Regulation of cardiac rhythm in hibernating mammals
The dramatic fall in heart rate exhibited by mammals entering hibernation begins before there is any noticeable fall in body temperature. The initial, progressive decrease in heart rate is the result of a cyclic parasympathetic activation that induces skipped beats and regular asystoles as well as slows the even heart beat. As body temperature subsequently falls, the parasympathetic influence is progressively withdrawn and periods of parasympathetic and sympathetic dominance alternate and give rise to regular periods of arrhythmia (tachycardia followed by bradycardia), and occasional long asystoles or periods of highly irregular cardiac activity. Superimposed on this is a vagally-mediated, respiratory sinus arrhythmia that is accentuated in species that breathe episodically. These events give way to a uniform heart rate in deep hibernation at low temperatures where both parasympathetic and sympathetic tone appear absent. The complete absence of tone is not a function of reduced temperature but is reflective of the state of deep, steady state hibernation. The elevation in heart rate that accompanies the onset of arousal is the result of dramatic increases in sympathetic activation that precede any increases in body temperature. ...Continue Reading
Reduction of metabolism during hibernation and daily torpor in mammals and birds: temperature effect or physiological inhibition?
Functional characteristics and responses to adrenergic stimulation of isolated heart preparations from hypothermic and hibernating subjects
Thermoregulatory, brain and behavioral mechanisms during entrance into hibernation in the squirrel, Citellus beecheyi
The endogenous tissue respiration of the Arctic ground squirrel as affected by hibernation and season
Membrane basis for fish oil effects on the heart: linking natural hibernators to prevention of human sudden cardiac death
Vertebrate cell death in energy-limited conditions and how to avoid it: what we might learn from mammalian hibernators and other stress-tolerant vertebrates
Extreme respiratory sinus arrhythmia enables overwintering black bear survival--physiological insights and applications to human medicine.
Nitric oxide synthase-dependent "on/off" switch and apoptosis in freshwater and aestivating lungfish, Protopterus annectens: skeletal muscle versus cardiac muscle
Preference of IRES-mediated initiation of translation during hibernation in golden-mantled ground squirrels, Spermophilus lateralis.
Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy.
Membrane phospholipid fatty acid composition regulates cardiac SERCA activity in a hibernator, the Syrian hamster (Mesocricetus auratus)
Central activation of the A1 adenosine receptor (A1AR) induces a hypothermic, torpor-like state in the rat
Mitochondrial phenotype of marsupial torpor: Fuel metabolic switch in the Chilean mouse-opossum Thylamys elegans
Differential NOS expression in freshwater and aestivating Protopterus dolloi (lungfish): heart vs kidney readjustments
Regulation of Torpor in the Gray Mouse Lemur: Transcriptional and Translational Controls and Role of AMPK Signaling
The effect of temperature on adrenergic receptors of alveolar type II cells of a heterothermic marsupial
Temporal variation of autonomic balance and diseases during circadian, seasonal, reproductive, and lifespan cycles
The parasympathetic nervous system and its influence on heart rate in torpid western pygmy possums, Cercatetus concinnus (Marsupialia: Burramyidae)
Central nervous system regulation of mammalian hibernation: implications for metabolic suppression and ischemia tolerance
Low body temperature governs the decline of circulating lymphocytes during hibernation through sphingosine-1-phosphate
Regulatory mechanism of body temperature in the central nervous system during the maintenance phase of hibernation in Syrian hamsters: involvement of β-endorphin
Differential regulation of glomerular and interstitial endothelial nitric oxide synthase expression in the kidney of hibernating ground squirrel
Comparison of brain transcriptome of the greater horseshoe bats (Rhinolophus ferrumequinum) in active and torpid episodes
Electrophysiological differences in cholinergic signaling between the hearts of summer and winter frogs (Rana temporaria)
Influence of torpor on cardiac expression of genes involved in the circadian clock and protein turnover in the Siberian hamster (Phodopus sungorus)
Central A1-receptor activation associated with onset of torpor protects the heart against low temperature in the Syrian hamster
Mitochondrial metabolic suppression and reactive oxygen species production in liver and skeletal muscle of hibernating thirteen-lined ground squirrels
Temporal relationships of blood pressure, heart rate, baroreflex function, and body temperature change over a hibernation bout in Syrian hamsters
Mild hypothermia causes a shift in the alternative splicing of cold-inducible RNA-binding protein transcripts in Syrian hamsters
Invited review: molecular adaptations in mammalian hibernators: unique adaptations or generalized responses?
Induction of hibernation-like hypothermia by central activation of the A1 adenosine receptor in a non-hibernator, the rat
Atrial fibrillation is a common arrhythmia that is associated with substantial morbidity and mortality, particularly due to stroke and thromboembolism. Here is the latest research.
Arrhythmias are abnormalities in heart rhythms, which can be either too fast or too slow. They can result from abnormalities of the initiation of an impulse or impulse conduction or a combination of both. Here is the latest research on arrhythmias.
Bradyarrhythmias are slow heart rates. Symptoms may include syncope, dizziness, fatigure, shortness of breath, and chest pains. Find the latest research on bradyarrhythmias here.