Differential roles of two types of voltage-gated Ca2+ channels in the dendrites of rat cerebellar Purkinje neurons
Differential roles of two types of voltage-gated Ca2+ channels in the dendrites of rat cerebellar Purkinje neurons
复制标题
大鼠小脑浦肯野神经元树突中两种电压门控 Ca2+ 通道的不同作用
DOI：
10.1016/s0006-8993(98)00048-1
复制
发表时间：
1998
期刊：
影响因子：
2.9
通讯作者：
H. Miyakawa
中科院分区：
文献类型：
--
作者：
Shigeo Watanabe;H. Takagi;Tsugumichi Miyasho;M. Inoue;Y. Kirino;Y. Kudo;H. Miyakawa
应用同步钙离子成像和全细胞膜片钳记录技术，研究了大鼠小脑片浦肯野神经元电压门控性钙通道的分布和功能。在河豚毒素存在的情况下，电压门控钙通道在电压钳制模式下通过连接在胞体的移液管施加去极化电压步骤来激活。由于树突的广泛树枝形成的不良空间钳制，使得树突能够发射钙离子尖峰。经移液管注入Fura-2的钙成像显示，胞体内[Ca~(2+)]i持续升高，树突内有短暂的棘波连接的[Ca~(2+)]i跳跃。ω-Agatoxin-IVA(200 NM)可抑制去极化引起的钙尖峰，树突内与尖峰相连的[Ca~(2+)]升高，胞体内稳定的[Ca~(2+)]升高。ω-芋螺毒素-GVIA(5μM)和硝苯地平(3μM)对去极化反应无明显影响。在4-氨基吡啶(2 MM)和ω-Agatoxin-IVA存在下，树突内仍有一过性的[Ca~(2+)]i升高。低浓度的Ni~(2+)(100μM)可逆地抑制[Ca~(2+)]i的升高。该成分的半峰激活和失活电压分别低于−50 mV和−31 mV。在正常情况下，低浓度的Ni2+可延缓钙峰的出现，但不改变峰的时程或伴随的[Ca2+]i升高的幅度。这些结果表明，ω-Agatoxin-IVA敏感的钙通道分布在胞体和树突中，并与树突钙峰有关，而低电压激活的镍敏感钙通道分布于整个树突，包括粗枝和细枝，并为尖峰的产生提供增强电流。
The distribution and function of voltage-gated Ca2+channels in Purkinje neurons in rat cerebellar slices were studied using simultaneous Ca2+imaging and whole-cell patch clamp recording techniques. Voltage-gated Ca2+channels were activated by applying depolarizing voltage steps through the pipette attached at the soma in a voltage-clamp mode in the presence of tetrodotoxin. Poor space clamp due to extensive arborization of the dendrites allowed the dendrites to fire Ca2+spikes. Ca2+imaging with Fura-2 injected through the pipette, showed a steady [Ca2+]iincrease at the soma and transient, spike-linked [Ca2+]ijumps in the dendrites. ω-Agatoxin-IVA (200 nM) abolished the depolarization-induced Ca2+spikes, the spike-linked [Ca2+]iincrease in the dendrites, and the steady [Ca2+]iincrease at the soma. ω-Conotoxin-GVIA (5 μM) and nifedipine (3 μM) had no significant effect on the depolarization-induced responses. In the presence of 4-aminopyridine(2 mM) and ω-Agatoxin-IVA, transient [Ca2+]iincreases remained in the dendrites. Low concentrations of Ni2+(100 μM) reversibly suppressed this [Ca2+]iincrease. The voltage for half-maximal activation and inactivation of this component were lower than −50 mV and −31 mV, respectively. In normal conditions, low concentration of Ni2+slowed the onset of the Ca2+spike without changing the time course of the spikes or the amplitude of the accompanying [Ca2+]iincrease. These results show that ω-Agatoxin-IVA-sensitive Ca2+channels are distributed both in the soma and the dendrites, and are responsible for dendritic Ca2+spikes, whereas low-voltage activated, Ni2+-sensitive Ca2+channels are distributed in the whole dendrites including both thick and fine branches, and provide boosting current for spike generation.
登录
查看更多内容
影响因子：
2.5
作者：
MIYAKAWA, H;LEVRAM, V;ROSS, WN
通讯作者：
ROSS, WN
DOI：
10.1073/pnas.86.5.1689
发表时间：
1989-03-01
影响因子：
11.1
作者：
LLINAS, R;SUGIMORI, M;CHERKSEY, B
通讯作者：
CHERKSEY, B
DOI：
10.1073/pnas.90.9.3787
发表时间：
1993-05-01
影响因子：
11.1
作者：
HORNE, WA;ELLINOR, PT;SCHWARZ, TL
通讯作者：
SCHWARZ, TL
体外海龟浦肯野细胞树突中 Ca2 流入的空间分布：瞬时外向电流的作用。
影响因子：
2.5
作者：
Midtgaard,J;Lasser-Ross,N;Ross,WN
通讯作者：
Ross,WN
影响因子：
5.5
作者：
LLINAS, R;SUGIMORI, M
通讯作者：
SUGIMORI, M