Dipeptide ASP-TYR extracted from the brain of hibernating squirrels was found to potentiate vagal effect on the cardiac rhythm, whereas pentapeptide neokyotorphin--to diminish it. In both cases the effect was due to an alteration of the tonic component's strength in the vagal chronotropic effect. The selective peptidergic modulation of the vagal effect on the cardiac rhythm suggests different physiological roles of the tonic and synchronizing components in regulation of the heart.
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Front Neurosci
December 2024
National Key Laboratory of Space Medicine, China Astronaut Research and Training Center, Beijing, China.
Hibernation, an adaptive mechanism to extreme environmental conditions, is prevalent among mammals. Its main characteristics include reduced body temperature and metabolic rate. However, the mechanisms by which hibernating animals re-enter deep sleep during the euthermic phase to sustain hibernation remain poorly understood.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
December 2024
Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia; Department of Physiology and Pathology, Faculty of Basic Medicine, M.V. Lomonosov Moscow State University, Moscow, Russia.
Hibernation is accompanied by dramatic decrease of blood flow in many organs due to the increase of their vascular resistances. We compared the responses of mesenteric, renal, and cerebral proximal resistance arteries in summer active (SA) and winter hibernating (WH) ground squirrels and studied the signaling pathways of Rho-kinase and NO. Wire myography and Western blotting were used to assess the arterial responses and protein abundances.
View Article and Find Full Text PDFSci Rep
December 2024
Insect Design Technology Group, Division of Insect Advanced Technology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, 305-8634, Ibaraki, Japan.
Adult females of the primitively eusocial wasp Polistes jokahamae can change caste in response to photoperiod length. Short-day photoperiod females store more lipids but have less developed ovaries for hibernation (becoming gynes), whereas long-day photoperiod females have fewer lipid stores but more developed ovaries under queenless conditions (becoming egg-laying workers). To explore the physiological mechanisms underlying photoperiod-related caste determination, analyses of gene expression levels in the brains of short- or long-day females were performed.
View Article and Find Full Text PDFScience
November 2024
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
Water deprivation is a life-threatening condition that engages a protective physiological response to couple osmolyte retention with potentiation of thirst. This response, typical for most mammals, safeguards against short-term water deprivation but fails in the long term. Thirteen-lined ground squirrels () use the short-term response during summer, whereas during winter, they lack thirst and survive without water for months.
View Article and Find Full Text PDFToxics
November 2024
Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing 100193, China.
Reptiles rely on hibernation to survive harsh winters, but climate change and pesticide use in agriculture jeopardize their survival, making the ecosystem vulnerable. S-metolachlor (SM), a commonly found herbicide in soil, and its metabolite metolachlor oxanilic acid (MO) induce oxidative stress and disrupt reproductive hormones. In this study, lizards were exposed to SM- and MO-contaminated soil for 45 days during hibernation.
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