ryanodine

Ryanodine, a diterpenoid poison derived from Ryania speciosa, acts as a modulator of the ryanodine receptor, which is permeable to cells. Depending on its concentration, ryanodine can either stimulate or inhibit Ca2+ release mediated by these receptors.

Cyclic ADP-ribose (cADPR) is an effective calcium mobilization second messenger synthesized from NAD+ by ADP-ribosyl cyclase. It mainly increases cytosolic calcium through Ryanodine receptor-mediated endoplasmic reticulum release and extracellular influx via the opening of TRPM2 channels.

Cyclic ADP-ribose ammonium (cADPR ammonium) is a potent calcium mobilization second messenger synthesized from NAD+ by ADP-ribosyl cyclase. It raises cytosolic calcium levels through Ryanodine receptor-mediated release from the endoplasmic reticulum and facilitates extracellular influx via TRPM2 channels [1][2][3].

Paraxanthine (1,7-dimethylxanthine) is a metabolite of caffeine (sc-202514) which functions as an adenosine receptor ligand and a PARP-1 inhibitor in pulmonary epithelial cells. Studies suggest that Paraxanthine is structurally similar to caffeine and possibly mediates the physiological effects of caffeine. Also Paraxanthine acts as a competitive phosphodiesterase inhibitor, which increases intracellular cAMP, activates PKA, inhibits TNF-α and leukotriene synthesis. In addition, Paraxanthine acts as a Na+ K+ ATPase enzymatic effector.

Verticilide, a ryanodine-binding inhibitor, effectively inhibits ryanodine binding to ryanodine receptors in cockroaches with an IC50 value of 4.2 μM (exhibiting weak inhibition against mouse ryanodine receptors, IC50 = 53.9 μM) [1].