Table 7.

QT interval duringexposure to PAF vehicle or the final concentration of PAF in hearts perfused with Krebs containingelevated K⁺ and/or supplementation with norepinephrine (NA)

	PAF vehicle	100 nmol PAF
Perfusion solution modification
None	62±3	74±3*
K elevated to 8 mM	61±9	79±5*
K elevated to 15 mM K	66±5	76±3*
+ 0.1 μM NA	67±6	77±2*
K elevated to 8 mM +0.1 μM NA	60±4	75±3*
K elevated to 15 mM +0.1 μM NA	57±5	71±7*

All groups shown were initially exposed to PAF (0–100 nmol). The data represent QT interval (ms; measured at 90% repolarisation), during the second exposure to PAF (only data for the highest dose, 100 nmol PAF, or a time-matched bolus of PAF vehicle, are shown). The hearts were perfused with K⁺ and/or norepinephrine added to the perfusion solution during the second exposure to PAF or vehicle; n=12 per group. Values are mean±s.e.m.

^*P<0.05 versus PAF vehicle.