Figure 5.

The effect of diazepam (10 μM), diazepam (10 μM) + picrotoxin (100 μM) (co-administration), and picrotoxin (100 μM) on heart rate (a), action potential duration (b), and coronary flow (c). Hearts were left to stabilize for a minimum of 30 min. 20 min of baseline recordings were performed, where heart rate and flow were monitored. The hearts were then paced from the right atrium at 240 BPM for 2 min in order to measure the action potential duration at a fixed heart rate. This (20+2) protocol was repeated for the different drugs investigated (n = 5; *P ≤ 0.05 (1-way ANOVA); (715 ± 129 g)).