Biological effects of prolonged exposure to ELF electromagnetic fields in rats: III. 50 Hz electromagnetic fields

Bioelectromagnetics. 1998;19(1):57-66. doi: 10.1002/(sici)1521-186x(1998)19:1<57::aid-bem7>;2-3.


Groups of adult male Sprague Dawley rats (64 rats each) were exposed for 8 months to electromagnetic fields (EMF) of two different field strength combinations: 5microT - 1kV/m and 100microT - 5kV/m. A third group was sham exposed. Field exposure was 8 hrs/day for 5 days/week. Blood samples were collected for hematology determinations before the onset of exposure and at 12 week intervals. At sacrifice, liver, heart, mesenteric lymph nodes, bone marrow, and testes were collected for morphology and histology assessments, while the pineal gland and brain were collected for biochemical determinations. At both field strength combinations, no pathological changes were observed in animal growth rate, in morphology and histology of the collected tissue specimens (liver, heart, mesenteric lymph nodes, testes, bone marrow), and in serum chemistry. An increase in norepinephrine levels occurred in the pineal gland of rats exposed to the higher field strength. The major changes in the brain involved the opioid system in frontal cortex, parietal cortex, and hippocampus. From the present findings it may be hypothesized that EMF may cause alteration of some brain functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3,4-Dihydroxyphenylacetic Acid / metabolism
  • Animals
  • Biogenic Amines / metabolism*
  • Body Weight / drug effects
  • Brain / metabolism*
  • Brain / radiation effects
  • Dopamine / metabolism
  • Dose-Response Relationship, Radiation
  • Electromagnetic Fields*
  • Homovanillic Acid / metabolism
  • Hydroxyindoleacetic Acid / metabolism
  • Male
  • Motor Activity / radiation effects
  • Neurotransmitter Agents / metabolism*
  • Pineal Gland / metabolism
  • Pineal Gland / radiation effects
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D2 / metabolism
  • Receptors, Dopamine D2 / radiation effects
  • Receptors, Opioid, mu / metabolism
  • Receptors, Opioid, mu / radiation effects
  • Serotonin / metabolism
  • Time Factors


  • Biogenic Amines
  • Neurotransmitter Agents
  • Receptors, Dopamine D2
  • Receptors, Opioid, mu
  • 3,4-Dihydroxyphenylacetic Acid
  • Serotonin
  • Hydroxyindoleacetic Acid
  • Dopamine
  • Homovanillic Acid