The seasonal peculiarities of force–frequency relationships in active ground squirrel Spermophilus undulatus ventricle

Nakipova, O. V.; Zakharova, N. M.; Andreeva, L. A.; Chumaeva, N. A.; Аверин, А. С.; Kosarskii, L. S.; Anufriev, A. I.; Lewinski, Dirk von; Kockskämper, Jens; Pieske, Burkert

doi:10.1016/j.cryobiol.2007.07.001

Cited by 33 publications

(22 citation statements)

References 26 publications

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“…Indeed, hibernating hearts continue to beat at temperatures far below those that cause hypothermia-induced cardiac arrest in most mammals (Liu et al, 1993;Wang et al, 2002). In addition, whereas heart rate is reduced to just 5-10 beats/min (compared to euthermic values of 350-400 beats/min), the strength of contractions needs to significantly increase in order to pump cold, viscous blood through the hibernator's body (Nakipova et al, 2007;Storey and Storey, 2004;Wickler et al, 1991). This leads to cardiac hypertrophy.…”

Section: Introductionmentioning

confidence: 96%

Myocyte enhancer factor-2 and cardiac muscle gene expression during hibernation in thirteen-lined ground squirrels

Tessier

Storey

2012

Gene

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Section: Introductionmentioning

confidence: 96%

Myocyte enhancer factor-2 and cardiac muscle gene expression during hibernation in thirteen-lined ground squirrels

Tessier

Storey

2012

Gene

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“…The plasticity of calcium homeostasis is of crucial importance for the unique ability of the heart during hibernation to function under conditions where body temperature changes from 37°C to near freezing point. It is an indicator of participation of various sources of calcium (external and intracellular) in the activation of contraction (Nakipova, 2005). The increase in pH of the serum (7.44) has also been reported with the event of hibernation (Lyman, 1952).…”

Section: Introductionmentioning

confidence: 98%

Increased Serum Magnesium and Calcium and their Regulation During Hibernation in the Indian Common Toad,Duttaphrynus melanostictus(Schneider, 1799)

Pratihar

Kundu

2009

South American Journal of Herpetology

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The present investigation reports the effect of hibernation on different blood-plasma biochemical parameters viz. plasma protein, plasma glucose and blood urea, thyroid hormone and cholesterol in the Indian Common toad (Duttaphrynus melanostictus). The study indicated that the total plasma protein is decreased significantly in hibernating toads. The decline in thyroid hormone concentration had its behavioral and physiological response that leads to increase and sustain cholesterol level in serum. But plasma glucose was significantly decreased in hibernating toads. During the hibernating phase increased urea concentration in blood acts as cryoprotectant agent, which helps the hibernating animals to sustain in winter. Thus during hibernation these altered metabolic changes appear to be essential for survival.

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“…Measurements of the isometric force of contraction of rat and ground squirrel papillary muscles were performed in oxygenated (95% O 2 /5% CO 2 ) Tyrode solution containing (in mM): NaCl, 135; KCl, 4; MgCl 2 , 1; CaCl 2 , 1.8; NaHCO 3 , 13.2; KH 2 PO 4 , 1.8; glucose, 11; (pH 7.4) as previously described [46]. In brief, isolated papillary muscles (length 2–3 mm, cross-sectional area 0.45 ± 0.07 mm 2 ) were mounted horizontally in a temperature controlled chamber (30°C), and stretched to a length at which tension of contraction is maximal.…”

Section: Methodsmentioning

confidence: 99%

Store-operated Ca2+ entry supports contractile function in hearts of hibernators

et al. 2017

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Hibernators have a distinctive ability to adapt to seasonal changes of body temperature in a range between 37°C and near freezing, exhibiting, among other features, a unique reversibility of cardiac contractility. The adaptation of myocardial contractility in hibernation state relies on alterations of excitation contraction coupling, which becomes less-dependent from extracellular Ca2+ entry and is predominantly controlled by Ca2+ release from sarcoplasmic reticulum, replenished by the Ca2+-ATPase (SERCA). We found that the specific SERCA inhibitor cyclopiazonic acid (CPA), in contrast to its effect in papillary muscles (PM) from rat hearts, did not reduce but rather potentiated contractility of PM from hibernating ground squirrels (GS). In GS ventricles we identified drastically elevated, compared to rats, expression of Orai1, Stim1 and Trpc1/3/4/5/6/7 mRNAs, putative components of store operated Ca2+ channels (SOC). Trpc3 protein levels were found increased in winter compared to summer GS, yet levels of Trpc5, Trpc6 or Trpc7 remained unchanged. Under suppressed voltage-dependent K+, Na+ and Ca2+ currents, the SOC inhibitor 2-aminoethyl diphenylborinate (2-APB) diminished whole-cell membrane currents in isolated cardiomyocytes from hibernating GS, but not from rats. During cooling-reheating cycles (30°C–7°C–30°C) of ground squirrel PM, 2-APB did not affect typical CPA-sensitive elevation of contractile force at low temperatures, but precluded the contractility at 30°C before and after the cooling. Wash-out of 2-APB reversed PM contractility to control values. Thus, we suggest that SOC play a pivotal role in governing the ability of hibernator hearts to maintain their function during the transition in and out of hibernating states.

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The seasonal peculiarities of force–frequency relationships in active ground squirrel Spermophilus undulatus ventricle

Cited by 33 publications

References 26 publications

Myocyte enhancer factor-2 and cardiac muscle gene expression during hibernation in thirteen-lined ground squirrels

Myocyte enhancer factor-2 and cardiac muscle gene expression during hibernation in thirteen-lined ground squirrels

Increased Serum Magnesium and Calcium and their Regulation During Hibernation in the Indian Common Toad,Duttaphrynus melanostictus(Schneider, 1799)

Store-operated Ca2+ entry supports contractile function in hearts of hibernators

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