SEPARATE MECHANISMS OF LONG-TERM POTENTIATION IN 2 INPUT SYSTEMS TO CA3 PYRAMIDAL NEURONS OF RAT HIPPOCAMPAL SLICES AS REVEALED BY THE WHOLE-CELL PATCH-CLAMP TECHNIQUE
SEPARATE MECHANISMS OF LONG-TERM POTENTIATION IN 2 INPUT SYSTEMS TO CA3 PYRAMIDAL NEURONS OF RAT HIPPOCAMPAL SLICES AS REVEALED BY THE WHOLE-CELL PATCH-CLAMP TECHNIQUE
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DOI：
10.1016/0168-0102(91)90070-f
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发表时间：
1991-11-01
影响因子：
2.9
通讯作者：
SATOH, M
中科院分区：
文献类型：
--
作者：
KATSUKI, H;KANEKO, S;SATOH, M
用全细胞膜片钳技术制作薄片，结合长时程增强(LTP)研究了两个输入系统向海马CA3区锥体神经元的兴奋性突触传递。刺激海马伞诱发的兴奋性突触后电流(EPSCs)由两部分组成，一部分被6-氰基-7-硝基-2，3-二酮(CNQX)阻断，另一部分持续于去极化的膜电位，并被D-2-氨基-5-磷酸戊酸(D-AP5)阻断。D-AP5敏感成分对刺激苔藓纤维诱发的EPSCs的贡献远小于对伞状EPSCs的贡献。高频刺激传入纤维，在电流钳条件下，可诱发LTP。沐浴D-AP5可阻断海马伞LTP的诱导，但不能阻断苔藓纤维突触LTP的诱导。细胞内注射10 mM BAPTA可完全阻断海马伞LTP的诱导。相反，10 mM BAPTA不能阻断苔藓纤维LTP。此外，在电压钳(-80 mV)条件下，高频刺激可诱导出苔藓纤维LTP，而不是伞状LTP。这些结果表明，NMDA受体的激活、突触后[Ca~(2+)]i的升高和突触后膜去极化是诱导海马伞而不是苔藓纤维LTP所必需的。
Excitatory synaptic transmission from two input systems to hippocampal CA3 pyramidal neurons was investigated by the whole-cell patch-clamp technique for thin slice preparation, with special reference to long-term potentiation (LTP) in these systems. Excitatory postsynaptic currents (EPSCs) evoked by fimbrial stimulation consisted of two components; one was blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and the other was persistent at depolarized membrane potentials and blocked by D-2-amino-5-phosphonovalerate (D-AP5). The contribution of the D-AP5-sensitive component to EPSCs evoked by stimulation of mossy fibers was much less than that to fimbrial EPSCs. High-frequency stimulation of afferent fibers, under current-clamp conditions, elicited LTP. Bath application of D-AP5 blocked the induction ot LTP in the fimbrial but not in the mossy fiber synapses. Induction of fimbrial LTP was completely blocked by 10 mM BAPTA applied intracellularly. In contrast, mossy fiber LTP was not blocked by 10 mM BAPTA. Furthermore, mossy fiber LTP, but not fimbrial LTP, was elicited by high-frequency stimulation under voltage-clamp (-80 mV) conditions. These results suggest that activation of NMDA receptors, increase in postsynaptic [Ca2+]i, and postsynaptic membrane depolarization are required for the induction of fimbrial but not for mossy fiber LTP.