Fig. 5.

Myofilament Ca²⁺ responsiveness decreases with ageing in AngII-TG male mice only. a Representative Ca²⁺-shortening phase loops from young and aged male AngII-TG mouse cardiomyocytes. Dashed arrow shows the direction of twitch cycle; solid arrow highlights the right shift of the phase loop. b Ca²⁺-shortening phase loops from young and aged female AngII-TG mouse cardiomyocytes. Dashed arrow shows the direction of twitch cycle. c Intracellular Ca²⁺ change from diastolic Ca²⁺ at 50 % myocyte relaxation, expressed as percentage change from young adult wild type for each sex. n = 7–11 cells/group. Data are presented as mean ± SEM. *p(age) < 0.05, ^# p(sex) < 0.05, two-way ANOVA