Effects of NM on the divalent cation sensitivity of TRPM7 currents. (A) representative I-V relationships for currents in response to voltage ramps (50 ms duration) from +100 mV to -100 mV (Vh = 0 mV) recorded with extracellular divalents at 10 nM and 0.1 mM in the absence (left) and presence of 500 μM NM (right). B, dose response curve for the inhibitory effect of divalents on TRPM7 current. Concentration response curve of NM inhibition at +100 mV in the absence of NM; IC50: 2.3 ± 0.2 μM; hill coefficient: 0.8; n = 9 and in the presence of NM; IC50: 200 ± 40 μM; hill coefficient: 0.8; n = 8. C, NM potentiates TRPM7 channels in TRPM7-transfected HEK293T cells under ramp-clamp (every 5 s at 4 mV/ms). Representative peak inward currents recorded at -100 mV (circle) (Vh = -60 mV) in the presence of 1 mM Ca2+ and 1 mM Mg2+. D, representative I-V relationships of currents evoked by 0.1 mM Ca2+ and 0.1 mM Mg2+ in response to voltage ramps before (a), during (b), and after (c) NM application. E, bar graph showing the potentiated ratio by NM on the TRPM7. n = 11, ***, p < 0.01 vs. control.
Chen et al. Molecular Brain 2010 3:38 doi:10.1186/1756-6606-3-38