pharmacology of honey bee products: 1. Actions of Propolis on rat arterial blood pressure, respiratory systems and some smooth muscles

ABSTRACT

The influence of the honey bee propolis was examined on the cardiovascular system the respiratory system and the in vivo uterine activity in rats together with its effects on the isolated rabbit jejunum. Administration of propolis in doses of [2.5-10 mg kg -1 i.v.] decreased the arterial blood pressure and the heart rate increased the respiratory rate and the intra tracheal and the intra-uterine pressures in a dose dependent manner. The cardiovascular depressant effects were antagonized by cyproheptadine and atropine. They were not antagonized by hexamethonium mepyramine, ranitidine indomethacin cutting of the vagus to the heart or by spinal pithing of the animals. The induced respiratory and uterine effects were antagonized by treatment of the animals with atropine and cyproheptadine respectively, suggesting mediation via muscarinic and serotoninergic mechanisms. Exposure of the isolated rabbit jejunum to propolis extract in concentrations of [5-20 micro gml-1] induced dose dependent contractions that were antagonized by pretreatment of the tissue with hexamethonium and atropine, suggesting propolis induced activation of the parasympathetic ganglia with concomitant release of Ach from the terminals of the postganglionic parasympathetic fibers. It was concluded that propolis contains constituents that directly or indirectly activate muscarinic and/or serotoninergic mechanisms in both rats and rabbits