Temporal resolution of activity-dependent pH shifts in rat hippocampal slices.
Temporal resolution of activity-dependent pH shifts in rat hippocampal slices.
复制标题
大鼠海马切片中活动依赖性 pH 值变化的时间分辨率。
DOI：
10.1152/jn.1996.76.4.2804
复制
发表时间：
1996
影响因子：
2.5
通讯作者：
Chesler,M
中科院分区：
文献类型：
--
作者：
Gottfried,JA;Chesler,M
1.通过记录荧光素结合葡聚糖的pH敏感荧光，在大鼠海马切片的CA 1放射层中测量活性依赖性细胞外pH变化的上升时间。光学数据进行了比较，同时pH微电极记录。2.当用490 nm光激发探针时，由CO2或刺激Schaffer侧枝产生的pH变化被535 nm处的荧光发射的变化所抵消（Δ F490）。在这些范例中，由440 nm光诱导的535 nm处的发射没有变化。3.以30秒的间隔重复一系列100 Hz的三个刺激，并对刺激触发的Δ F490进行平均。Δ F490的平均上升时间为69 ± 24（SE）ms（范围20-200 ms，n = 6）。发射的平均增加为基线的0.75 +/- 0.22%，与pH微电极响应+0.06 +/- 0.02单位pH相关。这些数据表明，突触诱发的碱性瞬变在几十毫秒内发展。在兴奋性突触后电流相同的时间范围内发生的碱化表明，这些pH值的变化出现足够的速度来调节突触传递。
1. The rise time of activity-dependent extracellular pH shifts was measured in the CA1 stratum radiatum of rat hippocampal slices by recording pH-sensitive fluorescence of a fluorescein-conjugated dextran. Optical data were compared with simultaneous pH microelectrode recordings. 2. The pH shifts generated by CO2 or by stimulation of the Schaffer collaterals were paralleled by shifts in fluorescence emissions at 535 nm when the probe was excited with 490-nm light (delta F490). Emissions at 535 nm induced by 440-nm light were unchanged in these paradigms. 3. A train of three stimuli at 100 Hz was repeated at 30-s intervals and the stimulus-triggered delta F490 was averaged. The mean rise time of the delta F490 was 69 +/- 24 (SE) ms (range 20-200 ms, n = 6). The mean increase in emission was 0.75 +/- 0.22% of baseline, associated with a pH microelectrode response of +0.06 +/- 0.02 unit pH. 4. These data demonstrate that synaptically evoked alkaline transients develop within tens of milliseconds. The occurrence of the alkalinization in the same time frame as excitatory postsynaptic currents indicates that these pH shifts arise with sufficient speed to modulate synaptic transmission.