“…Inactivation of IKI in isolated ventricular myocytes was viewed as being the result of two INTRODUCTION Since Katz (1949) first discovered the property of anomalous rectification in skeletal muscle, it has been described in several different preparations. This anomalous or inward rectification has been studied extensively in starfish (Hagiwara and Takahashi, 1974;Hagiwara et al, 1976;Hagiwara and Yoshii, 1979) and tunicate (Miyazaki et al, 1974;Ohmori, 1978Ohmori, , 1980Fukusbima, 1982) egg cells as well as skeletal muscle preparations (Adrian et al, 1970;Almers, 1972a, b;Standen and Stanfield, 1979;Hestrin, 1981;Leech and Stanfield, 1981). Inward rectification is associated with the presence of a background K ion conductance that contributes to the maintenance of the resting membrane potential.…”