Clementi F, Cabrini D, Gotti C, Sher E
J Neurochem. 1986 Jul;47(1):291-7. doi: 10.1111/j.1471-4159.1986.tb02861.x.
A human neuroblastoma cell line, IMR32, has been characterized as far as morphology, membrane receptors for neurotransmitters, and uptake and release of [3H]3,4-dihydroxyphenylethylamine ([3H]dopamine). These cells expressed at their surface both nicotinic and muscarinic cholinergic receptors, revealed by [125I]alpha-bungarotoxin and [3H]quinuclidinylbenzilate ([3H]QNB) binding, respectively. [125I]alpha-Bungarotoxin binding was efficiently inhibited by alpha-bungarotoxin, nicotine, carbachol, and d-tubocurarine. [3H]QNB binding was competitively inhibited by atropine, pirenzepine, and carbachol. Hexamethonium did not affect the binding of either ligand. In competition experiments with [3H]QNB, pirenzepine recognized only one binding site with "low affinity," and carbachol recognized two sites with different affinities. beta-adrenergic receptors were present in a very low amount, whereas alpha-adrenergic and dopaminergic receptors were not detectable. IMR32 cells had an imipramine-sensitive [3H]dopamine uptake, but carbachol, high levels of K+, the calcium ionophore A23187, and alpha-latrotoxin were not able to induce release of [3H]dopamine that had been taken up. The ultrastructural analysis showed that IMR32 cells contained very few dense-core vesicles, suggesting a low storage capacity for neurotransmitter. These cells could be an useful in vitro model for studying neurotransmitter receptors of the human CNS.
一种人神经母细胞瘤细胞系IMR32，在形态学、神经递质的膜受体以及[3H]3,4-二羟基苯乙胺（[3H]多巴胺）的摄取和释放方面已得到表征。这些细胞表面表达了烟碱型和毒蕈碱型胆碱能受体，分别通过[125I]α-银环蛇毒素和[3H]喹核醇基苯甲酸酯（[3H]QNB）结合得以揭示。[125I]α-银环蛇毒素结合可被α-银环蛇毒素、尼古丁、卡巴胆碱和d-筒箭毒碱有效抑制。[3H]QNB结合可被阿托品、哌仑西平及卡巴胆碱竞争性抑制。六甲铵不影响任何一种配体的结合。在与[3H]QNB的竞争实验中，哌仑西平仅识别一个“低亲和力”结合位点，而卡巴胆碱识别两个具有不同亲和力的位点。β-肾上腺素能受体含量极低，而α-肾上腺素能和多巴胺能受体无法检测到。IMR32细胞具有对丙咪嗪敏感的[3H]多巴胺摄取，但卡巴胆碱、高浓度K+、钙离子载体A23187和α-拉毒素均不能诱导已摄取的[3H]多巴胺释放。超微结构分析表明，IMR32细胞含有极少的致密核心囊泡，提示神经递质的储存能力较低。这些细胞可能是研究人类中枢神经系统神经递质受体的有用体外模型。
