Enhanced mortality of rat pups following inductions of epileptic seizures after perinatal exposures to 5 nT, 7 Hz magnetic fields.

While investigating the effects of weak complex magnetic fields upon neuroplasticity following induction of early epilepsy, an unprecedented increase in post-seizure mortality (76%) was observed for young rats that had been exposed perinatally to 7 Hz magnetic fields with maximum intensities around 5 nT. Pups exposed to less intense or more intense fields of this frequency did not display this magnitude of significant mortality. Perinatal exposure through the maternal water supply to either a putative nitric oxide donor or inhibitor did not affect this mortality. The non-linear relationship between perinatal 7 Hz magnetic field intensity and post-seizure mortality may be considered analogous to the non-linear relationship between the molarity of ligands and their sequestering to receptor subtypes. These unexpected results suggest that exposure to apparently innocuous stimuli during early development may affect vulnerability to stimuli presented later in ontogeny.