Exposure to extremely low frequency (50 Hz) electromagnetic field changes the survival rate and morphometric characteristics of neurosecretory neurons of the earthworm Eisenia foetida (Oligochaeta) under illumination stress

An in vivo model was set up to establish the behavioral stress response (rate of survival) and morphometric characteristics of A1 protocerebral neurosecretory neurons (cell size) of Eisenia foetida (Oligochaeta) as a result of the synergetic effect of extremely low frequency electromagnetic fields (ELF-EMF - 50 Hz, 50 μT, 17 V/m and 50 Hz, 150 μT, 17 V/m, respectively) and constant illumination (420-450 lux). If combined, these two stressors significantly (p<0.05) increased the survival rate of E. foetida in the 150 μT-exposed animals, because of delayed caudal autotomy reflex, an indicator of stress response. In addition, morphometric analysis indicated that there were changes in the protocerebral neurosecretory cells after exposure to the ELF-EMF. The present data support the view that short-term ELF-EMF exposure in “windows” of intensity is likely to stimulate the immune and neuroendocrine response of E. foetida.