Emerging role of cyclic ADP-ribose (cADPR) in smooth muscle

Cyclic adenosine diphosphate ribose (cADPR) is a naturally, occurring cyclic nucleotide and represents a novel class of endogenous Ca2+ messengers implicated in the regulation of the gating properties of ryanodine receptors (RvRs). This action of cADPR occurs, independantly. from the inositol-1.4.5-trisphosphate (IP3) receptor, The regulation of intracellular Ca2+ release is a fundamental element of cellular Ca-2 homeostasis since a number of smooth muscle functions (tone. proliferation. apoptosis. and gene expression) are modulated by intracellular Ca2+ concentration ([Ca2-](i)). There has been a surge in the efforts aimed at understanding the mechanisms of cADPR-mediated Ca-2 mobilization and its impact on smooth muscle function. This review summarizes the proposed roles of cADPR in the regulation of smooth muscle tone (C) 2004 Published by Elsevier Inc.