Spontaneous ictal-like discharges and sustained potential shifts in the developing rat neocortex.
Spontaneous ictal-like discharges and sustained potential shifts in the developing rat neocortex.
复制标题
发育中的大鼠新皮质中的自发发作样放电和持续的电位变化。
DOI：
10.1152/jn.1987.58.5.1052
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发表时间：
1987
影响因子：
2.5
通讯作者：
Hablitz,JJ
中科院分区：
文献类型：
--
作者：
Hablitz,JJ
1.本研究采用细胞内和细胞外记录技术研究未成熟大鼠新皮层离体脑片的癫痫发生。从5-60日龄的动物制备感觉运动皮层切片。通过浴用50 μ M印防己毒素诱导癫痫样活动。2.在最小年龄组（5-7天）中很少观察到惊厥诱导的阵发性活动，包括低振幅孤立放电的顺向诱发爆发。这种活动是不稳定的，只能在长的刺激间隔（大于10秒）诱发。3. 8- 15日龄大鼠脑片的细胞外记录显示自发性癫痫样活动，包括叠加在3- 5 mV负稳态电位上的10- 30 s重复性棘波放电阵发。该稳定电位在长时间放电过程中略有下降，并在最后一次尖峰放电后迅速恢复到基线。4.对8 ~ 15日龄大鼠的癫痫样活动进行的分层分析表明，皮层浅层的棘波放电是负的，并叠加在正的慢波上。在软膜表面以下100微米处，慢电位极性反转，并在整个皮质的其余部分保持负电位。尖峰放电在软膜表面下800微米处反转极性。5.在细胞内记录从9至14日龄的动物切片，每次发作开始与急剧上升的膜去极化（阵发性去极化移位，或PDS）。第二次PDS发生在细胞复极化到静息电位之前。然后，一系列的PDS，叠加在持续的膜去极化。这与输入电阻降低33%有关。后超极化（AHPs）终止后的去极化幅度低或不存在。6.在16至30日龄组中，细胞外记录显示阵发性活动，包括3-10个初始尖峰，随后是持续、缓慢的负电位偏移。这种慢电位的幅度可达30 mV，持续时间可达180 s。阵发性事件自发复发的时间间隔为4-11分钟。自发的PDS和缓慢，负电位的变化，没有观察到30天后的年龄，虽然PDS仍然可以诱发顺向刺激。7.在16至30日龄组的细胞内记录显示，每个阵发性事件包括突触活动和细胞放电增加的初始阶段，随后是明显的，持久的去极化（LLD），最终在AHP。（400字处截断摘要）
1. Intra- and extracellular recording techniques were used to study epileptogenesis in in vitro slices of immature rat neocortex. Slices of sensorimotor cortex were prepared from animals 5-60 days old. Epileptiform activity was induced by bath application of 50 microM picrotoxin. 2. Convulsant-induced paroxysmal activity was observed only rarely in the youngest age group (5-7 days) and consisted of orthodromically evoked bursts of low-amplitude isolated discharges. This activity was labile and could be evoked only at long interstimulus intervals (greater than 10 s). 3. Extracellular recordings in slices from 8- to 15-day-old rats showed spontaneous epileptiform activity consisting of 10- to 30-s paroxysms of repetitive spike discharges superimposed on a 3- to 5-mV negative steady potential. This steady potential declined slightly during the course of the prolonged discharge and returned quickly to base line following the last spike discharge. 4. Laminar analysis of epileptiform activity in 8- to 15-day-old rats showed that the spike discharges were negative and superimposed on a positive slow wave in superficial cortical layers. At 100 micron below the pial surface, the slow potential reversed polarity and remained negative throughout the remainder of the cortex. Spike discharges reversed polarity 800 micron below the pial surface. 5. In intracellular recordings from slices obtained from 9- to 14-day-old animals, each paroxysm began with a sharply rising membrane depolarization (paroxysmal depolarizing shift, or PDS). A second PDS occurred before the cells repolarized to their resting potential. A series of PDSs then followed, superimposed on a sustained membrane depolarization. This was associated with a 33% decrease in input resistance. Afterhyperpolarizations (AHPs) following termination of the depolarization were low in amplitude or absent. 6. In the 16- to 30-day-old age group, extracellular recordings showed paroxysmal activity consisting of 3-10 initial spikes followed by a sustained, slow, negative-potential shift. This slow potential could be as great as 30 mV in amplitude and could last as long as 180 s. Paroxysmal events recurred spontaneously at intervals of 4-11 min. Spontaneous PDSs and slow, negative-potential shifts were not observed after 30 days of age, although PDSs could still be evoked by orthodromic stimulation. 7. Intracellular recordings in the 16- to 30-day-old group revealed that each paroxysmal event consisted of an initial period of increased synaptic activity and cellular firing, followed by a marked, long-lasting depolarization (LLD), culminating in an AHP.(ABSTRACT TRUNCATED AT 400 WORDS)