Luminal Ca(2+) content regulates intracellular Ca(2+) release in subepicardial myocytes of intact beating mouse hearts: effect of exogenous buffers.

ABSTRACT: Ca(+)-induced Ca(2+) release tightly controls the function of ventricular cardiac myocytes under normal and pathological conditions. Two major factors contributing to the regulation of Ca(2+) release are the cytosolic free Ca(2+) concentration and sarcoplasmic reticulum (SR) Ca(2+) content. We hypothesized that the amount of Ca(2+) released from the SR during each heart beat strongly defines the refractoriness of Ca(2+) release. To test this hypothesis, EGTA AM, a high-affinity, slow-association rate Ca(2+) chelator, was used as a tool to modify luminal SR Ca(2+) content. An analysis of the cytosolic and luminal SR Ca(2+) dynamics recorded from the epicardial layer of intact mouse hearts indicated that the presence of EGTA reduced the diastolic SR free Ca(2+) concentration and fraction of

SUBMITTER: Kornyeyev D 

PROVIDER: S-EPMC2886618 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature