University of Wisconsin Solution Preserves Myocardial Calcium Current Response to Isoproterenol in Isolated Canine Ventricular Myocytes

Background University of Wisconsin (UW) solution has been shown to be an effective solution for cold storage of various organs. This study was designed to evaluate the subcellular protective mechanism of UW solution during cardiac myocyte storage using patch-clamp techniques for the first time as a tool for the detection of myocyte viability. Methods and Results The protective effects of UW solution on the preservation of dihydropyridine-sensitive Ca 2+ channel current response to catecholamine were evaluated in canine cardiac ventricular cells by measurement of single channel open probability. Single ventricular myocytes were isolated and stored in UW solution, in Stanford (SF) solution, or in St Thomas’ (ST) solution at 4°C for 2, 6, 12, and 24 hours, and after each storage period, recordings were made of cell-attached single Ca 2+ channel currents. When 0.1 μmol/L isoproterenol was applied, percent mean open probability of the Ca 2+ channel tested in freshly isolated cells was 167±4% (n=24) of controls (100%). The response was decrescent with increased duration of the hypothermic storage and was only 130±12% (n=4) after 24 hours of storage in SF solution and 135±9% (n=7) in ST solution. However, it was significantly highly preserved as much as 165±9% (n=6) in UW solution. Ca 2+ channel kinetics and channel conductance were not changed after up to 24 hours of hypothermic storage. Conclusions Hypothermic storage of canine cardiac myocytes in UW solution preserved β-adrenergic response, which suggests that UW solution during cold storage preserved high-energy phosphates in myocytes that are responsible for Ca 2+ channel phosphorylations.