Comparison of the tissue response during the loading with voltage-sensitive dye in two animal models

Two animal models - guinea pig and rabbit - were used to record monophasic action potentials using voltage sensitive dye di-4-ANEPPS in isolated hearts perfused according to Langendorf. The hearts undergo the same isolation and loading procedures. Changes in electrogram and coronary flow are followed. During the loading and washout, prominent electrophysiological changes occur (mainly decrease of spontaneous heart rate and changes in the shape of T wave), accompanied with decrease in mean coronary flow. However, these changes differ in the two species. It may be concluded that rabbit heart is more resistant to the changes which are triggered with VSD application. Although these changes are partially reversible in guinea pig heart, this model seems to be more sensitive and thus less reliable