Effect of caffeine on calcium in subcellular fractions of cardiac muscle

Publisher Website
Google Scholar
Abstract
Mitochondria isolated from toad ventricular muscle contain more Ca/mg mitochondrial protein than do mitochondria when similarly isolated from either rabbit or rat ventricular muscle. Mitochondria isolated from toad ventricular muscle that was immersed in Ca-free Tyrode solution containing 5 m[image] caffeine contain significantly less Ca that do mitochondria that are similarly isolated from paired ventricular muscle preparations immersed in caffeine-free, Ca-free Tyrode solution. The presence of 5 m[image] caffeine interferes with both the uptake and release of Ca++, detected as Ca45; from isolated cardiac mitochondria. These results are discussed in accordance with a hypothesis that the release of calcium from intracellular stores may be involved in the inotropic activity of certain cardioactive drugs, including caffeine.