Altered neuronal densities in sexually dimorphic structures: comparable effects from perinatal magnetic fields with nitric oxide synthase inhibitors and postnatal hypoxia.
Cytometry of the neuronal density within four sexually dimorphic nuclei was completed for adult rats that had been perinatally exposed to 0.5Hz, 5-10nT magnetic fields or sham conditions while their mothers drank tap water containing the nitric oxide synthase (NOS) inhibitor L-NAME or only tap water. One week after birth the rats were rendered hypoxic for 1 min or served as controls. Exposures to either the magnetic field or the NOS inhibitor reduced the numbers of neurons within the bed nucleus of the stria terminalis by about 25%, whereas exposure to either the hypoxia or magnetic fields resulted in comparable decreases in cell numbers within the ventromedial nucleus (dorsomedial part). For comparison males had 15% fewer neurons in these nuclei compared to females. The effect sizes for the interactions involving the perinatal exposure for 8 days to the magnetic fields were comparable to the magnitudes of those associated with 1 min of hypoxia 1 week postnatally. These results show the sensitivity of specific structures of the developing brain to interactions between subtle environmental variables.
McDonald
Karli K
KK
Behavioural Neuroscience Program, Laurentian University, Ramsey Lake Road, Sudbury, Ont., Canada P3E 2C6.
Persinger
Michael A
MA
D000704:Analysis of Variance; D000818:Animals; D002452:Cell Count; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000633:toxicity; D005260:Female; D000860:Hypoxia / Q000503:physiopathology*; D008280:Magnetics; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D012686:Septal Nuclei / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D012727:Sex Characteristics; D014697:Ventromedial Hypothalamic Nucleus / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester