Zhu Y, Ma R C
Sheng Li Xue Bao. 1989 Feb;41(1):63-9.
Intracellular recordings were made from the cells in the interm ediolateral nucleus (IML) of neonatal rat spinal cord slices in vitro. Both resting and active electrophysiological properties of the cellular membrane were investigated. Resting membrane potential ranged from -46 to -70 mV. The means of input resistance, time constant and membrane capacitance were 108.3 +/- 67.9 M omega (mean +/- SD), 9.9 +/- 5.6 ms and 138.6 +/- 124.2 pF, respectively. Repetitive firing at high frequency (up to 150 Hz) could be produced in thirty five cells (85.4%) in response to intracellular injection of depolarizing current, while single spike firing produced in the remaining cells (15.6%). The amplitude and duration of action potentials evoked by intracellular stimulation were 63.4 +/- 9.0 mV and 2.4 +/- 0.6 ms, respectively. The threshold at the level of 18.7 +/- 6.2 mV was more depolarized than the resting potential. In most of cells, spikes induced by intracellular stimulation were followed by afterhyperpolarization, whose peak amplitude and duration were 5.1 +/- 2.7 mV and 90 +/- 31.8 ms, respectively. EPSP, orthodromic action potentials and, rarely, IPSP could be evoked by dorsal root stimulation, and antidromic action potentials were obtained by ventral root stimulation. Identification of sympathetic preganglionic neuron and functional significance of electrophysiological properties were discussed.
在体外对新生大鼠脊髓切片中间外侧核（IML）中的细胞进行细胞内记录。研究了细胞膜的静息和活动电生理特性。静息膜电位范围为-46至-70 mV。输入电阻、时间常数和膜电容的平均值分别为108.3±67.9 MΩ（平均值±标准差）、9.9±5.6 ms和138.6±124.2 pF。对35个细胞（85.4%）进行细胞内注入去极化电流可产生高频（高达150 Hz）的重复放电，其余细胞（15.6%）产生单个动作电位放电。细胞内刺激诱发的动作电位的幅度和持续时间分别为63.4±9.0 mV和2.4±0.6 ms。阈值为18.7±6.2 mV，比静息电位更去极化。在大多数细胞中，细胞内刺激诱发的动作电位之后是超极化后电位，其峰值幅度和持续时间分别为5.1±2.7 mV和90±31.8 ms。背根刺激可诱发兴奋性突触后电位（EPSP）、顺向动作电位，很少能诱发抑制性突触后电位（IPSP），腹根刺激可获得逆向动作电位。讨论了交感神经节前神经元的鉴定及电生理特性的功能意义。
