title: Effects of chronic manganese exposure on cognitive and motor functioning in non-human primates.
abstract: Acute exposure to manganese is associated with complex behavioral/psychiatric signs that may include Parkinsonian motor features. However, little is known about the behavioral consequences of chronic manganese exposures. In this study, cynomolgus macaque monkeys were exposed to manganese sulfate (10-15 mg/kg/week) over an exposure period lasting 272+/-17 days. Prior to manganese exposure, animals were trained to perform tests of cognitive and motor functioning and overall behavior was assessed by ratings and by videotaped analyses. By the end of the manganese exposure period, animals developed subtle deficits in spatial working memory and had modest decreases in spontaneous activity and manual dexterity. In addition, stereotypic or compulsive-like behaviors such as compulsive grooming increased in frequency by the end of the manganese exposure period. Blood manganese levels measured at the end of the manganese exposure period ranged from 29.4 to 73.7 micro g/l (mean=55.7+/-10.8 (compared to levels of 5.1-14.2 micro g/l at baseline (mean=9.2+/-2.7)), placing them within the upper range of levels reported for human environmental, medical or occupational exposures. These results suggest that chronic exposure to levels of manganese achieved in this study may have detrimental effects on behavior, cognition and motor functioning.
authors.affiliation: Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 521 JAH, Philadelphia, PA 19107, USA. jay.schneider@jefferson.edu
authors.forename: Jay S
authors.initials: JS
authors.lastname: Schneider
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Decamp
authors.forename: Amy Jo
authors.initials: AJ
authors.lastname: Koser
authors.forename: Stephanie
authors.initials: S
authors.lastname: Fritz
authors.forename: Heather
authors.initials: H
authors.lastname: Gonczi
authors.forename: Tore
authors.initials: T
authors.lastname: Syversen
authors.forename: Tomás R
authors.initials: TR
authors.lastname: Guilarte
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology*; D002908:Chronic Disease; D003072:Cognition Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology*; D004195:Disease Models, Animal; D004409:Dyskinesia, Drug-Induced / Q000175:diagnosis / Q000503:physiopathology*; D007859:Learning Disabilities / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D008252:Macaca fascicularis; D008297:Male; D017895:Manganese Compounds; D020149:Manganese Poisoning / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D008569:Memory Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D019957:Motor Skills Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D009483:Neuropsychological Tests; D016273:Occupational Exposure; D013431:Sulfates / Q000633:toxicity; D013995:Time
chemical_list: D017895:Manganese Compounds; D013431:Sulfates; C039798:manganese sulfate