Correcting calcium handling in failing hearts.

Opening of the L-type calcium channels allows calcium to enter the cytoplasm of the myocyte. This calcium elicits calcium release from the sarcoplasmic reticulum via the ryanodine receptors. Calcium is pumped back to the sarcoplasmic reticulum by the SERCA2 pump. The plasma membrane pump PMCA4 also allows calcium entry to the cell. Novel interventions aim at increasing the activity of SERCA2, preventing the leak of the ryanodine receptors, or blocking of PMCA4. Some drugs aim at both stimulation of SERCA and the inhibition of the Na⁺/K⁺-ATPase pump to increase intracellular sodium, which reduces the driving force for the sodium calcium exchanger.