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Title: Effects of chronic exposure to cadmium, lead, and mercury on brain

Abstract

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.

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Ottawa
OSTI Identifier:
7254554
Resource Type:
Journal Article
Journal Name:
Res. Commun. Chem. Pathol. Pharmacol.; (United States)
Additional Journal Information:
Journal Volume: 15:3
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; 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

Citation Formats

Hrdina, P D, Peters, D A.V., and Singhal, R L. Effects of chronic exposure to cadmium, lead, and mercury on brain. United States: N. p., 1976. Web.
Hrdina, P D, Peters, D A.V., & Singhal, R L. Effects of chronic exposure to cadmium, lead, and mercury on brain. United States.
Hrdina, P D, Peters, D A.V., and Singhal, R L. 1976. "Effects of chronic exposure to cadmium, lead, and mercury on brain". United States.
@article{osti_7254554,
title = {Effects of chronic exposure to cadmium, lead, and mercury on brain},
author = {Hrdina, P D and Peters, D A.V. and Singhal, R L},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/7254554}, journal = {Res. Commun. Chem. Pathol. Pharmacol.; (United States)},
number = ,
volume = 15:3,
place = {United States},
year = {1976},
month = {11}
}