Effects of chronic exposure to cadmium, lead, and mercury on brain
Effects of chronic (45 days) treatment with different doses of cadmium chloride (0.25 and 1.0 mg/kg/day), methylmercury chloride (0.4 and 4.0 mg/k/day) and lead acetate (0.2 and 1.0 mg/kg/day) and of 28-day withdrawal of treatment on the levels of acetylcholine (ACh) and activity of acetylcholinesterase (AChE) in cerebral cortex, and concentration of norepinephrine (NE) and 5-hydroxytryptamine (5-HT) in brain-stem were examined in rats. Exposure to both cadmium and methylmercury produced significant decreases in cortical ACh and brain-stem 5-HT levels. In addition, brain-stem NE concentration was increased in methylmercury-treated rats. In contrast, chronic treatment with lead resulted in enhanced cerebrocortical ACh levels but a decreased brain-stem NE concentration. Treatment with cadmium also produced a transient enhancement of striatal dopamine levels. Cadmium-induced decrease in brain-stem 5-HT and lead-induced accumulation of cortical ACh persisted even after 28 days withdrawal of treatment. The data indicated that chronic exposure to low doses of heavy metals produces differential changes in regional levels of various brain biogenic amines. These changes may represent the early signs of adverse effects on CNS function since they occur before any overt symptoms of neurotoxic effects of heavy metals become apparent.
- Research Organization:
- Univ. of Ottawa
- OSTI ID:
- 7254554
- Journal Information:
- Res. Commun. Chem. Pathol. Pharmacol.; (United States), Vol. 15:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CADMIUM CHLORIDES
CHRONIC INTAKE
LEAD COMPOUNDS
ORGANIC MERCURY COMPOUNDS
ACETYLCHOLINE
AMINES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ACCUMULATION
BIOLOGICAL EFFECTS
BIOSYNTHESIS
BRAIN
CENTRAL NERVOUS SYSTEM
CEREBRAL CORTEX
CHOLINESTERASE
DOPAMINE
ENZYMES
METALS
METHYLMERCURY
RATS
SEROTONIN
TOXICITY
AMMONIUM COMPOUNDS
ANIMALS
AROMATICS
AZOLES
BODY
CADMIUM COMPOUNDS
CADMIUM HALIDES
CEREBRUM
CHLORIDES
CHLORINE COMPOUNDS
DRUGS
ELEMENTS
ESTERASES
ESTERS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROLASES
HYDROXY COMPOUNDS
INDOLES
INTAKE
KINETICS
MAMMALS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
PHENOLS
POLYPHENOLS
PYRROLES
QUATERNARY COMPOUNDS
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
RESPONSE MODIFYING FACTORS
RODENTS
SYMPATHOMIMETICS
SYNTHESIS
TRYPTAMINES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550500 - Metabolism
550200 - Biochemistry