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这些的结果是，''Na''V 通道的动力学决定于状态转换矩阵，其中转换速率以一种复杂的方式依赖于电压。由于这些通道本身在决定电位中起着重要作用，系统的全局动力学可能很难计算出来。为了解决这个问题，Hodgkin 和 Huxley 为决定离子通道状态的参数建立了一组微分方程，称为 Hodgkin-Huxley 方程（Hodgkin-Huxley equations）。这些方程在后续的研究被修正了很多，但构成很多动作电位生物物理学的理论研究的起点。

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[[File:Membrane Permeability of a Neuron During an Action Potential.svg|thumb|upright=1.75|right|动作电位过程中的离子移动。图注：a）钠离子（Na+）、b）钾离子（K+）、c） ~~钠通道、d）钾通道、e）钠钾泵。~~

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[[File:Membrane Permeability of a Neuron During an Action Potential.svg|thumb|upright=1.75|right|动作电位过程中的离子移动。图注：a）钠离子（Na+）、b）钾离子（K+）、c）钠通道、d）钾通道、e）钠钾泵。在动作电位发生的过程中，神经元质膜的通透性发生变化。在'''静息状态'''（1），钠离子和钾离子能有限地跨膜通过，神经元内部具有净负电荷。一旦触发动作电位，神经元'''去极化'''（2）激活钠通道，允许钠离子通过细胞膜进入细胞，导致神经元相对于细胞外液的净正电荷。达到动作电位峰值后，神经元开始'''复极化'''（3），其中钠通道关闭，钾通道打开，允许钾离子穿过膜进入细胞外液，使膜电位恢复为负值。最后，有一个'''不应期'''（4），在此期间，电压依赖的离子通道失活，而 Na+ 和 K+ 离子返回到其在膜上的静息状态分布（1），并且神经元准备重复该过程产生下一个动作电位。|链接=Special:FilePath/Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg]]

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~~在动作电位发生的过程中，神经元质膜的通透性发生变化。在~~'''静息状态'''（1），钠离子和钾离子能有限地跨膜通过，神经元内部具有净负电荷。一旦触发动作电位，神经元'''去极化'''（2）激活钠通道，允许钠离子通过细胞膜进入细胞，导致神经元相对于细胞外液的净正电荷。达到动作电位峰值后，神经元开始'''复极化'''（3），其中钠通道关闭，钾通道打开，允许钾离子穿过膜进入细胞外液，使膜电位恢复为负值。最后，有一个'''不应期'''（4），在此期间，电压依赖的离子通道失活，而 Na+ 和 K+ 离子返回到其在膜上的静息状态分布（1），并且神经元准备重复该过程产生下一个动作电位。|链接=Special:FilePath/Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg]]

随着膜电位的增加，钠离子通道打开，允许钠离子进入细胞。随后钾离子通道打开，允许钾离子流出细胞。钠离子内流增加了细胞中带正电荷的阳离子的浓度，导致去极化，这时细胞的电位高于细胞的静息电位。钠离子通道在动作电位峰值处关闭，而钾离子继续流出细胞。钾离子外流会降低细胞的膜电位或使细胞超极化。膜电位比静息电位高一点时，钾电流超过钠电流，而恢复到正常的静息值，通常为 -70 mV。然而，如果电位增加超过一个关键阈值，通常高于静息值 15 mV，钠电流将占主导地位。这就导致了一种失控的情况，即钠电流的正反馈激活了更多的钠通道。因此，细胞发放，产生动作电位。神经元诱发动作电位的频率通常被称为发放频率或神经放电频率。

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在动作电位过程中，电压门控通道的开放所产生的电流通常明显大于起初的刺激电流。因此，动作电位的幅度、持续时间和波形在很大程度上取决于可兴奋膜的性质，而不是刺激的幅度或持续时间。动作电位的这种全或无的特性使它有别于受体电位（receptor potentials）、电紧张电位（electrotonic potentials）、阈下膜电位振荡（subthreshold membrane potential oscillations）和突触电位（synaptic potentials）等随刺激强度变化的级量电位（graded potential）。取决于电压门控通道的类型、漏电通道、通道分布、离子浓度、膜电容、温度等因素，许多细胞类型和细胞分区中存在多种动作电位类型。

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与动作电位有关的主要离子是钠离子和钾离子；钠离子进入细胞，钾离子流出，恢复平衡。只需相对很少的离子跨膜就能引起膜电位剧烈的变化。因此，在动作电位期间交换的离子对内部和外部离子浓度的改变微不足道。少数跨膜的离子通过钠钾泵的连续作用再次泵出，钠钾泵与其他离子转运蛋白一起，维持了跨膜离子浓度的正常比例。钙离子和氯离子参与了几种类型的动作电位，比如分别参与心肌动作电位和单细胞的伞藻的动作电位。

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与动作电位有关的主要离子是钠离子和钾离子；钠离子进入细胞，钾离子流出，恢复平衡。只需相对很少的离子跨膜就能引起膜电位剧烈的变化。因此，在动作电位期间交换的离子对内部和外部离子浓度的改变微不足道。少数跨膜的离子通过钠钾泵（sodium–potassium pump）的连续作用再次泵出，钠钾泵与其他离子转运蛋白一起，维持了跨膜离子浓度的正常比例。钙离子和氯离子参与了几种类型的动作电位，比如分别参与心肌动作电位和单细胞的伞藻的动作电位。

虽然动作电位是在可兴奋的膜片上局部产生的，但由此产生的电流可以触发相邻膜片上的动作电位，促成多米诺骨牌般的传播。与被动传播的电位（电紧张电位）不同，动作电位沿着可兴奋的细胞膜重新产生，并且不衰减地传播<ref name="no_decrement">[[Knut Schmidt-Nielsen|Schmidt-Nielsen]], p. 484.</ref>。轴突的有髓鞘区域不可兴奋，不产生动作电位，信号被动地以电紧张电位的形式传播。在郎飞节，即规律性间隔的无髓鞘膜片，产生动作电位来增强信号。这种类型的信号传播被称为跳跃式传导，是在信号传播速度和轴突直径之间的折衷。轴突末梢的去极化通常触发神经递质释放进入突触间隙。此外，在新皮层广泛存在的锥体神经元的树突中也记录到了反向传播的动作电位<ref name="backpropagation_in_pyramidal_cells" group="lower-alpha">{{cite journal | vauthors = Golding NL, Kath WL, Spruston N | title = Dichotomy of action-potential backpropagation in CA1 pyramidal neuron dendrites | journal = Journal of Neurophysiology | volume = 86 | issue = 6 | pages = 2998–3010 | date = December 2001 | pmid = 11731556 | doi = 10.1152/jn.2001.86.6.2998 | s2cid = 2915815 | df = dmy-all }}</ref>。这些都被认为脉冲时序依赖的突触可塑性（STDP, Spike-timing-dependent_plasticity）中起着重要作用。

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轴丘产生的动作电位像波一样沿轴突传播。动作电位的膜内向电流会沿着轴突扩散，并使邻近的细胞膜去极化。足够强的去极化则会引起邻近的膜片发放类似的动作电位。Alan Lloyd Hodgkin 在 1937 年证明了这种基本的机制。他发现挤压（crushing）或冷却（cooling）神经节段，从而阻断动作电位，而传至阻断部位一侧的动作电位可以引发另一侧的动作电位，只要阻断的节段足够短。<ref name=":1" group="lower-alpha">{{cite journal | vauthors = Hodgkin AL | title = Evidence for electrical transmission in nerve: Part I | journal = The Journal of Physiology | volume = 90 | issue = 2 | pages = 183–210 | date = July 1937 | pmid = 16994885 | pmc = 1395060 | doi = 10.1113/jphysiol.1937.sp003507 | author-link = Alan Lloyd Hodgkin }} * {{cite journal | vauthors = Hodgkin AL | title = Evidence for electrical transmission in nerve: Part II | journal = The Journal of Physiology | volume = 90 | issue = 2 | pages = 211–32 | date = July 1937 | pmid = 16994886 | pmc = 1395062 | doi = 10.1113/jphysiol.1937.sp003508 | author-link = Alan Lloyd Hodgkin }}</ref>

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Once an action potential has occurred at a patch of membrane, the membrane patch needs time to recover before it can fire again. At the molecular level, this ''absolute refractory period'' corresponds to the time required for the voltage-activated sodium channels to recover from inactivation, i.e., to return to their closed state.{{sfn|Stevens|1966|pp=19–20}} There are many types of voltage-activated potassium channels in neurons. Some of them inactivate fast （A-type currents） and some of them inactivate slowly or not inactivate at all; this variability guarantees that there will be always an available source of current for repolarization, even if some of the potassium channels are inactivated because of preceding depolarization. On the other hand, all neuronal voltage-activated sodium channels inactivate within several milliseconds during strong depolarization, thus making following depolarization impossible until a substantial fraction of sodium channels have returned to their closed state. Although it limits the frequency of firing,{{sfn|Stevens|1966|pp=21–23}} the absolute refractory period ensures that the action potential moves in only one direction along an axon.{{sfn|Purves|Augustine|Fitzpatrick|Hall|2008|p=56}} The currents flowing in due to an action potential spread out in both directions along the axon.{{sfn|Bullock|Orkand|Grinnell|1977|pp=161–164}} However, only the unfired part of the axon can respond with an action potential; the part that has just fired is unresponsive until the action potential is safely out of range and cannot restimulate that part. In the usual [[orthodromic conduction]], the action potential propagates from the axon hillock towards the synaptic knobs（the axonal termini）; propagation in the opposite direction—known as [[antidromic conduction]]—is very rare.{{sfn|Bullock|Orkand|Grinnell|1977|p=509}} However, if a laboratory axon is stimulated in its middle, both halves of the axon are "fresh", i.e., unfired; then two action potentials will be generated, one traveling towards the axon hillock and the other traveling towards the synaptic knobs.

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细胞膜片上一旦发生动作电位，膜片需要时间恢复才能再次激活。在分子水平上，这个绝对不应期对应于电压激活的钠离子通道从失活状态恢复、回到关闭状态所需的时间。神经元中存在多种类型的电压激活钾通道。其中一些迅速失活（A 型电流），一些缓慢失活或从不失活；这种变异性保证了：即使一些钾离子通道因去极化而失活，总有电流使膜复极化。另一方面，去极化较强时，神经元所有的电压激活钠通道在几毫秒内失活，从而使去极化不可能再发生，直到相当一部分的钠通道恢复到关闭状态。绝对不应期虽然限制了动作电位的发放频率，但确保了其沿轴突单向传播。动作电位产生的电流会沿轴突双向扩布。然而，只有未发放的轴突部位才能产生动作电位的反应；刚发放过的部位不反应，直到动作电位移动到不再能刺激该部位的安全范围。在通常的正向传导（[[orthodromic conduction]]）中，动作电位从轴丘向突触扣结（轴突末梢）传导，向相反方向传导的反向传导（[[antidromic conduction]]）现象非常罕见。不过，如果实验中从中间刺激轴突，两边的轴突都是“新鲜的”，即未被刺激，那么就会产生两个动作电位，一个传向轴丘，另一个传向突触扣结。

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细胞膜片上一旦发生动作电位，膜片需要时间恢复才能再次激活。在分子水平上，这个绝对不应期对应于电压激活的钠离子通道从失活状态恢复到关闭状态所需的时间。神经元中存在多种类型的电压激活钾通道。其中一些迅速失活（A 型电流），一些缓慢失活或从不失活；这种变异性保证了，即使一些钾离子通道因去极化而失活，总有电流来源使膜复极化。另一方面，去极化较强时，神经元所有的电压激活钠通道在几毫秒内失活，从而使去极化不可能发生，直到相当一部分的钠通道恢复到关闭状态。绝对不应期虽然限制了发放频率，但确保了动作电位沿轴突单向传播。动作电位产生的电流会沿轴突双向扩布。然而，只有未发放的轴突部位才能作出动作电位的反应；刚刚发放过的部位是没有反应的，直到动作电位移到安全范围，不能再刺激该部位。在通常的正向传导（[[orthodromic conduction]]）中，动作电位从轴丘向突触扣结（轴突末梢）传导，向相反方向传导的反向传导（[[antidromic conduction]]）现象非常罕见。不过，如果实验中从中间刺激轴突，两边的轴突都是“新鲜的”，即未被刺激，那么就会产生两个动作电位，一个传向轴丘，另一个传向突触扣结。

===髓鞘和跳跃式传导===

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===电缆学说===

[[File:Cable theory Neuron RC circuit v3.svg|thumb|300x300px|电缆理论对神经元纤维的简化图。连接的 RC 电路对应于被动的神经突相邻的节段。（与胞内阻抗 ''ri'' 对应的）胞外阻抗 ''re'' 未显示，因其通常小到可以忽略不计；细胞外液可以认为是处处电位相等。|链接=Special:FilePath/Cable_theory_Neuron_RC_circuit_v3.svg]]

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~~The flow of currents within an axon can be described quantitatively by [[cable theory]]~~<ref name="rall_1989">[[Wilfrid Rall|Rall, W]] in {{harvnb|Koch|Segev|1989|loc=''Cable Theory for Dendritic Neurons'', pp. 9–62.}}</ref> ~~and its elaborations, such as the compartmental model.~~<ref name="segev_1989">{{cite book | vauthors = Segev I, Fleshman JW, Burke RE | chapter = Compartmental Models of Complex Neurons | title = Methods in Neuronal Modeling: From Synapses to Networks. | veditors = Koch C, Segev I | editor1-link = Christof Koch | date = 1989 | pages = 63–96 | publisher = The MIT Press | location = Cambridge, Massachusetts | isbn = 978-0-262-11133-1 | lccn = 88008279 | oclc = 18384545 }}</ref> ~~Cable theory was developed in 1855 by [[William Thomson, 1st Baron Kelvin|~~Lord Kelvin~~]] to model the transatlantic telegraph cable~~<ref name="kelvin_1855" group=lower-alpha>{{cite journal | vauthors = Kelvin WT | year = 1855 | title = On the theory of the electric telegraph | journal = Proceedings of the Royal Society | volume = 7 | pages = 382–99 | doi = 10.1098/rspl.1854.0093| s2cid = 178547827 | author-link = William Thomson, 1st Baron Kelvin }}</ref> ~~and was shown to be relevant to neurons by [[Alan Lloyd~~ Hodgkin~~|Hodgkin]] and [[W. A. H.~~ Rushton~~|Rushton]] in 1946.~~<ref name="hodgkin_1946" group=lower-alpha>{{cite journal | vauthors = Hodgkin AL, Rushton WA | title = The electrical constants of a crustacean nerve fibre | journal = Proceedings of the Royal Society of Medicine | volume = 134 | issue = 873 | pages = 444–79 | date = December 1946 | pmid = 20281590 | doi = 10.1098/rspb.1946.0024 | author-link1 = Alan Lloyd Hodgkin | bibcode = 1946RSPSB.133..444H | doi-access = free }}</ref> ~~In simple cable theory, the neuron is treated as an electrically passive, perfectly cylindrical transmission cable, which can be described by a [[partial~~ differential ~~equation]]<ref name="rall_1989" />~~

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轴突内电流的流动可以用电缆理论（cable theory）<ref name="rall_1989">[[Wilfrid Rall|Rall, W]] in {{harvnb|Koch|Segev|1989|loc=''Cable Theory for Dendritic Neurons'', pp. 9–62.}}</ref> 及其细化模型，如房室模型（compartmental model）来定量描述。<ref name="segev_1989">{{cite book | vauthors = Segev I, Fleshman JW, Burke RE | chapter = Compartmental Models of Complex Neurons | title = Methods in Neuronal Modeling: From Synapses to Networks. | veditors = Koch C, Segev I | editor1-link = Christof Koch | date = 1989 | pages = 63–96 | publisher = The MIT Press | location = Cambridge, Massachusetts | isbn = 978-0-262-11133-1 | lccn = 88008279 | oclc = 18384545 }}</ref> 电缆理论是 Lord Kelvin 在 1855 年提出的，用来对跨大西洋电报电缆进行建模 <ref name="kelvin_1855" group="lower-alpha">{{cite journal | vauthors = Kelvin WT | year = 1855 | title = On the theory of the electric telegraph | journal = Proceedings of the Royal Society | volume = 7 | pages = 382–99 | doi = 10.1098/rspl.1854.0093| s2cid = 178547827 | author-link = William Thomson, 1st Baron Kelvin }}</ref>，并于 1946 年被 Hodgkin 和 Rushton 证明对描述神经元也很有用。<ref name="hodgkin_1946" group="lower-alpha">{{cite journal | vauthors = Hodgkin AL, Rushton WA | title = The electrical constants of a crustacean nerve fibre | journal = Proceedings of the Royal Society of Medicine | volume = 134 | issue = 873 | pages = 444–79 | date = December 1946 | pmid = 20281590 | doi = 10.1098/rspb.1946.0024 | author-link1 = Alan Lloyd Hodgkin | bibcode = 1946RSPSB.133..444H | doi-access = free }}</ref> 简单的电缆理论中，神经元被看作是一个电被动的完美圆柱形的传输电缆，可用一个偏微分方程（partial differential equation）来描述<ref name="rall_1989" />

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轴突内电流的流动可以用电缆理论（cable theory）<ref name="rall_1989" /> 及其细化模型，如房室模型（compartmental model）来定量描述。<ref name="segev_1989" /> 电缆理论是 Lord Kelvin 在 1855 年提出的，用来对跨大西洋电报电缆进行建模 <ref name="kelvin_1855" group="lower-alpha" />，并于 1946 年被 Hodgkin 和 Rushton 证明描述神经元也很有用。<ref name="hodgkin_1946" group="lower-alpha" /> 简单的电缆理论中，神经元被看作是一个电被动的完美圆柱形的传输电缆，可用一个偏微分方程来描述<ref name="rall_1989" />

:<math>

\tau \frac{\partial V}{\partial t} = \lambda^2 \frac{\partial^2 V}{\partial x^2} - V

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植物和真菌细胞<ref name="Slayman_1976" group="lower-alpha">{{cite journal | vauthors = Slayman CL, Long WS, Gradmann D | title = "Action potentials" in Neurospora crassa, a mycelial fungus | journal = Biochimica et Biophysica Acta (BBA) - Biomembranes | volume = 426 | issue = 4 | pages = 732–44 | date = April 1976 | pmid = 130926 | doi = 10.1016/0005-2736(76)90138-3 }}</ref> 也是电兴奋性的。与动物动作电位的根本区别在于，植物细胞的去极化不是通过摄入带正电的钠离子，而是通过释放带负电的氯离子来完成的。<ref name="Mummert_1991" group="lower-alpha">{{cite journal | vauthors = Mummert H, Gradmann D | title = Action potentials in Acetabularia: measurement and simulation of voltage-gated fluxes | journal = The Journal of Membrane Biology | volume = 124 | issue = 3 | pages = 265–73 | date = December 1991 | pmid = 1664861 | doi = 10.1007/BF01994359 | s2cid = 22063907 }}</ref><ref name="Gradmann_2001" group="lower-alpha">{{cite journal | vauthors = Gradmann D | year = 2001 | title = Models for oscillations in plants | journal = Aust. J. Plant Physiol. | volume = 28 | issue = 7 | pages = 577–590 | doi = 10.1071/pp01017}}</ref> 1906 年，J. C. Bose 发表了对先前由 Burdon-Sanderson 和 Darwin 发现的植物动作电位 <ref name=":14">{{Cite journal|last=Tandon|first=Prakash N|date=2019-07-01|title=Jagdish Chandra Bose and Plant Neurobiology: Part I|url=http://insa.nic.in/writereaddata/UpLoadedFiles/IJHS/Vol54_2_2019__Art05.pdf|journal=Indian Journal of History of Science|volume=54|issue=2|doi=10.16943/ijhs/2019/v54i2/49660|issn=0019-5235|doi-access=free}}</ref> 进行首次测量的结果。细胞质中钙离子的增加可能是阴离子释放进入细胞中的原因。因此，钙是离子移动的前体，比如大麦（barley）叶中负氯离子的内流和正钾离子的外流时。<ref name=":15">{{cite journal | vauthors = Felle HH, Zimmermann MR | title = Systemic signalling in barley through action potentials | journal = Planta | volume = 226 | issue = 1 | pages = 203–14 | date = June 2007 | pmid = 17226028 | doi = 10.1007/s00425-006-0458-y | s2cid = 5059716 }}</ref>

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~~The initial influx of calcium ions also poses a small cellular depolarization, causing the voltage-gated ion channels to open and allowing full depolarization to be propagated by chloride ions.~~

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钙离子的初始注入也使细胞些许去极化，导致电压门控离子通道打开并让氯离子扩散产生完全的去极化。

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~~钙离子的初始注入也使细胞些许去极化，导致电压门控离子通道打开并让氯离子流动产生完全的去极化。~~

一些植物（例如捕蝇草（''Dionaea muscipula，也叫 Venus flytrap''））使用钠门控的通道操作运动，本质上是“计数”。捕蝇草可以在北卡罗来纳州和南卡罗来纳州的亚热带湿地见到。<ref name=":16">{{Cite journal|last=Luken|first=James O. | name-list-style = vanc |date= December 2005 |title=Habitats of Dionaea muscipula (Venus' Fly Trap), Droseraceae, Associated with Carolina Bays|journal=Southeastern Naturalist|language=en|volume=4|issue=4|pages=573–584|doi=10.1656/1528-7092(2005)004[0573:HODMVF]2.0.CO;2|issn=1528-7092}}</ref> 当土壤养分不足时，捕蝇草依靠昆虫和动物为食。<ref name=":1">{{cite journal | vauthors = Böhm J, Scherzer S, Krol E, Kreuzer I, von Meyer K, Lorey C, Mueller TD, Shabala L, Monte I, Solano R, Al-Rasheid KA, Rennenberg H, Shabala S, Neher E, Hedrich R | display-authors = 6 | title = The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake | journal = Current Biology | volume = 26 | issue = 3 | pages = 286–95 | date = February 2016 | pmid = 26804557 | pmc = 4751343 | doi = 10.1016/j.cub.2015.11.057 }}</ref> 尽管对这种植物进行了研究，但对于捕蝇草以及一般的食肉植物的分子机制还缺乏了解。<ref name=":2">{{cite journal | vauthors = Hedrich R, Neher E | title = Venus Flytrap: How an Excitable, Carnivorous Plant Works | journal = Trends in Plant Science | volume = 23 | issue = 3 | pages = 220–234 | date = March 2018 | pmid = 29336976 | doi = 10.1016/j.tplants.2017.12.004 }}</ref>

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However, the flytrap doesn't close after one trigger. Instead, it requires the activation of 2 or more hairs.<ref name=":1" /><ref name=":2" /> If only one hair is triggered, it throws the activation as a false positive. Further, the second hair must be activated within a certain time interval （0.75 s - 40 s） for it to register with the first activation.<ref name=":2" /> Thus, a buildup of calcium starts and slowly falls from the first trigger. When the second action potential is fired within the time interval, it reaches the Calcium threshold to depolarize the cell, closing the trap on the prey within a fraction of a second.<ref name=":2" />

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然而，捕蝇草不会在一次触发后闭合，而是需要激活 2 根或更多的毛。<ref name=":1" /><ref name=":2" /> 如果只有一根毛被触发，这个激活会被视为假阳性。而且第二根毛必须在一定的时间间隔（0.75 s - 40 s）内被激活，才能将其与第一次激活一起记录。<ref name=":2" /> 因此，钙的积累从第一次触发开始并且然后慢慢下降。当第二个动作电位在时间间隔内被激发时，它达到钙阈值使细胞去极化，在几分之一秒内关闭捕获物的陷阱。<ref name=":2" />

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然而，捕蝇草不会在一次触发后闭合，而是需要激活 2 根或更多的毛。<ref name=":1" /><ref name=":2" /> 如果只有一根毛被触发，这个激活会被视为假阳性。而且第二根毛必须在一定的时间间隔（0.75 s - 40 s）内被激活，才能将其与第一次激活一起记录。<ref name=":2" /> 因此，第一次触发开始钙的积累从并且然后慢慢下降。当第二个动作电位在时间间隔内被激发时，它达到钙阈值使细胞去极化，在几分之一秒内关闭捕获物的陷阱。<ref name=":2" />

Together with the subsequent release of positive potassium ions the action potential in plants involves an [[osmotic]] loss of salt （KCl）. Whereas, the animal action potential is osmotically neutral because equal amounts of entering sodium and leaving potassium cancel each other osmotically. The interaction of electrical and osmotic relations in plant cells<ref name="Gradmann_1998" group="lower-alpha">{{cite journal | vauthors = Gradmann D, Hoffstadt J | title = Electrocoupling of ion transporters in plants: interaction with internal ion concentrations | journal = The Journal of Membrane Biology | volume = 166 | issue = 1 | pages = 51–9 | date = November 1998 | pmid = 9784585 | doi = 10.1007/s002329900446 | s2cid = 24190001 }}</ref> appears to have arisen from an osmotic function of electrical excitability in a common unicellular ancestors of plants and animals under changing salinity conditions. Further, the present function of rapid signal transmission is seen as a newer accomplishment of [[metazoan]] cells in a more stable osmotic environment.<ref name="Gradmann_1980">

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Unlike the rising phase and peak, the falling phase and after-hyperpolarization seem to depend primarily on cations that are not calcium. To initiate repolarization, the cell requires movement of potassium out of the cell through passive transportation on the membrane. This differs from neurons because the movement of potassium does not dominate the decrease in membrane potential; In fact, to fully repolarize, a plant cell requires energy in the form of ATP to assist in the release of hydrogen from the cell – utilizing a transporter commonly known as H+-ATPase.<ref name="Opritov">Opritov, V A, et al. “Direct Coupling of Action Potential Generation in Cells of a Higher Plant (Cucurbita Pepo) with the Operation of an Electrogenic Pump.” ''Russian Journal of Plant Physiology'', vol. 49, no. 1, 2002, pp. 142–147.</ref><ref name=":2" />

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不同于上升相和峰值，下降相和后超极化似乎主要依赖于不是钙的阳离子。为了启动复极化，细胞需要钾离子通过细胞膜上的被动运输离开细胞。事实上，为了完全再极化，植物细胞需要能量以 ATP 的形式帮助细胞释放氢-利用一种通常被称为 H+-ATPase 酶的转运蛋白。<ref name="Opritov" /><ref name=":2" />

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不同于上升相和峰值，下降相和后超极化似乎主要依赖于非钙离子的阳离子。为了启动复极化，细胞需要将钾离子通过细胞膜上的结构被动运输到胞外。事实上，为了完全再极化，植物细胞需要能量以 ATP 的形式帮助细胞释放氢-利用一种通常被称为 H+-ATPase 酶的转运蛋白。<ref name="Opritov" /><ref name=":2" />

==分类学分布和进化优势==

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[[Image:Puffer Fish DSC01257.JPG|thumb|right|河豚中的河豚毒素是一种致命的毒素，其抑制电压敏感性钠通道，阻止动作电位|链接=Special:FilePath/Puffer_Fish_DSC01257.JPG]]

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Several [[neurotoxin]]s, both natural and synthetic, are designed to block the action potential. [[Tetrodotoxin]] from the [[pufferfish]] and [[saxitoxin]] from the ''[[Gonyaulax]]'' （the [[dinoflagellate]] genus responsible for "[[Paralytic shellfish poisoning|red tide]]s"） block action potentials by inhibiting the voltage-sensitive sodium channel;<ref name="TTX_refs" group="lower-alpha">{{cite journal | vauthors = Milligan JV, Edwards C | title = Some factors affecting the time course of the recovery of contracture ability following a potassium contracture in frog striated muscle | journal = The Journal of General Physiology | volume = 48 | issue = 6 | pages = 975–83 | date = July 1965 | pmid = 5855511 | pmc = 2195447 | doi = 10.1085/jgp.48.6.975 }} * {{cite book | vauthors = Ritchie JM, Rogart RB | title = Reviews of Physiology, Biochemistry and Pharmacology, Volume 79 | chapter = The binding of saxitoxin and tetrodotoxin to excitable tissue | volume = 79 | pages = 1–50 | year = 1977 | pmid = 335473 | doi = 10.1007/BFb0037088 | isbn = 0-387-08326-X | series = Reviews of Physiology, Biochemistry and Pharmacology }} * {{cite journal | vauthors = Keynes RD, Ritchie JM | title = On the binding of labelled saxitoxin to the squid giant axon | journal = Proceedings of the Royal Society of London. Series B, Biological Sciences | volume = 222 | issue = 1227 | pages = 147–53 | date = August 1984 | pmid = 6148754 | doi = 10.1098/rspb.1984.0055 | bibcode = 1984RSPSB.222..147K | s2cid = 11465181 }}</ref> similarly, [[dendrotoxin]] from the [[mamba|black mamba]] snake inhibits the voltage-sensitive potassium channel. Such inhibitors of ion channels serve an important research purpose, by allowing scientists to "turn off" specific channels at will, thus isolating the other channels' contributions; they can also be useful in purifying ion channels by [[affinity chromatography]] or in assaying their concentration. However, such inhibitors also make effective neurotoxins, and have been considered for use as [[Chemical warfare|chemical weapon]]s. Neurotoxins aimed at the ion channels of insects have been effective [[insecticide]]s; one example is the synthetic [[permethrin]], which prolongs the activation of the sodium channels involved in action potentials. The ion channels of insects are sufficiently different from their human counterparts that there are few side effects in humans.

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天然和人工合成的几种神经毒素（neurotoxins）能阻断动作电位。来自河豚（pufferfish）的河豚毒素（tetrodotoxin）和来自沟鞭藻（Gonyaulax）的石房蛤毒素（saxitoxin）通过抑制电压敏感性钠通道来阻断动作电位；<ref name="TTX_refs" group="lower-alpha">{{cite journal | vauthors = Milligan JV, Edwards C | title = Some factors affecting the time course of the recovery of contracture ability following a potassium contracture in frog striated muscle | journal = The Journal of General Physiology | volume = 48 | issue = 6 | pages = 975–83 | date = July 1965 | pmid = 5855511 | pmc = 2195447 | doi = 10.1085/jgp.48.6.975 }} * {{cite book | vauthors = Ritchie JM, Rogart RB | title = Reviews of Physiology, Biochemistry and Pharmacology, Volume 79 | chapter = The binding of saxitoxin and tetrodotoxin to excitable tissue | volume = 79 | pages = 1–50 | year = 1977 | pmid = 335473 | doi = 10.1007/BFb0037088 | isbn = 0-387-08326-X | series = Reviews of Physiology, Biochemistry and Pharmacology }} * {{cite journal | vauthors = Keynes RD, Ritchie JM | title = On the binding of labelled saxitoxin to the squid giant axon | journal = Proceedings of the Royal Society of London. Series B, Biological Sciences | volume = 222 | issue = 1227 | pages = 147–53 | date = August 1984 | pmid = 6148754 | doi = 10.1098/rspb.1984.0055 | bibcode = 1984RSPSB.222..147K | s2cid = 11465181 }}</ref> 类似地，非洲黑曼巴（black mamba）蛇的树眼睛蛇毒素（dendrotoxin）抑制电压敏感性钾离子通道。这些离子通道抑制剂有重要的研究用途，让科学家可以随意关闭特定的通道，从而分离出其他通道的作用；也可以用于通过亲和色谱法（affinity chromatography）来纯化离子通道或测定其浓度。然而，这些抑制剂也是有效的神经毒素，被考虑用于化学武器。针对昆虫离子通道的神经毒素一直用作有效的杀虫剂，例如人工合成的氯菊酯（permethrin），其延长了与动作电位相关的钠通道的激活。昆虫的离子通道与人类的离子通道不同，因此对人类几乎没有副作用。

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天然和人工合成的几种神经毒素（neurotoxins）被用来阻断动作电位。来自河豚（pufferfish）的河豚毒素（tetrodotoxin）和来自沟鞭藻（Gonyaulax）的石房蛤毒素（saxitoxin）通过抑制电压敏感性钠通道来阻断动作电位；类似地，非洲黑曼巴（black mamba）蛇的树眼睛蛇毒素（dendrotoxin）也会抑制电压敏感性钾离子通道。这些离子通道抑制剂有重要的研究用途，它可以让科学家随意关闭特定的通道，从而分离出其他通道的贡献；也可以用亲和色谱法（affinity chromatography）来纯化离子通道或测定其浓度。然而，这些抑制剂也是有效的神经毒素，被考虑用于化学武器。针对昆虫离子通道的神经毒素一直是有效的杀虫剂，一个例子是合成的氯菊酯（permethrin），其延长了与动作电位相关的钠通道的激活。昆虫的离子通道与人类的离子通道完全不同，因此对人类几乎没有副作用。

==动作电位研究的历史==

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[[Image:PurkinjeCell.jpg|thumb|left|~~Image of two [[Purkinje cell]]s （labeled as '''A'''） drawn by~~ [[Santiago Ramón y Cajal]] in 1899~~. Large trees of [[dendrite]]s feed into the [[soma (biology)|soma]], from which a single [[axon]] emerges and moves generally downwards with a few branch points. The smaller cells labeled~~ '''B''' ~~are [[granule cell]]s.~~

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[[Image:PurkinjeCell.jpg|thumb|left|[[Santiago Ramón y Cajal]] 于 1899 年绘制两个浦肯野细胞（标记为'''A'''）的图像。树突的大分支汇入胞体，单个轴突从中出来，大致向下移动，并带有几个分支点。标记为 '''B''' 的较小细胞是颗粒细胞。|alt=Hand drawn figure of two Purkinje cells side by side with dendrites projecting upwards that look like tree branches and a few axons projected downwards that connect to a few granule cells at the bottom of the drawing.]]

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~~两个浦肯野细胞的图像（标记为~~'''A'''），由圣地亚哥·拉蒙·卡哈尔于1899年绘制。大树状树状的树状物进入索玛，从中出现单个轴突，并通常向下移动，并带有几个分支点。标记B的较小细胞是颗粒细胞s。|alt=Hand drawn figure of two Purkinje cells side by side with dendrites projecting upwards that look like tree branches and a few axons projected downwards that connect to a few granule cells at the bottom of the drawing.]]

电在动物神经系统中的作用最早是由 Luigi Galvani 在解剖的青蛙中观察到的，他在 1791 年到 1797 年研究了这一现象。Galvani 的研究结果促成Alessandro Volta 发明了伏打电堆（voltaic pile）——已知最早的电池——他用这种电池研究了动物电（如电鳗）以及对直流电压的生理反应。<ref name="piccolino_2000" group="lower-alpha">{{cite journal | vauthors = Piccolino M | title = The bicentennial of the Voltaic battery (1800-2000): the artificial electric organ | journal = Trends in Neurosciences | volume = 23 | issue = 4 | pages = 147–51 | date = April 2000 | pmid = 10717671 | doi = 10.1016/S0166-2236(99)01544-1 | s2cid = 393323 }}</ref>

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Scientists of the 19th century studied the propagation of electrical signals in whole [[nerve]]s （i.e., bundles of [[neuron]]s） and demonstrated that nervous tissue was made up of [[cell (biology)|cells]], instead of an interconnected network of tubes （a ''reticulum''）.{{sfnm|1a1=Brazier|1y=1961|2a1=McHenry|2a2=Garrison|2y=1969|3a1=Worden|3a2=Swazey|3a3=Adelman|3y=1975}} [[Carlo Matteucci]] followed up Galvani's studies and demonstrated that [[cell membrane]]s had a voltage across them and could produce [[direct current]]. Matteucci's work inspired the German physiologist, [[Emil du Bois-Reymond]], who discovered the action potential in 1843.<ref name=":21">{{Cite book|title=Emil du Bois-Reymond : neuroscience, self, and society in nineteenth-century Germany|last=Finkelstein | first = Gabriel Ward | name-list-style = vanc |isbn=9781461950325|location=Cambridge, Massachusetts|oclc=864592470|year = 2013}}</ref> The [[conduction velocity]] of action potentials was first measured in 1850 by du Bois-Reymond's friend, [[Hermann von Helmholtz]].<ref name=":22">[[Kathryn Olesko|Olesko, Kathryn M.]], and Frederic L. Holmes. "Experiment, Quantification and Discovery: Helmholtz's Early Physiological Researches, 1843-50". In ''Hermann von Helmholtz and the Foundations of Nineteenth Century Science'', ed. David Cahan, 50-108. Berkeley; Los Angeles; London: University of California, 1994.</ref> To establish that nervous tissue is made up of discrete cells, the Spanish physician [[Santiago Ramón y Cajal]] and his students used a stain developed by [[Camillo Golgi]] to reveal the myriad shapes of neurons, which they rendered painstakingly. For their discoveries, Golgi and Ramón y Cajal were awarded the 1906 [[Nobel Prize in Physiology or Medicine|Nobel Prize in Physiology]].<ref name="Nobel_1906" group="lower-Greek">{{cite press release | url = http://nobelprize.org/medicine/laureates/1906/index.html | title = The Nobel Prize in Physiology or Medicine 1906 | publisher = The Royal Swedish Academy of Science | year = 1906 | access-date = 2010-02-21 | url-status = live | archive-url = https://web.archive.org/web/20081204190959/http://nobelprize.org/medicine/laureates/1906/index.html | archive-date = 4 December 2008 | df = dmy-all }}</ref> Their work resolved a long-standing controversy in the [[neuroanatomy]] of the 19th century; Golgi himself had argued for the network model of the nervous system.

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19 世纪的科学家研究了电信号在整个神经（即神经元束）中的传播，并证明神经组织是由细胞组成的，而不是一个互相连接的管网（网状结构）。Carlo Matteucci 继续伽伐尼的研究，证明细胞膜上有一个电压，可以产生直流电。[[Carlo Matteucci]] 的工作启发了德国生理学家 [[Emil du Bois-Reymond]]，后者在1843 年发现了动作电位.<ref name=":21" /> ~~。动作电位的传导速度最早是在1850年由du Bois-Reymond 杜波依斯-雷蒙德的朋友~~[[Hermann von Helmholtz]]~~赫尔曼·冯·亥姆霍兹 · 雷蒙德测量的.~~<ref name=":22" /> 为了证明神经组织是由离散的细胞组成的，西班牙物理学家 [[Santiago Ramón y Cajal]] 和他的学生们使用了 Camillo Golgi ~~开发的染色剂来显示神经元的无数形状，他们煞费苦心地进行了渲染。由于他们的发现，Golgi~~ 和 [[Santiago Ramón y Cajal|Ramón y Cajal]] ~~获得了1906年的诺贝尔生理学奖.~~<ref name="Nobel_1906" group="lower-Greek" /> ~~。他们的工作解决了19世纪神经解剖学中长期存在的争议；高尔基自己则主张神经系统的网络模型。~~

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19 世纪的科学家研究了电信号在整个神经（即神经元束）中的传播，并证明神经组织是由细胞组成的，而不是一个互相连接的管网（网状结构）。Carlo Matteucci 继续伽伐尼的研究，证明细胞膜上有一个电压，可以产生直流电。[[Carlo Matteucci]] 的工作启发了德国生理学家 [[Emil du Bois-Reymond]]，后者在1843 年发现了动作电位.<ref name=":21" /> 。动作电位的传导速度最早是在1850年由 [[Hermann von Helmholtz]] 测量的。<ref name=":22" /> 为了证明神经组织是由离散的细胞组成的，西班牙物理学家 [[Santiago Ramón y Cajal]] 和他的学生们使用了 Camillo Golgi 开发的染色剂显示了无数神经元的形状，他们煞费苦心地进行了绘制。由于他们的发现，Golgi 和 [[Santiago Ramón y Cajal|Ramón y Cajal]] 获得了 1906 年的诺贝尔生理学奖。<ref name="Nobel_1906" group="lower-Greek" /> 他们的工作解决了 19 世纪神经解剖学中长期存在的争议；高尔基自己则坚持神经系统的网络模型。

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[[Image:3b8e.png|thumb|right|[[Ribbon diagram]] of the sodium–potassium pump in its E2-Pi state. The estimated boundaries of the [[lipid bilayer]] are shown as blue （intracellular） and red （extracellular） planes.

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~~钠钾泵在其~~ E2-Pi ~~状态下的带状图（[[Ribbon diagram]]）。脂质双层的估计边界显示为蓝色（细胞内）和红色（细胞外）平面。~~|链接=Special:FilePath/3b8e.png]]

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[[Image:3b8e.png|thumb|right|钠钾泵在 E2-Pi 状态下的带状图（Ribbon diagram）。推测的脂双层边界显示为蓝色（胞内）和红色（胞外）的面。|链接=Special:FilePath/3b8e.png]]

The 20th century was a significant era for electrophysiology. In 1902 and again in 1912, [[Julius Bernstein]] advanced the hypothesis that the action potential resulted from a change in the [[permeation|permeability]] of the axonal membrane to ions.<ref name="bernstein_1902_1912" group="lower-alpha">{{cite journal | vauthors = Bernstein J | year = 1902 | title = Untersuchungen zur Thermodynamik der bioelektrischen Ströme | journal = Pflügers Archiv für die gesamte Physiologie | volume = 92 | pages = 521–562 | doi = 10.1007/BF01790181 | issue = 10–12| s2cid = 33229139 | author-link = Julius Bernstein | url = https://zenodo.org/record/2192363 }}</ref>{{sfn|Bernstein|1912}} Bernstein's hypothesis was confirmed by [[Kenneth Stewart Cole|Ken Cole]] and Howard Curtis, who showed that membrane conductance increases during an action potential.<ref group="lower-alpha" name=":16">{{cite journal | vauthors = Cole KS, Curtis HJ | title = Electric Impedance of the Squid Giant Axon During Activity | journal = The Journal of General Physiology | volume = 22 | issue = 5 | pages = 649–70 | date = May 1939 | pmid = 19873125 | pmc = 2142006 | doi = 10.1085/jgp.22.5.649 | author-link1 = Kenneth Stewart Cole }}</ref> In 1907, [[Louis Lapicque]] suggested that the action potential was generated as a threshold was crossed,<ref group="lower-alpha" name=":17">{{cite journal | vauthors = Lapicque L | year = 1907 | title = Recherches quantitatives sur l'excitationelectrique des nerfs traitee comme une polarisation | journal = J. Physiol. Pathol. Gen | volume = 9| pages = 620–635 }}</ref> what would be later shown as a product of the [[dynamical system]]s of ionic conductances. In 1949, [[Alan Lloyd Hodgkin|Alan Hodgkin]] and [[Bernard Katz]] refined Bernstein's hypothesis by considering that the axonal membrane might have different permeabilities to different ions; in particular, they demonstrated the crucial role of the sodium permeability for the action potential.<ref name="hodgkin_1949" group="lower-alpha">{{cite journal | vauthors = Hodgkin AL, Katz B | title = The effect of sodium ions on the electrical activity of giant axon of the squid | journal = The Journal of Physiology | volume = 108 | issue = 1 | pages = 37–77 | date = March 1949 | pmid = 18128147 | pmc = 1392331 | doi = 10.1113/jphysiol.1949.sp004310 | author-link1 = Alan Lloyd Hodgkin | author-link2 = Bernard Katz }}</ref> They made the first actual recording of the electrical changes across the neuronal membrane that mediate the action potential.<ref group="lower-Greek" name=":0">{{cite journal |last=Warlow|first=Charles| name-list-style = vanc |title=The Recent Evolution of a Symbiotic Ion Channel in the Legume Family Altered Ion Conductance and Improved Functionality in Calcium Signaling|journal=Practical Neurology|volume=7|issue=3|pages=192–197|url=http://pn.bmj.com/content/7/3/192.full|publisher=BMJ Publishing Group|access-date=23 March 2013|url-status=live|archive-url=https://web.archive.org/web/20120314104408/http://pn.bmj.com/content/7/3/192.full|archive-date=14 March 2012|df=dmy-all|date=June 2007}}</ref> This line of research culminated in the five 1952 papers of Hodgkin, Katz and [[Andrew Huxley]], in which they applied the [[voltage clamp]] technique to determine the dependence of the axonal membrane's permeabilities to sodium and potassium ions on voltage and time, from which they were able to reconstruct the action potential quantitatively.<ref name="hodgkin_1952" group="lower-alpha" /> Hodgkin and Huxley correlated the properties of their mathematical model with discrete [[ion channel]]s that could exist in several different states, including "open", "closed", and "inactivated". Their hypotheses were confirmed in the mid-1970s and 1980s by [[Erwin Neher]] and [[Bert Sakmann]], who developed the technique of [[patch clamp]]ing to examine the conductance states of individual ion channels.<ref name="patch_clamp" group="lower-alpha">{{cite journal | vauthors = Neher E, Sakmann B | title = Single-channel currents recorded from membrane of denervated frog muscle fibres | journal = Nature | volume = 260 | issue = 5554 | pages = 799–802 | date = April 1976 | pmid = 1083489 | doi = 10.1038/260799a0 | author-link1 = Erwin Neher | bibcode = 1976Natur.260..799N | s2cid = 4204985 }} * {{cite journal | vauthors = Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ | title = Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches | journal = Pflügers Archiv | volume = 391 | issue = 2 | pages = 85–100 | date = August 1981 | pmid = 6270629 | doi = 10.1007/BF00656997 | s2cid = 12014433 }} * {{cite journal | vauthors = Neher E, Sakmann B | title = The patch clamp technique | journal = Scientific American | volume = 266 | issue = 3 | pages = 44–51 | date = March 1992 | pmid = 1374932 | doi = 10.1038/scientificamerican0392-44 | author-link1 = Erwin Neher | bibcode = 1992SciAm.266c..44N }}</ref> In the 21st century, researchers are beginning to understand the structural basis for these conductance states and for the selectivity of channels for their species of ion,<ref name="yellen_2002" group="lower-alpha">{{cite journal | vauthors = Yellen G | title = The voltage-gated potassium channels and their relatives | journal = Nature | volume = 419 | issue = 6902 | pages = 35–42 | date = September 2002 | pmid = 12214225 | doi = 10.1038/nature00978 | bibcode = 2002Natur.419...35Y | s2cid = 4420877 }}</ref> through the atomic-resolution [[X-ray crystallography|crystal structures]],<ref name="doyle_1998" group="lower-alpha">{{cite journal | vauthors = Doyle DA, Morais Cabral J, Pfuetzner RA, Kuo A, Gulbis JM, Cohen SL, Chait BT, MacKinnon R | display-authors = 6 | title = The structure of the potassium channel: molecular basis of K+ conduction and selectivity | journal = Science | volume = 280 | issue = 5360 | pages = 69–77 | date = April 1998 | pmid = 9525859 | doi = 10.1126/science.280.5360.69 | bibcode = 1998Sci...280...69D }} * {{cite journal | vauthors = Zhou Y, Morais-Cabral JH, Kaufman A, MacKinnon R | title = Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution | journal = Nature | volume = 414 | issue = 6859 | pages = 43–8 | date = November 2001 | pmid = 11689936 | doi = 10.1038/35102009 | bibcode = 2001Natur.414...43Z | s2cid = 205022645 }} * {{cite journal | vauthors = Jiang Y, Lee A, Chen J, Ruta V, Cadene M, Chait BT, MacKinnon R | title = X-ray structure of a voltage-dependent K+ channel | journal = Nature | volume = 423 | issue = 6935 | pages = 33–41 | date = May 2003 | pmid = 12721618 | doi = 10.1038/nature01580 | bibcode = 2003Natur.423...33J | s2cid = 4347957 }}</ref> fluorescence distance measurements<ref name="FRET" group="lower-alpha">{{cite journal | vauthors = Cha A, Snyder GE, Selvin PR, Bezanilla F | title = Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy | journal = Nature | volume = 402 | issue = 6763 | pages = 809–13 | date = December 1999 | pmid = 10617201 | doi = 10.1038/45552 | bibcode = 1999Natur.402..809C | s2cid = 4353978 }} * {{cite journal | vauthors = Glauner KS, Mannuzzu LM, Gandhi CS, Isacoff EY | title = Spectroscopic mapping of voltage sensor movement in the Shaker potassium channel | journal = Nature | volume = 402 | issue = 6763 | pages = 813–7 | date = December 1999 | pmid = 10617202 | doi = 10.1038/45561 | bibcode = 1999Natur.402..813G | s2cid = 4417476 }} * {{cite journal | vauthors = Bezanilla F | title = The voltage sensor in voltage-dependent ion channels | journal = Physiological Reviews | volume = 80 | issue = 2 | pages = 555–92 | date = April 2000 | pmid = 10747201 | doi = 10.1152/physrev.2000.80.2.555 }}</ref> and [[cryo-electron microscopy]] studies.<ref name="cryoEM" group="lower-alpha">{{cite journal | vauthors = Catterall WA | title = A 3D view of sodium channels | journal = Nature | volume = 409 | issue = 6823 | pages = 988–9, 991 | date = February 2001 | pmid = 11234048 | doi = 10.1038/35059188 | bibcode = 2001Natur.409..988C | s2cid = 4371677 | doi-access = free }} * {{cite journal | vauthors = Sato C, Ueno Y, Asai K, Takahashi K, Sato M, Engel A, Fujiyoshi Y | title = The voltage-sensitive sodium channel is a bell-shaped molecule with several cavities | journal = Nature | volume = 409 | issue = 6823 | pages = 1047–51 | date = February 2001 | pmid = 11234014 | doi = 10.1038/35059098 | bibcode = 2001Natur.409.1047S | s2cid = 4430165 }}</ref>

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20 世纪是电生理的重要时期。1902 年和 1912 年，Julius Bernstein 提出了动作电位是由轴突膜对离子的渗透性改变引起的假说。<ref name="bernstein_1902_1912" group="lower-alpha" /> Ken Cole 和 Howard Curtis 证实了 Bernstein 的假说，他们发现在动作电位期间膜电导增加。<ref name=":16" group="lower-alpha" /> 1907年，Louis Lapicque 提出，动作电位产生的阈值被跨越,<ref name=":17" group="lower-alpha" /> w，后来被证明为离子电导动力学系统的乘积。1949年，Alan Hodgkin 和 Bernard Katz 完善了 Bernstein 的假说，他们认为轴突膜对不同的离子可能有不同的通透性；特别是，他们证明了钠通透性对动作电位的关键作用。<ref name="hodgkin_1949" group="lower-alpha" /> 。他们首次实际记录了神经元膜上的电变化，这些电变化介导了动作电位。<ref name=":0" group="lower-Greek" /> 这一系列的研究在 Hodgkin，Katz 和 Andrew Huxley 的 5 篇 1952 年的论文中达到了顶峰，他们应用电压钳技术来确定轴突膜对钠离子和钾离子的通透性对电压和时间的依赖性，从而能够定量地重建动作电位。<ref name="hodgkin_1952" group="lower-alpha" /> 。Hodgkin 和 Huxley 将其数学模型的性质与离散离子通道相关联，离散离子通道可以存在于几种不同的状态，包括“开放”、“封闭”和“失活”。他们的假设在20世纪70年代中期和80年代得到 Erwin Neher 和 Bert Sakmann 的证实，他们发明了膜片钳技术来检测单个离子通道的电导状态。<ref name="patch_clamp" group="lower-alpha" /> 。在21世纪，通过原子分辨率晶体结构，<ref name="doyle_1998" group="lower-alpha" /> 研究人员开始了解这些电导态的结构基础，以及离子种类的通道选择性，<ref name="yellen_2002" group="lower-alpha" /> 荧光距离测量<ref name="FRET" group="lower-alpha" /> 和冷冻电子显微研究。<ref name="cryoEM" group="lower-alpha" />

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Julius Bernstein ~~was also the first to introduce the~~ [[Nernst equation]] ~~for [[resting potential]] across the membrane; this was generalized by [[David~~ E. Goldman~~]] to the eponymous~~ [[Goldman equation]] ~~in 1943.~~<ref name="goldman_1943" group="lower-alpha" /> ~~The [[sodium–potassium pump]] was identified in~~ 1957<ref group="lower-alpha~~" name=":18~~">{{cite journal | vauthors = Skou JC | title = The influence of some cations on an adenosine triphosphatase from peripheral nerves | journal = Biochimica et Biophysica Acta | volume = 23 | issue = 2 | pages = 394–401 | date = February 1957 | pmid = 13412736 | doi = 10.1016/0006-3002(57)90343-8 }}</ref><ref group="lower-Greek~~" name=":1~~">{{cite press release | url = http://nobelprize.org/nobel_prizes/medicine/laureates/1997/press.html | title = The Nobel Prize in Chemistry 1997 | publisher = The Royal Swedish Academy of Science | year = 1997 | access-date = 2010-02-21 | url-status = live | archive-url = https://web.archive.org/web/20091023003257/http://nobelprize.org/nobel_prizes/medicine/laureates/1997/press.html | archive-date = 23 October 2009 | df = dmy-all }}</ref> ~~and its properties gradually elucidated,~~<ref name="hodgkin_1955" group="lower-alpha">{{cite journal | vauthors = Hodgkin AL, Keynes RD | title = Active transport of cations in giant axons from Sepia and Loligo | journal = The Journal of Physiology | volume = 128 | issue = 1 | pages = 28–60 | date = April 1955 | pmid = 14368574 | pmc = 1365754 | doi = 10.1113/jphysiol.1955.sp005290 | author-link1 = Alan Lloyd Hodgkin }}</ref><ref name="caldwell_1960" group="lower-alpha">{{cite journal | vauthors = Caldwell PC, Hodgkin AL, Keynes RD, Shaw TL | title = The effects of injecting 'energy-rich' phosphate compounds on the active transport of ions in the giant axons of Loligo | journal = The Journal of Physiology | volume = 152 | issue = 3 | pages = 561–90 | date = July 1960 | pmid = 13806926 | pmc = 1363339 | doi = 10.1113/jphysiol.1960.sp006509 }}</ref><ref name="caldwell_1957" group="lower-alpha">{{cite journal | vauthors = Caldwell PC, Keynes RD | title = The utilization of phosphate bond energy for sodium extrusion from giant axons | journal = The Journal of Physiology | volume = 137 | issue = 1 | pages = 12–3P | date = June 1957 | pmid = 13439598 | doi = 10.1113/jphysiol.1957.sp005830 | s2cid = 222188054 }}</ref> ~~culminating in the determination of its atomic-resolution structure by~~ [[X-ray crystallography]].<ref name="Na_K_pump_structure" group="lower-alpha">{{cite journal | vauthors = Morth JP, Pedersen BP, Toustrup-Jensen MS, Sørensen TL, Petersen J, Andersen JP, Vilsen B, Nissen P | display-authors = 6 | title = Crystal structure of the sodium-potassium pump | journal = Nature | volume = 450 | issue = 7172 | pages = 1043–9 | date = December 2007 | pmid = 18075585 | doi = 10.1038/nature06419 | bibcode = 2007Natur.450.1043M | s2cid = 4344526 }}</ref> ~~The crystal structures of related ionic pumps have also been solved, giving a broader view of how these [[molecular machine]]s work.~~<ref group="lower-alpha~~" name=":19~~">{{cite journal | vauthors = Lee AG, East JM | title = What the structure of a calcium pump tells us about its mechanism | journal = The Biochemical Journal | volume = 356 | issue = Pt 3 | pages = 665–83 | date = June 2001 | pmid = 11389676 | pmc = 1221895 | doi = 10.1042/0264-6021:3560665 }}</ref>

+

也是 Julius Bernstein 首次将能斯特方程（[[Nernst equation]] ）引入描述跨膜静息电位；David E. Goldman 在 1943 年将这个方程推广到了以他的名字命名的戈德曼方程（[[Goldman equation]]）。<ref name="goldman_1943" group="lower-alpha" /> 钠钾泵在 1957 年被鉴定出来 <ref name=":18" group="lower-alpha">{{cite journal | vauthors = Skou JC | title = The influence of some cations on an adenosine triphosphatase from peripheral nerves | journal = Biochimica et Biophysica Acta | volume = 23 | issue = 2 | pages = 394–401 | date = February 1957 | pmid = 13412736 | doi = 10.1016/0006-3002(57)90343-8 }}</ref><ref name=":1" group="lower-Greek">{{cite press release | url = http://nobelprize.org/nobel_prizes/medicine/laureates/1997/press.html | title = The Nobel Prize in Chemistry 1997 | publisher = The Royal Swedish Academy of Science | year = 1997 | access-date = 2010-02-21 | url-status = live | archive-url = https://web.archive.org/web/20091023003257/http://nobelprize.org/nobel_prizes/medicine/laureates/1997/press.html | archive-date = 23 October 2009 | df = dmy-all }}</ref>，其性质逐渐被阐明，<ref name="hodgkin_1955" group="lower-alpha">{{cite journal | vauthors = Hodgkin AL, Keynes RD | title = Active transport of cations in giant axons from Sepia and Loligo | journal = The Journal of Physiology | volume = 128 | issue = 1 | pages = 28–60 | date = April 1955 | pmid = 14368574 | pmc = 1365754 | doi = 10.1113/jphysiol.1955.sp005290 | author-link1 = Alan Lloyd Hodgkin }}</ref><ref name="caldwell_1960" group="lower-alpha">{{cite journal | vauthors = Caldwell PC, Hodgkin AL, Keynes RD, Shaw TL | title = The effects of injecting 'energy-rich' phosphate compounds on the active transport of ions in the giant axons of Loligo | journal = The Journal of Physiology | volume = 152 | issue = 3 | pages = 561–90 | date = July 1960 | pmid = 13806926 | pmc = 1363339 | doi = 10.1113/jphysiol.1960.sp006509 }}</ref><ref name="caldwell_1957" group="lower-alpha">{{cite journal | vauthors = Caldwell PC, Keynes RD | title = The utilization of phosphate bond energy for sodium extrusion from giant axons | journal = The Journal of Physiology | volume = 137 | issue = 1 | pages = 12–3P | date = June 1957 | pmid = 13439598 | doi = 10.1113/jphysiol.1957.sp005830 | s2cid = 222188054 }}</ref> 最终用 X 射线晶体学（[[X-ray crystallography]]）测定其原子分辨率的结构。<ref name="Na_K_pump_structure" group="lower-alpha">{{cite journal | vauthors = Morth JP, Pedersen BP, Toustrup-Jensen MS, Sørensen TL, Petersen J, Andersen JP, Vilsen B, Nissen P | display-authors = 6 | title = Crystal structure of the sodium-potassium pump | journal = Nature | volume = 450 | issue = 7172 | pages = 1043–9 | date = December 2007 | pmid = 18075585 | doi = 10.1038/nature06419 | bibcode = 2007Natur.450.1043M | s2cid = 4344526 }}</ref> 相关的离子泵的晶体结构也已经被解析，为理解这些分子机器的工作原理提供了更广阔的图景。<ref name=":19" group="lower-alpha">{{cite journal | vauthors = Lee AG, East JM | title = What the structure of a calcium pump tells us about its mechanism | journal = The Biochemical Journal | volume = 356 | issue = Pt 3 | pages = 665–83 | date = June 2001 | pmid = 11389676 | pmc = 1221895 | doi = 10.1042/0264-6021:3560665 }}</ref>

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Julius Bernstein 也是第一个将静息电位的能斯特方程引入到薄膜上的人；David E. Goldman 在1943年将这个方程推广到了以他的名字命名的戈德曼方程。<ref name="goldman_1943" group="lower-alpha" /> 钠钾泵在1957年被鉴定出来 <ref name=":18" group="lower-alpha" /><ref name=":1" group="lower-Greek" />，它的性质逐渐被阐明，<ref name="hodgkin_1955" group="lower-alpha" /><ref name="caldwell_1960" group="lower-alpha" /><ref name="caldwell_1957" group="lower-alpha" />，最终由 X光散射技术测定了它的原子分辨率结构。<ref name="Na_K_pump_structure" group="lower-alpha" /> 相关的离子泵的晶体结构也已经被解决，从而为这些分子机器如何工作提供了更广阔的视野。<ref name=":19" group="lower-alpha" />

==定量模型==

Okxy

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个编辑