Carvacrol (CAR) inhibits TRPM7 and TRPM7-like currents and protects cortical neurons from OGD-induced injury. A, HEK293 cells over-expressing TRPM7 were induced by tetracycline (1 μM) for 24 hours. TRPM7 current was recorded as described in methods section. Representative I-V curves are shown. Perfusion with carvacrol (500 μM and 1 mM) caused a dramatic decrease in the TRPM7 current in dose-dependent manner (n = 6 cells). B, TRPM7-like current in primary hippocampal neurons (HPC) was recorded as described in methods section. Perfusion with carvacrol (500 μM and 1 mM) dose-dependently blocked TRPM7-like current in HPC. Representative I-V curves are shown (n = 6 cells). C, cortical neurons were incubated with carvacrol or vehicle (0.1% DMSO) for 30 min and then treated with OGD for 1 hour and transferred to regular medium for 24 hours. Cells were then stained with PI and the fluorescent intensity was measured using Synergy HT Multi-Mode Micro plate Reader. Results demonstrated that carvacrol (200-800 μM) significantly protected neurons from OGD-induced injury (*, p < 0.05 compared with vehicle treated group, n = 5, One-way ANOVA followed by Newman-Keuls test). D and E, cortical neurons were treated with carvacrol (300 μM) for 30 min, and then OGD and PI staining were conducted as described above. Representative images were taken using a Zeiss LSM 710 Confocal Microscope. Scale bar = 10 μm. *, p < 0.05 compared with control group; #, p < 0.05 compared with OGD group, n = 4, One-way ANOVA followed by Newman-Keuls test.