Willets J M, Lambert D G, Lunec J, Griffiths H R
Division of Chemical Pathology, C.M.H.T., University of Leicester, UK.
Eur J Pharmacol. 1995 Dec 7;293(4):319-26. doi: 10.1016/0926-6917(95)90051-9.
We have studied the hypothesis that 6,7-dihydroxy-1-methyl-1,2,3,4-tetrahydroisoquinoline (salsolinol) is neurotoxic. Salsolinol induced a significant time and dose related inhibition of 3[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; thiazoyl blue (MTT) reduction, and increased lactate dehydrogenase release (LDH) release from human SH-SY5Y neuroblastoma cells, at concentrations within the range of 1-methyl-4-phenylpyridinium (MPP+) cytotoxicity, in vitro. Cytotoxicity was not inhibited by the addition of antioxidants, monoamine oxidase inhibitors or imipramine. In confluent monolayers, salsolinol stimulated catecholamine uptake with EC50 values of 17 muM and 11 muM, for noradrenaline and dopamine, respectively. Conversely, at concentrations above 100 muM, salsolinol inhibited the uptake of noradrenaline and dopamine, with IC50 values of 411 muM and 379 muM, respectively. The inhibition of catecholamine uptake corresponded to the increase displacement of [3H]nisoxetine from the uptake 1 site by salsolinol, as the Ki (353 muM) for displacement was similar to the IC50 (411 and 379 muM) for uptake. Salsolinol stimulated catecholamine uptake does not involve the uptake recognition site, or elevation of cAMP, cGMP, or inhibition of protein kinase C. Salsolinol also inhibited both carbachol (1 mM) and K+ (100 mM, Na+ adjusted) evoked released of noradrenaline from SH-SY5Y cells, with IC50 values of 500 muM and 120 muM, respectively. In conclusion, salsolinol appears to be cytotoxic to SH-SY5Y cells, via a mechanism that does not require uptake 1, bioactivation by monoamine oxidase, or membrane based free radical damage. The effects of salsolinol on catecholamine uptake, and the mechanism of toxicity require further investigation.
我们研究了6,7 - 二羟基 - 1 - 甲基 - 1,2,3,4 - 四氢异喹啉（salsolinol）具有神经毒性这一假说。在体外，salsolinol在1 - 甲基 - 4 - 苯基吡啶鎓（MPP +）细胞毒性范围内的浓度下，诱导了与时间和剂量相关的显著抑制3 - [4,5 - 二甲基噻唑 - 2 - 基] - 2,5 - 二苯基四氮唑溴盐；噻唑蓝（MTT）还原，并增加了人SH - SY5Y神经母细胞瘤细胞中乳酸脱氢酶释放（LDH）。添加抗氧化剂、单胺氧化酶抑制剂或丙咪嗪并不能抑制细胞毒性。在汇合的单层细胞中，salsolinol刺激儿茶酚胺摄取，去甲肾上腺素和多巴胺的EC50值分别为17μM和11μM。相反，在浓度高于100μM时，salsolinol抑制去甲肾上腺素和多巴胺的摄取，IC50值分别为411μM和379μM。儿茶酚胺摄取的抑制与salsolinol从摄取1位点置换[3H]尼索西汀的增加相对应，因为置换的Ki（353μM）与摄取的IC50（411和379μM）相似。salsolinol刺激儿茶酚胺摄取不涉及摄取识别位点，也不涉及cAMP、cGMP的升高或蛋白激酶C的抑制。Salsolinol还抑制卡巴胆碱（1 mM）和K +（100 mM，调整Na +）诱导的SH - SY5Y细胞中去甲肾上腺素的释放，IC50值分别为500μM和120μM。总之，salsolinol似乎通过一种不需要摄取1、单胺氧化酶生物活化或基于膜的自由基损伤的机制对SH - SY5Y细胞具有细胞毒性。Salsolinol对儿茶酚胺摄取的影响及其毒性机制需要进一步研究。
