Cyclic ADP-ribose (cADP-ribose) is an endogenous metabolite of NAD+ that mobilizes the release of stored Ca2+ in the endoplasmic reticulum via ryanodine receptors in various cell types.[1],[2],[3],[4],[5] This second messenger is generated via the cADP-ribose synthases CD38 and CD157.[6],[5],[7] cADP-Ribose may also trigger the cell surface Ca2+ influx channel TRPM2 in a temperature-dependent manner.[8] In vitro, cADP-ribose modulates Ca2+ signaling in rat and mouse cardiomyocytes treated with isoproterenol , and treatment with this metabolite at 100 μM under heat stress conditions induces the release of oxytocin from the mouse hypothalamus.[9],[4]