Body Temperature Regulation Research Articles

FORMULASI KRIM SARI BUAH MARKISA KUNING (Passiflora edulis L var. Flavicarpa Degener) SEBAGAI ANTI-AGING

On the outer surface of the skin there are pores (cavities) where sweat is released. The skin has many functions, as a protector of the body from various things that can be harmful, as a sense of touch, and as a regulator of body temperature.

Bombesin receptors in GtoPdb v.2021.2

Mammalian bombesin (Bn) receptors comprise 3 subtypes: BB1, BB2, BB3 (nomenclature recommended by the NC-IUPHAR Subcommittee on bombesin receptors, [115]). BB1 and BB2 are activated by the endogenous ligands neuromedin B (NMB), gastrin-releasing peptide (GRP), and GRP-(18-27). bombesin is a tetra-decapeptide, originally derived from amphibians. The three Bn receptor subtypes couple primarily to the Gq/11 and G12/13 family of G proteins [115]. Each of these receptors is widely distributed in the CNS and peripheral tissues [78, 115, 249, 278, 237, 362]. Activation of BB1 and BB2 receptors causes a wide range of physiological/pathophysiogical actions, including the stimulation of normal and neoplastic tissue growth, smooth-muscle contraction, gastrointestinal motility, feeding behavior, secretion and many central nervous system effects including regulation of circadian rhythm, body temperature control, sighing and mediation of pruritus [149, 202, 244, 115, 196, 249, 306, 68, 34, 332]. A physiological role for the BB3 receptor has yet to be fully defined although recently studies suggest an important role in glucose and insulin regulation, metabolic homeostasis, feeding, regulation of body temperature, obesity, diabetes mellitus and growth of normal/neoplastic tissues [148, 78, 162, 214, 346, 200]. Bn receptors are one of the most frequently overexpressed receptors in cancers and are receiving increased attention for their roles in tumor growth, as well as for tumour imaging and for receptor targeted cytotoxicity [202, 276, 8, 161].

FARELERDE SKOPOLAMİNLE BOZULMUŞ ÖĞRENME VE BELLEK ÜZERİNE NÖROTENSİN AGONİSTİ PD149163’ÜN ETKİSİ

Nörotensin (NT), santral sinir sisteminde nöromodülatör, nörotransmitter ve nörohormon olarak görev yapan bir tridekapeptittir. NT; vücut sıcaklığının düzenlenmesi, ağrı, motor aktivite, öğrenme ve bellek yapılanması gibi fizyolojik süreçlerde rol oynar. Bu çalışmada NT agonisti PD149163’ün akut ve kronik kullanımının skopolaminle oluşturulmuş bellek bozukluğu üzerine etkilerinin incelenmesi amaçlandı. Bu çalışma Trakya Üniversitesi Hayvan Deneyleri Yerel Etik kurulundan 2019.02.01 karar no ile onaylanmıştır. Çalışmada toplam 32 adet Balb/c türü erişkin erkek fare 4 gruba ayrıldı. Öğrenme ve bellek fonksiyonları Morris su labirenti testinde değerlendirildi. 7 gün boyunca skopolamin (1 mg/kg i.p.) uygulandıktan sonra akut ve kronik (7 gün, 4 mg/kg, i.p) PD149163 tedavisinin öğrenme ve bellek bozukluğunu geri döndürüp döndürmediği incelendi. Çalışmada yüzme eğitimlerinden elde edilen veriler, tekrarlayan ölçümler iki yönlü varyans analizi (ANOVA ) ile analiz edildi. Probe verileri tek yönlü varyans analizi ile değerlendirildi. Kronik PD149163 uygulamasının Morris su labirenti testinde ne öğrenme fazında ne de bellek fazında iyileştirici bir etkisi olmadı. Akut PD149163 uygulamasının skopolaminle oluşturulmuş bellek bozukluğu üzerine herhangi bir etkisi olmadı. Çalışmamızda NT agonistinin skopolaminle oluşturulan öğrenme ve bellek bozukluğunda düzeltici etkisi görülmemiştir. NT reseptörleri yeni ilaç hedefleri olarak değerlendirilmelerine karşın bu alanda yapılacak çok fazla sayıda çalışmaya ihtiyaç olduğu düşüncesindeyiz.

Dual-Specificity, Tyrosine Phosphorylation-Regulated Kinases (DYRKs) and cdc2-Like Kinases (CLKs) in Human Disease, an Overview.

Dual-specificity tyrosine phosphorylation-regulated kinases (DYRK1A, 1B, 2-4) and cdc2-like kinases (CLK1-4) belong to the CMGC group of serine/threonine kinases. These protein kinases are involved in multiple cellular functions, including intracellular signaling, mRNA splicing, chromatin transcription, DNA damage repair, cell survival, cell cycle control, differentiation, homocysteine/methionine/folate regulation, body temperature regulation, endocytosis, neuronal development, synaptic plasticity, etc. Abnormal expression and/or activity of some of these kinases, DYRK1A in particular, is seen in many human nervous system diseases, such as cognitive deficits associated with Down syndrome, Alzheimer’s disease and related diseases, tauopathies, dementia, Pick’s disease, Parkinson’s disease and other neurodegenerative diseases, Phelan-McDermid syndrome, autism, and CDKL5 deficiency disorder. DYRKs and CLKs are also involved in diabetes, abnormal folate/methionine metabolism, osteoarthritis, several solid cancers (glioblastoma, breast, and pancreatic cancers) and leukemias (acute lymphoblastic leukemia, acute megakaryoblastic leukemia), viral infections (influenza, HIV-1, HCMV, HCV, CMV, HPV), as well as infections caused by unicellular parasites (Leishmania, Trypanosoma, Plasmodium). This variety of pathological implications calls for (1) a better understanding of the regulations and substrates of DYRKs and CLKs and (2) the development of potent and selective inhibitors of these kinases and their evaluation as therapeutic drugs. This article briefly reviews the current knowledge about DYRK/CLK kinases and their implications in human disease.

Invasive species in the Anthropocene: Help or hindrance?

Under predicted climate change scenarios many parts of the world will be hotter. Higher temperature extremes present significant physiological challenges to ectothermic freshwater species that cannot regulate body temperature. Willows (Salix spp.) are highly invasive deciduous northern hemisphere shrubs and trees that have colonised riparian zones of southern hemisphere streams. Non–native willows are criticised for their high consumption of water and their capacity to form dense monostands along the margins and within waterways that limit light to streams in summer, alter the timing and quality of allochthonous inputs and modify ecosystem function. As such, governments invest heavily in the removal of willows from streams in order to preserve ecosystem integrity. Although detrimental effects of non–native willows are well documented, little attention has been focussed on consideration of potential ecosystem services that non–native willow infestation may provide under predicted climate warming. Here, we use a case study to illustrate that shading by non–native willows can provide thermal refugia for temperature sensitive endemic taxa and we provide a holistic approach to non–native willow removal that may provide benefits to aquatic species amid changing climate. We present a simple decision matrix for prioritising willow removal activities that may be applied to other invasive species and we discuss traditional views of invasive species management and river restoration and their relevance in a rapidly warming world. The concepts we discuss are of immediate relevance to environmental managers challenged with maintaining and restoring ecosystems that are rapidly changing in structure and function in response to climate warming.

Preoptic BRS3 neurons increase body temperature and heart rate via multiple pathways

The preoptic area (POA) is a key brain region for regulation of body temperature (Tb), dictating thermogenic, cardiovascular, and behavioral responses that control Tb. Previously characterized POA neuronal populations all reduced Tb when activated. Using mice, we now identify POA neurons expressing bombesin-like receptor 3 (POABRS3) as a population whose activation increased Tb; inversely, acute inhibition of these neurons reduced Tb. POABRS3 neurons that project to either the paraventricular nucleus of the hypothalamus or the dorsomedial hypothalamus increased Tb, heart rate, and blood pressure via the sympathetic nervous system. Long-term inactivation of POABRS3 neurons caused increased Tb variability, overshooting both increases and decreases in Tb set point, with RNA expression profiles suggesting multiple types of POABRS3 neurons. Thus, POABRS3 neuronal populations regulate Tb and heart rate, contribute to cold defense, and fine-tune feedback control of Tb. These findings advance understanding of homeothermy, a defining feature of mammalian biology.

Compliant three-dimensional thermoelectric generator filled with porous PDMS for power generation and solid-state cooling

Due to the mutual conversion of heat and electricity, thermoelectric devices (TEDs) have an outstanding display in the field of wearable electronics and human body temperature regulation. However, their rigidity affects their wearing comfort. In this paper, combined with finite element analysis (FEA), we present a flexible TED, which uses porous PDMS with low thermal conductivity to replace organic elastomer to fill thermoelectric (TE) pillars connected with liquid metal. Our design provides a method to reduce the heat transfer through TEDs. The optimal power density of 2.33 μW cm-2 can be obtained under the natural convection. And with an applied ΔT of 8.8 K, a power density of 27.02 μW cm-2 can be achieved. Moreover, at applied current of 1.0 A, the cooling effect of the flexible TED can reach up to 7 K under natural convection and 2.8 K on human wrist under 1-sun (1 kW m-2) irradiation.

Current State of SLC and ABC Transporters in the Skin and Their Relation to Sweat Metabolites and Skin Diseases.

With a relatively large surface area (2 m2) and 15% of total body mass, the skin forms the largest organ of the human body. The main functions of the skin include regulation of body temperature by insulation or sweating, regulation of the nervous system, regulation of water content, and protection against external injury. To perform these critical functions, the skin encodes genes for transporters responsible for the cellular trafficking of essential nutrients and metabolites to maintain cellular hemostasis. However, the knowledge on the expression, regulation, and function of these transporters is very limited and needs more work to elucidate how these transporters play a role both in disease progression and in healing. Furthermore, SLC and ABC transporters are understudied, and even less studied in skin. There are sparse reports on relation between transporters in skin and sweat metabolites. This mini review focuses on the current state of SLC and ABC transporters in the skin and their relation to sweat metabolites and skin diseases.

Thermoregulatory strategies of three reclusive lizards (genus Xantusia) from the Baja California peninsula, Mexico, under current and future microenvironmental temperatures.

The thermal quality of the habitat is key for the regulation of body temperature in terrestrial ectotherms and, therefore, permits them to carry out their fundamental biological activities. In thermally heterogeneous environments, ectotherms might follow different behavioral or physiological strategies to maintain their body temperature within biologically adequate boundaries, for which they depend on microhabitat selection. These aspects are, thus, relevant in the context of habitat degradation and land-use change. In this study, we characterized the thermal ecology of three lizard species (genus Xantusia) that differ in microhabitat use along the Baja California peninsula, Mexico. We made three predictions: (1) the three species will follow different thermoregulatory strategies according to habitat thermal quality; (2) the thermal requirements and tolerances of these species will match the environmental or microenvironmental thermal conditions; and (3) due to their habitat and range restriction, the species studied will be highly vulnerable to climate change. Our results indicate the existence of thermoregulatory mechanisms in Xantusia to face thermal heterogeneity, including behavioral thermoregulation by choosing different microhabitats, shifts in activity periods, and adaptation to particular high thermal quality microhabitats. Furthermore, despite their association to specific microhabitats and specialized physiology, the studied species will not be adversely affected by climate change, as the increased microenvironmental temperatures will lead to a higher habitat thermal quality and lower costs of thermoregulation. However, we do not discard other indirect adverse effects of climate change not considered in this study.

Orexin facilitates the hypoxic ventilatory response in rats

Orexin is a hypothalamic neuropeptide involved in a variety of functions including arousal, body temperature regulation, and feeding. Orexin neurons are active in wakefulness (or the dark phase in rats) and mostly silent in sleep (light phase), implying the effects of orexin are greater in wakefulness and/or dark phase. Recent evidence implicates orexin in the control of cardiorespiratory function, including the respiratory response to CO2 and blood pressure regulation. Whether orexin influences normal breathing in a state-dependent manner is unresolved. In addition, although the role of orexin in the hypercapnic ventilatory response is well established, its effects on the acute hypoxic ventilatory response (HVR) has not been investigated. We hypothesized that orexin receptor blockade would lead to hypoventilation in wakefulness but not sleep and would reduce the HVR. To test these hypotheses, we conducted two separate experiments, both of which were performed in the light phase. First, we used whole-body plethysmography to measure the ventilation of adult rats in room air. Rats were implanted with EEG and EMG electrodes to determine vigilance state, which was confirmed by applying Fast Fourier Transform on the EEG signals. After a 1hr baseline period, we injected i.p. either suvorexant (an OxR1 and OxR2 antagonist, 20 mg/kg i.p.) or vehicle (100% DMSO, i.p.) and allowed the rats to freely behave for 4 hours in the chamber while breathing room air. Separate groups of rats, also instrumented with EEG and EMG electrodes, were exposed to graded hypoxia (15%, 13%, 11%, and 9% O2) following administration of either 20 mg/kg i.p. suvorexant or vehicle. We found that, irrespective of state of vigilance, OxR1 and OxR2 blockade had no effect on baseline breathing, but significantly reduced the HVR (treatment × O2 level: p=0.03). The effect on the HVR was especially evident at 13% and 11% O2 when the response was reduced by ~30%. We show that orexin facilitates the HVR in the light phase, even though the orexin neurons are silent. Whether orexin has a larger effect on the HVR during the dark phase, when orexin neurons are active, has yet to be determined.

The Effects of Chronic Stress on Brown Adipose Tissue Remodeling and Metabolism

Adipose tissue has been found to exist in two predominant forms, white and brown. White adipose tissue (WAT) is the body's conventional storage organ, while brown adipose tissue (BAT) is responsible for non-shivering thermogenesis, which allows mammals to produce heat and regulate body temperature. Studies examining BAT and its role in whole-body metabolism have found that active BAT can lead to improved metabolic outcomes. While the beiging/ browning of WAT is a growing area of interest, the possibility of the BAT depot to “whiten” and store more triglycerides and adopt a lipid storage phenotype of WAT may have important health implications. Currently, there are limited studies that examine the direct effects of chronic stress in BAT and its ability to induce a white-like phenotype in this adipose tissue depot. This current research aimed to determine the impact of high levels of the murine stress hormone, corticosterone, on the whitening process of BAT. Six-week-old male C57BL/6J mice were exposed to high levels (100µg/ml) of corticosterone in their drinking water for four weeks. The effect of the corticosterone on BAT was investigated for its impact on insulin resistance, and the expression of uncoupling protein 1 (UCP1), which is integral to the non-shivering thermogenesis pathway. Corticosterone treatment significantly (p≤0.05) increased body weight, both WAT and BAT mass, and adipocyte size in each adipose depot. Corticosterone treatment significantly (p≤0.05) increased plasma insulin concentrations. The homeostatic model of assessment for insulin resistance (HOMA-IR) demonstrated that the corticosterone treated mice were also significantly (p≤0.05) more insulin resistant than controls. Surprisingly, the BAT of the corticosterone treated mice had significantly (p≤0.05) higher protein expression levels of UCP1 than controls. The alterations found in our in vivo model illustrated that chronic treatment with corticosterone for 4 weeks resulted in tissue remodeling, altered glucose metabolism, and adipose tissue whitening. By understanding these altered adipocyte morphologies and metabolic phenotypes in mice under chronic stress, we will be better equipped to uncover pathological effects of metabolic diseases weighing the world down today.

Chest-to-Back Skin-to-Skin Contact to Regulate Body Temperature for Low Birth Weight and/or Premature Babies: A Crossover Randomized Controlled Clinical Trial.

Skin-to-skin contact (SSC) is one of the critical components of kangaroo mother care (KMC), which is an intervention to enhance the survival of low birth weight (LBW) and/or premature infants in low-income settings. Chest-to-chest (CC) contact has been practiced widely; however, mothers face practical challenges to continuously provide CC-SSC. Hence, we assessed the efficacy of chest-to-back (CB) SSC as an alternative to CC-SSC in regulating body temperature for LBW and/or premature babies in Ethiopia. We applied a noninferiority clinical trial among LBW and/or premature infants admitted to a referral hospital neonatal intensive care unit (NICU) in Ethiopia. The study randomized the infants into two crossover arms; arm 1 applied first CB-SSC followed by CC-SSC, and arm 2 applied first CC-SSC followed by CB-SSC. The outcome measure was a change in skin temperature. We used a linear mixed-effect model for analysis. The result showed no statistically significant difference in the mean temperature between the comparison arms. In conclusion, we found that the CB-SSC was not inferior to the CC-SSC in regulating body temperature of the babies. Thus, CB-SSC can be further investigated as an alternative to CC-SSC in the kangaroo care model in low-income settings.

Adenosine 5’-monophosphate induces hypothermia and alters gene expressions in the brain and liver of chicks

The adenosine A1 receptor is important for body temperature regulation in mammals; however, little is known about its function in avian species. In this study, we investigated the effects of the adenosine A1 receptor agonist and antagonist (adenosine 5′-monophosphate [5′-AMP] and 8 p-sulfophenyl theophylline [8-SPT], respectively) on thermoregulation in chickens. Male chicks were used in this study. After administration of 5′-AMP and 8-SPT, the rectal temperature, plasma metabolites, and gene expressions in the hypothalamus and liver were measured. The rectal temperature was reduced by peripheral administration of 5′-AMP, and the hypothermic effect of 5′-AMP was attenuated by central injection of 8-SPT in chicks. In the hypothalamus, the mRNA level of the agouti-related protein (AgRP) was increased by 5′-AMP administration, whereas it was suppressed by 8-SPT. The plasma levels of free fatty acid were elevated in 5′-AMP-treated chicks and that elevation was suppressed by the 8-SPT treatment. The gene expression of proopiomelanocortin in the hypothalamus was affected by 8-SPT. Nevertheless, the gene expressions of the thermoregulation-related genes, such as the thyrotropin-releasing hormone, were not affected by 5′-AMP and 8-SPT. Hepatic gene expressions related to lipid intake and metabolism were suppressed by 5′-AMP. However, the gene expression of the uncoupling protein was upregulated by 5′-AMP. Based on these results, birds, like mammals, will undergo adenosine A1 receptor-induced hypothermia. In conclusion, it is suggested that 5′-AMP-mediated hypothermia via the adenosine A1 receptor may affect the central melanocortin system and suppress hepatic lipid metabolism in chickens.

The Role of Exosomes Derived From Mesenchymal Stromal Cells in Dermatology.

The skin is the largest organ of the human body and its main functions include providing protection from external harmful agents, regulating body temperature, and homeostatic maintenance. Skin injuries can damage this important barrier and its functions so research focuses on approaches to accelerate wound healing and treat inflammatory skin diseases. Due to their regenerative and immunomodulatory properties, mesenchymal stromal cells (MSCs) have been reported to play a significant role in skin repair and regeneration. However, it seems that the secretome of these cells and exosomes in particular may be responsible for their functions in skin regeneration and the immunomodulation field. The present review aims to gather the available information about the role of MSC-derived exosomes for both in vitro and in vivo models of different skin conditions and to highlight the need for further research in order to overcome any limitations for clinical translation.

Thermoregulation comparisons between a threatened native and an invasive lizard species

Lizard thermoregulation is costly and is largely behavioural. Podarcis raffonei, endemic of few islets of the Aeolian archipelago (southern Italy), is one of the most threatened lizards in Europe, its survival being under threat also due to the presence of the congeneric P. siculus, a successful invader characterised by behavioural plasticity and effectiveness and precision at regulating body temperature (Tb). We tested whether thermoregulation behaviour diverges between the two species by analysing (i) the heating rates under a standard thermal condition, and (ii) the temperature at which lizards ended basking (Tfinal) along a thermal gradient. Overall, we found behavioural differences between the two lizards (i.e. P. siculus exhibited lower Tfinal), although both species had comparable heating rates and thermoregulated in the same thermal conditions. The invasive P. siculus had lower Tfinal and, since heating rates were similar between species, it expended less time basking than native P. raffonei. We speculate that the observed thermal ecology differences could provide a selective advantage to P. siculus in the harsh island environment.

Environmental determinants of minimum body temperature in mammals

Physiological regulation of body temperature, set at a high level, is one of the key features of endothermic homeotherms, such as birds and mammals. However, many mammals and some birds have evolved the ability for temporal down-regulation of core body temperature. We investigated how variation in environment temperature and habitat primary productivity determine variation in daily body temperature down-regulation among mammalian species. Nearly half of the variation in minimum daily body temperature among species was explained by variation in both primary productivity and environmental temperature. Mammals expressing low minimum body temperature inhabited regions of low annual temperature with wide daily and seasonal temperature variation. Simultaneously, those regions were characterized by low productivity and low seasonality in productivity. Furthermore, regions characterized by a high level of among-year variation in environmental temperature, but not in primary productivity, were inhabited by species with low minimum body temperature, but only by those adapted to relatively humid conditions. Our results suggest that daily heterothermy can be selectively advantageous in the environmental circumstances when high energetic demands for maintaining endothermic homeothermy, physiological regulation of a high and stable body temperature, cannot be supported. The results corroborate the hypothesis that mammals that have evolved daily down-regulation of body temperature may have higher chances of surviving extinction events caused by climatic changes. Therefore, daily heterothermy adaptation in contemporary mammals represents a mechanism for surviving the ongoing global warming.

Central GABAA receptor mediates taurine-induced hypothermia and possibly reduces food intake in thermo-neutral chicks and regulates plasma metabolites in heat-exposed chicks.

The aim of this study was to examine the central action of taurine on body temperature and food intake in neonatal chicks under control thermoneutral temperature (CT) and high ambient temperature (HT). Intracerebroventricular injection of taurine caused dose-dependent hypothermia and reduced food intake under CT. The mRNA expression of the GABAA receptors, GABAAR-α1 and GABAAR-γ, but not that of GABABR, significantly decreased in the diencephalon after central injection of taurine. Subsequently, we found that picrotoxin, a GABAAR antagonist, attenuated taurine-induced hypothermia. Central taurine significantly decreased the brain concentrations of 3-methoxy-4-hydroxyphenylglycol, a major metabolite of norepinephrine; however, the concentrations of serotonin, dopamine, and the epinephrine metabolites, 3,4-hydroxyindoleacetic acid and homovanillic acid, were unchanged. Although hypothermia was not observed under HT after central injection of taurine, plasma glucose and uric acid levels were higher, and plasma sodium and calcium levels were lower, than those in chicks under CT. In conclusion, brain taurine may play a role in regulating body temperature and food intake in chicks through GABAAR. The changes in plasma metabolites under heat stress suggest that brain taurine may play an important role in maintaining homeostasis in chicks.

Parabrachial opioidergic projections to preoptic hypothalamus mediate behavioral and physiological thermal defenses.

Maintaining stable body temperature through environmental thermal stressors requires detection of temperature changes, relay of information, and coordination of physiological and behavioral responses. Studies have implicated areas in the preoptic area of the hypothalamus (POA) and the parabrachial nucleus (PBN) as nodes in the thermosensory neural circuitry and indicate that the opioid system within the POA is vital in regulating body temperature. In the present study we identify neurons projecting to the POA from PBN expressing the opioid peptides dynorphin and enkephalin. Using mouse models, we determine that warm-activated PBN neuronal populations overlap with both prodynorphin (Pdyn) and proenkephalin (Penk) expressing PBN populations. Here we report that in the PBN Prodynorphin (Pdyn) and Proenkephalin (Penk) mRNA expressing neurons are partially overlapping subsets of a glutamatergic population expressing Solute carrier family 17 (Slc17a6) (VGLUT2). Using optogenetic approaches we selectively activate projections in the POA from PBN Pdyn, Penk, and VGLUT2 expressing neurons. Our findings demonstrate that Pdyn, Penk, and VGLUT2 expressing PBN neurons are critical for physiological and behavioral heat defense.

Vertebrate Life, 10th edition

Vertebrate Life, 10th edition

Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm.

Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.