REDUCED INHIBITION DURING EPILEPTIFORM ACTIVITY IN THE INVITRO HIPPOCAMPAL SLICE
REDUCED INHIBITION DURING EPILEPTIFORM ACTIVITY IN THE INVITRO HIPPOCAMPAL SLICE
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DOI：
10.1113/jphysiol.1980.sp013364
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发表时间：
1980-01-01
影响因子：
5.5
通讯作者：
GJERSTAD, L
中科院分区：
文献类型：
--
作者：
DINGLEDINE, R;GJERSTAD, L
在离体海马脑片上，用豚鼠海马CA 1区锥体细胞制作细胞内记录。顺向和逆向激活和离子导入应用GABA的反应进行了研究。致痫剂苄青霉素钠降低了由阈下逆向刺激诱发的复发性ipsp[抑制性突触后电位]。对ipsp的抑制电位研究和电阻测量表明，这种降低主要是由于ipsp电导的降低。青霉素减少了电导和相关的膜电位的变化引起的喷射GABA附近的索马或进入顶端树突状区域。当ipsp被阻断时，由顺向刺激诱发的混合epsp[兴奋性突触后电位]-ipsp转换为纯去极化电位。同时，放电到恒定的顺向刺激的概率增加。在低氯化物溶液中观察到类似的变化。抑制减少的时间过程与青霉素治疗后观察到的增强的顺向反应相似。突触后抑制的减少显然是青霉素引起的顺向放电概率增加的部分原因。在某些细胞中观察到的较长潜伏期的全有或全无爆发似乎需要额外的机制，尽管抑制减少可能有助于触发这种爆发。
Intracellular recordigs were made from guinea pig CA1 pyramidal cells in a hippocampal slice in vitro. The responses to orthodromic and antidromic activation and to ionophoretically applied GABA were studied. The epileptogenic agent sodium benzyl penicillin reduced the recurrent ipsp[inhibitory postsynaptic potential]evoked by subthreshold antidromic stimulation. Reversal potential studies of the ipsp and resistance measurements showed that this reduction was mainly due to a decrease in ipsp conductance. Penicillin reduced the conductance and associated membrane potential changes induced by ejecting GABA near the soma or into the apical dendritic region. The mixed epsp[excitatory postsynaptic potential]-ipsp evoked by orthodromic stimulation was converted to a pure depolarizing potential as the ipsp was blocked. Concurrently the probability of discharge to a constant orthodromic stimulus was increased. Similar changes were seen in a low chloride solution. The time course of the reduction of inhibition was similar to that of the enhanced orthodromic response seen after penicillin treatment. Reduction of postsynaptic inhibition apparently is partly responsible for the increased probability of orthodromic discharge caused by penicillin. The longer latency all-or-nothing burst seen in some cells seems to require an additional mechanism, although reduced inhibition may facilitate the triggering of this burst.