BASAL VERSUS APICAL DENDRITIC LONG-TERM POTENTIATION OF COMMISSURAL AFFERENTS TO HIPPOCAMPAL CA1 - A CURRENT-SOURCE DENSITY STUDY
BASAL VERSUS APICAL DENDRITIC LONG-TERM POTENTIATION OF COMMISSURAL AFFERENTS TO HIPPOCAMPAL CA1 - A CURRENT-SOURCE DENSITY STUDY
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DOI：
10.1523/jneurosci.13-06-02391.1993
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发表时间：
1993-06-01
影响因子：
5.3
通讯作者：
LEUNG, LS
中科院分区：
文献类型：
--
作者：
KAIBARA, T;LEUNG, LS
电流源密度分析被用来估计在刺激乌拉坦麻醉大鼠的连合后，在theta频率模式的预激爆发性破伤风前后，在CA1的基础和顶端树突突触的突触兴奋的幅度。刺激对侧CA3层或对侧CA1层东侧，对CA1的树突和基底树突的兴奋程度大致相同。然而，对侧CA3或CA1层的爆发性强直电刺激仅在基底树突处产生显著的长时程增强(LTP)，而在顶树突上无明显的LTP。刺激对侧CA1层放射层对顶端树突的兴奋作用大于对侧CA1基端树突的兴奋作用，但强直刺激对侧CA1层放射层对顶端或基础树突状细胞的兴奋作用无明显影响。然而，在脑室内注射GABA(A)拮抗剂荷包牡丹碱后，对侧CA1放射层的Tetan化导致了顶端和基底部树突的显著长时程增强。结果表明，在完整的活体海马体中，LTP在连合顶树突处的阈值高于在基底树突处的LTP阈值，这一高阈值可能部分是由主要分布在顶树突上的抑制性中间神经元引起的。因此，CA1锥体细胞的基端和顶端树突在长期可塑性方面的倾向并不相同。
Current-source density analysis was used to estimate the magnitude of the synaptic excitation at the basal and apical dendritic synapses of CA1 following commissural stimulation in the urethane-anesthetized rat, before and after a theta-frequency patterned primed burst tetanus. Stimulation of the contralateral CA3 or the contralateral CA1 stratum oriens excited both the basal and apical dendrites in CA1 about equally. However, primed burst tetanization of the contralateral CA3 or CA1 stratum oriens resulted in significant long-term potentiation (LTP) only at the basal dendrites and not at the apical dendrites. Stimulation of the contralateral CA1 stratum radiatum excited the apical dendrites more than the basal dendrites of CA1, but tetanization of this contralateral site gave little change in the apical or basal dendritic excitation. Tetanization of the contralateral CA1 stratum radiatum after an intraventricular administration of bicuculline, a GABA(A) antagonist, however, resulted in significant LTP at both the apical and basal dendrites. It was concluded that, in the intact hippocampus in vivo, the threshold for LTP at the commissural apical dendritic synapse was high in comparison to that at the basal dendritic synapse and this high threshold may be partly caused by inhibitory interneurons that predominantly synapsed on the apical dendrites. Thus, the basal and apical dendrites of the CA1 pyramidal cells are not equal in their propensity for long-term plasticity.