Clementi E, Martini A, Stefani G, Meldolesi J, Volpe P
Chair of Pharmacology, Faculty of Pharmacy, University of Reggio Calabria, Catanzaro, Italy.
Eur J Pharmacol. 1995 Mar 15;289(1):23-31. doi: 10.1016/0922-4106(95)90164-7.
The effects of 1-[2-(4-fluorophenyl)cyclohexyl]-2-[4-(3-phenylalkyl)-piperazin -1-yl]- ethanol, LU52396, on a) Ca2+ influx across the plasma membrane and b) Ca2+ mobilization from intracellular rapidly-exchanging Ca2+ stores were investigated in HeLa cells and in isolated microsomal fractions derived from the cerebellum and the skeletal muscle. LU52396 was found to be a potent inhibitor (Ki of about 2 microM) of the Ca2+ influx activated by depletion of intracellular Ca2+ stores, a phenomenon referred to as store-dependent or capacitative Ca2+ influx. Such an effect, which was reversed by cell washing, was mediated neither by a depolarization of the cell, with decrease in the driving force for cation influx, nor by a change of the intracellular pH, and might therefore be due to a direct action of the drug on either the responsible channel in the plasma membrane or, less likely, on its regulatory mechanisms. Additional effects, i.e. inhibition of receptor-mediated Ca2+ influx, of Ca2+ release from intracellular stores via either inositol 1,4,5-trisphosphate or ryanodine receptors, and of Ca2+ reuptake into the stores via sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPases, were also induced by the drug, however at concentrations 20-fold or more than those effective on the store-dependent influx. To our knowledge LU52396 is the first pharmacological tool that is found to be addressed with some preference to the store-dependent Ca2+ influx. It promises, therefore, to be useful for the characterization of the process, the identification of the responsible channel and, possibly, also of the molecular mechanisms through which these channels operate.
研究了1-[2-(4-氟苯基)环己基]-2-[4-(3-苯基烷基)-哌嗪-1-基]-乙醇（LU52396）对以下方面的影响：a）Ca²⁺跨质膜内流；b）从细胞内快速交换的Ca²⁺储存库中动员Ca²⁺。研究对象为HeLa细胞以及源自小脑和骨骼肌的分离微粒体部分。发现LU52396是细胞内Ca²⁺储存库耗竭激活的Ca²⁺内流的有效抑制剂（Ki约为2 μM），这种现象被称为储存依赖性或容量性Ca²⁺内流。这种可通过细胞洗涤逆转的效应，既不是由细胞去极化（伴随阳离子内流驱动力降低）介导的，也不是由细胞内pH变化介导的，因此可能是由于药物直接作用于质膜中的相关通道，或者可能性较小地作用于其调节机制。该药物还诱导了其他效应，即抑制受体介导的Ca²⁺内流、通过肌醇1,4,5-三磷酸或兰尼碱受体从细胞内储存库释放Ca²⁺以及通过肌浆网-内质网Ca²⁺-ATP酶将Ca²⁺重新摄取到储存库中，然而这些效应所需的浓度是对储存依赖性内流有效浓度的20倍或更高。据我们所知，LU52396是首个被发现对储存依赖性Ca²⁺内流有一定偏好作用的药理学工具。因此，它有望用于该过程的表征、相关通道的鉴定，以及可能用于鉴定这些通道运作的分子机制。
