Ned-K is a specific and potent inhibitor of NAADP (nicotinic acid adenine dinucleotide phosphate) signaling that suppresses Ca2+ oscillations via two-pore channels (TPC1) and opening of the mitochondrial permeability transition pore (mPTP) in cardiomyocytes during simulated ischaemia and reperfusion. Ned-K protected cardiomyocytes from cell death during ischaemia and reperfusion injury in rats.