The Na+/Ca2+ exchanger (NCX) is a major regulator of intracellular calcium concentration that is largely expressed in cardiac sarcolemma (NCX1) but also in brain and skeletal muscle (NCX2). KB-R7943 is an isothiourea derivative that selectively inhibits the reverse mode of NCX1 (IC50 = 1.2-2.4 μM), preventing intracellular sodium-dependent calcium uptake in whole cells. It is much less potent at preventing extracellular sodium-dependent calcium efflux from intact cells (IC50 > 30 μM). In cultured hippocampal neurons, KB-R7943 exhibits neuroprotection from glutamate-induced excitotoxicity by blocking NMDA receptor-mediated activity (IC50 = 13.4 μM) and inhibiting complex I in the mitochondrial respiratory chain (IC50 = 11.4 μM). KB-R7943 has also been shown to block transient receptor potential canonical channels, which are important mediators of calcium-dependent signal transduction.
![2-[2-[4-(4-NITROBENZYLOXY)PHENYL]ETHYL]ISOTHIOUREA MESYLATE](https://www.chemicalbook.com/CAS/GIF/182004-65-5.gif)
