Cytoprotective role of Ca²⁺-activated K⁺ channels in the cardiac inner mitochondrial membrane

Ion channels on the mitochondrial inner membrane influence cell function in specific ways that can be detrimental or beneficial to cell survival. At least one type of potassium (K⁺) channel, the mitochondrial adenosine triphosphate-sensitive K⁺ channel (mitoK_ATP) is an important effector of protection against necrotic and apoptotic cell injury after ischemia. Here another channel with properties similar to the surface membrane calcium-activated K⁺ channel was found on the mitochondrial inner membrane (mitoK_Ca) of guinea pig ventricular cells. MitoK_Ca significantly contributed to mitochondrial K⁺ uptake of the myocyte, and an opener of mitoK_Ca protected hearts against infarction.