New Linear Precursors of cIDPR Derivatives as Stable Analogs of cADPR: A Potent Second Messenger with Ca2+-Modulating Activity Isolated from Sea Urchin Eggs.

Herein, we report on the synthesis of a small set of linear precursors of an inosine analogue of cyclic ADP-ribose (cADPR), a second messenger involved in Ca2+ mobilization from ryanodine receptor stores firstly isolated from sea urchin eggs extracts. The synthesized compounds were obtained starting from inosine and are characterized by an N1-alkyl chain replacing the "northern" ribose and a phosphate group attached at the end of the N1-alkyl chain and/or 5'-sugar positions. Preliminary Ca2+ mobilization assays, performed on differentiated C2C12 cells, are reported as well.