Anandamide transport is independent of fatty-acid amide hydrolase activity and is blocked by the hydrolysis-resistant inhibitor AM1172
Anandamide transport is independent of fatty-acid amide hydrolase activity and is blocked by the hydrolysis-resistant inhibitor AM1172
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DOI：
10.1073/pnas.0400997101
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发表时间：
2004-06-08
影响因子：
11.1
通讯作者：
Piomelli, D
中科院分区：
文献类型：
--
作者：
Fegley, D;Kathuria, S;Piomelli, D
内源性大麻素anandamide通过神经元和星形胶质细胞中存在的高亲和力转运系统从突触间隙中去除，其被N-（4-羟基苯基）花生四烯酸酰胺（AM404）抑制。内化后，花生四烯酸被脂肪酸酰胺水解酶（FAAH）水解，FAAH是一种细胞内膜结合酶，也可以切割AM404。基于动力学证据，最近有人提出，花生四烯酸内在化可能是由FAAH活性驱动的被动扩散介导的。为了测试这种可能性，在本研究中，我们研究了野生型和FAAH缺陷（FAAH（-/-））小鼠中的花生四烯酸内在化。来自任一小鼠品系的皮质神经元通过类似的机制内化[（3）H]花生四烯酸，即，通过一个快速的温度敏感和饱和的过程，这是由AM404阻断。此外，对野生型或FAAH（-/-）小鼠全身给予AM404可增强外源性大麻素的低温效应，CB（大麻素拮抗剂利莫那班）（SR 141716 A）可阻止这种反应。结果表明，花生四烯酸酰胺在小鼠脑神经元中的内化与FAAH活性无关。进一步支持这一结论的是，化合物N-（5 Z，8 Z，11 Z，14 Z二十碳四烯基）-4-羟基苯甲酰胺（AM 1172）阻断[H-3]花生四烯酸在啮齿动物皮层神经元和人星形细胞瘤细胞中的内化，而不作为FAAH底物或抑制剂。AM 1172可作为具有增加的代谢稳定性的新型大麻素转运抑制剂的原型。
The endogenous cannabinoid anandamide is removed from the synaptic space by a high-affinity transport system present in neurons and astrocytes, which is inhibited by N-(4-hydroxyphenyl)arachidonamide (AM404). After internalization, anandamide is hydrolyzed by fatty-acid amide hydrolase (FAAH), an intracellular membrane-bound enzyme that also cleaves AM404. Based on kinetic evidence, it has recently been suggested that anandamide internalization may be mediated by passive diffusion driven by FAAH activity. To test this possibility, in the present study, we have investigated anandamide internalization in wild-type and FAAH-deficient (FAAH(-/-)) mice. Cortical neurons from either mouse strain internalized [(3) H]anandamide through a similar mechanism, i.e., via a rapid temperature-sensitive and saturable process, which was blocked by AM404. Moreover, systemic administration of AM404 to either wild-type or FAAH(-/-) mice enhanced the hypothermic effects of exogenous anandamide, a response that was prevented by the CB, cannabinoid antagonist rimonabant (SR141716A). The results indicate that anandamide internalization in mouse brain neurons is independent of FAAH activity. in further support of this conclusion, the compound N-(5Z, 8Z, 11Z, 14Z eicosatetraenyl)-4-hydroxybenzamide (AM1172) blocked [H-3]anandamide internalization in rodent cortical neurons and human astrocytoma cells without acting as a FAAH substrate or inhibitor. AM1172 may serve as a prototype for novel anandamide transport inhibitors with increased metabolic stability.