Potassium currents and their modulation by muscarine and substance P in neuronal cultures from adult guinea pig celiac ganglia.
Potassium currents and their modulation by muscarine and substance P in neuronal cultures from adult guinea pig celiac ganglia.
复制标题
成年豚鼠腹腔神经节神经元培养物中钾电流及其受毒蕈碱和 P 物质的调节。
DOI：
10.1152/jn.1993.69.5.1632
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发表时间：
1993
影响因子：
2.5
通讯作者：
Surprenant,A
中科院分区：
文献类型：
--
作者：
Vanner,S;Evans,RJ;Matsumoto,SG;Surprenant,A
1.从在组织培养物中生长7-14天的成年豚鼠腹腔神经节神经元获得细胞内微电极和全细胞膜片钳记录。使用任一类型的记录电极，超过 90% 的神经元显示出相型动作电位放电；他们对儿茶酚胺、酪氨酸羟化酶和神经肽 Y 进行免疫组织化学染色。全细胞记录的输入电阻（140 M Ω）和动作电位幅度（103 mV）显着大于微电极记录，但其他被动电特性相似。 2. 表征了五种钾电流：apamin 敏感的超极化后电流 (IAHP)、apamin 和四乙基铵不敏感的慢 IAHP、M 样电流、瞬态外向 IA 电流和延迟整流器 IK 电流。还存在超极化激活的阳离子 Ih 电流。全细胞记录中未观察到前三个电流。 3. 镉 (200 µM)、钴 (1 mM)、镧 (30 µM) 或低钙/高镁溶液会阻断 IAHPS 和类 M 电流；钡 (1 mM) 也能阻止这些电流。 4. M 类电流的动力学最好通过双指数拟合来描述，以在 -50 mV 下以 50 和 390 ms 的时间常数去激活尾电流。 apamin 敏感的和慢速的 IAHP 呈指数衰减，时间常数分别为 145 ms 和 3.5 s。 M 样电流（95% 的神经元）和慢 IAHP（40% 的神经元）的发生之间没有相关性，在表现出两种电流的细胞中，M 样电流的大小和 IAHP 之间也没有任何相关性。 5. 毒蕈碱和 P 物质 (SP) 在静息电位 (-55 mV) 下引起去极化或内向电流（在电压钳下），并与膜电导降低相关。缓慢的 IAHP 和 M 样电流，但不是 apamin 敏感的 IAHP 或 IA，被毒蕈碱和 SP 阻断（IC50 分别为 3 microM 和 100 nM）。毒蕈碱和 SP 还降低了“泄漏”钾电流。 6. 我们得出结论，腹腔神经元表达两种钙依赖性 IAHP 电流和一种钙依赖性 M 电流；这些可以通过细尖细胞内微电极看到，但不能通过全细胞贴片电极看到。尖峰频率调节不需要这些电流。毒蕈碱和 SP 可减少这些电流以及与电压无关的漏钾电流。
1. Intracellular microelectrode and whole-cell patch-clamp recordings were obtained from adult guinea pig celiac ganglion neurons grown in tissue culture for 7-14 days. Over 90% of neurons showed phasic-type action-potential discharge with the use of either type of recording electrode; they stained immunohistochemically for catecholamines, tyrosine hydroxylase, and neuropeptide Y. Input resistance (140 M omega) and action-potential amplitude (103 mV) were significantly greater with whole-cell than with microelectrode recordings, but other passive electrical properties were similar. 2. Five potassium currents were characterized: an apamin-sensitive after hyperpolarizing current (IAHP), an apamin and tetraethylammonium-insensitive slow IAHP, an M-like current, a transient outward IA current, and a delayed rectifier IK current. A hyperpolarization-activated cationic Ih current was also present. The first three currents were not observed with whole-cell recordings. 3. Cadmium (200 microM), cobalt (1 mM), lanthanum (30 microM), or a low calcium/high magnesium solution blocked both IAHPS and the M-like current; barium (1 mM) also blocked these currents. 4. Kinetics of the M-like current were best described by a double exponential fit to deactivating tail currents with time constants of 50 and 390 ms at -50 mV. The apamin-sensitive and slow IAHP decayed exponentially with time constants of 145 ms and 3.5 s, respectively. There was no correlation between occurrence of M-like current (95% of neurons) and slow IAHP (40% of neurons), nor any correlation between magnitude of M-like current and IAHP in those cells exhibiting both currents. 5. Muscarine and substance P (SP) caused depolarizations or inward currents (under voltage clamp) at the resting potential (-55 mV) associated with a decreased membrane conductance. The slow IAHP and the M-like current, but not the apamin-sensitive IAHP nor the IA, were blocked by muscarine and SP (IC50 3 microM and 100 nM, respectively). Muscarine and SP also decreased a "leak" potassium current. 6. We conclude that celiac neurons express two calcium-dependent IAHP currents and a calcium-dependent M-current; these are seen by fine-tipped intracellular microelectrodes but not by whole-cell patch electrodes. These currents are not required for spike frequency accommodation. Muscarine and SP reduce these currents, as well as voltage-independent leakage potassium current.