Brain monoaminergic neurotransmission parameters in weanling rats after perinatal exposure to methylmercury and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153).
The individual and joint effects of methylmercury (MeHg; 1 mg/kg body weight/day, GD7-PND7) and PCB153 (20 mg/kg body weight/day, GD10-GD16), administered orally to rat dams, were explored in 21-day-old rat offspring brain in terms of monoamine oxidase B (MAO-B) activity and regional content of dopamine (DA), serotonin (5-HT), 5-hydroxy-indole-3-acetic acid (5-HIAA) and homovanillic acid (HVA). Neither treatment altered MAO-B in striatum, hippocampus, cerebellum and cerebral cortex of female pups. In males the cerebellum displayed a significantly reduced enzyme activity (25-45%) following all treatments. Concerning biogenic amines, 5-HT levels were decreased by 30-50% in the cerebral cortex of males and females by PCB153 alone and combined with MeHg, without changes in 5-HIAA and dopaminergic endpoints. In cerebellum of all pups, MeHg enhanced 5-HIAA levels, whereas PCB153, either alone or combined with MeHg, did not affect this endpoint. In striatum, PCB153 reduced the content of DA, HVA and 5-HIAA (respective control values: 2-3; 60-80; 8-10 ng/mg protein) to a similar extent when administered alone or together with MeHg (20-40%). Perinatal exposure to MeHg and/or PCB153 results in regionally and/or gender-specific alterations in the central dopaminergic and serotonergic systems at weaning. The combined treatment with MeHg and PCB153 does not exacerbate the neurochemical effects of the individual compounds.
Castoldi
Anna F
AF
IRCCS Maugeri Foundation, Toxicology Division, Research Centre, Via Palestro 26, 27100 Pavia, Italy. acastoldi@fsm.it
Blandini
Fabio
F
Randine
Giovanna
G
Samuele
Alberta
A
Manzo
Luigi
L
Coccini
Teresa
T
D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects*; D005260:Female; D008297:Male; D008767:Methylmercury Compounds / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley
D008767:Methylmercury Compounds; D018377:Neurotransmitter Agents; D011078:Polychlorinated Biphenyls; C014024:2,4,5,2',4',5'-hexachlorobiphenyl