Özet:

Purpose: Ginkgo biloba is used in the traditional Chinese medicine in the treatment of various diseases such as asthma, cough and enuresis. The standardized Ginkgo biloba extract, EGb-761, contains flavonoids and terpenoids that cause vasodilatation in animal studies. There is very little information about the effects of EGb-761 on human umbilical circulation. This in vitro study aims to assess the vascular effects of EGb-761 on the isolated human umbilical artery and the role of nitric oxide (NO) and prostaglandins in these effects. Tools and Methods: Isolated human umbilical arterial stripes, hanging in organ baths containing the Krebs-Henseleit solution, are constantly gazed with 95% O2-5% CO2. Isometric vasoactive changes created by the agents applied after the rest period were recorded. In different tissue groups (n=9) the following experimental procedures were performed; 1) the cumulative effect of EGb-761 (50-500 μg/ml) on the basal tone of the umbilical artery stripes. 2) The relaxing effect of the cumulative EGb-761 on the accumulation response created in the arteric stripes with 10-6 M 5-HT. 3) The relaxing effect of the cumulative EGb-761 on the contraction response created in the L-NAME after incubation with 5-HT with the arterial stripes 4) The relaxing effect of the cumulative EGb-761 on the contraction response created in the indometazine and 5-HT with the arterial stripes after incubation and 5) The relaxing effect of the cumulative EGb-761 on the contraction response created in the arterial stripes with 5-HT with the L-NAME and the indometazine after incubation. In the statistical analysis of the data, a mixed impact model was used. p<0.05 was accepted meaningfully. Results: The cumulative application of EGb-761 (50-500 μg/ml) did not change the basal tone of the arteric stripes (p>0.05). The cumulative EGb-761 (50-500 μg/ml) created a concentration-related relaxation in 5-HT-based accumulation responses (p<0.05). L-NAME significantly reduced the relief reactions of EGb-761 (50-500 μg/ml) on 5-HT accumulations in all concentrations (p<0.05). L-NAME completely inhibited the relief reactions of EGb-761 in low concentrations (50-100 μg/ml). Indometazine significantly inhibited these responses at higher concentrations of EGb-761 (200-500 μg/ml) (p<0.05). L-NAME + indometazine significantly inhibited all EGb-761 concentrations (50-500 μg/ml) in response (p<0.05). Furthermore, the joint application of L-NAME and indometazine resulted in a stronger inhibition of L-NAME and indometazine alone in specific EGb-761 concentrations in these relaxation responses. The result: EGb-761 does not affect the basal tone of the human umbilical artery. The accumulative application of EGb-761 to humane umbilical arterial stripes created by 5-HT pre-concentration significantly creates a concentration-related relaxation response. NOs and prostaglandins contribute to the potential variing depending on the EGb-761 concentration in this vasodilation mechanism. Also, prostaglandins create synergic effects with NO in these responses.