Institute of Clinical Pharmacy & Pharmacology, The Second Xiangya Hospital of Central South University, Changsha 410011, PR China.
Eur J Pharmacol. 2012 Sep 5;690(1-3):68-76. doi: 10.1016/j.ejphar.2012.06.032. Epub 2012 Jun 30.
Brucine is a central agonist that can pass through the blood-brain barrier (BBB). The goal of this study is to examine whether brucine is one of the substrates of the drug transporter P-glycoprotein (P-gp) and to examine the effects of P-gp on the brucine transport at the in vitro BBB model. The P-gp ATPase assay was utilized to investigate the in vitro affinity of P-gp to brucine. Results suggested that K(m) of brucine (11.4 μmol/l) was smaller than the positive control, verapamil (16.4 μmol/l). In this study, we developed an in vitro BBB model, comprising a co-culture of primary rat brain microvessel endothelial cells and astrocytes for the transport study. The validated model was correct and available. Transendothelial electrical resistance reached (283.78 ± 18.85) Ω cm(2). The model displayed limited permeability to fluorescein sodium and [(125)I]albumin, with the apparent permeability coefficient Papp of (10.36 ± 0.86) × 10(-6) cm/s and (6.00 ± 0.78) × 10(-6)cm/s, respectively. The quantity of the bidirectional transport of brucine was determined by ultra-performance liquid chromatography-tandem mass spectrometry. In the absence of verapamil, the transport of brucine from basolateral compartment to apical compartment (BL-AP) was higher than from AP to BL at low, middle, and high concentrations (P<0.05). The excretion rate was 1.32, 1.56, and 1.54, respectively. However, following exposure to verapamil, the excretion rate at three different concentrations was decreased (P<0.05). All the results suggest that P-gp prevented brucine from passing through the in vitro BBB model.
马钱子碱是一种可以穿透血脑屏障 (BBB) 的中枢激动剂。本研究旨在考察马钱子碱是否为药物转运蛋白 P-糖蛋白 (P-gp) 的底物之一，并研究 P-gp 对体外 BBB 模型中马钱子碱转运的影响。利用 P-gp ATP 酶测定法研究 P-gp 对马钱子碱的体外亲和力。结果表明，马钱子碱的 K(m)（11.4 μmol/l）小于阳性对照药维拉帕米（16.4 μmol/l）。在这项研究中，我们建立了一个体外 BBB 模型，由原代大鼠脑微血管内皮细胞和星形胶质细胞共培养用于转运研究。验证后的模型是正确和可用的。跨内皮电阻达到（283.78 ± 18.85）Ωcm(2)。该模型对荧光素钠和 [(125)I] 白蛋白的通透性有限，表观渗透系数 Papp 分别为（10.36 ± 0.86）×10(-6)cm/s 和（6.00 ± 0.78）×10(-6)cm/s。通过超高效液相色谱-串联质谱法测定马钱子碱的双向转运量。在没有维拉帕米的情况下，马钱子碱从基底外侧腔到顶侧腔（BL-AP）的转运高于从 AP 到 BL 的转运，在低、中、高浓度下均如此（P<0.05）。排泄率分别为 1.32、1.56 和 1.54。然而，暴露于维拉帕米后，三个不同浓度下的排泄率均降低（P<0.05）。所有结果表明，P-gp 阻止了马钱子碱通过体外 BBB 模型。
