Lai W S, Ramkumar V, el-Fakahany E E
J Neurochem. 1985 Jun;44(6):1936-42. doi: 10.1111/j.1471-4159.1985.tb07190.x.
The interaction of the potassium channel blocker 4-aminopyridine (4-AP) and its analogs with muscarinic acetylcholine receptors was studied in rat brain homogenate. 4-AP displaced specific [3H]quinuclidinyl benzilate [( 3H]QNB) binding in a concentration-dependent fashion. Hill coefficient values decreased with increasing the concentration of [3H]QNB and different analogs of 4-AP demonstrated varying potencies. Scatchard analysis of saturation isotherms of specific [3H]QNB binding showed that low concentrations of 4-AP slightly reduced maximum binding without affecting the equilibrium dissociation constant, whereas higher concentrations reduced maximum binding further and significantly increased the equilibrium dissociation constant. Schild plots of these data resulted in curvilinear functions. The results are discussed in terms of possible allosteric interactions between potassium channels and muscarinic receptor binding sites.
在大鼠脑匀浆中研究了钾通道阻滞剂4-氨基吡啶（4-AP）及其类似物与毒蕈碱型乙酰胆碱受体的相互作用。4-AP以浓度依赖性方式取代特异性[3H]喹核醇基苯甲酸酯[（3H]QNB）结合。随着[3H]QNB浓度的增加，希尔系数值降低，并且4-AP的不同类似物表现出不同的效力。对特异性[3H]QNB结合的饱和等温线进行Scatchard分析表明，低浓度的4-AP略微降低最大结合量而不影响平衡解离常数，而较高浓度则进一步降低最大结合量并显著增加平衡解离常数。这些数据的Schild图产生曲线函数。根据钾通道与毒蕈碱受体结合位点之间可能的变构相互作用对结果进行了讨论。
