Slater N T, Carpenter D O
Cell Mol Neurobiol. 1984 Sep;4(3):263-71. doi: 10.1007/BF00733589.
The blocking actions of strychnine on excitatory acetylcholine (ACh) responses in isolated, voltage clamped Aplysia neuronal cell bodies has been studied using a rapid drug application technique. Rapid microperfusion of strychnine (10-50 microM) produced a reduction of the steady-state ACh-induced inward current in Aplysia neurons which decayed exponentially with a highly dose-dependent time constant. At the cessation of strychnine perfusion the ACh-induced current recovered to its original value with an exponential time course which was not sensitive to the dose of strychnine previously applied. The calculated association (k1) and dissociation (k-1) constants for a pseudo-first-order reaction between strychnine and its binding site were k1 = 1.2 X 10(4) M-1. sec-1 and k-1 = 0.12 sec-1 (KD = 1 X 10(-5) M-1). These results demonstrate that concentration jump relaxation experiments can be performed on isolated neurons for the study of voltage-independent antagonists by the use of rapid microperfusion systems and provide the first direct estimates to date of the rate constants of the cholinolytic effect of strychnine.
使用快速药物施加技术，研究了士的宁对分离的、电压钳制的海兔神经元细胞体中兴奋性乙酰胆碱（ACh）反应的阻断作用。快速微量灌注士的宁（10 - 50微摩尔）可使海兔神经元中由ACh诱导的稳态内向电流降低，该电流以高度剂量依赖性的时间常数呈指数衰减。在停止灌注士的宁后，ACh诱导的电流以指数时间进程恢复到其原始值，该进程对先前施加的士的宁剂量不敏感。士的宁与其结合位点之间的假一级反应的计算缔合常数（k1）和解离常数（k - 1）分别为k1 = 1.2×10⁴ M⁻¹·秒⁻¹和k - 1 = 0.12秒⁻¹（KD = 1×10⁻⁵ M⁻¹）。这些结果表明，通过使用快速微量灌注系统，可以在分离的神经元上进行浓度跳跃弛豫实验，以研究电压非依赖性拮抗剂，并提供了迄今为止士的宁胆碱分解作用速率常数的首次直接估计。
