[Effects of ginkgolide A, B and K on platelet aggregation].

To investigate the effects of ginkgolide A (GA), ginkgolide B (GB) and ginkgolide K (GK) on platelet aggregation in rabbits, and compare the similarities and differences among these three components. The effects of different doses of ginkgolide A, B and K on platelet aggregation induced by platelet activating factor (PAF) were observed by using in vitro experiment. The results showed that three compounds could inhibit platelet aggregation induced by PAF in vitro, and the intensity was GK> GB> GA. It was further found that all of them can mobilize [Ca2+]i and enhance intracellular c-AMP level in a dose-dependent manner, which was consistent to the ability to antagonize PAF receptor. These findings indicated that GK was highly selective for PAF receptor, and may inhibit platelet aggregation by activating cAMP signaling pathway and inhibiting intracellular [Ca2+]i mobilization; GB and GA also had strong antagonism to PAF receptor, but the effect was weaker than that of GK.

[Cerebral vascular protective effect of ginkgo diterpene lactone meglumine injection].

The left middle cerebral artery occlusion (MCAO) model was made by inserting the nylon thread plug into the internal carotid artery. The behavioral score, cerebral infarction area, brain water content, ethidium bromide (EB) spillover, coagulation four indices, occludin and MMP-9 expression in brain tissues were detected after 14 days of administration, to investigate whether the protective effect of ginkgo diterpene lactone meglumine injection (GDLMI) which had obvious protective effect on cerebral ischemic injury in the previous experiment was related to reducing the permeability of the blood-brain barrier (BBB) and reducing the risk of bleeding, and to explore its possible mechanism of action. The results showed that GDLMI could effectively alleviate the behavioral changes caused by MCAO at 24 h, reduce the behavioral score, improve the edema of brain tissue, reduce the EB overflow rate, reduce the bleeding tendency caused by long-term administration, significantly reduce the occlusion deficiency in ischemic brain tissue of model rats, and down-regulate MMP-9 expression. The above results indicate that GDLMI has obvious effect on cerebral ischemia, and the therapeutic effect of GDLMI may mainly depend on lowering the permeability of blood-brain barrier to improve brain edema.