Figure 2. APD response to 50 μM cytochalasin D (10 min) for a normal cell (top) and LVH cell (bottom).

Conditions identical to those shown in Fig. 1. Exposure of the normal cell to cytochalasin D induced a slight prolongation in APD. Note the increased control APD of the LVH cell; exposure to cytochalasin D (10 min) markedly lengthened APD of the LVH cell; these results were observed in four other paired experiments. Washout with drug-free solution (10 min) reversed much of the APD prolongation induced by cytochalasin D.