Kanno Takeshi, Tanaka Akito, Nishizaki Tomoyuki
Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Japan.
Cell Physiol Biochem. 2012;30(1):75-82. doi: 10.1159/000339049. Epub 2012 Jun 8.
BACKGROUND/AIMS: We have earlier found that the linoleic acid derivative DCP-LA could ameliorate learning and memory impairment by targeting α7 ACh receptor. The present study aimed at understanding DCP-LA-regulated α7 ACh receptor trafficking.
We monitored currents through α7 ACh receptors expressed in Xenopus oocytes and assayed the receptor mobilizations using fractions with a sucrose density gradient centrifugation, synaptosome preparation, and acutely dissociated neurons from rat hippocampal slices.
DCP-LA persistently potentiated α7 ACh receptor currents, and the effect was inhibited by a protein kinase C (PKC) inhibitor or vesicular transport inhibitors. DCP-LA did not induce PKC phosphorylation of α7 ACh receptors. DCP-LA stimulated translocation of α7 ACh receptors from the cytosol toward the plasma membrane or from extra-synaptosomes into synaptosomes and accumulated the receptors at the presynaptic site in hippocampal neurons.
The results of the present study demonstrate that DCP-LA increases surface localization of α7 ACh receptors in hippocampal neurons, specifically at presynaptic terminals, by stimulating vesicular transport of the receptors, resulting in potentiation of α7 ACh receptor responses, regardless of PKC phosphorylation of the receptors.
背景/目的：我们之前发现亚油酸衍生物DCP-LA可通过作用于α7乙酰胆碱受体改善学习和记忆障碍。本研究旨在了解DCP-LA对α7乙酰胆碱受体转运的调控作用。
我们监测了非洲爪蟾卵母细胞中表达的α7乙酰胆碱受体的电流，并使用蔗糖密度梯度离心分离组分、制备突触体以及分离大鼠海马脑片急性解离的神经元来检测受体的转运情况。
DCP-LA持续增强α7乙酰胆碱受体电流，该作用被蛋白激酶C（PKC）抑制剂或囊泡运输抑制剂所抑制。DCP-LA不会诱导α7乙酰胆碱受体的PKC磷酸化。DCP-LA刺激α7乙酰胆碱受体从胞质溶胶向质膜转运，或从突触体外向突触体内转运，并使受体在海马神经元的突触前位点聚集。
本研究结果表明，DCP-LA通过刺激受体的囊泡运输增加海马神经元中α7乙酰胆碱受体的表面定位，特别是在突触前终末，从而增强α7乙酰胆碱受体反应，而与受体的PKC磷酸化无关。
