Effects of Panax notoginseng saponins on monophasic action potentials of heart and automaticity and contractility of isolated atria
Abstract
The effects of Panax notoginseng saponins (PNS) on monophasic action potentials (MAP) recorded from the myocardial surface by means of contact electrode were studied in 30 open-chest rabbits. The MAPA was increased and MAPD50, MAPD90 were prolonged with PNS (100, 200 mg.kg-1, iv), while the Vmax remained unchanged. PNS (300-1200 micrograms.ml-1) inhibited the automaticity of isolated guinea pig right atria and the contractility of the left atria. The positive inotropic action of ouabain (0.2 mumol.L-1) on isolated guinea pig left atria was decreased in the presence of PNS 300 micrograms.ml-1.
Keywords: