Influence of anomalous rectifier activation on afterhyperpolarizations of neurons from cat sensorimotor cortex in vitro.
Influence of anomalous rectifier activation on afterhyperpolarizations of neurons from cat sensorimotor cortex in vitro.
复制标题
异常整流器激活对体外猫感觉运动皮层神经元后超极化的影响。
DOI：
10.1152/jn.1988.59.2.468
复制
发表时间：
1988
影响因子：
2.5
通讯作者：
Crill,WE
中科院分区：
文献类型：
--
作者：
Schwindt,PC;Spain,WJ;Crill,WE
1.本文研究了猫感觉运动皮层V层大神经元（贝茨细胞）的异常整流电流（IAR）对慢后超极化（AHPs）的影响。在离体脑片制备中，使用细胞内记录和单微电极电压钳检查神经元。2.一个更快的中期层次分析法（mAHP）和较慢的层次分析法（sAHP）遵循重复射击（22，23）。在膜电位超极化过程中，mAHP的振幅经常增加或保持不变。仅由IAR激活引起的膜电位轨迹与mAHP相似。3.用放电后电压钳直接测量不同膜电位下的慢衰减钾电流（IK）和IAR。IK表现出快速和缓慢的衰减。IK和IAR激活的快速衰减的时间常数相似。IAR随超极化或细胞外K+浓度[（K+）] o的升高而增加，而IK的快、慢成分在-100 mV附近发生逆转或消失，表现为纯K+电流。4.为了确定IK和IAR对AHP波形的精确贡献，使用基于电压钳测量的定量模型计算理论AHP。计算的AHPs与测量的AHPs定性相似。mAHP的幅度变化不大，超极化，因为在更负的膜电位的IAR的优势增加。IAR激活对sAHP影响不大。5.在计算中改变贝茨细胞中受生物学变化影响的几个模型参数，以确定它们在AHP波形中的重要性。在IK参数保持不变的情况下，mAHP的幅度和时程取决于静息电位、膜时间常数、异常整流电导（GAR）的动力学以及GAR的最大值。即使在计算中忽略IK的快速衰减，IAR激活也可能导致双相AHP。6.模型参数的更广泛变化揭示了可能与其他神经元相关的行为。膜或IAR激活时间常数的某些值导致在一个双相AHP，即使当IK的快速衰减。双相AHP的衰减可以反映IAR的开始或IK的快速衰减，这取决于它们的时间常数的相对值。程序概述了这些可能性之间的区别使用电流钳方法。（400字处截断摘要）
1. Large neurons from layer V of cat sensorimotor cortex (Betz cells) were studied to determine the influence of the anomalous rectifier current (IAR) on slow afterhyperpolarizations (AHPs). The neurons were examined using intracellular recording and single-microelectrode voltage clamp in an in vitro brain slice preparation. 2. A faster medium-duration AHP (mAHP) and slower AHP (sAHP) followed repetitive firing (22, 23). The amplitude of the mAHP often increased or remained constant during membrane potential hyperpolarization. The membrane potential trajectory resulting solely from IAR activation was similar to the mAHP. 3. Postrepetitive firing voltage clamp was used to measure directly slowly decaying K+ currents (IK) and IAR at different membrane potentials. IK exhibited both a fast and slow decay. The time constants of the fast decay of IK and IAR activation were similar. IAR increased with hyperpolarization or raised extracellular K+ concentration [( K+]o), whereas both the fast and slow components of IK reversed or nulled near -100 mV and behaved as pure K+ currents in response to raised [K+]o. 4. To determine the precise contribution of IK and IAR to the AHP waveform, theoretical AHPs were computed using a quantitative model based on voltage-clamp measurements. The calculated AHPs were qualitatively similar to measured AHPs. The amplitude of the mAHP showed little change with hyperpolarization because of the increasing dominance of IAR at more negative membrane potentials. The sAHP was little affected by IAR activation. 5. Several model parameters subject to biological variation among Betz cells were varied in the calculations to determine their importance in the AHP waveform. With IK parameters held constant, the amplitude and time course of the mAHP depended on resting potential, membrane time constant, the kinetics of the anomalous rectifier conductance (GAR), and the maximum value of GAR. IAR activation could result in a biphasic AHP even when the fast decay of IK was omitted from the calculations. 6. A wider variation of model parameters revealed behavior that may be relevant to other neurons. Certain values of membrane or IAR activation time constants resulted in a monophasic AHP even when the fast decay of IK was present. The decay of a biphasic AHP could reflect either the onset of IAR or the fast decay of IK, depending on the relative value of their time constants. Procedures are outlined to discriminate between these possibilities using current clamp methods.(ABSTRACT TRUNCATED AT 400 WORDS)
影响因子：
17.3
作者：
G. Hammes
通讯作者：
G. Hammes
DOI：
--
发表时间：
1988
期刊：
影响因子：
--
作者：
A. Maelicke
通讯作者：
A. Maelicke