MODIFICATION OF DRUG-INDUCED HYPOTHERMIA

1964 ◽  
Vol 42 (6) ◽  
pp. 745-755 ◽  
Author(s):  
H. F. Lettau ◽  
E. A. Sellers ◽  
E. Schönbaum

Male albino rats, acclimated to 23 °C, were exposed to 2 °C and hypothermia was induced by means of reserpine, chlorpromazine, or noradrenaline. Pretreatment with imipramine, iproniazid, pargyline, or l-triiodothyronine of rats receiving reserpine resulted in better maintenance of metabolic rate and body temperature, and decreased mortality compared with animals receiving reserpine alone. In the case of chlorpromazine and noradrenaline the reverse occurred. Pretreatment with hydrocortisone reduced the hypothermic effect of reserpine, and to a lesser extent that of noradrenaline, but was ineffective with chlorpromazine.The findings are consistent with the hypothesis that noradrenaline is intimately involved with thermogenesis; when tissue stores are depleted, adrenotropic drugs exert a beneficial action but when large amounts of noradrenaline are injected or released endogenously the same drugs increase toxicity. It is suggested that pretreatment with hydrocortisone produces its beneficial effect by altering the pattern of metabolic pathways involved in heat production.

Author(s):  
Jane I Khudyakov ◽  
Michael D Treat ◽  
Mikayla C Shanafelt ◽  
Jared S Deyarmin ◽  
Benjamin A Neely ◽  
...  

Many mammals use adaptive heterothermy (e.g. torpor, hibernation) to reduce metabolic demands of maintaining high body temperature (Tb). Torpor is typically characterized by coordinated declines in Tb and metabolic rate (MR) followed by active rewarming. Most hibernators experience periods of euthermy between bouts of torpor during which homeostatic processes are restored. In contrast, the common tenrec, a basoendothermic Afrotherian mammal, hibernates without interbout arousals and displays extreme flexibility in Tb and MR. We investigated the molecular basis of this plasticity in tenrecs by profiling the liver proteome of animals that were active or torpid with high and more stable Tb (~32°C) or lower Tb (~14°C). We identified 768 tenrec liver proteins, of which 50.9% were differentially abundant between torpid and active animals. Protein abundance was significantly more variable in active cold and torpid compared to active warm animals, suggesting poor control of proteome abundance. Our data suggest that torpor in tenrecs may lead to mismatches in protein pools due to poor coordination of anabolic and catabolic processes. We propose that the evolution of endothermy leading to a more realized homeothermy of boreoeutherians likely led to greater coordination of homeostatic processes and reduced mismatches in thermal sensitivities of metabolic pathways.


1990 ◽  
Vol 50 (2) ◽  
pp. 319-331 ◽  
Author(s):  
J. Slee ◽  
S. P. Simpson ◽  
A. W. Stott ◽  
J. C. Williams ◽  
D. E. Samson

ABSTRACTDifferent procedures for measuring cold resistance and metabolic rate of newborn lambs were evaluated by varying the extent of induced hypothermia, the rate of cooling and the method of rewarming. Relatively fast cooling followed by a simple self-rewarming procedure proved harmless and satisfactory.The effect of age, from birth up to 2 weeks, on thermoregulation was studied. There was no difference in cold resistance between 0·5 h and 30 h after birth, and between 1 day and 2 weeks after birth, despite a large increase in insulation, body weight and coat depth over this period. Weight-specific resting metabolic rate and cold-induced peak metabolic rate similarly did not change significantly in the first 30 h, although resting metabolic rate tended to be lower at birth than at 30 h of age. Peak metabolic rate decreased significantly between 1 day and 2 weeks of age.The effect of fasting, for 3 to 4 h after birth, on thermoregulation was also studied. Cold resistance and peak metabolic rate were not significantly affected by fasting. Recovery from hypothermia was slightly slower in fasted lambs.These results may reflect the newborn lamb's initial reliance on heat production derived from brown fat and non-shivering thermogenesis. Older lambs, which benefit from better insulation, rely more upon shivering. Fasted lambs showed a tendency to rely more on insulation and slightly less on heat production than suckled lambs.


Rangifer ◽  
1981 ◽  
Vol 1 (1) ◽  
pp. 29 ◽  
Author(s):  
R. Hissa ◽  
S. Saarela ◽  
M. Nieminen

<p>Development of temperature regulation was investigated by determining the ability of newborn reindeer calves (Rangifer tarandus tarandus) to maintain a normal body temperature when exposed to an incrementially decreasing ambient temperature. Newborn calves (1 day old) can maintain their body temperature even at -15 &deg;C. They can increase their metabolic rate five- to sixfold. Heat production is primarily stimulated by the sympathetic nervous system. The response to exogenous administration of noradrenaline and propranolol was investigated.</p><p>Poronvasan l&aring;mmons&aring;&aring;telyn syntym&aring;nj&aring;lkeinen kehittyminen.</p><p>Abstract in Finnish / Yhteenveto: Vastasyntyneiden poronvasojen kylmansietoa ja lammonsaatelya tutkittiin toukokuussa 1981 Inarin Kaamasessa Paliskuntain yhdistyksen koetarhassa. Tutkittavat vasat olivat 1-10 vuorokauden ikaisia. Vasa asetettiin j&aring;&aring;hdytett&aring;va&aring;n mittauskammioon. Sen aineenvaihdunta, lampotilat niin ihon eri kohdista kuin perasuolesta, lihasvarina ja sydanfrekvenssi rekisteroitiin jatkuvasti. Tulosten mukaan naytt&aring;a silt&aring; kuin 1 vuorokauden ikaiselle vasalle -15 &deg;C olisi ehdoton alaraja l&aring;mpotilan s&aring;&aring;telyssa. Se kykeni kohottamaan hapenkulutusta talloin 5-kertaisesti. Lihasvarinan merkitys on vahainen verrattuna kemialliseen l&aring;mmontuottoon kylmassa. Tama voitiin osoittaa injisoimalla vasaan sympaattisen hermoston valittajaainetta noradrenaliinia.</p><p>Temperaturreguleringens utvikling hos nyf&oslash;dte reinkalver.</p><p>Abstract in Norwegian / Sammendrag: Temperaturreguleringens utvikling er studert ved &aring; bestemme nyf&oslash;dte reinkalvers evne til &aring; opprettholde normal kroppstemperatur under p&aring;virkning av gradvis synkende omgivelsestemperatur. Nyf&oslash;dte kalver (1 d&oslash;gn gamle) kan opprettholde sin kroppstemperatur selv ved -15 &deg;C. De kan &oslash;ke sin omsetningshastighet fem til seks ganger. I starten er varmeproduksjonen stimulert av det sympatiske nervesystem. Virkningen av tilf&oslash;rt noradrenalin og propranolol ble studert og skjelving synes &aring; spille bare en mindre rolle umiddelbart etter f&oslash;dselen.</p>


1995 ◽  
Vol 198 (11) ◽  
pp. 2385-2392 ◽  
Author(s):  
M May

The large, endothermic dragonfly Anax junius regulates the temperatures of its thorax (Tth) and head (Th) during flight. At high ambient temperature (Ta) it is able to dispose of excess heat from the thorax by increasing hemolymph circulation to the abdomen, but recent evidence suggests that heat loss to the abdomen is largely passive at Ta&lt;30 &deg;C. Nevertheless, these insects continue to regulate Tth and Th at least down to 20 &deg;C and probably at much lower values of Ta. As Ta declines, A. junius glide less, probably fly faster when feeding, and increase their wingbeat frequency when patrolling. Presumably as a result of these behavioral changes, heat production, and thus inferred flight metabolic rate, is inversely proportional to Ta. This is the first demonstration based on field data that an insect regulates body temperature while flying by altering heat production.


1967 ◽  
Vol 45 (4) ◽  
pp. 723-732 ◽  
Author(s):  
Alphonse J. Ingenito ◽  
Desmond D. Bonnycastle

To test the previously reported theory that changes in brain amine levels caused by drugs would lead to disturbances in body temperature regulation, the levels of 5-hydroxytryptamine and noradrenaline in the whole brain of male albino rats were determined after the animals were treated with drugs and then exposed to room temperature or elevated temperatures of 37 or 40 °C. Control experiments with untreated animals were run in parallel. The drugs used were reserpine, α-methyl-m-tyrosine (MMT), 4-chloro-N-methyl-amphetamine, 3,4-dihydroxyphenyl-L-alanine (dopa), 5-hydroxy-DL-tryptophan (5-HTP), chlorpromazine, and 2,4-dinitrophenol. The results indicated that amine levels of the brain could be increased or decreased pharmacologically without a significant interference in body temperature regulation, and also that certain drugs which interfered with body temperature regulation did so without any effect on whole-brain amine levels. It was concluded that, in the rat, there were no clear-cut relationships between whole-brain 5-hydroxytryptamine or noradrenaline levels and the ability to regulate body temperature.


2013 ◽  
Vol 999 (999) ◽  
pp. 1-6
Author(s):  
Meijuan Zhang ◽  
Haiying Wang ◽  
Jinbing Zhao ◽  
Cong Chen ◽  
Rehana K. Leak ◽  
...  

CNS Spectrums ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 179-180
Author(s):  
Daniel Dowd ◽  
David S. Krause

AbstractBackgroundThere is a plethora of drugs available to psychiatrists for treatment of mental illness, which can vary in efficacy, tolerability, metabolic pathways and drug-drug interactions. Psychotropics are the second most commonly listed therapeutic class mentioned in the FDA’s Table of Pharmacogenomic Biomarkers in Drug Labeling. Pharmacogenomic (PGx) assays are increasingly used in psychiatry to help select safe and appropriate medication for a variety of mental illnesses. Our commercial laboratory offers PGx expert consultations by PharmDs and PhDs to clinician-users. Our database contains valuable information regarding the treatment of a diverse and challenging population.MethodsGenomind offers a PGx assay currently measuring variants of 24 genes relevant for selection of drugs with a mental illness indication. Since 2012 we have analyzed > 250,000 DNA samples. Between 10/18 - 8/20 6,401 reports received a consult. The data contained herein are derived from those consults. Consultants record information on prior meds, reason for failure or intolerability, potential risk-associated or useful drugs based on the genetic variants. Consultants only recommend specific drugs and doses consistent with a published PGx guideline.ResultsThe 5 most commonly discussed genes were SLC6A4, MTHFR, CACNA1C, COMT and BDNF. The 3 most commonly discussed drugs were fluoxetine, lithium and duloxetine. The most common reasons for drug failure were inefficacy and drug induced “agitation, irritability and/or anxiety”. SSRIs were the most common class of discontinued drug; sertraline, escitalopram and fluoxetine were the three most commonly reported discontinuations and were also the 3 most likely to be associated with “no improvement”. Aripiprazole was the most commonly reported discontinued atypical antipsychotic. The providers rated 94% of consultations as extremely or very helpful at the time of consult. An independent validation survey of 128 providers confirmed these ratings, with 96% reporting a rating of “very helpful” or “extremely helpful”. In addition, 94% reported that these consults were superior to PGx consults provided through other laboratories. Patient characteristics captured during consults via a Clinical Global Impressions-Severity (CGI-S) scale revealed that the majority of patients were moderately (54%) or markedly ill (23%). The most frequent symptoms reported were depression, anxiety, insomnia and inattentiveness.DiscussionThe large variety of psychotropic drugs available to providers, and their highly variable response rates, tolerability, capacity for drug-drug interactions and metabolic pathways present a challenge for even expert psychopharmacologists. Consultation with experts in PGx provides additional useful information that may improve outcomes and decrease healthcare resource utilization. This database may provide future opportunities for machine learning algorithms to further inform implications of included gene variants.FundingGenomind, Inc.


1998 ◽  
Vol 85 (1) ◽  
pp. 204-209 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
Michael N. Sawka ◽  
Kent B. Pandolf

This study examined whether serial cold-water immersions over a 10-h period would lead to fatigue of shivering and vasoconstriction. Eight men were immersed (2 h) in 20°C water three times (0700, 1100, and 1500) in 1 day (Repeat). This trial was compared with single immersions (Control) conducted at the same times of day. Before Repeat exposures at 1100 and 1500, rewarming was employed to standardize initial rectal temperature. The following observations were made in the Repeat relative to the Control trial: 1) rectal temperature was lower and heat debt was higher ( P < 0.05) at 1100; 2) metabolic heat production was lower ( P < 0.05) at 1100 and 1500; 3) subjects perceived the Repeat trial as warmer at 1100. These data suggest that repeated cold exposures may impair the ability to maintain normal body temperature because of a blunting of metabolic heat production, perhaps reflecting a fatigue mechanism. An alternative explanation is that shivering habituation develops rapidly during serially repeated cold exposures.


Nature ◽  
2019 ◽  
Vol 572 (7771) ◽  
pp. 651-654 ◽  
Author(s):  
Jorge Avaria-Llautureo ◽  
Cristián E. Hernández ◽  
Enrique Rodríguez-Serrano ◽  
Chris Venditti

2015 ◽  
Vol 16 ◽  
pp. S186-S187 ◽  
Author(s):  
I. Park ◽  
M. Kayaba ◽  
K. Iwayama ◽  
H. Ogata ◽  
Y. Sengoku ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document