Voltage-Dependent Currents in Merkel Cell

默克尔盒中的电压相关电流

• 批准号: 02670055
• 负责人: OGAWA Hisashi
• 金额: $ 1.41万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02670055/
• 关键词: Rat; Merkel cell; Potassium current; Calcium current Quinacrine; Quinacrine; Patch-clamp; 走査電子顕微鏡; ラット; カルシウムアンタゴニスト; 静止膜電位

Merkel cells were dissociated enzymatically from the footpad epidermis of 10 to 20-day-old rats pretreated with fluorescent dye, quinacrine, for purposes of staining. Electrical recordings were performed in whole-dell configuration using a conventional patch-clamp technique. The mean resting membrane potential of fluorescent Merkel cells was -54.0 mV, the value being greater than the -26.1 mV of non-fluorescent epidermal cells. The Merkel cells had no Na^+ spike in an external standard solution, but tetrodotoxin-resistant long-lasting action potentials were evoked by depolarization with injection of constant currents in an external solution containing Ba^<2+>. In Merkel cells under voltage-clamp, depolarizing step pulses from a holding potential (V_H) of -80 mV elicited predominantly outward K^+ currents composed of transient and sustained components : the former was selectively inhibited by 4-aminopyridine (4-AP), while the latter. was inhibited by both tetraethylammonium (TEA) and qu … More inacrine. The sustained outward K^+ current (I_<KD>) was activated at potentials more positive than -20 or -10 mV at a V^H of -50 mV, at which potential the transient outward K^+ channel was completely inactivated. The transient outward K^+ current (I_A) was activated at potentials more positive than -50 mV at a V_H of -80 mV. When the outward K^+ currents were blocked by adding both TEA and 4-AP, only a sustained inward Ca^<2+> current was observed. In an external solution containing 10 mM-Ca^<2+>, I_<ca> was evoked by potentials more positive than -20 mV at a V^H of -80 mV, and the maximum inward current appeared around +10 mV. Increases of external Ca^<2+> concentration induced a hyperbolic increase of I_<ca>. The selectivity of the Ca^<2+> channel for divalent cations was in the order of Ba^<2+> > Sr^<2+> > Ca^<2+>. It was concluded that Merkel cells have at least three distinct voltage-gated currents : a delayed K^+ current (I_<KD>), a transient A current (I_A) and a high-threshold (L-type) Ca^<2+> current (I_<ca>). Less

从用荧光染料奎纳克林预处理的10至20日龄大鼠的足垫表皮酶促分离默克尔细胞，用于染色目的。使用传统的膜片钳技术在整个戴尔配置中进行电记录。荧光默克尔细胞的平均静息膜电位为-54.0 mV，该值大于非荧光表皮细胞的-26.1 mV。默克尔细胞在外部标准溶液中没有Na^+峰，但在含有Ba^2+的外部溶液中注入恒定电流去极化可诱发河豚毒素抗性的持久动作电位。在电压钳条件下，默克尔细胞在保持电位为-80 mV的阶跃去极化脉冲下，主要产生由瞬时和持续成分组成的外向K^+电流，前者可被4-氨基吡啶（4-AP）选择性抑制，而后者可被4-AP选择性抑制。四乙铵（TEA）和槲皮素均抑制该作用 ...更多信息 无分泌物。当V^H为-50 mV时，持续外向K^+电流（I_<KD>）在比-20 mV或-10 mV更正的电位下被激活，在此电位下，瞬时外向K^+通道完全失活。瞬时外向K^+电流（I_A）在V_H为-80 mV、电位大于-50 mV时被激活。当同时加入TEA和4-AP阻断外向K^+电流时，只观察到持续的内向Ca^&lt;2+&gt;电流。在含有10 mM-Ca^&lt;2+&gt;的外溶液中，<ca>当V^H为-80 mV时，大于-20 mV的电位可诱发I_2，最大内向电流出现在+10 mV左右。增加细胞外Ca^&lt;2+&gt;浓度可使I_（max）呈双曲线增加<ca>。Ca^2+通道对二价阳离子的选择性顺序为Ba^2+&gt; Sr^2+&gt; Ca^2+。结果表明，默克尔细胞至少具有三种不同的电压门控电流：延迟K^+电流（I_<KD>）、瞬时A电流（I_A）和高阈值（L型）Ca^2+电流（I_<ca>）。少

项目成果

Yamashita,Y.: "The L-type calcium channel in solitary Merkel cells of rats." Jpn.J.Physiol.40. S22 (1990)

Yamashita,Y.：“大鼠孤立默克尔细胞中的 L 型钙通道。”

Yamashita,Y.: "Voltage-dependent currents in isolated single Merkel cells of rats." J.Physiol.(Lond.). 450. 143-162 (1992)

Yamashita，Y.：“大鼠分离的单个默克尔细胞中的电压依赖性电流。”

Yamashita,Y.: "Voltageーdependent currents in isolated single Merkel cells of rats." J.Physiol.(Lond.). 450. 143-162 (1992)

Yamashita, Y.：“大鼠分离的单个默克尔细胞中的电压依赖性电流。”J.Physiol.(Lond.) 450. 143-162 (1992)。

Yamashita, Y. et al.: "Voltage-Dependent Currents in Isolated Single Merkel cells of Rats." J. Physiol. (Lond.). 450. 143-162 (1992)

Yamashita, Y. 等人：“大鼠离体单默克尔细胞中的电压依赖性电流。”

YAMASHITA,Y.: "THE LーTYPE CALCIUM CHANNEL IN SOLITARY MERKEL CELLS OF RATS." Japanese Journal of Physiology. 40. S22 (1990)

YAMASHITA, Y.：“大鼠孤立默克尔细胞中的 L 型钙通道。”日本生理学杂志 40. S22 (1990)