Chronic sympathectomy of the caudal artery delays cutaneous heat loss during passive heating

Lima, Milene Rodrigues Malheiros; Pires, Washington; Fonseca, Ivana Alice Teixeira; Fonseca, C. G.; Martinelli, Patrícia Massara; Wanner, Samuel Penna; Lima, Nilo Resende Viana

doi:10.1016/j.neulet.2013.01.013

Cited by 12 publications

(15 citation statements)

References 23 publications

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“…Using the method proposed by Romanovsky et al., 82 we observed HLI values ranging from 0.20 to 0.30 in a resting rat maintained inside the chamber that contained the treadmill belt (with the electrical fan off) at a local T AMB of 24-25°C. 36 Similar findings (average HLI values of 0.23) were reported by Lima et al., 99 who maintained the rats inside the same chamber, but with the electrical fan on and at a local temperature of 26°C. 36 Collectively, these data suggest that ambient temperatures ranging from 24 to 26°C correspond to the lower extremity of the TNZ of rats in the treadmill setup.…”

Section: Factors That Influence Running-induced Changes In Thermoregusupporting

confidence: 82%

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

Wanner¹,

Prímola-Gomes²,

Pires³

et al. 2015

Temperature

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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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Section: Factors That Influence Running-induced Changes In Thermoregusupporting

confidence: 82%

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

Wanner¹,

Prímola-Gomes²,

Pires³

et al. 2015

Temperature

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“…The ambient temperature was maintained at 25.2±0.2°C during all experimental trials by the use of air conditioning. According to our previous experiments, rats exhibit a mean heat loss index of 0.23 when resting in the same experimental setup for 60 min and with the ambient temperature set at 25-26°C (19). The heat loss index data suggest that the environmental conditions used in the present study were within the thermoneutral zone (20).…”

Section: Methodsmentioning

confidence: 99%

Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment

Kunstetter

Wanner

Madeira

et al. 2014

Braz J Med Biol Res

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There is evidence that brain temperature (Tbrain) provides a more sensitive index than other core body temperatures in determining physical performance. However, no study has addressed whether the association between performance and increases in Tbrain in a temperate environment is dependent upon exercise intensity, and this was the primary aim of the present study. Adult male Wistar rats were subjected to constant exercise at three different speeds (18, 21, and 24 m/min) until the onset of volitional fatigue. Tbrain was continuously measured by a thermistor inserted through a brain guide cannula. Exercise induced a speed-dependent increase in Tbrain, with the fastest speed associated with a higher rate of Tbrain increase. Rats subjected to constant exercise had similar Tbrain values at the time of fatigue, although a pronounced individual variability was observed (38.7-41.7°C). There were negative correlations between the rate of Tbrain increase and performance for all speeds that were studied. These results indicate that performance during constant exercise is negatively associated with the increase in Tbrain, particularly with its rate of increase. We then investigated how an incremental-speed protocol affected the association between the increase in Tbrain and performance. At volitional fatigue, Tbrain was lower during incremental exercise compared with the Tbrain resulting from constant exercise (39.3±0.3 vs 40.3±0.1°C; P<0.05), and no association between the rate of Tbrain increase and performance was observed. These findings suggest that the influence of Tbrain on performance under temperate conditions is dependent on exercise protocol.

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“…An electric fan positioned at one end of the chamber generated an air flow rate of 2·0–2·5 m/s. The environment inside the chamber was heated by placing an electric heater (model AB 1100; Britânia) at the same level 20–30 cm away from the fan and turned on at 1200 W ( 33 ) .…”

Section: Experimental Methodsmentioning

confidence: 99%

Dietary glutamine prevents the loss of intestinal barrier function and attenuates the increase in core body temperature induced by acute heat exposure

et al. 2014

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Dietary glutamine (Gln) supplementation improves intestinal function in several stressful conditions. Therefore, in the present study, the effects of dietary Gln supplementation on the core body temperature (T core ), bacterial translocation (BT) and intestinal permeability of mice subjected to acute heat stress were evaluated. Male Swiss mice (4 weeks old) were implanted with an abdominal temperature sensor and randomly assigned to one of the following groups fed isoenergetic and isoproteic diets for 7 d before the experimental trials: group fed the standard AIN-93G diet and exposed to a high ambient temperature (398C) for 2 h (H-NS); group fed the AIN-93G diet supplemented with L-Gln and exposed to a high temperature (H-Gln); group fed the standard AIN-93G diet and not exposed to a high temperature (control, C-NS). Mice were orally administered diethylenetriaminepentaacetic acid radiolabelled with technetium ( 99m Tc) for the assessment of intestinal permeability or 99m Tc-Escherichia coli for the assessment of BT. Heat exposure increased T core (approximately 418C during the experimental trial), intestinal permeability and BT to the blood and liver (3 h after the experimental trial) in mice from the H-NS group relative to those from the C-NS group. Dietary Gln supplementation attenuated hyperthermia and prevented the increases in intestinal permeability and BT induced by heat exposure. No correlations were observed between the improvements in gastrointestinal function and the attenuation of hyperthermia by Gln. Our findings indicate that dietary Gln supplementation preserved the integrity of the intestinal barrier and reduced the severity of hyperthermia during heat exposure. The findings also indicate that these Gln-mediated effects occurred through independent mechanisms.

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Chronic sympathectomy of the caudal artery delays cutaneous heat loss during passive heating

Cited by 12 publications

References 23 publications

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment

Dietary glutamine prevents the loss of intestinal barrier function and attenuates the increase in core body temperature induced by acute heat exposure

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