Fig. 3

β-Adrenoceptor stimulation Ca²⁺response blunted in hypertrophic female HHR cardiomyocytes. a Representative cardiomyocyte shortening trace (central portion time compressed) showing isoproterenol (10 nM) exposure-elicited response of rapid and sustained increase in cell twitch. b–d The extent of increase in shortening and maximum rate of shortening was similar in male and female cardiomyocytes, but more pronounced in the presence of pathological hypertrophy. Rate of lengthening was unchanged. e The extent of isoproterenol-induced increase in Ca²⁺ transient amplitude was selectively blunted in female HHR myocytes. f Diastolic Ca²⁺ levels were stable with isoproterenol challenge in all treatment groups, whilst tau (g) was significantly faster in HHR of both sexes (#strain p < 0.05; †sex-strain interaction; §post hoc male vs female p < 0.05, mean ± SEM, n = 9–11 cells from four to five hearts/group)