QUANTIFICATION OF MEMBRANE-PROPERTIES OF TRIGEMINAL ROOT GANGLION NEURONS IN GUINEA-PIGS
QUANTIFICATION OF MEMBRANE-PROPERTIES OF TRIGEMINAL ROOT GANGLION NEURONS IN GUINEA-PIGS
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DOI：
10.1152/jn.1986.55.5.995
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发表时间：
1986-05-01
影响因子：
2.5
通讯作者：
MIURA, RM
中科院分区：
文献类型：
--
作者：
PUIL, E;GIMBARZEVSKY, B;MIURA, RM
被动和主动（电压和时间依赖性）的膜特性的三叉神经根神经节神经元的去脑豚鼠已被确定使用频域分析的小幅度扰动的膜电压。三叉神经节神经元的复阻抗函数计算从细胞内记录的电压响应的神经元和输入电流，其中具有定义的振荡波形的快速傅立叶变换的比率。阻抗幅值函数和相应的阻抗轨迹图与各种膜模型拟合，从而量化被动和主动特性。在被广泛研究的105个神经元中，只有不到四分之一的神经元的复阻抗可以用简单RC电路的复阻抗函数来描述。在这样的神经元中，使用传统的电桥平衡技术，对恒定电流脉冲的电压响应可以拟合单指数曲线，这也表明了被动的膜行为。简单模型的复阻抗函数与实验观察到的复阻抗的非线性最小二乘拟合产生了电极电阻的估计值，以及神经元的输入电容（范围，56至490 pF）和输入电阻（范围，0.8至30 M Ω）。大多数三叉神经节神经元的特点是在50- 250-Hz带宽的阻抗幅度函数的共振。当使用桥平衡技术注入“大”超极化电流脉冲时，这些神经元显示出“下垂”的膜电压响应（时间依赖性整流）。此外，重复发射通常发生与去极化电流脉冲，这一特点的神经元共振在其阻抗幅值函数中没有观察到的神经元与“纯粹”的被动膜行为。基于膜模型的五参数阻抗拟合函数的非线性最小二乘拟合到具有共振的神经元的阻抗轨迹图产生了其膜特性的估计：输入电容、电导的时不变部分、由小振荡输入电流激活的电导以及该电导的弛豫时间常数。输入电容和输入电阻的估计范围与表现出“纯粹”被动行为的神经元的相应属性的范围相当。（400字处删节）
Passive and active (voltage- and time-dependent) membrane properties of trigeminal root ganglion neurons of decerebrate guinea pigs have been determined using frequency-domain analyses of small-amplitude perturbations of membrane voltage. The complex impedance functions of trigeminal ganglion neurons were computed from the ratios of the fast Fourier transforms of the intracellularly recorded voltage response from the neuron and of the input current, which had a defined oscillatory waveform. The impedance magnitude functions and corresponding impedance locus diagrams were fitted with various membrane models such that the passive and active properties were quantified. The complex impedances of less than one-quarter of the 105 neurons which were investigated extensively could be described by the complex impedance function for a simple RC-electrical circuit. In such neurons, the voltage responses to constant-current pulses, using conventional bridge-balance techniques, could be fitted with single exponential curves, also suggesting passive membrane behavior. A nonlinear least-squares fit of the complex impedance function for the simple model to the experimentally observed complex impedance yielded estimates of the resistance of the electrode, and of input capacitance (range, 56 to 490 pF) and input resistance (range, 0.8 to 30 M omega) of the neurons. The majority of trigeminal ganglion neurons were characterized by a resonance in the 50- to 250-Hz bandwidth of their impedance magnitude functions. Such neurons when injected with "large" hyperpolarizing current pulses using bridge-balance techniques showed membrane voltage responses that "sagged" (time-dependent rectification). Also, repetitive firing commonly occurred with depolarizing current pulses; this characteristic of neurons with resonance in their impedance magnitude functions was not observed in neurons with "purely" passive membrane behavior. A nonlinear least-squares fit of a five-parameter impedance fitting function based on a membrane model to the impedance locus diagram of a neuron with resonance yielded estimates of its membrane properties: input capacitance, the time-invariant part of the conductance, the conductance activated by the small oscillatory input current, and the relaxation time constant for this conductance. The ranges of the estimates for input capacitance and input resistance were comparable to the ranges of corresponding properties derived for neurons exhibiting "purely" passive behavior.(ABSTRACT TRUNCATED AT 400 WORDS)