Figure 4.

ATP evokes TRPM7-like currents. Whole-cell currents were recorded in HEK_hP2X7 cells in a low-DIC bath, using either Mg²⁺-free or Mg²⁺-containing (3 mM) pipette solutions. Cells were repetitively exposed to 1 mM ATP for 4 s at 120-s intervals in the continuous presence of 0.3 µM AZ-10606120 and 30 µM TNP-ATP to inhibit P2X receptors. (A and B) Representative currents in response to pulses of 1 mM ATP, recorded with Mg²⁺-free (A) or Mg²⁺-containing (B) pipette solutions. (C) Statistical evaluation of 11 experiments each, performed as in A and B. Note that intracellular Mg²⁺ (gray circles) blunted responses to ATP. (D) Preconditioned (not depicted) TRPM7-like currents evoked by 1 mM ATP (left, I₁), 6 min after adding the TRPM7 modulator NS-8593 (30 µM; middle, I₂), and 6 min after removal of the blocker (right). (E) Statistical analysis of experiments similar to those in D (n = 6–7 each). Peak currents in the presence of test compounds I₂ are shown normalized with respect to the pre-application peak current I₁. *, P < 0.001, significant difference from the DMSO control. In electrophysiological figures, dotted lines indicate the zero current level. Error bars indicate SEM.