NM completely and reversibly inhibits TRPM7 current in cultured mouse hippocampal neurons. A, top, experimental protocol showing voltage ramps (-100 to +100 mV) and applied low divalent cations. TRPM7 was elicited by lowing divalent cations from 2 mM Ca2+, 1 mM Mg2+ to indicated lower concentrations. Bottom, current trace examples of 0 Ca2+ and 0 Mg2+-induced TRPM7 current at the presence and absence of NM. Co-application of NM (200 μM) reversibly blocked TRPM7 evoked by zero divalent cations. n = 6. B, NM (200 μM) completely blocks TRPM7 evoked by 0.1 mM Ca2+ (and 0.1 mM Mg2+). Example current traces superimposed (left) and I-V curve (right). n = 8. C, concentration response of NM blockade of TRPM7 current, Left, currents trace examples. NM was acutely applied in the presence of 0.1 mM Ca2+ and 0.1 mM Mg2+. The onset time constrant of NM inhibition (200 μM) was 0.29 ± 0.04 s (n = 9) and the offset time constant was 1.07 ± 0.20 s (n = 9). Exponential fitting curves (red) were inserted with the trace (when NM is 200 μM). Right, concentration response curve of NM inhibition; IC50: 27 ± 6 μM; hill coefficient: 1.4; n = 6.