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Abstract：
BACKGROUND: Triptans are anti-migraine drugs with a potential central site of action. However, it is not known to what extent triptans cross the blood-brain barrier (BBB). The aim of this study was therefore to determine if triptans pass the brain capillary endothelium and investigate the possible underlying mechanisms with focus on the involvement of the putative proton-coupled organic cation (H+/OC) antiporter. Additionally, we evaluated whether triptans interacted with the efflux transporter, P-glycoprotein (P-gp).
METHODS: We investigated the cellular uptake characteristics of the prototypical H+/OC antiporter substrates, pyrilamine and oxycodone, and seven different triptans in the human brain microvascular endothelial cell line, hCMEC/D3. Triptan interactions with P-gp were studied using the IPEC-J2 MDR1 cell line. Lastly, in vivo neuropharmacokinetic assessment of the unbound brain-to-plasma disposition of eletriptan was conducted in wild type and mdr1a/1b knockout mice.
RESULTS: We demonstrated that most triptans were able to inhibit uptake of the H+/OC antiporter substrate, pyrilamine, with eletriptan emerging as the strongest inhibitor. Eletriptan, almotriptan, and sumatriptan exhibited a pH-dependent uptake into hCMEC/D3 cells. Eletriptan demonstrated saturable uptake kinetics with an apparent Km of 89 ± 38 µM and a Jmax of 2.2 ± 0.7 nmol·min-1·mg protein-1 (n = 3). Bidirectional transport experiments across IPEC-J2 MDR1 monolayers showed that eletriptan is transported by P-gp, thus indicating that eletriptan is both a substrate of the H+/OC antiporter and P-gp. This was further confirmed in vivo, where the unbound brain-to-unbound plasma concentration ratio (Kp,uu) was 0.04 in wild type mice while the ratio rose to 1.32 in mdr1a/1b knockout mice.
CONCLUSIONS: We have demonstrated that the triptan family of compounds possesses affinity for the H+/OC antiporter proposing that the putative H+/OC antiporter plays a role in the BBB transport of triptans, particularly eletriptan. Our in vivo studies indicate that eletriptan is subjected to simultaneous brain uptake and efflux, possibly facilitated by the putative H+/OC antiporter and P-gp, respectively. Our findings offer novel insights into the potential central site of action involved in migraine treatment with triptans and highlight the significance of potential transporter related drug-drug interactions.
METHODS: We investigated the cellular uptake characteristics of the prototypical H+/OC antiporter substrates, pyrilamine and oxycodone, and seven different triptans in the human brain microvascular endothelial cell line, hCMEC/D3. Triptan interactions with P-gp were studied using the IPEC-J2 MDR1 cell line. Lastly, in vivo neuropharmacokinetic assessment of the unbound brain-to-plasma disposition of eletriptan was conducted in wild type and mdr1a/1b knockout mice.
RESULTS: We demonstrated that most triptans were able to inhibit uptake of the H+/OC antiporter substrate, pyrilamine, with eletriptan emerging as the strongest inhibitor. Eletriptan, almotriptan, and sumatriptan exhibited a pH-dependent uptake into hCMEC/D3 cells. Eletriptan demonstrated saturable uptake kinetics with an apparent Km of 89 ± 38 µM and a Jmax of 2.2 ± 0.7 nmol·min-1·mg protein-1 (n = 3). Bidirectional transport experiments across IPEC-J2 MDR1 monolayers showed that eletriptan is transported by P-gp, thus indicating that eletriptan is both a substrate of the H+/OC antiporter and P-gp. This was further confirmed in vivo, where the unbound brain-to-unbound plasma concentration ratio (Kp,uu) was 0.04 in wild type mice while the ratio rose to 1.32 in mdr1a/1b knockout mice.
CONCLUSIONS: We have demonstrated that the triptan family of compounds possesses affinity for the H+/OC antiporter proposing that the putative H+/OC antiporter plays a role in the BBB transport of triptans, particularly eletriptan. Our in vivo studies indicate that eletriptan is subjected to simultaneous brain uptake and efflux, possibly facilitated by the putative H+/OC antiporter and P-gp, respectively. Our findings offer novel insights into the potential central site of action involved in migraine treatment with triptans and highlight the significance of potential transporter related drug-drug interactions.
摘要：
背景：Triptans是抗偏头痛药物，具有潜在的中枢作用位点。然而,目前尚不清楚曲坦通过血脑屏障（BBB）的程度。因此，这项研究的目的是确定曲坦类药物是否通过脑毛细血管内皮，并研究可能的潜在机制，重点是推定的质子偶联有机阳离子（H/OC）反转运蛋白的参与。此外,我们评估了曲坦是否与外排转运蛋白相互作用，P-糖蛋白(P-gp)。
方法：我们研究了原型H+/OC反转运底物的细胞摄取特征，吡喃胺和羟考酮，和人脑微血管内皮细胞系中的七种不同的曲坦类药物，hCMEC/D3。使用IPEC-J2MDR1细胞系研究了曲坦与P-gp的相互作用。最后,在野生型和mdr1a/1b基因敲除小鼠中进行了eletriptan未结合脑-血浆配置的体内神经药代动力学评估.
结果：我们证明大多数曲坦类药物能够抑制H+/OC反转运底物的摄取，吡喃胺,其中eletriptan成为最强的抑制剂。Eletriptan,阿莫曲坦,和舒马曲坦表现出pH依赖性摄取到hCMEC/D3细胞中。Eletriptan表现出可饱和的摄取动力学，表观Km为89±38µM，Jmax为2.2±0.7nmol·min-1·mg蛋白-1（n=3）。跨IPEC-J2MDR1单层的双向运输实验表明，eletriptan通过P-gp运输，因此表明eletriptan是H/OC反转运蛋白和P-gp的底物。这在体内得到进一步证实，其中未结合的脑与未结合的血浆浓度比(Kp，uu）在野生型小鼠中为0.04，而mdr1a/1b敲除小鼠的比率上升至1.32。
结论：我们已经证明了化合物的曲坦家族对H+/OC反转运蛋白具有亲和力，表明推定的H+/OC反转运蛋白在曲坦的BBB转运中起作用。尤其是依来曲坦.我们的体内研究表明，eletriptan同时进行脑摄取和外排，可能是由推定的H+/OC反转录因子和P-GP促进的，分别。我们的发现为曲坦类药物治疗偏头痛的潜在中枢作用位点提供了新的见解，并强调了潜在转运蛋白相关药物-药物相互作用的重要性。
方法：我们研究了原型H+/OC反转运底物的细胞摄取特征，吡喃胺和羟考酮，和人脑微血管内皮细胞系中的七种不同的曲坦类药物，hCMEC/D3。使用IPEC-J2MDR1细胞系研究了曲坦与P-gp的相互作用。最后,在野生型和mdr1a/1b基因敲除小鼠中进行了eletriptan未结合脑-血浆配置的体内神经药代动力学评估.
结果：我们证明大多数曲坦类药物能够抑制H+/OC反转运底物的摄取，吡喃胺,其中eletriptan成为最强的抑制剂。Eletriptan,阿莫曲坦,和舒马曲坦表现出pH依赖性摄取到hCMEC/D3细胞中。Eletriptan表现出可饱和的摄取动力学，表观Km为89±38µM，Jmax为2.2±0.7nmol·min-1·mg蛋白-1（n=3）。跨IPEC-J2MDR1单层的双向运输实验表明，eletriptan通过P-gp运输，因此表明eletriptan是H/OC反转运蛋白和P-gp的底物。这在体内得到进一步证实，其中未结合的脑与未结合的血浆浓度比(Kp，uu）在野生型小鼠中为0.04，而mdr1a/1b敲除小鼠的比率上升至1.32。
结论：我们已经证明了化合物的曲坦家族对H+/OC反转运蛋白具有亲和力，表明推定的H+/OC反转运蛋白在曲坦的BBB转运中起作用。尤其是依来曲坦.我们的体内研究表明，eletriptan同时进行脑摄取和外排，可能是由推定的H+/OC反转录因子和P-GP促进的，分别。我们的发现为曲坦类药物治疗偏头痛的潜在中枢作用位点提供了新的见解，并强调了潜在转运蛋白相关药物-药物相互作用的重要性。
