Wali F A, Hayter A P
Anaesthetics Unit, London Hospital Medical College, Whitechapel, U.K.
Alcohol Alcohol. 1988;23(4):299-303.
The effect of ethanol on neuromuscular transmission in the isolated phrenic nerve-diaphragm preparation of the rat was studied by analysing its effect on directly- and indirectly-elicited twitch tension, tetanic and post-tetanic twitch tensions, and on the phenomenon of post-tetanic twitch potentiation (PTP). The results show that ethanol (1.0 X 10(-4)-1.0 M) depresses neuromuscular transmission, by reducing the amplitudes of both directly and indirectly elicited twitch and tetanic contractions. Ethanol produces a greater reduction in the amplitude of indirectly- than directly-elicited twitch tension and the mean concentration of ethanol which produced a 50% reduction was 38 mM. High concentrations of ethanol (greater than 10(-3) M) completely blocked the indirectly-elicited twitch tension in 4 min exposure. Ethanol also reduced the tetanic tension and increased the PTP value. There was no tetanic fade in the presence of ethanol, but the peak tetanic tension was reduced by 20-50%. It is suggested that ethanol inhibits neuromuscular transmission in the rat phrenic nerve-diaphragm preparation, possibly via a mixture of pre- and postjunctional mechanisms and produces a greater reduction in the twitch than tetanic tension.
通过分析乙醇对大鼠膈神经 - 膈肌标本直接和间接诱发的抽搐张力、强直收缩和强直后抽搐张力以及强直后抽搐增强现象（PTP）的影响，研究了乙醇对大鼠离体膈神经 - 膈肌标本神经肌肉传递的作用。结果表明，乙醇（1.0×10⁻⁴ - 1.0 M）通过降低直接和间接诱发的抽搐及强直收缩幅度来抑制神经肌肉传递。乙醇对间接诱发的抽搐张力幅度的降低作用大于直接诱发的抽搐张力，产生50%降低作用的乙醇平均浓度为38 mM。高浓度乙醇（大于10⁻³ M）在4分钟暴露时完全阻断间接诱发的抽搐张力。乙醇还降低了强直张力并增加了PTP值。在有乙醇存在时没有强直衰减，但强直峰值张力降低了20 - 50%。提示乙醇可能通过节前和节后机制的混合作用抑制大鼠膈神经 - 膈肌标本的神经肌肉传递，并且对抽搐的降低作用大于强直张力。
