THE ROLE OF CA2+ CHANNELS IN HIPPOCAMPAL MOSSY FIBER SYNAPTIC TRANSMISSION AND LONG-TERM POTENTIATION
THE ROLE OF CA2+ CHANNELS IN HIPPOCAMPAL MOSSY FIBER SYNAPTIC TRANSMISSION AND LONG-TERM POTENTIATION
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DOI：
10.1016/0896-6273(94)90269-0
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发表时间：
1994-02-01
期刊：
影响因子：
16.2
通讯作者：
NICOLL, RA
中科院分区：
文献类型：
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作者：
CASTILLO, PE;WEISSKOPF, MG;NICOLL, RA
我们已经讨论了 Ca2+ 通道在混乱的纤维突触传递和长时程增强 (LTP) 中的作用。当突触传递被谷氨酸受体拮抗剂犬尿酸盐阻断时，杂乱纤维 LTP 的诱导是完全正常的，而在细胞外 Ca2+ 不存在的情况下，LTP 会被阻断。这些发现表明，突触前 Ca2+ 进入对于杂乱的纤维 LTP 至关重要。因此，研究了不同类型的突触前Ca2+通道在突触传递和LTP中的作用。 L 型 Ca2+ 通道阻滞剂硝苯地平对杂乱纤维反应的影响很小。它们被 omega-芋螺毒素-GVIA（N 型）部分阻断，几乎完全被 omega-agatoxin-IVA（P 型）阻断。这些拮抗剂都不能阻断杂乱纤维 LTP，其表达也与突触传递对两种毒素的敏感性变化无关。这些结果与之前的发现一起表明，杂乱纤维 LTP 的诱导关键依赖于 Ca2+ 进入突触前末端，从而触发一系列步骤，从而导致诱发谷氨酸释放的长期持续增强。尽管 P 型 Ca2+ 通道在杂乱纤维突触传递中至关重要，但杂乱纤维 LTP 的诱导和表达都可以在没有 P 型（或 N 型）Ca2+ 通道的情况下发生。
We have addressed the role of Ca2+ channels in messy fiber synaptic transmission and long-term potentiation (LTP). Whereas the induction of messy fiber LTP is entirely normal when synaptic transmission is blocked by the glutamate receptor antagonist kynurenate, LTP is blocked in the absence of extracellular Ca2+. These findings suggest that presynaptic Ca2+ entry is essential for messy fiber LTP. Therefore, the role of different types of presynaptic Ca2+ channels in synaptic transmission and LTP was investigated. Messy fiber responses were little affected by the L-type Ca2+ channel blocker nifedipine. They were blocked partially by omega-conotoxin-GVIA (N-type) and almost entirely by omega-agatoxin-IVA (P-type). None of these antagonists blocked messy fiber LTP, nor was its expression associated with a change in sensitivity of synaptic transmission to either of the two toxins. These results, together with previous findings, suggest that the induction of messy fiber LTP is critically dependent on the entry of Ca2+ into the presynaptic terminal to trigger a series of steps resulting in the long lasting enhancement of evoked glutamate release. Whereas P-type Ca2+ channels are of primary importance in messy fiber synaptic transmission, both the induction and expression of messy fiber LTP can occur in the absence of P-type (or N-type) Ca2+ channels.