Background and Objective: Nitric Oxide in the small intestine causes relaxation of smooth muscles. Research indicates that extremely low frequency electromagnetic fields (ELF) affect nitric oxide level in the tissues. The objective of this study was to grasp the effect of prolonged exposure to ELF on the nitrergic system in the small intestine.

Materials and Methods: 21 adult male rats were allocated to three groups: the experimental group exposed to ELF (50Hz, 1mT) for 75 days, the sham-operated group underwent similar conditions except ELF exposure; and the control group mice were kept under the laboratory normal condition. The isolated strips of the colon were inserted into organ bath and were linked to force transducer power lab A to D system and their mechanical activity were recorded in response to L-NAME. Data was analyzed using one way ANOVA test.

Results: The results exhibited a significant increase (p≤0.05) of ileum basal contractions in experimental group when compared to control and sham groups. However, administration of L-NAME (inhibitor of NO synthesis) led to a significant decrease in ileum contraction in the experimental group compared to the sham and control groups (p≤0.05).

Conclusion: It can be concluded that prolonged exposure to extremely low-frequency electromagnetic fields may decrease the activity of nitrergic system in small intestine of the male rats.