Li Shao, Sun Chang-Kai, Ji Xin-Cai, Zhang Jian
Department of Physiology and Institute for Brain Disorder and Disease, Dalian Medical University, Dalian 116027, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2007 Aug;23(3):305-8.
To investigate effect of ginkgo biloba extract (GBE) on N-methyl-D-aspartate (NMDA)-activated currents (I(NMDA)) and evaluate further the modulatory effects of Micro-GBE/Nano-GBE.
By means of whole-cell patch clamp technique, NMDA-activated currents from acutely isolated rat hippocampal neurons were recored.
The majority of the neurons examined (81.8%, 90/110) were sensitive to NMDA (1 mmol/L) and its co-agonist Gly (10 micromol/L). NMDA activated an inward current, which manifested apparent desensitization and could be blocked by its specific antagonist MK-801. After the neurons were treated with Micro/Nano GBE (0.1 mg/ml) followed by the application of NMDA (1 mmol/L) and Gly (10 micromol/L) for 30 s, it was show that NMDA-activated currents were obviously inhibited (P < 0.01, n = 8). The inhibitory rate were 40% +/- 17% and 64% +/- 15% respectively. It showed that the modulatory effect of Nano-GBE (dissolved in the stander extracellular solution) on NMDA-activated current was significantly higher than that of Micro-GBE (dissolved in DMSO) (P < 0.05).
The inward currents activated by NMDA could be depressed by Micro-GBE and Nano-GBE. The modulatory effects of GBE on NMDA-activated current are expected to contribute to the neuroprotective effects of ginkgo biloba extracts. In addition, at the same concentration, the modulatory effect of Nano-GBE on NMDA-activated current is better than that of Micro-GBE.
研究银杏叶提取物（GBE）对N-甲基-D-天冬氨酸（NMDA）激活电流（I(NMDA)）的影响，并进一步评估微银杏叶提取物/纳米银杏叶提取物（Micro-GBE/Nano-GBE）的调节作用。
采用全细胞膜片钳技术，记录急性分离的大鼠海马神经元的NMDA激活电流。
大多数被检测的神经元（81.8%，90/110）对NMDA（1 mmol/L）及其共激动剂甘氨酸（Gly，10 μmol/L）敏感。NMDA激活内向电流，表现出明显的脱敏现象，且可被其特异性拮抗剂MK-801阻断。在用微/纳米银杏叶提取物（0.1 mg/ml）处理神经元后，再施加NMDA（1 mmol/L）和甘氨酸（10 μmol/L）30秒，结果显示NMDA激活电流明显受到抑制（P < 0.01，n = 8）。抑制率分别为40%±17%和64%±15%。结果表明，纳米银杏叶提取物（溶解于标准细胞外溶液中）对NMDA激活电流的调节作用明显高于微银杏叶提取物（溶解于二甲基亚砜中）（P < 0.05）。
微银杏叶提取物和纳米银杏叶提取物可抑制NMDA激活的内向电流。银杏叶提取物对NMDA激活电流的调节作用有望有助于其神经保护作用。此外，在相同浓度下，纳米银杏叶提取物对NMDA激活电流的调节作用优于微银杏叶提取物。
