Maintenance of ion concentration gradients in the cold in aorta from rat and ground squirrel

Kamm, Kristine E.; Zatzman, Marvin L.; Jones, Allan W.; South, Frank E.

doi:10.1152/ajpcell.1979.237.1.c17

Cited by 23 publications

(12 citation statements)

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“…Hibernators are also markedly resistant to ventricular fibrillation (35) and to the cardiac conduction block that generally accompanies hypothermia in mammals (26). Moreover, the hibernator's heart maintains Na ϩ /K ϩ ion homeostasis during torpor, while nonhibernating mammals lose ion homeostasis over time (36).While insightful, these studies provide a partial view of cardioprotection in hibernators, because they sampled few physiological states and focused on relatively few gene products. To maximize its potential to reveal novel medical treatment strategies, however, the cardiac phenotype of hibernators must be characterized in detail.…”

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confidence: 99%

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Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy

Grabek

Karimpour-Fard

Epperson³

et al. 2011

Physiological Genomics

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SL. Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy. Physiol Genomics 43: 1263-1275. First published September 13, 2011 doi:10.1152/physiolgenomics.00125.2011.-The hibernator's heart functions continuously and avoids damage across the wide temperature range of winter heterothermy. To define the molecular basis of this phenotype, we quantified proteomic changes in the 13-lined ground squirrel heart among eight distinct physiological states encompassing the hibernator's year. Unsupervised clustering revealed a prominent seasonal separation between the summer homeotherms and winter heterotherms, whereas within-season state separation was limited. Further, animals torpid in the fall were intermediate to summer and winter, consistent with the transitional nature of this phase. A seasonal analysis revealed that the relative abundances of protein spots were mainly winter-increased. The winter-elevated proteins were involved in fatty acid catabolism and protein folding, whereas the winter-depleted proteins included those that degrade branched-chain amino acids. To identify further statedependent changes, protein spots were re-evaluated with respect to specific physiological state, confirming the predominance of seasonal differences. Additionally, chaperone and heat shock proteins increased in winter, including HSPA4, HSPB6, and HSP90AB1, which have known roles in protecting against ischemia-reperfusion injury and apoptosis. The most significant and greatest fold change observed was a disappearance of phospho-cofilin 2 at low body temperature, likely a strategy to preserve ATP. The robust summer-to-winter seasonal proteomic shift implies that a winter-protected state is orchestrated before prolonged torpor ensues. Additionally, the general preservation of the proteome during winter hibernation and an increase of stress response proteins, together with dephosphorylation of cofilin 2, highlight the importance of ATP-conserving mechanisms for winter cardioprotection. 2D DiGE; CFL2; hibernating; Ictidomys (spermophilus) tridecemlineatus; mass spectrometry HIBERNATION IN MAMMALS IS characterized by dramatic, but reversible, reductions in body temperature (T b ) and metabolic rate. During this torpid phase, respiration and heart rate also decline to 1-4% of their euthermic values (for review, see Ref. 11). Torpor bouts are punctuated by interbout arousals (54), when physiological rates are restored to or even surpass euthermic levels (11). For circannual hibernators such as 13-lined ground squirrels, Ictidomys tridecemlineatus, the ability to orchestrate reversible metabolic depression exists only in winter (reviewed in Ref. 38). This heterothermic winter phenotype contrasts markedly with summer, when animals remain homeotherms. A "two-switch" mechanism in which animals first switch from summer homeothermy to a state that is permissive for winter heterothermy (switch 1), and then cycle between periods of torpor and arousal in winte...

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confidence: 99%

Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy

Grabek

Karimpour-Fard

Epperson³

et al. 2011

Physiological Genomics

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“…In the 13-lined ground squirrel, the autoregulation of coronary flow and the cardiac output of isolated working heart persist down to at least 7°C but both are abolished in the rat below 17°C (Burlington et al 1986). Similarly, the arotic smooth muscle from the 13-lined ground squirrels can maintain a normal transmembrane K + and Na + gradient down to 7°C for 48 h, whereas in the rat, halftimes for loss of intracellular K + and gain of Na + are 14 and 11 h, respectively, at the same temperature (Kamm et al 1979). In the hedgehog, the cardiac action potential lacks a plateau phase in contrast to the prominent plateau phase found in the guinea pig (Duker et al 1986), indicating a difference in trans-sarcolemmal Ca 2 + flux during depolarization.…”

Section: Cardiovascular Functionsmentioning

confidence: 99%

Mammalian Hibernation: An Escape from the Cold

Wang

1988

Advances in Comparative and Environmental Physiology

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“…25 The slight reduction in cellular content of K may be related to a similar reduction in aortic cell water, 25 perhaps the result of the loss of some cellular material. The increase in the rate constants for 42 K on Day 2 compared with freshly dissected arteries may also be contributory.…”

Section: Cold Stored Tissuementioning

confidence: 99%

Temperature dependence of ionic transport and norepinephrine stimulation of rat aorta during DOCA hypertension.

Warden¹,

Jones²

1984

Hypertension

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SUMMARY Temperature perturbation was used to determine whether increased turnover of Na, K, and Cl at 37° C in aortas from rats made hypertensive with deoxycorticosterone acetate salt treatment (DOCH) reflects an increased number of transport sites that individually maintain relatively normal function. Decreasing temperature reduced the resting effluxes of 42 K, ^Cl, and M Na (active and passive) from control and DOCH in parallel fashion. The slope of the Arrhenius plots (activation energies) and the transition temperatures at which major changes in slope occurred were similar in controls and DOCH. In contrast to the results for resting effluxes, the temperature dependence for the effects of norepinephrine (NE) on contraction and on K and "^Cl effluxes in DOCH differed from controls. At 20° C, the responses to NE were either abolished or greatly suppressed in DOCH, as compared to controls, while no significant differences between the two groups were observed at 30° C. These results indicate that alterations in resting 42 K, -"Cl, and 24 Na effluxes in DOCH may result from an increased number of transport sites in the membranes of vascular smooth muscle. The concept that alterations occurred in the integral components of the membrane is also supported by the observation that increased resting 42 K and Cl effluxes in DOCH at 37° C persisted in aortas that had undergone cold storage for 2 days before incubation at 37° C. The altered temperature dependence for the effects of NE on DOCH, compared to controls, indicates that the involvement of agonist-receptor-membrane events may be dissociated from the alterations in resting ionic fluxes. K occurred in the aorta and femoral arteries from rats made hypertensive either with deoxycorticosterone acetate (DOCA) or aldosterone.1 -2 The net exchange of cellular Na and K in tail arteries for extracellular Li also proceeded at a faster rate in DOCA hypertensive rats.3 One important consequence of such alteration would be to increase the leak of ions along their electrochemical gradient, which would lead to altered excitability. In addition to these passive movements, evidence exists for an inFrom the Department of Physiology, University of Missouri at Columbia, Columbia, Missouri 65212.

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Maintenance of ion concentration gradients in the cold in aorta from rat and ground squirrel

Cited by 23 publications

References 25 publications

Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy

Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy

Mammalian Hibernation: An Escape from the Cold

Temperature dependence of ionic transport and norepinephrine stimulation of rat aorta during DOCA hypertension.

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