The Role of Cardiac Carbonic Anhydrases In Vivo: A Hyperpolarised

4 , providing the first technique which may allow direct study of CA in vivo. Consequently, the aim of this study was to determine the effects of intra- and extracellular isoforms of CA on CO2 efflux from the heart, in vivo. 13 CO2 production over the first 6 s following pyruvate infusion. Statistical differences between control (n = 8), C23 (n = 6), and ETZ (n = 4) groups were assessed using one- way ANOVA with a post-hoc Tukey's multiple comparison test. Statistical significance was considered at p < 0.05. A system of ordinary differential equations was formulated to model the effects of diffusion, reaction with intracellular and extracellular isoforms of CA, and convection on in vivo CO2 venting from the myocardium. Results C23 (50 μM) had no significant effect on the production of either H 13 CO3 -