Intracellular calcium modulators for cardiac muscle in pathological conditions.

This is a brief review of agents that stabilize calcium release from the sarcoplasmic reticulum in cardiac muscle. An excess intracellular calcium concentration (calcium overload) is a common feature in a variety of cardiac cell injuries. Calcium overload elicits diastolic and systolic failure, and is involved in the genesis of arrhythmias. These abnormalities appear in part to be caused by the spontaneous release of calcium ions from the sarcoplasmic reticulum. Previous efforts to treat calcium overload were made with the intention to decrease the total intracellular content of calcium ions. However, such procedures would result in a decrease in contractility. Agents that stabilized calcium release from the sarcoplasmic reticulum may therefore be useful to correct abnormalities in calcium overload. In this review, after briefly describing intracellular calcium homeostasis, strategies against calcium overload, especially those involving magnesium ion, ryanodine, caffeine, dantrolene, phenytoin, R56865, KT361 and flunarizine will be discussed.