrique Santos Barbosa
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Filipe Ferreira Vaz
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Letícia Maria de Souza Cordeiro
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte (MG), Brazil
| | - Cândido Celso Coimbra
- Laboratory of Endocrinology and Metabolism, Institute of Biological Sciences, 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
- Department of Physical Education, Institute of Life Sciences, Universidade Federal de Juiz de Fora, Governador Valadares (MG), Brazil
| | - Danusa Dias Soares
- 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
| |
Collapse
|
18
|
Fekete Z, Csernai M, Kocsis K, Horváth ÁC, Pongrácz A, Barthó P. Simultaneousin vivorecording of local brain temperature and electrophysiological signals with a novel neural probe. J Neural Eng 2017; 14:034001. [DOI: 10.1088/1741-2552/aa60b1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
19
|
Drummond LR, Kunstetter AC, Vaz FF, Campos HO, de Andrade AGP, Coimbra CC, Natali AJ, Wanner SP, Prímola-Gomes TN. Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments. PLoS One 2016; 11:e0155919. [PMID: 27214497 PMCID: PMC4877067 DOI: 10.1371/journal.pone.0155919] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 04/20/2016] [Indexed: 12/21/2022] Open
Abstract
This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment.
Collapse
Affiliation(s)
- Lucas Rios Drummond
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Ana Cançado Kunstetter
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Filipe Ferreira Vaz
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Helton Oliveira Campos
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | | | - Cândido Celso Coimbra
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Antônio José Natali
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - Samuel Penna Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thales Nicolau Prímola-Gomes
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| |
Collapse
|
20
|
Wanner SP, Leite LHR, Guimarães JB, Coimbra CC. Increased brain L-arginine availability facilitates cutaneous heat loss induced by running exercise. Clin Exp Pharmacol Physiol 2016; 42:609-16. [PMID: 25881674 DOI: 10.1111/1440-1681.12407] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 01/20/2015] [Accepted: 04/09/2015] [Indexed: 11/30/2022]
Abstract
The effects of increased brain availability of L-arginine (L-arg), a precursor for nitric oxide synthesis, on core body temperature (Tcore ) and cutaneous heat loss were evaluated in running rats. One week prior to the experiments, adult male Wistar rats received the following implants: a chronic guide cannula in the lateral cerebral ventricle and a temperature sensor in the abdominal cavity. On the day of the experiments, the rats were assigned to receive a 2-μL intracerebroventricular injection of either NaCl (0.15 mol/L) or L-arg solution (0.825, 1.65 or 3.30 mol/L); Tcore and tail skin temperature were measured while the rats ran at a speed of 18 m/min until they were fatigued. L-arginine induced a dose-dependent reduction in the threshold Tcore required for cutaneous heat loss (38.09 ± 0.20°C for 3.30-mol/L L-arg vs 38.61 ± 0.10°C for saline; P < 0.05), which attenuated the exercise-induced hyperthermia. Although the rats treated with L-arg presented a lower Tcore at the end of exercise (~0.7°C lower after treatment with the highest dose), no changes in the time to fatigue were observed relative to the control trial. These results suggest that brain L-arg controls heat loss during exercise, most likely by modulating the sympathetic vasoconstrictor tonus to skin vessels. Furthermore, despite facilitating cutaneous heat loss mechanisms, increased brain L-arg availability did not enhance physical performance.
Collapse
Affiliation(s)
- Samuel Penna Wanner
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.,Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Laura Hora Rios Leite
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.,Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Juliana Bohnen Guimarães
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.,State University of Minas Gerais, Ibirité, Brazil
| | - Cândido Celso Coimbra
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Yoo Y, LaPradd M, Kline H, Zaretskaia MV, Behrouzvaziri A, Rusyniak DE, Molkov YI, Zaretsky DV. Exercise activates compensatory thermoregulatory reaction in rats: a modeling study. J Appl Physiol (1985) 2015; 119:1400-10. [PMID: 26472864 DOI: 10.1152/japplphysiol.00392.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 10/13/2015] [Indexed: 11/22/2022] Open
Abstract
The importance of exercise is increasingly emphasized for maintaining health. However, exercise itself can pose threats to health such as the development of exertional heat shock in warm environments. Therefore, it is important to understand how the thermoregulation system adjusts during exercise and how alterations of this can contribute to heat stroke. To explore this we measured the core body temperature of rats (Tc) running for 15 min on a treadmill at various speeds in two ambient temperatures (Ta = 25°C and 32°C). We assimilated the experimental data into a mathematical model that describes temperature changes in two compartments of the body, representing the muscles and the core. In our model the core body generates heat to maintain normal body temperature, and dissipates it into the environment. The muscles produce additional heat during exercise. According to the estimation of model parameters, at Ta = 25°C, the heat generation in the core was progressively reduced with the increase of the treadmill speed to compensate for a progressive increase in heat production by the muscles. This compensation was ineffective at Ta = 32°C, which resulted in an increased rate of heat accumulation with increasing speed, as opposed to the Ta = 25°C case. Interestingly, placing an animal on a treadmill increased heat production in the muscles even when the treadmill speed was zero. Quantitatively, this "ready-to-run" phenomenon accounted for over half of the heat generation in the muscles observed at maximal treadmill speed. We speculate that this anticipatory response utilizes stress-related circuitry.
Collapse
Affiliation(s)
- Yeonjoo Yoo
- Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, Indiana
| | - Michelle LaPradd
- Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, Indiana
| | | | - Maria V Zaretskaia
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | | | - Daniel E Rusyniak
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yaroslav I Molkov
- Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, Indiana
| | - Dmitry V Zaretsky
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| |
Collapse
|
23
|
Chiu HY, Huang HC, Chen PY, Hou WH, Tsai PS. Walking Improves Sleep in Individuals With Cancer: A Meta-Analysis of Randomized, Controlled Trials. Oncol Nurs Forum 2015; 42:E54-62. [DOI: 10.1188/15.onf.e54-e62] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
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.
Collapse
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:
| |
Collapse
|