Inhibition of the sarcoplasmic reticulum Ca2+ pump with thapsigargin to estimate the contribution of Na+-Ca2+ exchange to ventricular myocyte relaxation. R.A. Bassani and J.W.M. Bassani. Brazilian Journal of Medical and Biological Research, 36 (12): 1717, 2003.
Figure 1. Ca2+ transients during inhibition of Ca2+ transporters. A, Typical Ca2+ transients recorded from an adult rat ventricular myocyte during electrical stimulation at 0.5 Hz under control conditions (TW) and at 0.1 Hz after treatment with thapsigargin (TG-TW), and in quiescence after application of 10 mM caffeine in the presence (Cf-NT) and absence (Cf-00) of extracellular Na+ and Ca2+. The gray curves superimposed on the traces represent single exponential functions fitted to the phase of [Ca2+]i decline of each transient (R2 > 0.97 in all cases). B, Values of diastolic [Ca2+]i and Ca2+ transient amplitude (D[Ca2+]i, left panel) and rate constant of [Ca2+]i decline (right panel) for all four types of transient. *P < 0.05 compared to TW (one-way ANOVA for paired samples, followed by the Bonferroni test).