Figure 5.

Effect of extracellular Na⁺ removal and of Ca²⁺ channel blockers on kainate-induced [Ca²⁺]_i response. A, [Ca²⁺]_i responses to 0.5 mmol/liter kainate (KA) for 10 sec in the presence and absence of Na⁺ (n = 5). The 135 mm extracellular Na⁺ was replaced by equimolar NMDG⁺ to prevent depolarization by Na⁺ influx through iGluRs. The [Ca²⁺]_i trace in this figure is the average for all measured cells, and has error bars. B–E, [Ca²⁺]_i with several Ca²⁺ channel blockers. Kainate-evoked [Ca²⁺]_i increase was measured in the presence of 200 μm CdCl₂ as a nonselective blocker of Ca²⁺ channels (n = 9), 10 μm nimodipine (“Nimo”) for blocking L-type Ca²⁺ channels (n = 12), 2 μmol/liter ω-conotoxin GIVA (“ω-CTX”) for N-type Ca²⁺ channels (n = 18), and 100 nmol/liter SNX482 for R-type Ca²⁺ channels (n = 11). F, Percent inhibition of kainate-induced [Ca²⁺]_i peaks by each condition. Data are shown as mean ± sem.