Cat Heart Muscle in Vitro : II. The steady state resting potential in quiescent papillary muscles

The steady state transmembrane resting potential difference (V_m) has been measured in quiescent papillary muscles. V_m was determined as a function of the external K concentration in Cl and SO₄ solutions and compared with the K equilibrium potential. Other measurements were made after replacement of external Na by choline, K by Rb and Cs, and Cl by SO₄, CH₃SO₄, and NO₃. Effects on V_m of albumin, temperature, and variation in internal K concentration are described.