Spinal cord thermosensitivity and sorting of neural signals in cold-exposed rats

1977 ◽  
Vol 42 (2) ◽  
pp. 154-158 ◽  
Author(s):  
C. A. Fuller ◽  
J. M. Horowitz ◽  
B. A. Horwitz
Keyword(s):  
Spinal Cord ◽  
Oxygen Consumption ◽  
Study Data ◽  
Direct Influence ◽  
Nonshivering Thermogenesis ◽  
Neural Signals ◽  
Spinal Cord Temperature ◽  
Identical Manner ◽  
Rate Of Oxygen Consumption ◽  
Spinal Cord Thermosensitivity

In the present study, data relevant to the presence or absence of sorting of neural signals were obtained by evaluating the thermal responses to spinal warming in the chronically prepared rat. Specifically, shivering activity and the rate of oxygen consumption (VO2) were measured in unanesthetized rats during cold exposure (10–16 degrees C). Warming the spinal cord at the level of T2 resulted in a significant decrease in shivering (P less than 0.001), without a significant change in VO2. The shivering response was reversed upon cessation of heating. These results are interpreted as indicating a direct influence of spinal cord temperature on shivering but not nonshivering thermogenesis in the rat. Similarly, in previous work with the rat, we have obtained data supporting hypothalamic receptor control of nonshivering but not shivering heat production. These findings are thus consistent with the suggestion that in the rat there occurs a sorting of neural signals. That is, impulses from the three thermoreceptor locations are not integrated in an identical manner for the control of shivering and nonshivering thermogenesis.

Halothane Selectively Inhibits Nonshivering Thermogenesis 

1995 ◽  
Vol 82 (2) ◽  
pp. 491-501 ◽  
Author(s):  
Andrea Dicker ◽  
Kerstin B. E. Ohlson ◽  
Lennart Johnson ◽  
Barbara Cannon ◽  
Sten G.E. Lindahl ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Inhibitory Effect ◽  
Nonshivering Thermogenesis ◽  
Halothane Anesthesia ◽  
Control Series ◽  
Mechanically Ventilated ◽  
Anesthetized Rats ◽  
Rate Of Oxygen Consumption ◽  
Spontaneously Breathing ◽  
Thermogenic Response

Background During halothane anesthesia, infants fail to increase oxygen consumption in response to a cold stimulus in the form of an increase in temperature gradient between body and environment. Based on recent observations with isolated brown-fat cells, it seemed feasible that this inability to respond could be due to an inhibition of nonshivering thermogenesis during halothane anesthesia. Methods The rate of oxygen consumption was measured in cold-acclimated hamsters and rats. The rate evoked by norepinephrine injection in hamsters at an environmental temperature of approximately 24 degrees C was used as a measure of the capacity for nonshivering thermogenesis. Anesthesia was induced by 3% halothane and maintained by 1.5% halothane. One experimental series with spontaneously breathing hamsters and a second control series with spontaneously breathing rats and with rats whose lungs were mechanically ventilated were conducted. Results Norepinephrine injection led to a fourfold increase in the rate of oxygen consumption in control hamsters; after this response had subsided, a second injection led to a similar effect. Halothane anesthesia caused an approximately 20% decrease in resting metabolic rate (P < 0.05) and a 70% inhibition of the thermogenic response to norepinephrine (P < 0.001). The halothane concentration yielding half-maximal inhibitory effect was estimated to be less than 1.0%. After the animals had recovered from halothane anesthesia, a completely restored thermogenic response to norepinephrine was observed. The inhibitory effect of halothane also was observed in hamsters maintained at normothermia and was therefore not secondary to the slight hypothermia that otherwise developed during anesthesia. In a series of control experiments, it was confirmed that rats also showed large thermogenic responses to norepinephrine injections, and it was found that, in spontaneously breathing halothane-anesthetized rats, the thermogenic response to norepinephrine was also much inhibited. Further, in halothane-anesthetized rats whose lungs were mechanically ventilated, and where blood gases were kept at virtually normal levels, the thermogenic response to norepinephrine was found to be similarly markedly inhibited. Conclusions A much diminished or abolished thermogenic response to injected norepinephrine was demonstrated in halothane-anesthetized animals. This implies that there would be a diminished ability to elicit nonshivering thermogenesis even when this process is physiologically induced. Such a diminished ability could in part explain the susceptibility of neonates and infants to hypothermia during halothane anesthesia.

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.

Shivering and nonshivering thermogenic responses of cold-exposed rats to hypothalamic warming

1975 ◽  
Vol 228 (5) ◽  
pp. 1519-1524 ◽  
Author(s):  
CA Fuller ◽  
BA Horwitz ◽  
JM Horowitz
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
Neural Control ◽  
Nonshivering Thermogenesis ◽  
Neural Controllers ◽  
Rate Of Oxygen Consumption ◽  
Exposed Animal ◽  
Unanesthetized Animals ◽  
Shivering Thermogenesis ◽  
Rule Out

The concurrent neural control of two thermoregulatory responses, shivering thermogenesis (ST) and nonshivering thermogenesis (NST), was investigated in chronically implanted cold-exposed rats. The effects of heating the preoptic/anterior hypothalamus (POAH) on shivering and on the rate of oxygen consumption (Vo2) were measured in these unanesthetized animals. With ambient temperature maintained constant (at some value between 10 and 16 degrees C), warming the hypothalamus 2-3 degrees C resulted in a significant decrease in Vo2 (Psmaller than 0.001) and an increase in shivering (Psmaller than .01), these responses being reversed on cessation of hypothalamic warming. These results are consistent with the proposal that, in the cold-exposed animal, elevated POAH temperatures directly inhibit NST even though shivering may increase (possibly as a compensation for the decrease in nonshivering heat production). They also rule out the possibility that, in the rat, signals from cutaneous and hypothalamic thermoreceptors are integrated in an indentical manner by the neural controllers for ST and NST.

Effect of propranolol on endotoxin-induced pyrogenesis in newborn and adult guinea pigs

1976 ◽  
Vol 40 (1) ◽  
pp. 35-39 ◽  
Author(s):  
C. M. Blatteis
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Guinea Pigs ◽  
Salmonella Enteritidis ◽  
Nonshivering Thermogenesis ◽  
Fat Pad ◽  
Adrenergic Blocker ◽  
Rate Of Oxygen Consumption ◽  
Propranolol Administration ◽  
Newborn Animals

Previous studied have shown that nonshivering thermogenesis (NST) is the prevailing mechanism of fever production in both newborn (during the first 2–3 wk of life) and adult cold-acclimated guinea pigs. This study was undertaken to determine whether this process may be mediated by noradrenergic sympathetics. The temperatures in the interscapular brown fat pad (Tbat) and the colon (Tre), the rate of oxygen consumption (VO2), and shivering activity were measured continuously for 5 h at 27 degrees C ambient temperature in 8- and 16-day-old and adult cold-acclimated guinea pigs following 2 mug/kg iv of Salmonella enteritidis endotoxin, with and without 6.0 mg/kg of propranolol (a beta-adrenergic blocker) injected ip 2 min before the endotoxin. In the older animals, the increase in Tbat normally produced by endotoxin was reduced by propranolol administration, but shivering set in, maintaining both VO2 and Tre at their febrile levels. In the newborn animals, Tbat also was decreased by propranolol, but shivering did not set in, so that VO2 and Tre fell below their febrile values. It is concluded that endotoxin-induced NST is controlled by noradrenergic sympathetics. The failure of NST to be replaced in the present newborn guinea pigs by visible shivering might be related to other observations that the onset of shivering at this age occurs only when Tre is significantly reduced.

scholarly journals Cardiorespiratory Responses to 10 Weeks of Exoskeleton-Assisted Overground Walking Training inChronic Nonambulatory Patients with Spinal Cord Injury

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5022
Author(s):  
Jae Hyeon Park ◽  
Hyeon Seong Kim ◽  
Seong Ho Jang ◽  
Dong Jin Hyun ◽  
Sang In Park ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Oxygen Consumption ◽  
Exercise Intensity ◽  
Moderate Physical Activity ◽  
Intensity Level ◽  
Cardiorespiratory System ◽  
Cardiorespiratory Responses ◽  
Cord Injury ◽  
Walking Efficiency

Exercise intensity of exoskeleton-assisted walking in patients with spinal cord injury (SCI) has been reported as moderate. However, the cardiorespiratory responses to long-term exoskeleton-assisted walking have not been sufficiently investigated. We investigated the cardiorespiratory responses to 10 weeks of exoskeleton-assisted walking training in patients with SCI. Chronic nonambulatory patients with SCI were recruited from an outpatient clinic. Walking training with an exoskeleton was conducted three times per week for 10 weeks. Oxygen consumption and heart rate (HR) were measured during a 6-min walking test at pre-, mid-, and post-training. Exercise intensity was determined according to the metabolic equivalent of tasks (METs) for SCI and HR relative to the HR reserve (%HRR). Walking efficiency was calculated as oxygen consumption divided by walking speed. The exercise intensity according to the METs (both peak and average) corresponded to moderate physical activity and did not change after training. The %HRR demonstrated a moderate (peak %HRR) and light (average %HRR) exercise intensity level, and the average %HRR significantly decreased at post-training compared with mid-training (31.6 ± 8.9% to 24.3 ± 7.3%, p = 0.013). Walking efficiency progressively improved after training. Walking with an exoskeleton for 10 weeks may affect the cardiorespiratory system in chronic patients with SCI.

scholarly journals Recovery heat in muscular contraction without lactic acid formation

1931 ◽  
Vol 108 (757) ◽  
pp. 279-301 ◽  
Keyword(s):  
Acetic Acid ◽  
Oxygen Consumption ◽  
Lactic Acid ◽  
Muscular Contraction ◽  
Acid Formation ◽  
Anaerobic Conditions ◽  
Spontaneous Breakdown ◽  
Rate Of Oxygen Consumption ◽  
Resting Muscle

In a comparison of muscles poisoned with mono-iodo-acetic acid (IAA) in the presence and in the absence of oxygen respectively, Lundsgaard (1930) found:- (1) That the spontaneous breakdown of phosphagen in poisoned resting muscle is much more rapid under anaerobic conditions. (2) That the onset of the characteristic contracture produced by IAA is accompanied always by an increase in the rate of oxygen consumption.

Proximal tubule dysfunction in cystine-loaded tubules: effect of phosphate and metabolic substrates

1996 ◽  
Vol 271 (3) ◽  
pp. F717-F722
Author(s):  
G. Bajaj ◽  
M. Baum
Keyword(s):  
Oxygen Consumption ◽  
Proximal Tubule ◽  
Tricarboxylic Acid Cycle ◽  
Dimethyl Ester ◽  
Proximal Tubules ◽  
Intracellular Atp ◽  
Metabolic Substrates ◽  
Rate Of Oxygen Consumption ◽  
Intracellular Phosphate

Intracellular cystine loading by use of cystine dimethyl ester (CDME) results in a generalized inhibition in proximal tubule transport due, in part, to a decrease in intracellular ATP. The present study examined the importance of phosphate and metabolic substrates in the proximal tubule dysfunction produced by cystine loading. Proximal tubule intracellular phosphorus was 1.8 +/- 0.1 in control tubules and 1.1 +/- 0.1 nmol/mg protein in proximal tubules incubated in vitro with CDME P < 0.001). Infusion of sodium phosphate in rabbits and subsequent incubation of proximal tubules with a high-phosphate medium attenuated the decrease in proximal tubule respiration and prevented the decrease in intracellular ATP with cystine loading. Tricarboxylic acid cycle intermediates have been shown to preserve oxidative metabolism in phosphate-depleted proximal tubules. In proximal tubules incubated with either 1 mM valerate or butyrate, there was a 42 and 34% reduction (both P < 0.05) in the rate of oxygen consumption with cystine loading. However, tubules incubated with 1 mM succinate or citrate had only a 13 and 14% P = NS) reduction in the rate of oxygen consumption, respectively. These data are consistent with a limitation of intracellular phosphate in the pathogenesis of the proximal tubule dysfunction with cystine loading.

Viability and respiratory activity ofPseudomonas syringaecells starved in buffer

1995 ◽  
Vol 41 (4-5) ◽  
pp. 372-377 ◽  
Author(s):  
João P. S. Cabral
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Pseudomonas Syringae ◽  
Respiratory Activity ◽  
Bacterial Cells ◽  
Intact Cells ◽  
Rate Of Oxygen Consumption ◽  
Metabolic Activities ◽  
Different Levels ◽  
Number Of Cells

Pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. The number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. The results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. Starvation also resulted in a decrease in the rate of oxygen consumption with acetate, glycerol, and succinate, but at different levels. Whereas the respiration of acetate and glycerol decreased concomitantly with culturability, the respiration of succinate decreased to levels similar to the concentration of intact cells, suggesting that all intact particles respired the succinate, but only the culturable cells respired the acetate and glycerol. The results suggest that measuring the activity of the electron-transport system can overestimate the viability of starved bacterial cells, and that complex metabolic activities such as the respiration of acetate and glycerol are probably better suited for the evaluation of this parameter.Key words: Pseudomonas syringae, starvation, culturability, viability, respiration.

scholarly journals EFFECTS OF AZIDE AND CHLORETONE ON THE SODIUM AND POTASSIUM CONTENTS AND THE RESPIRATION OF FROG SCIATIC NERVES

1958 ◽  
Vol 41 (5) ◽  
pp. 959-988 ◽  
Author(s):  
W. P. Hurlbut
Keyword(s):  
Oxygen Consumption ◽  
Respiratory Depression ◽  
Conduction Block ◽  
Slow Conduction ◽  
Ionic Distribution ◽  
Rate Of Oxygen Consumption ◽  
Sciatic Nerves ◽  
Time Courses ◽  
Sodium And Potassium

Azide (0.2 to 5.0 mM) and chloretone (2.0 to 15.0 mM) reversibly inhibited 20 to 90 per cent of the resting respiration of frog sciatic nerves, and caused a loss of potassium and a gain of sodium in this tissue. The changes in ionic contents that developed after 5 or 10 hours were roughly correlated with the degree of respiratory depression, but the time courses of these changes were different with the two reagents. In azide these changes appeared to begin immediately, while in chloretone, at concentrations between 3.0 and 5.0 mM, the ionic shifts developed after a delay of several hours. Fifteen millimolar chloretone produced immediate changes in ionic contents several times greater than those produced by anoxia. The changes in ionic distribution produced in 5 hours by anoxia, 5.0 mM azide, or 5.0 mM chloretone were at least partially reversible; those produced by 15.0 mM chloretone were irreversible. With the exception of 15.0 mM chloretone the ionic shifts produced by these reagents may be due primarily to the depression of the respiration, although there are indications that azide acts, in addition, by another pathway. Concentrations of azide or chloretone that depressed the resting rate of oxygen consumption more than 50 per cent produced a slow conduction block, while 15.0 mM chloretone blocked conduction within 15 minutes.

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