XB-IMG-120674
Xenbase Image ID: 120674
|
Figure 6. Fast Ca dynamics imaged with Ca-green–dextran. The experimental setup was identical to Fig. 5 except that images were collected every 100 ms, starting 400 ms before the +40 mV[1] step from a 15 pixel–wide box across the entire oocyte. The oocyte was injected with IP3 > 10 min before the experiment. (a) Ca dynamics measured at a fast time scale (every 100 ms). (b) Correlation of Ca fluorescence (○) with the Cl currents (solid line) measured during the same voltage-clamp episode. The Ca fluorescence is superimposed on the Cl currents. (c) Changes in Ca fluorescence traces during the course of an experiment. In this case, we used a two-step voltage protocol, from 0 to +40 mV for 1.5 s, and then to −140 mV for 1.5 s with an interepisode interval of 15 s. Each trace is the average of five consecutive traces. The x axis shows the start time of the beginning of each average trace, but each trace is 3 s in duration and not to scale of the major x axis. After IP3 injection, Ca-dependent fluorescence increased gradually to reach a maximum ∼2 min later. However, the first two traces after IP3 injection are flat, indicating that there is no significant voltage-dependent Ca entry as Ca is released from the stores. As time progresses, the levels of Ca Green fluorescence at −140 mV, as compared with +40 mV, increase gradually, indicating the development of robust Ca influx. Image published in: Machaca K and HC Hartzell null (1999) Image reproduced on Xenbase with permission of the publisher and the copyright holder. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |