齿状颗粒细胞长时程增强的出现而近端树突钙未增加。

Occurrence of dentate granule cell LTP without proximal dendritic Ca2+ increase.

作者信息

Hashimoto K, Isomura Y, Kato N

机构信息

Department of Integrative Brain Science, Kyoto University Graduate School of Medicine, Japan.

出版信息

Neuroreport. 1999 Aug 20;10(12):2509-13. doi: 10.1097/00001756-199908200-00014.

DOI:10.1097/00001756-199908200-00014

PMID:10574361

Abstract

We investigated activity-dependent calcium increases in proximal dendrites of dentate granule cells in the rat hippocampus, and its relationship with induction of LTP at perforant path synapses (PP-synapses). LTP was induced at PP-synapses by high-frequency stimulation (HFS; 100 Hz for 0.4 s), and the same HFS evoked a dendritic calcium increase in the proximal dendrite. However, bath-application of the L-type voltage-dependent calcium channel (VDCC) blocker nimodipine noticeably reduced this calcium increase without abolishing induction of LTP. This calcium increase mediated by high-threshold VDCCs is likely to be evoked by action potentials. LTP induction at PP-synapses is hence suggested to be independent of action potential-induced calcium increases in the proximal dendrite.

摘要

我们研究了大鼠海马齿状颗粒细胞近端树突中依赖活动的钙增加及其与穿通通路突触（PP 突触）处长时程增强（LTP）诱导的关系。通过高频刺激（HFS；100Hz，持续 0.4s）在 PP 突触处诱导 LTP，相同的 HFS 可引起近端树突中树突钙增加。然而，浴用 L 型电压依赖性钙通道（VDCC）阻滞剂尼莫地平可显著减少这种钙增加，但不消除 LTP 的诱导。由高阈值 VDCC 介导的这种钙增加可能由动作电位诱发。因此，提示在 PP 突触处诱导 LTP 与近端树突中动作电位诱导的钙增加无关。