Effects of long term exposure to low frequency electromagnetic fields on the cholinergic system in rat colon

  Background: Acetylcholine is the most abundant neurotransmitter that is released from the enteric excitatory motor neurons. Acetylcholine binds to metabotropic muscarinic receptors in intestinal smooth muscle and causes increased bowel movements.   Objective: The aim of this study was to determine the effects of long term exposure to low frequency electromagnetic fields (EMF) on the cholinergic system in rat colon.   Methods: In this experimental study, twenty adult male rats were randomly divided into two groups: the experimental group was exposed to EMF at 1000µT and 50Hz for 140 days in a solenoid and the control group was subjected to sham exposure in which the solenoid did not generate a magnetic field. The isolated strips of the colon were inserted into organ bath and were linked to power lab A to D system force transducer and their mechanical activity were recorded in response to cumulative doses of acetylcholine. Data were analyzed using student T- test.   Findings: The mechanical response of the tissue to the drug in the experimental group (solenoid on) was significantly increased in some minutes compared to the control group (solenoid off).   Conclusion: With regards to the results, it seems that long-term exposure to low frequency electromagnetic fields leads to increased sensitivity of the cholinergic receptors.