CONTROL OF EPILEPTIFORM BURST RATE BY CA3 HIPPOCAMPAL CELL AFTERHYPERPOLARIZATIONS INVITRO
CONTROL OF EPILEPTIFORM BURST RATE BY CA3 HIPPOCAMPAL CELL AFTERHYPERPOLARIZATIONS INVITRO
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DOI：
10.1016/0006-8993(89)90917-7
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发表时间：
1989-07-17
期刊：
影响因子：
2.9
通讯作者：
DINGLEDINE, R
中科院分区：
文献类型：
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作者：
CHAMBERLIN, NL;DINGLEDINE, R
在高[K]o(7-10.5 mm)浸泡的海马片中，自发发作的发生率较高，而在低[Cl]o(53 Mm)溶液中浸泡的脑片中，自发发作的发生率较低。CA3b/c神经元在高[K]O条件下的细胞内记录显示，每次自发癫痫样发作后后超极化的幅度变化为-50.+-。[K]o每十年变化7 mV(n=7)。后超极化时程与7~10.5 mm[K]o的阵发间期高度相关，而在低[Cl]o(3.5 mm[K]o)时与阵发间期无相关性。后超极化持续时间占79.+-。猝发间隔的2%(1.4.+-.S)在8.5 mm[K]o，但只有51.+-。8%的低[Cl]o(区间6.6.+-.1.2 S)。用佛波醇12，13-二乙酸酯(2-20微米)浸泡8.5 mM的脑片，可使后超极化的幅度和持续时间减小，爆发率增加41%。此外，在CA3区还出现了类似于惊厥时相的自发放电。GABAB受体阻滞剂苯氯芬(0.2-1 mM)对突发率无影响。我们认为，超极化后的癫痫样发作限制了自发发作间歇性发作的最大速率，其持续时间的缩短允许随后在CA3区出现电活动。
Spontaneous interictal bursts occurred at a high rate in hippocampal slices bathed in raised [K]o (7-10.5 mM) and at a slower rate in slices bathed in low [Cl]o (53 mM) solutions. Intracellular recordings from CA3b/c neurons bathed in high [K]o showed that the amplitude of the afterhyperpolarization that followed each spontaneous epileptiform burst varied-50 .+-. 7 mV per decade change in [K]o (n = 7). Afterhyperpolarization duration was highly correlated with the interburst interval in 7-10.5 mM [K]o but not in low [Cl]o (3.5 mM [K]o). The duration of the afterhyperpolarization accounted for 79 .+-. 2% of the interburst interval (1.4 .+-. 0.1 s) in 8.5 mM [K]o but only 51 .+-. 8% in low [Cl]o (interval 6.6 .+-. 1.2 s). Treatment of slices bathed in 8.5 mM [K]o wiht phorbol 12,13-diacetate (2-20 .mu.M) caused a decrease in the amplitude and duration of the afterhyperpolarization and a concomitant 41% increase in burst rate. In addition, spontaneous discharges that resembled the tonic phase of electrographic seizures appeared in the CA3 region. The GABAB receptor blocker phaclofen (0.2-1 mM) had no effect on the burst rate. We suggest that the epileptiform burst afterhyperpolarization limits the maximum rate of spontaneous interictal-like bursting and that a decrease in its duration allowed the subsequent of electrographic seizure activity in area CA3.