Nature of the calcium dependent potassium leak induced by (+)‐propranolol, and its possible relevance to the drug's antiarrhythmic effect

Abstract

1 Manninen (1970) recently reported that in the presence of calcium ions, (+)-propranolol causes a massive loss of potassium ions from human red cells, together with a marked inward ‘counter-transport’ of potassium ions from the medium. 2 This paper shows, theoretically, that counter-transport of the kind he observed may be accounted for by the setting up of a diffusion potential across the cell membrane and does not imply that, under the influence of propranolol, potassium ions cross the membrane by some process other than free diffusion. 3 The physiological and pharmacological significance of this interpretation of Manninen's findings is briefly discussed.