MRS 2578 is a potent and insurmountable antagonist of P2Y6 nucleotide receptor with IC50 value of 37nM [1].

MRS 2578, a diisothiocyanate derivative, is an insurmountable antagonist of P2Y6 receptors which are associated with vasoconstriction. Thus MRS 2578 is expected to be used in treatment of vasospasm. In 1321N1 human astrocytes expressing P2Y6 receptors, MRS 2578 inhibits the UDP-induced accumulation of inositol phosphates in a dose-dependent manner. MRS 2578 also inhibits the rat P2Y6 receptor activation with IC50 value of 98nM. These effects are selective. MRS 2578 has no effect on the UTP-induced responses of cells expressing human P2Y2 or P2Y4 receptors. It also has no effect on the 2-MeSADP-induced responses of cells expressing the P2Y1 receptor. Moreover, since the UDP-induced activation of P2Y6 receptor can protect the cells from apoptosis induced by TNFα, MRS 2578 completely blocks the protection of cells [1].

References:
[1] Mamedova L K, Joshi B V, Gao Z G, et al. Diisothiocyanate derivatives as potent, insurmountable antagonists of P2Y6 nucleotide receptors[J]. Biochemical pharmacology, 2004, 67(9): 1763-1770.