Ca2+ waves and intracellular Ca2+ concentration in guinea pig and rat myocytes.
We measured [Ca2+]i of guinea pig and rat myocytes with Ca2+ waves, using fura-2 fluorescence image processing. In guinea pig myocytes, Ca2+ waves were absent during the control perfusion period, but could be induced by the addition of strophanthidin (100 microM) or sodium cyanide (NaCN: 2 mM) to the perfusate. The [Ca2+]i increased from the control values of 69 +/- 5 nM and 46 +/- 2 nM, to 263 +/- 9 (p < 0.05 vs. control) nM and 225 +/- 20 (p < 0.05) nM, respectively, when cells exhibited Ca2+ waves. Although 13% (16 of 121) of the rat myocytes displayed Ca2+ waves during the control perfusion, the [Ca2+]i with Ca2+ waves (56 +/- 9 nM) did not differ from [Ca2+]i in the absence of Ca2+ waves (54 +/- 3 nM). Ca2+ waves were induced by the perfusion with a high Ca2+ solution (24.5 microM) or NaCN (2 microM), and [Ca2+]i increased from the control values of 67 +/- 11 nM and 74 +/- 5 nM, to 231 +/- 41 (p < 0.05 vs. control) nM and 266 +/- 64 nM, respectively, when cells exhibited Ca2+ waves. The Ca2+ waves were abolished by the removal of extracellular Ca2+, or by the perfusion with ryanodine (10 microM) or caffeine (20 mM). In conclusion, it was shown that Ca2+ waves were due to oscillatory Ca2+ release and that the absolute value of [Ca2+]i is important for the appearance of Ca2+ waves in guinea pig and rat myocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
Hayashi
H
H
Photon Medical Research Center, Hamamatsu University School of Medicine, Japan.
Miyata
H
H
Terada
H
H
Satoh
H
H
Katoh
H
H
Nakamura
T
T
Kobayashi
A
A
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D008297:Male; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D012966:Sodium Cyanide / Q000494:pharmacology; D013045:Species Specificity; D013327:Strophanthidin / Q000494:pharmacology
D002110:Caffeine; D013327:Strophanthidin; D012966:Sodium Cyanide; D002118:Calcium