ATP evokes TRPM7-like currents but no P2X7 activity in rat C6 glioma cells. (A and B) Shown are whole-cell currents evoked by repetitive (4 s at 120-s intervals) application of 10 mM ATP in rat C6 glioma cells, when recording with a Mg²⁺-free (A) or 3 mM Mg²⁺–containing pipette solution (B). (C) Statistical evaluation of experiments similar to those in A (open circles) and B (filled circles; n = 8 each). (D) Shown are superimposed whole-cell currents in response to 1 mM ATP during preconditioning (left), after 2, 4, and 6 min in the presence of 30 µM TNP-ATP plus 0.3 µM AZ-10606120 (middle), and 2, 4, and 6 min after removal of the P2X antagonists (right). (E) Data accumulated from seven experiments as in D. Note the lack of effect of P2X receptor blockade. (F–H) Functional detection of TRPM7-like currents in C6 glioma cells. (F and G) TRPM7-like currents evoked by repetitive (6 s at 30-s intervals) application of no-DIC bath solution in cells internally perfused with a Mg²⁺-free (F) or 3 mM Mg²⁺–containing pipette solution (G). (H) Statistical evaluation of experiments similar to those in F (open circles) and G (filled circles; n = 8 and 6). Note that intracellular Mg²⁺ equally abolished the responses to ATP (C) and to the no-DIC bath (H). In electrophysiological figures, dotted lines indicate the zero current level. Error bars indicate SEM.