UNIVERSITY-OF-WISCONSIN SOLUTION PRESERVES MYOCARDIAL CALCIUM CURRENTRESPONSE 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 w as designed to evaluate the subcellular protective mechanism of UW sol ution during cardiac myocyte storage using patch-clamp techniques for the first time as a tool for the detection of myocyte viability. Metho ds and Results The protective effects of UW solution on the preservati on of dihydropyridine-sensitive Ca2+ channel current response to catec holamine were evaluated in canine cardiac ventricular cells by measure ment of single channel open probability. Single ventricular myocytes w ere isolated and stored in UW solution, in Stanford (SF) solution, or in St Thomas' (ST) solution at 4 degrees C for 2, 6, 12, and 24 hours, and after each storage period, recordings were made of cell-attached single Ca2+ channel currents. When 0.1 mu mol/L isoproterenol was appl ied, percent mean open probability of the Ca2+ channel tested in fresh ly 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 p reserved as much as 165+/-9% (n=6) in UW solution. Ca2+ channel kineti cs and channel conductance were not changed after up to 24 hours of hy pothermic storage. Conclusions Hypothermic storage of canine cardiac m yocytes in UW solution preserved beta-adrenergic response, which sugge sts that UW solution during cold storage preserved high-energy phospha tes in myocytes that are responsible for Ca2+ channel phosphorylations .