Figure 8.
K+ channel sensitivity to TEA and 4AP in embryonic, adult, and aged NSCs. A, Percentage of the current left unblocked by 20 mm TEA, 2 mm 4AP, or 20 mm TEA and 2 mm 4AP in proliferating embryonic, adult, and aged NSCs. Means ± SEM; n = 11, 10, 7 and 9, 9, 7 and 17, 17, 13 in embryonic, adult, and aged, respectively. B, C, Representative traces of outward K+ currents activated by a depolarizing voltage step from the resting membrane potential to +40 mV in proliferating NSCs. The currents are blocked by 20 mm TEA (B) or 2 mm 4AP (C). Calibration: 500 pA, 25 ms. D, Percentage of the current left unblocked by 20 mm TEA, 2 mm 4AP, or 20 mm TEA and 2 mm 4AP in neurons differentiated from embryonic, adult, and aged NSCs. Means ± SEM; n = 5, 5, 5 and 6, 5, 7 and 8, 10, 11 in embryonic, adult, and aged, respectively. E, F, Representative traces of outward K+ currents activated by a depolarizing voltage step from the resting membrane potential to +40 mV in neurons differentiated from aged NSCs. The currents are blocked by 20 mm TEA (E) or 2 mm 4AP (F). Calibration: 250 pA, 25 ms. G, Effect of 100 μm glutamate (left) or glutamate together with 10 μm NBQX and 50 μm d-AP5 (right) on neurons differentiated from embryonic, adult, and aged NSCs. Calibration: for embryonic and aged, 100 pA, 50 ms; for adult cells, 20 pA, 50 ms. n = 6, 8, and 6 in embryonic, adult, and aged, respectively. H, The effect of 100 μm GABA (left) or 100 μm GABA together with 10 μm PTX (right) on neurons differentiated from embryonic, adult, and aged NSCs. Calibration: for embryonic and aged, 500 pA, 50 ms; for adult cells, 40 pA and 50 ms. n = 8, 7, and 5 in embryonic, adult, and aged, respectively.