On the metabolic basis of pseudopotentiation and superposition in the frog myocardium

Potentiation phenomena, tetanization and staircase of isolated surviving ventricle strips excised from hearts of 16 frogs (Rana esculenta) were studied under quasiisometric conditions. Pseudopotentiation of all kind, biphasic staircases and superposition of contractions characterizing the hypodynamic state following excision disappear in-vitro not only during normodynamic conditions but also in hypodynamia following in-vitro normodynamia.