Contribution of Sigma-1 receptor to cytoprotective effect of afobazole

Anxiolytic afobazole (5-Ethoxy-2-[2-(morpholino)-ethylthio]benzimidazole dihidrochloride) has pronounced ligand properties toward Sigma-1 receptor (σ1 receptor,SigmaR1) and MT ₃ receptors. Our previous work demonstrated that afobazole possess cytoprotective effect in the in vitro model of menadione genotoxicity (Woods et al. 1997) through interaction with MT ₃ receptor (Kadnikov et al. 2014). Present study utilized previously described models to address the contribution of SigmaR1 to cytoprotective action of afobazole. The reduction in afobazole cytoprotective effect observed after preincubation of cell suspension with selective SigmaR1 antagonist BD-1047 revealed an important contribution of SigmaR1 in afobazole-mediated effect. We confirmed our observation using selective SigmaR1 agonist PRE-084. We conclude that pronounced cytoprotective effect of afobazole over PRE-084 is likely achieved by additive SigmaR1 and MT ₃-mediated effects.