Effects of fura-2 and indo-1 on [Ca++]i in spontaneously beating cultured heart cells.
Changes in contractility and intracellular free Ca([Ca++]i) were measured in spontaneously beating cultured heart cells following exposure to indo-1 acetoxymethyl ester (indo-1AM) and fura-2 acetoxymethyl ester (fura-2AM). Although a 10 microM concentration of indo-1AM slightly decreased the beating rate, 5 and 10 microM concentrations of fura-2AM produced arrest of contraction within 10 min. However, contractility returned to normal after washing. With indo-1, the diastolic and peak systolic levels of [Ca++]i were 282 +/- 23 and 1107 +/- 122 nM, respectively, and 84 +/- 8 and 582 +/- 93 nM, respectively, with fura-2. The difference between the indo-1 and fura-2 generated responses are statistically significant (p less than 0.01). These results demonstrate that indo-1 and fura-2 can affect [Ca++]i, but the influence of indo-1 is less than that of fura-2 in the heart cells.
Ishida
H
H
Department of Physiology 2, School of Medicine, Tokai University, Kanagawa, Japan.
Seguchi
H
H
Sakata
N
N
Ohusuzu
F
F
Aosaki
N
N
Nakamura
H
H
Okino
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005456:Fluorescent Dyes / Q000494:pharmacology; D016257:Fura-2 / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology*; D007700:Kinetics; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000166:cytology / Q000378:metabolism
D005456:Fluorescent Dyes; D007211:Indoles; C048960:indo-1; D002118:Calcium; D016257:Fura-2