Size constraints of telemeters in rats

Moran, Maarit; Roy, Roland R.; Wade, Charles E.; Corbin, B. J.; Grindeland, R. E.

doi:10.1152/jappl.1998.85.4.1564

Cited by 15 publications

(11 citation statements)

References 20 publications

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“…Various tissues in the body may contribute to this thermogenesis, but according to blood flow measurement, the main contributor is the heart muscle itself (9). This would be consistent with our observations since cardiac acceleration, which is observed during fear, cold exposure, and arousal, is under ␤-adrenergic control (5,19,20,28,29).…”

Section: Discussionsupporting

confidence: 89%

“…These muscles would be activated during fear because their tonic contraction contributes to the tense immobile freezing posture, characteristic of conditioned fear. They would also be activated during cold exposure because the animals were behaviorally active during the test (personal observation, 19). In fact, it may also be the origin of the quick but short increase in differential temperature (also in the ϩ1°C range) displayed by sham-conditioned rats and rats exposed to the refrigerator at room temperature.…”

Section: Discussionmentioning

confidence: 99%

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Nonshivering thermogenesis without interscapular brown adipose tissue involvement during conditioned fear in the rat

Marks¹,

Vianna²,

Carrive³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Marks A, Vianna DM, Carrive P. Nonshivering thermogenesis without interscapular brown adipose tissue involvement during conditioned fear in the rat. Am J Physiol Regul Integr Comp Physiol 296: R1239 -R1247, 2009. First published February 11, 2009 doi:10.1152/ajpregu.90723.2008.-As with other forms of psychological stress, conditioned fear causes an increase in body temperature. The mechanisms underlying this stress-induced hyperthermia are not well understood, but previous research suggests that nonshivering thermogenesis might contribute, as it does during cold exposure. The major source of nonshivering thermogenesis in the rat is brown adipose tissue (BAT), and the largest BAT deposit in that species is in the interscapular area just below the skin. BAT is also under sympathetic control via ␤-adrenoceptors. If BAT contributes to fear-induced hyperthermia, then the interscapular skin should warm up faster than other skin areas, and this response should be suppressed by the ␤-adrenoceptor antagonist, propranolol. We tested this noninvasively by infrared thermography. In conscious rats, 30 min of contextual fear caused hyperthermia (as indicated by a ϩ1.5°C increase in lumbar back skin temperature) and increased the difference in temperature between interscapular and lumbar back skin (TiScap Ϫ TBack) by ϩ1°C. Propranolol (10 mg/kg ip) completely abolished this hyperthermia; however, the TiScap-TBack increase was not reduced. In contrast, exposure to cold air (4°C) induced a ϩ2.7°C increase in TiScap-TBack, which was reduced to ϩ1°C after propranolol. The results show that conditioned fear-induced hyperthermia is of nonshivering origin and mediated by ␤-adrenoceptors, but interscapular BAT does not contribute to it and does not appear to be activated, either. stress hyperthermia; thermoregulation; tail skin; freezing; sympathetic responses MANY PSYCHOLOGICAL STRESSORS can cause an increase in body temperature (2,11,25,29), an effect also known as stress hyperthermia (2, 18). There are two ways in which body temperature can be elevated, either by reducing heat loss or by increasing heat production. The most effective way of reducing heat loss in the animal is through skin vasoconstriction (13). Increased heat production or thermogenesis can be achieved via two mechanisms: shivering thermogenesis if the heat comes from contracting skeletal muscles (15) or nonshivering thermogenesis if it comes from elsewhere (13, 17). The best studied effector of nonshivering thermogenesis is brown adipose tissue (BAT), which is under sympathetic control (4, 20). Only present in mammals, BAT is classically called into action during cold exposure. It is most often found in newborns, small mammals, and hibernating species, which are the ones who are most prone to suffer from cold stress, but it might also be functional in adult humans (6,20). Moreover, it is the only site where cold adaptation, that is, the development of increased recruitable thermogenic capacity in response to chronic cold exposure, occurs (4, 9, 12). In rats and ...

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Nonshivering thermogenesis without interscapular brown adipose tissue involvement during conditioned fear in the rat

Marks¹,

Vianna²,

Carrive³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…implantation (Perry et al, 2000), suggesting a decrease in physical activity. In contrast, subcutaneous implantation in rats of telemetry transmitters corresponding to 15% of the animals' initial mass did not impair activity levels during a 5·h measurement period (Moran et al, 1998) supporting the observation that energy expenditure was not influenced by the additional weight. These different observations suggest that the site of implantation (intraperitoneal versus subcutaneous) might have an impact on physical activity and overall energy expenditure.…”

Section: Discussionsupporting

confidence: 67%

Gender dimorphism of body mass perception and regulation in mice

Wiedmer

Boschmann

Schimrigk

2004

Journal of Experimental Biology

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SUMMARY According to the set-point theory of body mass, changes in body mass are perceived by the body, leading to activation of compensatory feedback mechanisms, which in turn restores the set-point body mass. However, this theory is still under debate. To test if mass per se might be sensed and regulated, we implanted loads corresponding to 10% (HI) or 2% (LO,control) of body mass into mice in addition to sham-operated mice (SO). We recorded body mass, food intake, energy expenditure and body composition over 14 weeks. Both male and female mice showed an initial stress-induced loss of body mass, which was more pronounced in males. Subsequently, male HI mice displayed a permanently decreased biological body mass(MBB, body mass exclusive of the implant mass), equivalent to approximately half of the mass of the implant, and obtained by a decrease in fat mass compared to SO males. In contrast, female HI mice rapidly recovered and maintained their initial MBB and body composition following a mass load. Initial lean body mass was maintained in all male and female groups, and energy intake was similar in all male and female groups. Body mass changes could not be explained by measurable changes in energy intake or expenditure. We conclude that changes in body mass are perceived and partially compensated in male but not in female mice, suggesting that mass-specific regulation of body mass might not play a major role in overall body mass regulation. Different compartments of the body are possibly regulated by different signals and stimuli. Our results suggest that lean body mass rather than body mass per se seems to be tightly regulated. Higher efficiency of energy utilization in females compared to males could explain the gender-specific changes in energy balance.

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“…Critics of this technology correctly inquire as to the effects of the weight and volume of the implanted transmitter on animal behavior and stress and on physiological functions (Morton DB, Hawkins P, Bevan R, Heath K, Kirkwood J, Pearce P, Scott E, Whelan G, and Webb A, unpublished observations). Animals seem to tolerate the implantations of the transmitter without obvious problems, so long as high-quality sterile techniques are used (7,64). Baumans et al (7) assessed changes in body weight and behavior of BALB/c and 129/Sv mice, after implantation of an intra-abdominal transmitter (DSI).…”

Section: Applications and Evaluationmentioning

confidence: 99%

Evaluation and applications of radiotelemetry in small laboratory animals

Krämer

Kinter

2003

Physiological Genomics

201

158

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Radiotelemetry is the "state of the art" for monitoring physiological functions in awake and freely moving laboratory animals, while minimizing stress artifacts. For researchers, especially those in the fields of pharmacology and toxicology, the technique provides a valuable tool for defining the physiological and pathophysiological consequences derived from advances molecular, cellular, and tissue biology and in predicting the effectiveness and safety of new compounds in humans. There is ample evidence that radiotelemetry systems for measuring physiological functions has been sufficiently validated. Today, the technology is an important tool for collection of a growing number of physiological parameters, for contributing to animal welfare (reduction and refinement alternatives), and for reducing overall animal research costs.

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Size constraints of telemeters in rats

Cited by 15 publications

References 20 publications

Nonshivering thermogenesis without interscapular brown adipose tissue involvement during conditioned fear in the rat

Nonshivering thermogenesis without interscapular brown adipose tissue involvement during conditioned fear in the rat

Gender dimorphism of body mass perception and regulation in mice

Evaluation and applications of radiotelemetry in small laboratory animals

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