Geophysical Variables and Behavior: XI. Open-Field Behaviors in Young Rats Exposed to an ELF Rotating Magnetic Field

Abstract

Male and female albino rats 27 days of age were exposed to a 0.5-Hz rotating magnetic field (RMF) (2-30 gauss) for 21 days. Both experimental and control rats were tested in an open-field apparatus prior to imposition of experimental conditions, at 7, 15, and 21 days after the start of the experiment, and a final test occurred 3 days after the magnets were removed from the RMF apparatus. Male rats increased their activity levels and decreased their latency to ambulate in the open field, relative to control rats. The female experimental rats did not differ from controls on these measures. Both male and female RMF-exposed rats defecated less than control rats. Effects on latency and activity were still evident 3 days after removal of the magnets. These results indicate that exposure to a 0.5-Hz RMF makes rats less emotionally reactive to novel situations. It is suggested that these effects may be mediated by an effect of the RMF on the pineal gland.