Sıçan kalp dokusunda ökse otu nun (Viscum album L.) etkileri

Viscum album L. (European mistletoe) comprises a semi parasitic plant which grows on various host trees in Turkey and Europe. It has been widely used as a herbal treatment since ancient times for hypertension and other cardiovascular disorders. Its cardioprotective action has been attributed to the vasodilatation increased by nitric oxide synthase activity and antioxidant activity. However, little is known about its effects on atrial tissue and myocardial ischaemia-reperfusion injury. We hypothesized that V. album is able to limit infarct size under ischeamia-reperfusion injury. This study was designed to evaluate the cardiac & cardioprotective effects of V. album crude extracts on isolated heart preparation, using the Langendorff technique in an ischaemia-reperfusion infarct model and isolated rat atrial muscle. Both administration of aqueous V. album (AVa) and methanolic V. album (MVa) extracts during ischaemia - reperfusion significantly limited infarct size compared to controls. Inhibition of nitric oxide synthesis completely abrogated this protection in both extracts. KATP channel blockage by glibenclamide also abrogated the protection afforded by MVa but perfusion of glibenclamide along with AVa showed a synergistic action. Nevertheless, aqueous V. album extract induced negative inotropic and chronotropic effects in the rat atrial muscles, in vitro. None of the pharmacological agents used in this study abrogated the negative inotropic effects of V. album extract. These data suggest that V. album extracts can afford cardioprotection by limiting infarct size during ischaemia reperfusion. Furthermore, our study is of great significance in terms of being the first research in the experimental field of infarct model with V. album. Further studies need to be performed to investigate the interaction of V. album extracts and more specific agents. These need to be focused on the isolation, purification, structural dilucidation, pharmacological reevaluation in order to find the chemical compound responsible for such a pharmacological effect. Keywords: Viscum album L., cardioprotective, ischaemia - reperfusion injury, nitric oxide, vasodilation, Langendorff, infarct, KATP channel, inotropy, antioxidant.