Mechanical activity of isolated aorta strips after prolonged exposure to low frequency electromagnetic fields and its interaction with the cholinergic and adrenergic systems in male rat

Introduction: Public concern about the potential effects of electromagnetic field (EMF) on human health is increased by progressive usage of electrical devices in modern life. The aim of this study was to investigate the effect of prolonged exposure to low frequency EMF on the mechanical activity of isolated thoracic aorta strips in rats. Methods: Fourteen male rats were randomly allocated into sham and experimental groups. Experimental group was continuously exposed to 1mT, 50Hz EMF, for 75 days in a magnetic coil box. Sham group was kept under conditions similar to experimental group, without being exposed to EMF. After 75 days, the rats were anaesthetized and the thoracic aorta was dissected and cut into 1cm strips. Aortic strips were suspended in organ bath chambers containing of Krebs&rsquo; buffer and were bubbled with a gas mixture (5% CO2, 95% O2). Then the aortic isometric tension was measured during 20-min equilibration period and after cumulative administration of acetylcholine and phenylephrine in different concentrations. Results: Increased vasocontraction responses to 10-6 M phenylephrine were observed in experimental group compared to sham group (P<0.05). Moreover, reduced vasorelaxation responses to 8&times;10-5 M acetylcholine were observed in the experimental group compared to sham group (P<0.05). Conclusion: It can be suggested that prolonged exposure to EMF have an effect on the vascular sensitivity to cholinergic and adrenergic system, can lead to alteration of the vascular resistance.