Voltage clamp analysis of lamprey neurons--role of N-methyl-D-aspartate receptors in fictive locomotion.
Voltage clamp analysis of lamprey neurons--role of N-methyl-D-aspartate receptors in fictive locomotion.
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七鳃鳗神经元的电压钳分析——N-甲基-D-天冬氨酸受体在虚构运动中的作用。
DOI：
10.1016/0006-8993(87)90616-0
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Grillner,S
中科院分区：
文献类型：
--
作者：
Moore,LE;Hill,RH;Grillner,S
对七鳃鳗脊髓神经元在虚拟运动过程中产生的兴奋电流进行了电压钳分析，特别是电压依赖性N-甲基-d-天冬氨酸(NMDA)受体的相激活。在NMDA诱导的假想游泳过程中观察到的电压钳制神经元分别与同侧和对侧的腹根放电呈现兴奋性和抑制性突触电流同相。兴奋性突触电流表现出明显的电压依赖性，提示NMDA离子载体等潜在敏感电导参与了突触事件的节律性运动活动。在NMDA诱导的起搏器样振荡过程中，还分析了应用河豚毒素时NMDA受体激活的影响。在电压钳位期间，这种由NMDA引起的振荡基本上被消除。在NMDA存在的情况下，电流-电压图显示在固有振荡的电势范围内电导为负斜率。将四乙基铵(TEA)加入到NMDA溶液中，由于部分阻断了外向电流，使净稳态内向电流增加了10倍以上。动力学分析是用频域技术完成的，使用白噪声刺激在很宽的频率范围内线性扰动膜电位。分析表明，感应负导导致的响应与低频激励的相位相差近180°。这是一种不稳定的条件，导致了诱导振荡的去极化阶段。
Spinal neurons in the lamprey have been subjected to a voltage clamp analysis of the excitatory currents generated during fictive locomotion with particular reference to the phasic activation of voltage dependentN-methyl-d-aspartate(NMDA) receptors. Voltage-clamped neurons observed during NMDA-induced fictive swimming show excitatory and inhibitory synaptic currents in phase with the ipsilateral and contralateral ventral root discharges, respectively. The excitatory synaptic currents showed a marked voltage dependence suggesting that potential sensitive conductances such as the NMDA ionophore are involved in the synaptic events underlying rhythmic locomotor activity. The effect of NMDA receptor activation during application of tetrodotoxin has also been analyzed during NMDA-induced pacemaker-like oscillations. Such NMDA-induced oscillations are essentially abolished during the voltage clamp. In the presence of NMDA current voltage plots reveal a negative slope conductance in the potential range of the inherent oscillations. The addition of tetraethyl ammonium (TEA) to the NMDA solution enhanced a net steady state inward current by more than 10-fold due to a partial block of the outward currents. A kinetic analysis was done with a frequency domain technique using a white noise stimulus to linearly perturb the membrane potential over a wide range of frequencies. The analysis revealed that the induced negative conductance leads to a response which is nearly 180° out of phase with the stimulus at low frequencies. This is an unstable condition which leads to the depolarizing phase of the induced oscillations.