Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE

Original Publication: San Francisco, CA : Public Library of Science

Calcium/*metabolism ; Myocytes, Cardiac/*metabolism; Animals ; Cytosol/metabolism ; Electrophysiology ; Homeostasis ; Membrane Potentials/physiology ; Rats ; Sciuridae ; Temperature

Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+) homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+) current (I(Ca)) was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca) did not compromise the Ca(2+)-induced Ca(2+) release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca). Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+) removal were more rapid in ground squirrels. Ca(2+) sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca) threshold, low SR Ca(2+) leak and rapid cytosolic Ca(2+) clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+) homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+) overload-related heart diseases.

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R01 TW007269 United States TW FIC NIH HHS; United States ImNIH Intramural NIH HHS

SY7Q814VUP (Calcium)

Date Created: 20110922 Date Completed: 20120228 Latest Revision: 20220317

20250114

PMC3173481

10.1371/journal.pone.0024787

21935466