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https://www.readbyqxmd.com/read/27933367/antipsychotic-inductors-of-brain-hypothermia-and-torpor-like-states-perspectives-of-application
#1
REVIEW
Yury S Tarahovsky, Irina S Fadeeva, Natalia P Komelina, Maxim O Khrenov, Nadezhda M Zakharova
Hypothermia and hypometabolism (hypometabothermia) normally observed during natural hibernation and torpor, allow animals to protect their body and brain against the damaging effects of adverse environment. A similar state of hypothermia can be achieved under artificial conditions through physical cooling or pharmacological effects directed at suppression of metabolism and the processes of thermoregulation. In these conditions called torpor-like states, the mammalian ability to recover from stroke, heart attack, and traumatic injuries greatly increases...
December 8, 2016: Psychopharmacology
https://www.readbyqxmd.com/read/27914963/hypothermia-in-mouse-is-caused-by-adenosine-a1-and-a3-receptor-agonists-and-amp-via-three-distinct-mechanisms
#2
Jesse Lea Carlin, Shalini Jain, Elizabeth Gizewski, Tina C Wan, Dilip K Tosh, Cuiying Xiao, John A Auchampach, Kenneth A Jacobson, Oksana Gavrilova, Marc L Reitman
Small mammals have the ability to enter torpor, a hypothermic, hypometabolic state, allowing impressive energy conservation. Administration of adenosine or adenosine 5'-monophosphate (AMP) can trigger a hypothermic, torpor-like state. We investigated the mechanisms for hypothermia using telemetric monitoring of body temperature in wild type and receptor knock out (Adora1(-/-), Adora3(-/-)) mice. Confirming prior data, stimulation of the A3 adenosine receptor (AR) induced hypothermia via peripheral mast cell degranulation, histamine release, and activation of central histamine H1 receptors...
November 30, 2016: Neuropharmacology
https://www.readbyqxmd.com/read/27853604/hibernation-in-a-primate-does-sleep-occur
#3
Marina B Blanco, Kathrin H Dausmann, Sheena L Faherty, Peter Klopfer, Andrew D Krystal, Robert Schopler, Anne D Yoder
During hibernation, critical physiological processes are downregulated and thermogenically induced arousals are presumably needed periodically to fulfil those physiological demands. Among the processes incompatible with a hypome tabolic state is sleep. However, one hibernating primate, the dwarf lemur Cheirogaleus medius, experiences rapid eye movement (REM)-like states during hibernation, whenever passively reaching temperatures above 30°C, as occurs when it hibernates in poorly insulated tree hollows under tropical conditions...
August 2016: Royal Society Open Science
https://www.readbyqxmd.com/read/27848158/evidence-of-prolonged-torpor-in-goodman-s-mouse-lemurs-at-ankafobe-forest-central-madagascar
#4
Marina B Blanco, Andon'ny A Andriantsalohimisantatra, Tahiry V Rivoharison, Jean-Basile Andriambeloson
The small-bodied mouse lemurs of Madagascar (Microcebus) are capable of heterothermy (i.e., torpor or hibernation). The expression of these energy-saving strategies has been physiologically demonstrated in three species: M. berthae, the pygmy mouse lemur (daily torpor), M. murinus, the gray mouse lemur (daily torpor and hibernation), and M. griseorufus, the reddish-gray mouse lemur (daily, prolonged torpor and hibernation). Additional evidence, based on radiotracking and seasonal body mass changes, indicated that mouse lemur capabilities for heterothermy extended to M...
November 15, 2016: Primates; Journal of Primatology
https://www.readbyqxmd.com/read/27845399/hypometabolism-during-daily-torpor-in-mice-is-dominated-by-reduction-in-the-sensitivity-of-the-thermoregulatory-system
#5
Genshiro A Sunagawa, Masayo Takahashi
Some mammals enter a hypometabolic state either daily torpor (minutes to hours in length) or hibernation (days to weeks), when reducing metabolism would benefit survival. Hibernators demonstrate deep torpor by reducing both the sensitivity (H) and the theoretical set-point temperature (TR) of the thermogenesis system, resulting in extreme hypothermia close to ambient temperature. However, these properties during daily torpor remain poorly understood due to the very short steady state of the hypometabolism and the large variation among species and individuals...
November 15, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27830334/the-effect-of-body-mass-and-diet-composition-on-torpor-patterns-in-a-malagasy-primate-microcebus-murinus
#6
Sheena L Faherty, C Ryan Campbell, Susan A Hilbig, Anne D Yoder
One of the most obvious physiological changes accompanying seasonal heterothermy in mammals is a fattening stage preceding periods of resource scarcity. This phenomenon reflects the interplay of both diet and physiology. Though the accrual of fat stores is known to be essential for overwintering in some species, the influence of diet on the physiology of torpor is not fully understood. Results from captive studies in heterothermic rodents and marsupials have indicated that when autumn diets are enriched with polyunsaturated fatty acids (PUFAs), animals receiving these diets experience deeper and more frequent torpor bouts than their counterparts receiving a control diet...
November 9, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/27813827/the-central-control-of-energy-expenditure-exploiting-torpor-for-medical-applications
#7
Matteo Cerri
Autonomic thermoregulation is a recently acquired function, as it appears for the first time in mammals and provides the brain with the ability to control energy expenditure. The importance of such control can easily be highlighted by the ability of a heterogeneous group of mammals to actively reduce metabolic rate and enter a condition of regulated hypometabolism known as torpor. The central neural circuits of thermoregulatory cold defense have been recently unraveled and could in theory be exploited to reduce energy expenditure in species that do not normally use torpor, inducing a state called synthetic torpor...
October 28, 2016: Annual Review of Physiology
https://www.readbyqxmd.com/read/27792535/dietary-supplementation-with-n-3-polyunsaturated-fatty-acids-reduces-torpor-use-in-a-tropical-daily-heterotherm
#8
Pauline Vuarin, Pierre-Yves Henry, Martine Perret, Fabien Pifferi
Polyunsaturated fatty acids (PUFAs) are involved in a variety of physiological mechanisms, including heterothermy preparation and expression. However, the effects of the two major classes of PUFAs, n-6 and n-3, can differ substantially. While n-6 PUFAs enhance torpor expression, n-3 PUFAs reduce the ability to decrease body temperature. This negative impact of n-3 PUFAs has been revealed in temperate hibernators only. Yet because tropical heterotherms generally experience higher ambient temperature and exhibit higher minimum body temperature during heterothermy, they may not be affected as much by PUFAs as their temperate counterparts...
November 2016: Physiological and Biochemical Zoology: PBZ
https://www.readbyqxmd.com/read/27755687/seasonal-control-of-mammalian-energy-balance-recent-advances-in-the-understanding-of-daily-torpor-and-hibernation
#9
Martin Jastroch, Sylvain Giroud, Perry Barrett, Fritz Geiser, Gerhard Heldmaier, Annika Herwig
Endothermic mammals and birds require intensive energy turnover to sustain high body temperatures and metabolic rates. To cope with energetic bottlenecks associated with the change of seasons, and to minimise energy expenditure, complex mechanisms and strategies, such as daily torpor and hibernation, are used. During torpor metabolic depression and low body temperatures save energy. However, these bouts of torpor lasting for hours to weeks are interrupted by active 'euthermic' phases with high body temperatures...
October 18, 2016: Journal of Neuroendocrinology
https://www.readbyqxmd.com/read/27734149/torpor-and-basking-after-a-severe-wildfire-mammalian-survival-strategies-in-a-scorched-landscape
#10
Jaya K Matthews, Clare Stawski, Gerhard Körtner, Cassandra A Parker, Fritz Geiser
Wildfires can completely obliterate above-ground vegetation, yet some small terrestrial mammals survive during and after fires. As knowledge about the physiological and behavioural adaptations that are crucial for post-wildfire survival is scant, we investigated the thermal biology of a small insectivorous marsupial (Antechinus flavipes) after a severe forest fire. Some populations of antechinus survived the fire in situ probably by hiding deep in rocky crevices, the only fire-proof sites near where they were trapped...
October 12, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/27708046/primate-torpor-expression-ghost-of-the-climatic-past
#11
Kathrin H Dausmann, Lisa Warnecke
Torpor, the controlled depression of virtually all bodily function during scarce periods, was verified in primates under free-ranging conditions less than two decades ago. The large variety of different torpor patterns found both within and among closely related species is particularly remarkable. To help unravel the cause of these variable patterns, our review investigates primate torpor use within an evolutionary framework. First, we provide an overview of heterothermic primate species, focusing on the Malagasy lemurs, and discuss their use of daily torpor or hibernation in relation to habitat type and climatic conditions...
November 1, 2016: Physiology
https://www.readbyqxmd.com/read/27698492/first-direct-evidence-of-long-distance-seasonal-movements-and-hibernation-in-a-migratory-bat
#12
Theodore J Weller, Kevin T Castle, Felix Liechti, Cris D Hein, Michael R Schirmacher, Paul M Cryan
Understanding of migration in small bats has been constrained by limitations of techniques that were labor-intensive, provided coarse levels of resolution, or were limited to population-level inferences. Knowledge of movements and behaviors of individual bats have been unknowable because of limitations in size of tracking devices and methods to attach them for long periods. We used sutures to attach miniature global positioning system (GPS) tags and data loggers that recorded light levels, activity, and temperature to male hoary bats (Lasiurus cinereus)...
October 4, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27678249/molecular-characterization-of-gpr50-gene-and-study-of-its-comparative-genetic-variability-in-sheep-breeds-adapted-to-different-thermo-contrasting-climatic-regimens
#13
Vijay Kumar Saxena, Davendra Kumar, S M K Naqvi
GPR50, formerly known as a melatonin-related receptor, is one of the three subtypes of melatonin receptor subfamily, together with MTNR1A and MTNR1B. GPR50, despite its high identity with the melatonin receptor family, does not bind melatonin and is considered to be an ortholog of MTNR1C in mammals. GPR50-expressing cells have been found in the dorsomedial nucleus of the hypothalamus, the periventricular nucleus, and the median eminence. Genetic and functional evidence have been recently investigated linking GPR50 to adaptive thermogenesis and torpor, but still, it is an orphan receptor and is yet to be studied conclusively...
September 27, 2016: International Journal of Biometeorology
https://www.readbyqxmd.com/read/27660641/the-bear-circadian-clock-doesn-t-sleep-during-winter-dormancy
#14
Heiko T Jansen, Tanya Leise, Gordon Stenhouse, Karine Pigeon, Wayne Kasworm, Justin Teisberg, Thomas Radandt, Robert Dallmann, Steven Brown, Charles T Robbins
BACKGROUND: Most biological functions are synchronized to the environmental light:dark cycle via a circadian timekeeping system. Bears exhibit shallow torpor combined with metabolic suppression during winter dormancy. We sought to confirm that free-running circadian rhythms of body temperature (Tb) and activity were expressed in torpid grizzly (brown) bears and that they were functionally responsive to environmental light. We also measured activity and ambient light exposures in denning wild bears to determine if rhythms were evident and what the photic conditions of their natural dens were...
2016: Frontiers in Zoology
https://www.readbyqxmd.com/read/27638521/the-influence-of-natural-photoperiod-on-seasonal-torpor-expression-of-two-opportunistic-marsupial-hibernators
#15
James M Turner, Fritz Geiser
Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months...
September 16, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/27599501/phospholipids-of-liver-cell-nuclei-during-hibernation-of-yakutian-ground-squirrel
#16
A A Lakhina, L N Markevich, N M Zakharova, V N Afanasyev, I K Kolomiytseva, E E Fesenko
In hibernating Yakutian ground squirrels S. undulatus, the content of total phospholipids in the nuclei of liver increased by 40% compared to that in animals in summer. In torpid state, the amount of sphingomyelin increased almost 8 times; phosphatidylserine, 7 times; and cardiolipin, 4 times. In active "winter" ground squirrels, the amount of sphingomyelin, phosphatidylserine, and cardiolipin decreased compared to the hibernating individuals but remained high compared to the "summer" ones. The torpor state did not affect the amount of lysophosphatidylcholine and phosphatidylinositol...
July 2016: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/27593478/inhibition-of-skeletal-muscle-atrophy-during-torpor-in-ground-squirrels-occurs-through-downregulation-of-myog-and-inactivation-of-foxo4
#17
Yichi Zhang, Shannon N Tessier, Kenneth B Storey
Foxo4 and MyoG proteins regulate the transcription of numerous genes, including the E3 ubiquitin ligases MAFbx and MuRF1, which are activated in skeletal muscle under atrophy-inducing conditions. In the thirteen-lined ground squirrel, there is little muscle wasting that occurs during hibernation, a process characterized by bouts of torpor and arousal, despite virtual inactivity. Consequently, we were interested in studying the regulatory role of Foxo4 and MyoG on ubiquitin ligases throughout torpor-arousal cycles...
October 2016: Cryobiology
https://www.readbyqxmd.com/read/27583287/transitioning-between-entry-and-exit-from-mammalian-torpor-the-involvement-of-signal-transduction-pathways
#18
Shannon N Tessier, Kenneth B Storey
Signal transduction pathways transmit information received at the cell surface to intracellular targets which direct a response. We highlight the involvement of signaling pathways in mediating transitions between mammalian torpor and euthermia and suggest these promote survival under stressors (e.g., hypothermia, ischemia-reperfusion) that would otherwise cause damage in nonhibernators.
July 2014: Temperature: Multidisciplinary Biomedical Journal
https://www.readbyqxmd.com/read/27583286/hypothermia-torpor-and-the-fundamental-importance-of-understanding-the-central-control-of-thermoregulation
#19
Domenico Tupone, Shaun Morrison
Activation of central adenosine A1 receptors in the rat, a non-hibernating species, mimics the physiological characteristics of torpor and could thus represent a basis for the development of pharmacological approaches to induce therapeutic hypothermia in pathologies such as brain hemorrhage and ischemia, and to facilitate long-term space travel.
July 2014: Temperature: Multidisciplinary Biomedical Journal
https://www.readbyqxmd.com/read/27581948/aestivation-and-brain-of-the-african-lungfish-protopterus-annectens
#20
COMMENT
Shit F Chew, Kum Hiong
Scientists have long been fascinated by animals undergoing aestivation, a state of torpor at high temperature, due to its great potential in fields ranging from medicine to space travel. The brain of the African lungfish is able to coordinate a whole-body response to induce aestivation and to arouse from aestivation.
July 2014: Temperature: Multidisciplinary Biomedical Journal
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