Effects of Mistletoe (<i>Viscum Album</i>L., Loranthaceae) Extracts on Arterial Blood Pressure in Rats Treated with Atropine Sulfate and Hexocycline

Abstract

Acute effects of different extracts of mistletoe stem (Viscum album) were investigated on values of arterial blood pressure in Wistar rats. Arterial blood pressure was registered by direct method in the left carotid artery and the investigated extracts (total ethanol, ether and ethyl acetate) of mistletoe stem were administered into the right jugular vein. The total ethanol extract exhibited the best effect even on the lowest applied concentration (3.33 x 10(-5) mg kg(-1)) and significantly decreased the blood pressure after applied concentration 1.00 x 10(-3) mg kg(-1). On the contrary, the ether and ethyl acetate extracts exhibited notable activity only by higher administered doses. Atropine as a nonselective blocker of muscarinic receptors reduced the hypotensive effects of ethanol extract of mistletoe. Hexocycline, a selective blocker of muscarine receptors, significantly raised blood pressure and decreased the hypotensive effect of ethanol extract of mistletoe on arterial blood pressure in rats.