Sustained outward rectification of oxytocinergic neurones in the rat supraoptic nucleus: ionic dependence and pharmacology.
Sustained outward rectification of oxytocinergic neurones in the rat supraoptic nucleus: ionic dependence and pharmacology.
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大鼠视上核催产素能神经元的持续向外整流：离子依赖性和药理学。
DOI：
10.1113/jphysiol.1997.sp022036
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Armstrong,WE
中科院分区：
文献类型：
--
作者：
Stern,JE;Armstrong,WE
1.从发情间期和哺乳期雌性大鼠的催产素和加压素神经元获得细胞内记录。在电流钳下，催产素神经元的特征是去极化激活的持续外向整流(SOR)和反弹去极化(RD)。2.细胞外K+的增加使SOR和RD的表达向更去极化的膜电位方向移动，表明这些事件的发生机制依赖于细胞外钾。3.外加10 mM的四乙基铵和0.1-0.5 mM的Ba2+可阻断SOR和RD。CS+(2 MM)阻断超极化激活的内向整流，但不影响SOR和RD的表达。4.4-氨基吡啶(6 MM)对SOR无影响。然而，反弹幅度显著增强，表明瞬时外向电流的激活与反弹的表达相互作用。5.伊比利亚毒素(100 NM)和阿帕明(50 NM)是已知的阻断某些钙依赖钾电导的毒素，它们不影响SOR和RD的表达。6.Cd~(2+)(0.5 mM)显著降低SOR和RD，而Ni~(2+)(0.25 mM)对SOR和RD无明显影响。7.毒扁豆碱(10微米)对SOR和RD无影响。8.这些结果表明，SOR和RD依赖于去极化激活的持续外向钾电流，这可能是钙依赖的。具有这些特征的电流以前从未在巨细胞系统中被描述过。需要电压钳实验来完整地描述催产素神经元选择性表达的这种钾电导。
1. Intracellular recordings were obtained in vitro from oxytocin and vasopressin neurones from dioestrous and lactating female rats. Oxytocin neurones were characterized under current clamp by the expression of a depolarization‐activated, sustained outward rectification (SOR) and a rebound depolarization (RD). 2. An increment in extracellular K+ shifted the expression of the SOR and RD towards a more depolarized membrane potential, indicating that the mechanisms underlying these events are dependent on extracellular potassium. 3. The SOR and RD were blocked by external tetraethylammonium (10 mM) and Ba2+ (0.1‐0.5 mM). Cs+ (2 mM) blocked the hyperpolarization‐activated inward rectification without affecting the expression of the SOR and RD. 4. The SOR was not affected by 4‐aminopyridine (6 mM). However, the rebound amplitude was significantly enhanced, indicating that the activation of a transient outward current interacts with the expression of the rebound. 5. Iberiotoxin (100 nM) and apamin (50 nM), toxins known to block some calcium‐dependent potassium conductances, did not affect the expression of the SOR and RD. 6. The SOR and RD were significantly reduced by Cd2+ (0.5 mM) but not by Ni2+ (0.25 mM). 7. Muscarine (10 microM) did not affect the SOR or the RD. 8. These results indicate that the SOR and RD depend upon a depolarization‐activated, sustained outward potassium current, which might be calcium dependent. A current with these characteristics has never been described before in the magnocellular system. Voltage‐clamp experiments are needed to completely characterize this potassium conductance selectively expressed by oxytocin neurones.
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DOI：
10.1113/jphysiol.1987.sp016406
发表时间：
1987
期刊：
The Journal of physiology
影响因子：
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作者：
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影响因子：
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DOI：
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发表时间：
1995
期刊：
The Journal of physiology
影响因子：
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作者：
Stern,JE;Armstrong,WE
通讯作者：
Armstrong,WE
影响因子：
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DOI：
10.1113/jphysiol.1989.sp017543
发表时间：
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期刊：
The Journal of Physiology
影响因子：
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