Padjen A L, Hashiguchi T
Can J Physiol Pharmacol. 1983 Jun;61(6):626-31. doi: 10.1139/y83-096.
The mechanism of primary afferent depolarization (PAD) was studied in the isolated frog spinal cord using intrafibre recording (microelectrodes filled with 0.6 M potassium sulfate) from large myelinated axons of dorsal roots. Standard current-clamp technique was used to obtain voltage-current (V-I) relationship. It was found that: (i) PAD is voltage dependent: its amplitude and rate of rise are increased with hyperpolarization; (ii) the slope of the linear part of the V-I curve obtained during PAD is decreased compared with the V-I curve at rest; (iii) the PAD equilibrium potential, estimated by extrapolation, ranged from -66 to -40 mV. These results suggest that PAD is associated with an increase in conductance of primary afferent terminals and thus seem to provide the first experimental evidence for the hypothesis that shunting of primary afferent membrane is the mechanism of presynaptic inhibition in the vertebrate nervous system.
采用纤维内记录法（用充满0.6M硫酸钾的微电极），从背根的有髓大轴突记录，在离体蛙脊髓中研究了初级传入去极化（PAD）的机制。使用标准电流钳技术获得电压-电流（V-I）关系。结果发现：（i）PAD是电压依赖性的：其幅度和上升速率随超极化而增加；（ii）与静息时的V-I曲线相比，PAD期间获得的V-I曲线线性部分的斜率降低；（iii）通过外推估计的PAD平衡电位范围为-66至-40mV。这些结果表明，PAD与初级传入终末的电导增加有关，因此似乎为初级传入膜分流是脊椎动物神经系统中突触前抑制机制这一假说提供了首个实验证据。
