Subchronic Exposure to Methylmercury in Male Wistar Rats:
Effects on Neurobehavioral Performance
Tünde Vezér and András Papp
Department of Public Health, University of Szeged, Hungary
Corresponding author: Tünde Vezér
Department of Public Health
University of Szeged
Dóm tér 10.
H-6720 Szeged, Hungary
Telephone: +36-62-545-119
Fax number: +36-62-545-120
E-mail address: vezer@puhe.szote.u-szeged.hu
CEJOEM 2002, Vol.8. No.2–3.:131–141
Key words:
Methylmercury, spatial learning, locomotor activity, sensorimotor performance, rat
Abstract:
Humans are exposed to mercury by industrial emission, dental fillings, use of mercury-based
fungicides and bactericides, and via food. Mercury exposure results in altered behavioral,
cognitive, coordinative, and emotional functions of humans and animals. Cognitive behavior, open
field activity and psychomotor performance was studied in young adult male Wistar rats treated
subchronically with methylmercury (II) chloride (0.5 and 2.0 mg/kg b.w.) per os by gavage. Spatial
learning of the animals, investigated in a maze, was altered, demonstrated by lower performance in
short-term, long-term and reference memory compared to the controls. Depending on the dose and the
length of treatment, the number of animals making mistakes and the number of errors per animal was
increasing. In the open field test, the treated rats showed decreased locomotor activity and
diminished spontaneous exploratory activity. The changes seen in the methylmercury-treated rats
were similar to those found in exposed humans which stresses the importance of monitoring and
control of direct and indirect environmental exposure.
Received: 3 July 2002
Accepted: 12 September 2002
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