THE SKELETAL-MUSCLE RELAXANT ACTION OF PORTULACA-OLERACEA - ROLE OF POTASSIUM-IONS

An aqueous extract of the stems and leaves of Portulaca oleracea aboli shes the twitch contraction of the directly stimulated rat hemidiaphra gm preparation. The effects of the extract mimic qualitatively the act ion of potassium oxalate - a known constituent of Portulaca oleracea - on the diaphragm. Removal of K+ ions from the methanol extract by pas sing it through a cation exchange resin reduced the inhibitory effect of the extract. There was a positive correlation between the concentra tion of K+ ions in the extract and the effects of potassium chloride o f similar molarity. It is concluded that the K+ ion content of Portula ca oleracea is at least partly responsible for the relaxant effect obs erved on the isolated rat diaphragm.