Using microelectrode technique we studied the effects of interleukin-17A on the activity of rat atrial myocardium under normal conditions and after gradual stretching of the tissue. Perfusion with interleukin-17A for 35 min without stretch, led to an increase in APD25, APD50 and APD90. The effect on the frequency and force of the contraction was absent. Stretching during interleukin-17A perfusion led to an increase only at the level of APD90. In the same condition, the repetition frequency of the action potentials did not change as well. Close observation of the cytokine induced mechanisms, confirmed that IL-17A act on different levels and induce different signaling pathways involved in the regulation of cardiac function.