Effects of long-term treatment with methyl mercury on the developing rat brain

Journal Article · Sun Dec 01 00:00:00 EST 1991 · Environmental Research; (United States)

DOI:https://doi.org/10.1016/S0013-9351(05)80005-2· OSTI ID:7159280

Lindstroem, H; Luthman, J; Olson, L ^[1]; Oskarsson, A; Sundberg, J ^[2]

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1. Karolinska Inst., Stockholm (Sweden)
2. National Food Administration, Uppsala (Sweden)

Sprague-Dawley rats were exposed to low doses of methyl mercury (3.9 mg mercury/kg diet), via their dams during gestation and lactation and directly via their diet until sacrifice at 50 days postpartum, in order to study possible detrimental effects on CNS development. The methyl mercury exposure of the rats resulted in a brain concentration of 1.45 {plus minus} 0.06 mg mercury/kg wet weight (mean {plus minus} SEM). No general toxic effects were observed; body weight was not affected, brain weight was only slightly increased. No discernible general morphological alterations were seen in the brain as evaluated using cresyl violet histology. Furthermore, no effects on GFA-positive astrocytes in brain sections were observed and computerized morphometry of smeared astrocytes from frontal cortex, hippocampus, and cerebellum did not reveal any effects of the methyl mercury treatment. The noradrenaline (NA) and dopamine (DA) systems were also studied. In cerebellum the NA levels were increased whereas in other regions analyzed NA and DA levels were unchanged. Thus, long-term low-dosage exposure of methyl mercury in rats during development does not appear to exert any major effects on the morphological maturation of neurons and astrocytes. However, the results indicate the effects may occur in specific transmitter-identified systems, such as the NA input to cerebellum.

• OSTI ID: 7159280
• Journal Information: Environmental Research; (United States), Vol. 56:2; ISSN 0013-9351
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BRAIN
ONTOGENESIS
METHYLMERCURY
TOXICITY
CHRONIC EXPOSURE
DIET
DOPAMINE
ECOLOGICAL CONCENTRATION
LACTATION
NORADRENALINE
PRENATAL EXPOSURE
RATS
ADRENAL HORMONES
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
DRUGS
HORMONES
HYDROXY COMPOUNDS
MAMMALS
MERCURY COMPOUNDS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
RODENTS
SYMPATHOMIMETICS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology