Nishida Seiichiro, Satoh Hiroyasu
Department of Pharmacology, Division of Crude and Herbal Medicine, Nara Medical University, School of Medicine, Kashihara, Nara 634-8521, Japan.
Clin Chim Acta. 2005 Apr;354(1-2):141-6. doi: 10.1016/j.cccn.2004.11.030. Epub 2005 Jan 19.
Age-related modulation in vasodilating actions induced by Ginkgo biloba extract (GBE) and bilobalide, a main constituent of GBE, were examined using rat aorta ring strips.
Wistar rats from 5 to 25 weeks old were used, and the isolated aorta ring strips were fixed in Krebs-Henseleit solution.
GBE and bilobalide concentration-dependently dilated norepinephrine (NE)-induced vasoconstriction in all aged rats. The vasodilating actions generally decreased in accordance with aging. GBE at 1 mg/ml decreased from 28.4+/-3.8% (n=5) in 5-week-old rats to 23.7+/-7.1 (n=7) in 25-week-old rats, but not significantly. GBE (3 mg/ml)-induced vasodilation was maximum by 73.7+/-2.1% (n=4, P<0.001) in 10-week-old rats. GBE had the marked vasodilation at younger ages and further decreased it with developing ages. In the rats older than 20 weeks, however, GBE tended to rather increase the strength of vasodilating action. On the other hand, the vasorelaxation induced by 30 micromol/l bilobalide significantly decreased from 11.8+/-1.4% (n=4) in 5-week-old rats to 2.3+/-1.5% (n=5, P<0.01) in 25-week-old rats, and by 100 micromol/l from 20.2+/-3.4% (n=4) to 5.6+/-2.5% (n=5, P<0.01), respectively. Bilobalide had the similar age-related actions. The age-dependent attenuation was produced milder by bilobalide than by GBE. At lower concentrations, however, bilobalide caused the weak vasocontriction in 20- and 25-week-old rats.
GBE and bilobalide possess a similar characteristic for age-related modification, clinically suggesting the more effective actions of GBE for elder persons.
使用大鼠主动脉环条检测了银杏叶提取物（GBE）及其主要成分白果内酯诱导的血管舒张作用的年龄相关性调节。
使用5至25周龄的Wistar大鼠，将分离的主动脉环条固定于Krebs-Henseleit溶液中。
GBE和白果内酯能浓度依赖性地舒张所有年龄大鼠中去甲肾上腺素（NE）诱导的血管收缩。血管舒张作用通常随年龄增长而降低。1mg/ml的GBE使5周龄大鼠的血管舒张率从28.4±3.8%（n=5）降至25周龄大鼠的23.7±7.1（n=7），但差异不显著。3mg/ml的GBE诱导的血管舒张在10周龄大鼠中最大，为73.7±2.1%（n=4，P<0.001）。GBE在较年轻年龄段有明显的血管舒张作用，并随着年龄增长而进一步降低。然而，在20周龄以上的大鼠中，GBE倾向于增强血管舒张作用的强度。另一方面，30μmol/l白果内酯诱导的血管舒张从5周龄大鼠的11.8±1.4%（n=4）显著降至25周龄大鼠的2.3±1.5%（n=5，P<0.01），100μmol/l时从20.2±3.4%（n=4）降至5.6±2.5%（n=5，P<0.01）。白果内酯具有类似的年龄相关性作用。白果内酯引起的年龄依赖性减弱比GBE更轻微。然而，在较低浓度下，白果内酯在20周龄和25周龄大鼠中引起微弱的血管收缩。
GBE和白果内酯具有年龄相关性调节的相似特征，临床表明GBE对老年人更有效。
