Figure 5.

Ca²⁺-dependent and -independent change in E_gly. A, B, Data from one cell comparing glycine responses and E_gly measurements in control condition (A) with those in zero-Ca²⁺ (B). Time 0 is the moment the 8 s depolarizing current injection terminated. Ai, After 56 high-threshold Ca²⁺ spikes induced with a 220 pA injection, the glycine response shifted negative. Aii, The E_gly series measured along with the V_m recording in Ai is shown (●) with two other series obtained with different amounts of current injections. The negative E_gly shifts peaked at 8.5 s. HTSs, High-threshold spikes. Bi, ii, The V_m and E_gly series in zero-Ca²⁺ (replaced with Mg²⁺) are displayed in the same way as in A. After a depolarization in zero-Ca²⁺, no negative shift but a positive shift in E_gly occurred. Bias current was −40 pA in Ai and −55 pA in Bi. C, Bar graphs showing the peak change in E_gly after an 8 s current injection (amount in pA indicated above each bar) in control condition and in zero-Ca²⁺ from six cells. The number of Ca²⁺ spikes evoked is shown in parentheses under each bar belonging to control conditions. All data were obtained in TTX.