Cyclic ADP-ribose ammonium (cADPR ammonium) is a powerful calcium mobilization second messenger synthesized from NAD+ by an ADP-ribosyl cyclase. It primarily raises cytosolic calcium levels through Ryanodine receptor-mediated release from the endoplasmic reticulum, while also facilitating extracellular influx through the opening of TRPM2 channels [1][2][3].