Van Wilgenburg H
Eur J Pharmacol. 1979 May 15;55(4):355-61. doi: 10.1016/0014-2999(79)90109-2.
Prednisolone, in concentrations of 0.004--0.032 mmol/l, increased the amplitude of the miniature end-plate potentials (MEPPs). A maximum increase to 134% of the control values was seen at 0.016 mmol/l. At higher prednisolone concentrations the MEPP amplitude gradually decreased to reach 77% of the control value at 0.62 mmol/l. The MEPP frequency was increased to twice the control value at 0.62 mmol/l. The quantal content of the end-plate potential (EPP), however, was not influenced by prednisolone. The response to iontophoretically applied acetylcholine was diminished, especially at 0.62 mmol/l prednisolone. Prednisolone, therefore, caused presynaptic effects as was shown by an increase in unitary MEPP amplitude and by a considerable number of giant MEPPs, which at increasing prednisolone concentrations was antagonized increasingly by a postsynaptic depressant effect. These results also provide an explanation for the adverse effects of prednisolone on the end-plate potential and on neuromuscular transmission.
泼尼松龙浓度在0.004 - 0.032 mmol/l时，可增加微小终板电位（MEPPs）的幅度。在0.016 mmol/l时，最大增幅可达对照值的134%。在更高的泼尼松龙浓度下，MEPP幅度逐渐降低，在0.62 mmol/l时降至对照值的77%。在0.62 mmol/l时，MEPP频率增加至对照值的两倍。然而，终板电位（EPP）的量子含量不受泼尼松龙影响。对离子电渗法施加的乙酰胆碱的反应减弱，尤其是在泼尼松龙浓度为0.62 mmol/l时。因此，泼尼松龙产生了突触前效应，表现为单个MEPP幅度增加以及出现相当数量的巨大MEPPs，随着泼尼松龙浓度增加，这些效应越来越受到突触后抑制效应的拮抗。这些结果也为泼尼松龙对终板电位和神经肌肉传递的不良反应提供了解释。
