scholarly journals Physiological responses to self-induced burrowing and metabolic rate depression in the ocean quahog Arctica islandica

2011 ◽  
Vol 214 (24) ◽  
pp. 4223-4233 ◽  
Author(s):  
J. Strahl ◽  
T. Brey ◽  
E. E. R. Philipp ◽  
G. Thorarinsdottir ◽  
N. Fischer ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Physiological Responses ◽  
Metabolic Rate Depression ◽  
Arctica Islandica

scholarly journals The benefit of being still: energy savings during winter dormancy in fish come from inactivity and the cold, not from metabolic rate depression

2018 ◽  
Vol 285 (1886) ◽  
pp. 20181593 ◽  
Author(s):  
Ben Speers-Roesch ◽  
Tommy Norin ◽  
William R. Driedzic
Keyword(s):  
Metabolic Rate ◽  
Fish Species ◽  
Energy Savings ◽  
Thermal Sensitivity ◽  
Resting Metabolic Rate ◽  
Winter Dormancy ◽  
Metabolic Rate Depression ◽  
Spontaneous Movement ◽  
Anoxic Waters ◽  
Physico Chemical

Winter dormancy is used by many animals to survive the cold and food-poor high-latitude winter. Metabolic rate depression, an active downregulation of resting cellular energy turnover and thus standard (resting) metabolic rate (SMR), is a unifying strategy underlying the persistence of organisms in such energy-limited environments, including hibernating endotherms. However, controversy exists about its involvement in winter-dormant aquatic ectotherms. To address this debate, we conducted simultaneous, multi-day measurements of whole-animal oxygen consumption rate (a proxy of metabolic rate) and spontaneous movement in a model winter-dormant marine fish, the cunner ( Tautogolabrus adspersus ). Winter dormancy in cunner involved a dampened diel rhythm of metabolic rate, such that a low and stable metabolic rate persisted throughout the 24 h day. Based on the thermal sensitivity ( Q 10 ) of SMR as well as correlations of metabolic rate and movement, the reductions in metabolic rate were not attributable to metabolic rate depression, but rather to reduced activity under the cold and darkness typical of the winter refuge among substrate. Previous reports of metabolic rate depression in cunner, and possibly other fish species, during winter dormancy were probably confounded by variation in activity. Unlike hibernating endotherms, and excepting the few fish species that overwinter in anoxic waters, winter dormancy in fishes, as exemplified by cunner, need not involve metabolic rate depression. Rather, energy savings come from inactivity combined with passive physico-chemical effects of the cold on SMR, demonstrating that thermal effects on activity can greatly influence temperature–metabolism relationships, and illustrating the benefit of simply being still in energy-limited environments.

scholarly journals The effect of a 48 h fast on the physiological responses to food ingestion in normal-weight women

1990 ◽  
Vol 63 (1) ◽  
pp. 53-64 ◽  
Author(s):  
I. W. Gallen ◽  
I. A. Macdonald ◽  
P. I. Mansell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Metabolic Rate ◽  
Diastolic Blood Pressure ◽  
Test Meal ◽  
Forearm Blood Flow ◽  
Physiological Responses ◽  
Normal Weight ◽  
Plasma Catecholamine ◽  
Food Ingestion

The thermogenic, cardiovascular and metabolic responses to a 30 kJ/kg body-weight test meal were studied in eight normal-weight, healthy female subjects after a 6 or 48 h fast. There was no significant change in metabolic rate following the 48 h fast, but plasma glucose, insulin, noradrenaline and respiratory exchange ratio were all reduced, and plasma β-hydroxybutyrate was increased. Forearm blood flow was increased, with reduction in diastolic blood pressure. After the 48 h fast, there was a reduction in the metabolic rate response 40–90 min after food (control+0·54 (se0·05), 48 h fast + 0·27 (se0·12) kJ/min,I< 0·01), and in forearm blood flow and diastolic blood pressure responses, but increases in heart rate, blood glucose and plasma insulin responses to the ingestion of the test meal. There was no significant relationship between plasma catecholamine concentration and food ingestion or metabolic rate. Fasting induced considerable adaptation in these subjects and altered some of the physiological responses to food ingestion.

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions

2014 ◽  
Vol 307 (8) ◽  
pp. R1042-R1048 ◽  
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Water Vapor ◽  
Metabolic Rate ◽  
Environmental Conditions ◽  
Water Loss ◽  
Physiological Responses ◽  
Ambient Air ◽  
Minute Volume ◽  
Evaporative Water Loss ◽  
Evidence Based ◽  
Evaporative Water

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice ( Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals.

Metabolic rate depression in animals: transcriptional and translational controls

2004 ◽  
Vol 79 (1) ◽  
pp. 207-233 ◽  
Author(s):  
Kenneth B. Storey ◽  
Janet M. Storey
Keyword(s):  
Metabolic Rate ◽  
Metabolic Rate Depression

scholarly journals Predator-induced physiological responses in tadpoles challenged with herbicide pollution

2013 ◽  
Vol 59 (4) ◽  
pp. 475-484 ◽  
Author(s):  
Pablo Burraco ◽  
Lidia Jiménez Duarte ◽  
Ivan Gomez-Mestre
Keyword(s):  
Metabolic Rate ◽  
Physiological Responses ◽  
Physiological State ◽  
Antioxidant Response ◽  
Standard Metabolic Rate ◽  
Corticosterone Concentration ◽  
Natural Predator ◽  
Aquatic Beetle ◽  
Multiple Assessment ◽  
Plastic Responses

Abstract Predators induce plastic responses in multiple prey taxa, ranging from morphological to behavioral or physiological changes. In amphibians, tadpoles activate plastic responses to reduce predation risk by reducing their activity rate and altering their morphology, specifically tail depth and pigmentation. Furthermore, there is now evidence that tadpoles’ defenses are modified when predators combine with other stressful factors such as pollutants or competitors, but our knowledge on the physiological responses underlying these responses is still scarce. Here we study physiological responses in Pelobates cultripes tadpoles exposed to a natural predator (larvae of the aquatic beetle Dytiscus circumflexus), non-lethal concentrations of herbicide (gly-phosate, 0.5 mg/L and 1.0 mg/L) or both factors combined. We measured corticosterone levels, standard metabolic rate, oxidative damage (TBARS) and activity of antioxidant enzymes, and immune response (via leukocyte count). Tadpoles reduced their corticosterone concentration by ca. 24% in the presence of predator cues, whereas corticosterone did not change in the presence of glyphosate. Two enzymes involved in antioxidant response also decreased in the presence of predators (14.7% and 13.2% respectively) but not to glyphosate. Herbicide, however, increased the number of neutrophils and reduced that of lymphocytes, and had an interaction effect with predator presence. Standard metabolic rate did not vary across treatments in our experiment. Thus we show a marked physiological response to the presence of predators but little evidence for interaction between predators and low levels of herbicide. Multiple assessment of the physiological state of animals is important to understand the basis and consequences of phenotypic plasticity.

The regulation of AMPK signaling in a natural state of profound metabolic rate depression

2009 ◽  
Vol 335 (1-2) ◽  
pp. 91-105 ◽  
Author(s):  
Christopher J. Ramnanan ◽  
David C. McMullen ◽  
Amy G. Groom ◽  
Kenneth B. Storey
Keyword(s):  
Metabolic Rate ◽  
Natural State ◽  
Metabolic Rate Depression ◽  
Ampk Signaling
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