Manzini S, Maggi C A, Parlani M, Subissi A, Meli A
Pharmacology Department, Malesci Pharmacobiological Institute, Florence, Italy.
Drugs Exp Clin Res. 1988;14(4):265-70.
At concentrations ranging from 8.5 to 30 microM, octylonium bromide (OB) did not affect sodium channel availability measured as maximal rate of depolarization (Vmax) of cardiac action potential. On the other hand, at equieffective spasmolytic concentrations (1.1 mM), procaine markedly inhibited Vmax as well as other electrophysiological parameters. These experiments indicate that at fully effective spasmolytic concentrations OB is devoid of local anaesthetic properties. In concentrations up to 10 microM OB did not affect phosphodiesterase activity in crude homogenates of rat colon which were inhibited by both papaverine (EC50 = 0.7 mM) and theophylline (EC50 = 3.5 mM). OB was more effective in antagonizing spasmogen-induced contractions on colonic as compared to tracheal preparations. Inhibition of Neurohormone-induced calcium ion mobilization from cellular and extracellular pools remains the mechanism of action which best explains the spasmolytic effects of OB on intestinal smooth muscle.
在8.5至30微摩尔的浓度范围内，辛基溴化铵（OB）不影响以心脏动作电位的最大去极化速率（Vmax）衡量的钠通道可用性。另一方面，在等效的解痉浓度（1.1毫摩尔）下，普鲁卡因显著抑制Vmax以及其他电生理参数。这些实验表明，在完全有效的解痉浓度下，OB没有局部麻醉特性。在高达10微摩尔的浓度下，OB不影响大鼠结肠粗匀浆中的磷酸二酯酶活性，而罂粟碱（EC50 = 0.7毫摩尔）和茶碱（EC50 = 3.5毫摩尔）均可抑制该活性。与气管制剂相比，OB在拮抗结肠痉挛原诱导的收缩方面更有效。抑制神经激素诱导的钙离子从细胞内和细胞外池的动员仍然是最能解释OB对肠道平滑肌解痉作用的作用机制。
