(+/-)-Pseudophrynaminol inhibited carbamylcholine-elicited sodium-22 influx with an IC50 value of about 0.3 mu M in both rat pheochromocytoma PC12 cells (ganglionic-type nicotinic receptor) and human medulloblastoma TE671 cells (neuromuscular-type nicotinic receptor). The inhibition in both cell lines appeared to be noncompetitive in nature. In rat cerebral cortical membranes, pseudophrynaminol had only low affinity (K-i 35 mu M) for the agonist site on central nicotinic receptors at which [H-3]nicotine binds. Pseudophrynaminol, at 10 mu M, had marginal effects on a variety of other central receptors, and even at 100 mu M inhibited batrachotoxin-elicited sodium-22 influx in a synaptoneurosomal preparation by only 40%. It had no effect at 30 mu M on acetylcholinesterase and was a weak inhibitor of butyrylcholinesterase. Thus, pseudophrynaminol appears to be a potent, rather specific, noncompetitive inhibitor of ganglionic and neuromuscular nicotinic receptor-channels. (C) 1997 Elsevier Science Inc.
(±)-Pseudophrynaminol在大鼠嗜
铬细胞瘤PC12细胞(神经节型
烟碱受体)和人类髓母细胞瘤TE671细胞(神经肌肉型
烟碱受体)中,以约0.3微米的IC50值抑制了甲基酰
胆碱引起的
钠-22流入。在两种
细胞系中,抑制作用似乎是非竞争性的。在大鼠 cerebral cortical 膜中,Pseudophrynaminol仅对中枢
烟碱受体的激动剂结合位点具有低亲和力(Ki 35 微米),此处[3H]
烟碱结合。Pseudophrynaminol在10微米时对多种其他中枢受体的影响有限,甚至在100微米时仅抑制了 synaptoneurosomal 制备物中蛙毒素引起的
钠-22流入的40%。在30微米时,它对
乙酰胆碱酯酶没有影响,仅是丁酰
胆碱酯酶的弱
抑制剂。因此,Pseudophrynaminol似乎是一种对神经节和神经肌肉
烟碱受体-通道作用较强的特异性非竞争性
抑制剂。 (C) 1997 Elsevier Science Inc.