Calcium channel subtypes in lamprey sensory and motor neurons.
Calcium channel subtypes in lamprey sensory and motor neurons.
复制标题
七鳃鳗感觉和运动神经元中的钙通道亚型。
DOI：
10.1152/jn.1997.78.3.1334
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发表时间：
1997
影响因子：
2.5
通讯作者：
N. Bussières
中科院分区：
文献类型：
--
作者：
A. El Manira;N. Bussières
七鳃鳗幼体脊髓的分离皮肤感觉神经元和运动神经元中具有药理学上不同的钙通道。为了实现细胞识别，在解离前，在体外完整脊髓中用荧光素偶联的葡聚糖胺选择性标记感觉背细胞和运动神经元。使用全细胞电压钳记录和特定的钙通道激动剂和拮抗剂来表征感觉背细胞、运动神经元和其他脊髓神经元中存在的钙通道。结果表明，瞬时低电压激活（LVA）钙电流存在于一部分感觉背细胞中，但不存在于运动神经元中，而高电压激活（HVA）钙电流在所有记录的神经元中都可见。从药理学角度对 HVA 电流的不同成分进行了剖析，背侧细胞和运动神经元都获得了相似的结果。 N 型钙通道拮抗剂 omega-芋螺毒素-GVIA (omega-CgTx) 可阻断 > 70% 的 HVA 电流。毒素洗掉后，大部分 omega-CgTx 阻断被逆转。 L 型钙通道拮抗剂尼莫地平阻断了大约 15% 的总 HVA 电流。二氢吡啶激动剂(+/-)-BayK 8644 显着增加钙通道电流的幅度。 BayK 增强电流不受 omega-CgTx 的影响，表明 omega-CgTx 效应的可逆性不是由于 L 型通道的阻断所致。同时应用omega-CgTx和尼莫地平留下约15%的HVA钙通道电流，其中一小部分被P/Q型通道拮抗剂omega-agatoxin-IVA阻断。在三种拮抗剂存在的情况下，持续剩余电流（约10%）被镉完全阻断。我们的结果为七鳃鳗感觉神经元和运动神经元中存在 N、L 和 P/Q 型 HVA 钙通道以及其他 HVA 钙通道提供了证据。此外，某些类型的神经元表达 LVA 钙通道。
Pharmacologically distinct calcium channels have been characterized in dissociated cutaneous sensory neurons and motoneurons of the larval lamprey spinal cord. To enable cell identification, sensory dorsal cells and motoneurons were selectively labeled with fluorescein-coupled dextran amine in the intact spinal cord in vitro before dissociation. Calcium channels present in sensory dorsal cells, motoneurons, and other spinal cord neurons were characterized with the use of whole cell voltage-clamp recordings and specific calcium channel agonist and antagonists. The results show that a transient low-voltage-activated (LVA) calcium current was present in a proportion of sensory dorsal cells but not in motoneurons, whereas high-voltage-activated (HVA) calcium currents were seen in all neurons recorded. The different components of HVA current were dissected pharmacologically and similar results were obtained for both dorsal cells and motoneurons. The N-type calcium channel antagonist omega-conotoxin-GVIA (omega-CgTx) blocked >70% of the HVA current. A large part of the omega-CgTx block was reversed after washout of the toxin. The L-type calcium channel antagonist nimodipine blocked approximately 15% of the total HVA current. The dihydropyridine agonist (+/-)-BayK 8644 markedly increased the amplitude of the calcium channel current. The BayK-potentiated current was not affected by omega-CgTx, indicating that the reversibility of the omega-CgTx effect is not due to a blockade of L-type channels. Simultaneous application of omega-CgTx and nimodipine left approximately 15% of the HVA calcium channel current, a small part of which was blocked by the P/Q-type channel antagonist omega-agatoxin-IVA. In the presence of the three antagonists, the persistent residual current (approximately 10%) was completely blocked by cadmium. Our results provide evidence for the existence of HVA calcium channels of the N, L, and P/Q types and other HVA calcium channels in lamprey sensory neurons and motoneurons. In addition, certain types of neurons express LVA calcium channels.
影响因子：
5.5
作者：
FOX, AP;NOWYCKY, MC;TSIEN, RW
通讯作者：
TSIEN, RW