Role of SERCA and the sarcoplasmic reticulum calcium content on calcium waves propagation in rat ventricular myocytes

2016 ◽  
Vol 604 ◽  
pp. 11-19 ◽  
Author(s):  
Ayleen Salazar-Cantú ◽  
Perla Pérez-Treviño ◽  
Dolores Montalvo-Parra ◽  
Jaime Balderas-Villalobos ◽  
Norma L. Gómez-Víquez ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Ventricular Myocytes ◽  
Calcium Content ◽  
Calcium Waves ◽  
Rat Ventricular Myocytes ◽  
Waves Propagation ◽  
Sarcoplasmic Reticulum Calcium

Rapid cooling contractures as an index of sarcoplasmic reticulum calcium content in rabbit ventricular myocytes

1989 ◽  
Vol 257 (5) ◽  
pp. H1369-H1377 ◽  
Author(s):  
L. V. Hryshko ◽  
V. Stiffel ◽  
D. M. Bers
Keyword(s):  
Electrical Stimulation ◽  
Sarcoplasmic Reticulum ◽  
Ventricular Myocytes ◽  
Calcium Content ◽  
Isometric Tension ◽  
Free Solution ◽  
Rapid Cooling ◽  
Rabbit Ventricular Myocytes ◽  
Sarcoplasmic Reticulum Calcium

Rapid cooling contractures (RCCs) were used to assess changes in sarcoplasmic reticulum (SR) Ca content in both isolated rabbit ventricular myocytes and multicellular preparations. The main difference observed between these preparations was the magnitude of RCCs relative to twitches, apparently due to differences in measured parameters, i.e., unloaded shortening vs. isometric tension. When multicellular preparations were unloaded, RCC shortening was similar to that observed in myocytes. RCC magnitude decreased as the time between the last electrical stimulation and the RCC was increased (rest decay). RCC rest decay closely paralleled that of postrest twitches, suggesting that SR Ca loss is responsible for this process. Paired RCC experiments were used to investigate RCC relaxation and rest decay. When a second RCC (RCC2) was induced immediately after the first (RCC1), a large contracture was still observed (RCC2/RCC1 x 100 = 77.8 +/- 7.3%, mean +/- SD), indicating that the SR resequestered the majority of Ca on rewarming. This fraction was increased (to 92.9 +/- 5.5%) if Na and Ca-free solution was used during RCCs and rewarming, indicating that Na-Ca exchange also contributes to RCC relaxation. Increasing the interval between paired RCCs led to a decrease in RCC2, analogous to rest decay. This rest decay was abolished by inhibiting Na-Ca exchange, indicating that SR Ca loss during rest is mediated primarily by this process. RCCs were abolished by 10 mM caffeine. Ryanodine (1 microM) greatly accelerated RCC rest decay but had less effect on RCCs generated immediately after a train of stimulation. This accelerated rest decay was also dependent on Na-Ca exchange.(ABSTRACT TRUNCATED AT 250 WORDS)

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