Kelly S S, Roberts D V
Br J Anaesth. 1977 Mar;49(3):217-22. doi: 10.1093/bja/49.3.217.
An analysis of neuromuscular transmission has been made in phrenic nerve/diaphragm preparations from male rats aged 30 days or 110 days. The amplitude of miniature end-plate potentials was found to decrease with age, being 0.969 +/- SEM 0.058 mV at 30 days and 0.510 +/- SEM 0.031 mV at 110 days. Over the same period, the quantum content of the first end-plate potential of a train of 40 at 10 Hz, increased from 144.5, SEM + 11.1, -10.4 to 346, SEM +41.4, -37.0. A corresponding change was observed also in the average quantum contents of the last 30 end-plate potentials of each train; from 50.6, SEM +3.5, -3.2, to 138.9, SEM + 15.0,--13.6. The safety factor for neuromuscular transmission, calculated from these measured parameters, was found at 30 days to be only 70-80% of that at 110 days. It was estimated that the lower safety factor found in young rats was approximately equivalent to the neuromuscular blocking action of a dose of, at least, 0.0225 mg/kg of d-tubocurarine. Extrapolation of these results to man would support previous reports of increased sensitivity to d-tubocurarine in neonates.
对30日龄或110日龄雄性大鼠的膈神经/膈肌标本进行了神经肌肉传递分析。发现微小终板电位的幅度随年龄增长而降低，30日龄时为0.969±标准误0.058 mV，110日龄时为0.510±标准误0.031 mV。在同一时期，10 Hz频率下40个刺激串中第一个终板电位的量子含量从144.5（标准误+11.1，-10.4）增加到346（标准误+41.4，-37.0）。在每个刺激串的最后30个终板电位的平均量子含量中也观察到了相应的变化；从50.6（标准误+3.5，-3.2）到138.9（标准误+15.0，-13.6）。根据这些测量参数计算得出的神经肌肉传递安全系数，在30日龄时仅为110日龄时的70-80%。据估计，幼鼠中较低的安全系数大约相当于至少0.0225 mg/kg d-筒箭毒碱的神经肌肉阻滞作用。将这些结果外推至人类，将支持先前关于新生儿对d-筒箭毒碱敏感性增加的报道。
