Fig. 3.

A Intracellular Ca²⁺-transient (Fura-4F fluorescence) alternans for a RV myocyte isolated from a FAIL animal stimulated at 9 Hz. B SERCA activity estimated as K_SERCA was significantly reduced in RV myocytes from FAIL animals. K_SERCA was calculated as the difference between the rate constant of decay of the electrically stimulated Ca²⁺-transient at 5 Hz (e, representing Ca²⁺ removal by SERCA and Na–Ca exchange) and caffeine stimulated Ca²⁺ transient (c, representing Ca²⁺ removal by Na–Ca exchange). C Levels of SERCA protein, estimated by Western blot, were significantly lower in HYP and FAIL RV myocardium than CON (data expressed as % of the mean density of CON samples, N = 6 in each group) D. In the HYP group SERCA density was significantly correlated with the RV weight:body weight ratio R² = 0.7, P < 0.05). E Levels of mRNA for SERCA, estimated by real-time RT-PCR, were significantly lower in FAIL myocardium than HYP or CON (data expressed relative to a calibrator sample normalised to the housekeeper gene 18S, N = CON 12, HYP 7, FAIL 14). A and B modified from (Benoist et al., 2012). *P < 0.05; **P < 0.01; ***P < 0.001.