IL-1 provokes electrical abnormalities in rat atrial myocardium

• IL-1α caused increasing in the APD at the level of 90% re-polarization.
• IL-1α caused appearance of single extrasystols.
• IL-lβ perfusion resulted in appearance of extrasysolic patterns.

Using a micro-electrode technique we studied the effects of interleukin 1α and interleukin 1β on bio-electric activity of rat atrial myocardium under normal conditions and after gradual stretching. Perfusion with interleukin 1α increased the duration of the action potential at the level of 90% re-polarization. Stretch induced tachy-arrhythmia in the presence of interleukin 1α is mainly regulated via stretch increased nitric oxide production, while the ionotropic effect of the interleukin-1α during stretching is not pronounced. The perfusion with interleukin 1β did not change the values of the duration of the action potentials at the levels of 25, 50 and 90% repolarization. The interleukin lβ caused an appearance of extra-systolic patterns which turned into normal rhythm, alternating with periods of normal activity. The total intracellular nitric oxide level induced by both interleukin 1β and stretching is balanced by interleukin-1β induced cation influx.