Effect of bupivacaine (Bupi) and isoprenaline (Iso) on mouse ventricular cardiomyocyte Ca²⁺ transients and contractility. Original registrations and averages of Ca²⁺ transient amplitude and contraction in isolated, Fura-2–loaded ventricular mouse cardiomyocytes. Ca²⁺ transients in (A) time-matched controls (TMCs), (B) with 5 µM bupivacaine, (C) controls (C) with 100 nM isoprenaline, and (D) with 5 µM bupivacaine and 100 nM isoprenaline. (E) Average sarcomere shortening in percentage in TMCs and with 5 µM bupivacaine. (F) Average Ca²⁺ transient height with or without 5 µM bupivacaine. (G) Average sarcomere shortening in percentage with or without 5 µM bupivacaine and 100 nM isoprenaline. (H) Average Ca²⁺ transient height with or without 5 µM bupivacaine and 100 nM isoprenaline. Mean values ± SD, *P < 0.05, **P < 0.01, ***P < 0.001 versus prebupivacaine (E and F) or versus preisoprenaline (G and H); #P < 0.05 versus untreated control value, two-way ANOVA with Bonferroni posttest. a.u. = arbitrary units; F = fluorescence; NS = nonsignificant.