Ca 2+ cycling in heart cells from ground squirrels: Adaptive strategies for intracellular ca 2+ homeostasis

Xiao Chen Li, Ling Wei, Guang Qin Zhang, Zai Ling Bai, Ying Ying Hu, Peng Zhou, Shu Hua Bai, Zhen Chai, Edward G. Lakatta, Xue Mei Hao, Shi Qiang Wang

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


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.

Original languageEnglish (US)
Article numbere24787
JournalPloS one
Issue number9
StatePublished - Sep 14 2011
Externally publishedYes

ASJC Scopus subject areas

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