Extracellular potassium changes in the spinal cord of the cat and their relation to slow potentials, active transport and impulse transmission.
Extracellular potassium changes in the spinal cord of the cat and their relation to slow potentials, active transport and impulse transmission.
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猫脊髓中细胞外钾的变化及其与慢电位、主动运输和脉冲传递的关系。
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
E. S. A. L. Vyklickv
中科院分区：
文献类型：
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作者：
N. By;Kru;E. S. A. L. Vyklickv
1.通过K-特异性双管微电极，在非麻醉、丘间去脑和脊髓化猫中，检查外周强直刺激后和混合外周神经单次齐射后腰椎脊髓细胞外间隙中K+浓度变化的时间过程。2.强直刺激（100 Hz）使[K]e从3 mM增加到9 mM，随后是[K] e降低的阶段，在此期间[K]e降低0.5 mM，低于静息水平，持续1-2分钟，然后恢复到其原始静息水平。证据表明，这低于正常阶段的[K]e反映了积极的过程重新分配积累的K+从细胞外空间。3.只有当微电极位于非常靠近放电神经元的位置时，才能记录[K]e的低于正常相位，并且主要不依赖于[K]e增加的绝对水平。这可以被认为是神经元而不是神经胶质细胞负责从细胞外空间主动重吸收K+的证据。4. E1 K]e增加反映在局灶性记录的电位中为负性，[K]e减少反映为正性。然而，局灶性记录的阳性反应的潜伏期比减少的[K]e的潜伏期短。这使得阳性反应不仅反映了胶质细胞成分的被动超极化，而且反映了跨神经元膜的主动生电离子转运。5.发现在混合周围神经中由单次齐射引起的增加的[K]e的最短潜伏期为9毫秒;在40毫秒后达到峰值，代表0.5 mM，总持续时间为200毫秒。提出了一个理论上的考虑，[K]e的瞬时增加的时间过程是一致的建议，K+的积累在脊髓神经元放电后，负责初级传入去极化。6.有证据表明，增加[K]e，引起的持久的外周刺激，伴随着脉冲传输的功效降低。
1. By means of K‐specific double‐barrelled micro‐electrodes the time course of changes in K+ concentration in the extracellular space of the lumbar spinal cord was examined after peripheral tetanic stimulation and after a single volley in a mixed peripheral nerve in non‐anaesthetized, intercollicularly decerebrated and spinalized cats. 2. Tetanic stimulation (100 Hz) which increases the [K]e from 3 to 9 mM is followed by a phase of reduced [K]e during which [K]e decreases by 0.5 mM below resting level, lasting 1–2 minutes before returning to its original resting level. Evidence is presented that this subnormal phase of [K]e reflects active processes redistributing accumulated K+ from extracellular space. 3. The subnormal phase of [K]e can be registered only when the microelectrode is located in very close vicinity of discharging neurones and is not primarily dependent on the absolute level of increased [K]e. This can be considered as evidence that the neurones and not the glial cells are responsible for active reabsorption of K+ from the extracellular space. 4. Increased E1K]e is reflected in focally recorded potentials as a negativity and decreased [K]e as a positivity. The latency of focally recorded positivity is, however, shorter than the latency of reduced [K]e. This makes it likely that the positivity reflects not only passive hyperpolarization of glial elements, but also an active, electrogenic ion transport across neuronal membrane. 5. The shortest latency of increased [K]e induced by a single volley in a mixed peripheral nerve was found to be 9 msec; the peak, representing 0.5 mM, was attained after 40 msec and the total duration was 200 msec. A theoretical consideration is put forward that the time course of transient increase in [K]e is consistent with the suggestion that K+ which accumulates in the spinal cord after neuronal discharge is responsible for primary afferent depolarization. 6. Evidence is presented that increased [K]e, induced by a long lasting peripheral stimulation, is accompanied by decreased efficacy of impulse transmission.