Nonshivering thermogenesis induced by repetitive hypothalamic cooling in the rat

1976 ◽  
Vol 230 (2) ◽  
pp. 522-526 ◽  
Author(s):  
M Banet ◽  
H Hensel
Keyword(s):  
Oxygen Uptake ◽  
Cold Exposure ◽  
Preoptic Area ◽  
Temperature Sensitive ◽  
Nonshivering Thermogenesis ◽  
Hypothalamic Area ◽  
Hypothalamic Temperature ◽  
Experimental Animals ◽  
Unanesthetized Animals ◽  
Better Than

The effect of prolonged and repetitive cooling of the preoptic/anterior hypothalamic area on the sensitivity to the metabolic effect of noradrenaline and on the resistance to cold exposure was studied in the white rat. The preoptic area of 18 unanesthetized animals was cooled 9 h/day 5 days/wk, for a total of 80-150 h. One hour after a noradrenaline test injection (0.4 mg/kg), the experimental animals in which the preoptic area had been cooled to about 24 degrees C increased oxygen uptake by 81%, whereas those in which the preoptic area had been cooled to about 28 degrees C increased oxygen uptake by 48% (the control animals by only 37%). Despite their increased capacity for nonshivering thermogenesis, the experimental animals did not tolerate cold exposure (-10 degrees C) better than the controls. This development of nonshivering thermogenesis is thought to have been mediated by the hypothalamic temperature-sensitive neurons, and the possibility that it could explain the shift from shivering to nonshivering thermogenesis seen during adaptation to cold is discussed.

Nonshivering thermogenesis induced by repetitive cooling of spinal cord in the rat

1976 ◽  
Vol 230 (3) ◽  
pp. 720-723 ◽  
Author(s):  
M Banet ◽  
H Hensel
Keyword(s):  
Spinal Cord ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Rectal Temperature ◽  
Cold Adaptation ◽  
White Male ◽  
Metabolic Effect ◽  
Male Rat ◽  
Nonshivering Thermogenesis ◽  
Experimental Animals

The effect of prolonged and repetitive cooling of the spinal cord on the sensitivity to the metabolic effect of exogenous noradrenaline and on the resistance to cold exposure was studied in the white male rat. The spinal cord of 10 animals was cooled for an average of 90 h-9 h/day 5 days/wk - to a level that induced an increase in oxygen uptake of almost 70%. Oxygen consumption was then measured at 30 degrees C before and 1 h after a subcutaneous injection of noradrenaline (0.4 mg/kg). Following the noradrenaline injection, the experimental animals increased oxygen uptake by 71%, while the control ones increased it by only 33% (P less than 0.01). During exposure to -20 degrees C, the experimental animals, despite their increased capacity for nonshivering thermogenesis, did not maintain rectal temperature longer than the control ones, thus showing that other factors also play a significant role in cold adaptation in the rat.

OVULATORY DISCHARGE OF GONADOTROPHINS INDUCED BY HYPOTHALAMIC STIMULATION IN CASTRATED MALE RATS BEARING A TRANSPLANTED OVARY

1966 ◽  
Vol 51 (2) ◽  
pp. 281-289 ◽  
Author(s):  
J. Moll ◽  
G. H. Zeilmaker
Keyword(s):  
Electrical Stimulation ◽  
Preoptic Area ◽  
Hypothalamic Stimulation ◽  
Male Rats ◽  
Corpora Lutea ◽  
Histological Changes ◽  
Experimental Animals ◽  
Cumulus Oophorus ◽  
Dc Current ◽  
Stimulation Of

ABSTRACT Castrated young adult inbred male rats bearing ovarian transplants were subjected to electrical stimulation of the hypothalamus. This was done in order to investigate whether discharge of ovulatory amounts of gonadotrophins could be induced in such male animals by this procedure. Bilateral stimulations with unipolar electrodes and a DC current of 1.5 mA applied during 10 seconds induced in the ovarian grafts histological changes indicating the discharge of ovulatory amounts of gonadotrophins. In animals killed one day after stimulation these changes consisted of displacement of the ova towards the centre of the follicles with loosening of the cumulus oophorus. In one animal the ova had left the follicles. In animals killed three days after stimulation numerous young corpora lutea could be observed. These results were obtained with electrode tips either close to the median eminence, or in the preoptic area. Shamstimulations were ineffective. Some of the experimental animals received progesterone pretreatment. This rendered the stimulations ineffective, if continued until the day preceding stimulation, but seemed without effect on the results of stimulation, if two or three days without progesterone preceded the stimulations.

scholarly journals Validity of heart rate, pedometry, and accelerometry for predicting the energy cost of children’s activities

1998 ◽  
Vol 84 (1) ◽  
pp. 362-371 ◽  
Author(s):  
Roger G. Eston ◽  
Ann V. Rowlands ◽  
David K. Ingledew
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Standard Error ◽  
Energy Cost ◽  
Population Studies ◽  
Large Population ◽  
Multiple Regression Equation ◽  
Heart Rate Monitoring ◽  
Children's Activities ◽  
Better Than

Eston, Roger G., Ann V. Rowlands, and David K. Ingledew.Validity of heart rate, pedometry, and accelerometry for predicting the energy cost of children’s activities. J. Appl. Physiol. 84(1): 362–371, 1998.—Heart rate telemetry is frequently used to estimate daily activity in children and to validate other methods. This study compared the accuracy of heart rate monitoring, pedometry, triaxial accelerometry, and uniaxial accelerometry for estimating oxygen consumption during typical children’s activities. Thirty Welsh children (mean age 9.2 ± 0.8 yr) walked (4 and 6 km/h) and ran (8 and 10 km/h) on a treadmill, played catch, played hopscotch, and sat and crayoned. Heart rate, body accelerations in three axes, pedometry counts, and oxygen uptake were measured continuously during each 4-min activity. Oxygen uptake was expressed as a ratio of body mass raised to the power of 0.75 [scaled oxygen uptake (sV˙o 2)]. All measures correlated significantly ( P < 0.001) with sV˙o 2. A multiple-regression equation that included triaxial accelerometry counts and heart rate predicted sV˙o 2 better than any measure alone ( R 2 = 0.85, standard error of the estimate = 9.7 ml ⋅ kg−0.75 ⋅ min−1). The best of the single measures was triaxial accelerometry ( R 2 = 0.83, standard error of the estimate = 10.3 ml ⋅ kg−0.75 ⋅ min−1). It is concluded that a triaxial accelerometer provides the best assessment of activity. Pedometry offers potential for large population studies.

Use of respiratory quotients in assessment of aerobic work capacity

1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Output ◽  
Ergometer Test ◽  
Aerobic Work Capacity ◽  
Bicycle Ergometer Test ◽  
Better Than

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.

Responses of cold- and warm-adapted dogs to infused norepinephrine and acute body cooling

1965 ◽  
Vol 209 (1) ◽  
pp. 227-230 ◽  
Author(s):  
Tetsuo Nagasaka ◽  
Loren D. Carlson
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Cold Exposure ◽  
Nonshivering Thermogenesis ◽  
Mechanically Ventilated ◽  
Cold Adapted ◽  
Pentobarbital Sodium ◽  
Acute Cold Exposure ◽  
Increased Sensitivity ◽  
Body Cooling

Oxygen consumption, heart rate, and colonic, pinna, and paw temperatures were recorded continuously in warm-adapted (W-A) and cold-adapted (C-A) dogs anesthetized with pentobarbital sodium (30 mg/kg), paralyzed with Flaxedil (5 mg/kg per hr), and mechanically ventilated. The dogs were infused with norepinephrine (1.25 µg/kg per min) for 20 min at 30 C and after 45 min of acute cold exposure to 5 C. Oxygen consumption of C-A dogs increased with a slight increase in the heart rate during the initial 18–20 min of body cooling. O2 consumption decreased continuously during cold exposure in W-A dogs. Calorigenic effects of infused noradrenaline were similar in C-A and W-A dogs at 30 C and 5 C. Heart rate increased in W-A dogs at 30 and 5 C. These results show that nonshivering thermogenesis is well developed by cold acclimation in dogs, and suggest that the increase may be due to an increase in noradrenaline in blood rather than to increased sensitivity of the animals to the calorigenic effects of noradrenaline.

Sweating responses during changes of hypothalamic temperature in the rhesus monkey

1976 ◽  
Vol 40 (5) ◽  
pp. 653-657 ◽  
Author(s):  
K. A. Smiles ◽  
R. S. Elizondo ◽  
C. C. Barney
Keyword(s):  
Rhesus Monkey ◽  
Skin Temperature ◽  
Sweat Rate ◽  
Brain Temperature ◽  
Hypothalamic Area ◽  
Indirect Measurements ◽  
Hypothalamic Temperature ◽  
Temperature Changes ◽  
Experimental Analogue ◽  
The Brain

A technique is presented for preparing a durable thermode implant in the hypothalamus of the rhesus monkey. In unanesthetized monkeys implanted with thermodes in the anterior hypothalamic area of the brain, a linear relation was found between local sweat rates on the general body surface and clamped hypothalamic temperature. Changes in skin temperature were found to shift the hypothalamic set-point temperature at which sweating began but did not alter the gain of the hypothalamic temperature-sweat rate relationship. This study provides direct support for the concept that central brain temperature and skin temperature interact additively in the control of sweating in higher primates. Due to the very close similarity between these responses and those seen with indirect measurements of brain temperature in men, the rhesus monkey is seen as an excellent experimental analogue for studying human thermoregulation.

Respiration of liver slices from normal and altitude-acclimatized rats

1961 ◽  
Vol 200 (3) ◽  
pp. 527-529 ◽  
Author(s):  
John L. Frehn ◽  
Adam Anthony
Keyword(s):  
Oxygen Uptake ◽  
Liver Tissue ◽  
Cellular Respiration ◽  
Tissue Respiration ◽  
Tissue Slices ◽  
Experimental Animals ◽  
Altitude Acclimatization ◽  
Liver Slices

Analyses were made of the respiratory rates of liver tissue slices from normal rats and from rats continuously exposed to simulated altitudes of 21,000 ft. for periods varying from 1 to 56 days. Seventy-one rats were used. Oxygen uptake was measured in 100%, 20% and 1% oxygen. There was no difference in tissue respiration between the control and experimental animals, either with no added substrate or with glucose or succinate as added substrates. It was concluded from these data that alterations in cellular respiration do not constitute an important feature of altitude acclimatization.

Hypergravic fields and parallel controllers for thermoregulation

1983 ◽  
Vol 55 (3) ◽  
pp. 990-995 ◽  
Author(s):  
C. B. Monson ◽  
J. M. Horowitz ◽  
B. A. Horwitz
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Temperature Regulation ◽  
Room Temperature ◽  
Male Rats ◽  
Nonshivering Thermogenesis ◽  
Long Evans

To test the proposal that mammals have parallel neurocontrollers for temperature regulation, Long-Evans hooded male rats were exposed to cold while in a 3-G field. When exposed to cold, these rats consumed 35% less oxygen/min at 3 G than they did when exposed to cold at 1 G. However, rats acclimated for 6 wk to 5 degrees C consumed oxygen at the same rate during cold exposure at 3 G as at 1 G. Because cold-acclimated rats generate heat primarily by nonshivering thermogenesis while rats acclimated to room temperature rely to a greater extent on shivering, the 35% decrease in oxygen consumption of cold-exposed room-temperature rats in 3-G fields may reflect an inactivation of shivering. These oxygen consumption measurements, together with measurements of core and tail temperatures of rats in 3-G fields, are consistent with the proposal that neurocontrollers for thermoregulation are arranged in parallel and can be uncoupled by hypergravic fields.

scholarly journals Localization of Neuroendocrine Functions Within the Hypothalamus

1974 ◽  
Vol 1 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Lee L. Bernardis
Keyword(s):  
Luteinizing Hormone ◽  
Preoptic Area ◽  
Follicle Stimulating Hormone ◽  
Hypothalamic Area ◽  
Paraventricular Nuclei ◽  
Inhibiting Factor ◽  
Hypothalamic Nuclei ◽  
Cyclic Control ◽  
Neuroendocrine Functions ◽  
Stimulating Hormone

SUMMARYThe results of lesion, stimulation, deafferentation, implantatión and transplantation studies employed in the identification of hypophysiotrophic control areas in the hypothalamus to date suggest the following probable locations: corticotropic releasing factor (CRF) is formed in a diffuse area along the base of the median eminence, if not the base of the entire hypothalamus. Follicle stimulating hormone releasing factor (FSHRF) is elaborated in the paraventricular-suprachiasmatic areas but its cyclic control may reside in the anterior hypothalamic area. Luteinizing hormone (LH) is controlled by luteinizing hormone releasing factor (LHRF) formed in the suprachiasmatic area: its cyclic control may be in the preoptic area. Prolactin is controlled by prolactin inhibiting factor (PIF) localized in a diffuse area comprising the ventromedial, dorsomedial, arcuate and paraventricular nuclei. The hypothalamic area involved in thyroid control is also rather large, since thyrotropin stimulating hormone releasing factor (TSHRF) has been found in an area including the supraoptic and chiasmatic nuclei. Growth hormone releasing factor (GHRF) is elaborated in a rather narrow zone, the ventromedial hypothalamic nuclei.

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