对氧磷在大鼠膈神经-膈肌标本中诱发的逆向冲动发放与抽搐增强之间的关系。
The relationship between stimulus-induced antidromic firing and twitch potentiation produced by paraoxon in rat phrenic nerve-diaphragm preparations.
作者信息
Clark A L, Hobbiger F, Terrar D A
出版信息
Br J Pharmacol. 1983 Sep;80(1):17-25. doi: 10.1111/j.1476-5381.1983.tb11044.x.
The relationship between stimulus-induced repetitive antidromic firing (ADF) in the motor nerve and twitch potentiation produced by the organophosphate anticholinesterase paraoxon, has been investigated in rat diaphragm preparations. Little or no ADF was produced by paraoxon in preparations bathed in a Tyrode solution containing 1 mM calcium and 1 mM magnesium ions although the preparations showed marked twitch potentiation. Increases in the calcium:magnesium ion ratio produced a ratio-dependent increase in the ADF but had no consistent effect on peak twitch potentiation. Dithiothreitol, a disulphide bond reducing agent which decreases the affinity of acetylcholine for nicotinic cholinoceptors, abolished ADF but only modified the time course of twitch potentiation. Dithiothreitol, a disulphide bond reducing agent which decreases the affinity of acetylcholine for nicotinic cholinoceptors, abolished ADF but only modified the time course of twitch potentiation. It is concluded that the initiation of ADF is a consequence of the prolonged action of acetylcholine within the synaptic cleft following inhibition of acetylcholinesterase, and that ADF is not the only mechanism by which twitch potentiation can be produced.
在大鼠膈肌制备物中，研究了运动神经中刺激诱导的重复性逆向发放（ADF）与有机磷酸酯类抗胆碱酯酶对氧磷所产生的抽搐增强之间的关系。在含有1 mM钙和1 mM镁离子的台氏液中浸泡的制备物中，对氧磷几乎不产生或不产生ADF，尽管制备物表现出明显的抽搐增强。钙镁离子比例的增加使ADF呈比例依赖性增加，但对峰值抽搐增强没有一致的影响。二硫苏糖醇是一种二硫键还原剂，可降低乙酰胆碱对烟碱型胆碱受体的亲和力，它消除了ADF，但仅改变了抽搐增强的时间进程。二硫苏糖醇是一种二硫键还原剂，可降低乙酰胆碱对烟碱型胆碱受体的亲和力，它消除了ADF，但仅改变了抽搐增强的时间进程。得出的结论是，ADF的起始是乙酰胆碱酯酶受到抑制后，乙酰胆碱在突触间隙内作用延长的结果，并且ADF不是产生抽搐增强的唯一机制。
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