Behavioural and Electrophysiological Changes Caused by Subchronic Lead Exposure in Rats

László Nagymajtényi, Horst Schulz, András Papp and Illés Dési

Department of Public Health, Albert Szent-Györgyi Medical University and
WHO Collaborating Centre for Chemical Safety, Szeged, Hungary
 
Corresponding author: László Nagymajtényi,MD, Ph.D.
Department of Public Health
Albert Szent-Györgyi Medical University
Dóm tér 10, 6720 Szeged, Hungary
Tel: 36-62-455-119
Fax: 36-62-455-120
E-mail: nml@puhe.szote.u-szeged.hu

CEJOEM 1997, 3:195-209


Key words:
Lead acetate, open field behaviour, electrocorticogram, cortical evoked potentials, conduction velocity, refractory period, rat
Abstract:
Male Wistar rats were treated per os through gavage with 80.0, 160.0 and 320.0 mg/kg lead (in form of lead acetate) for 4, 8 and 12 weeks. The changes of certain behavioural features (exploratory horizontal and vertical ambulation scores, grooming in an open field situation) as well as of some parameters of the spontaneous (electrocorticogram, ECoG) and evoked electrical activity in the somatosensory, visual and auditory cortical foci, and also the conduction velocity and refractory periods of peripheral nerve were analyzed. Treated animals showed a significant time-dependent reduction of horizontal exploratory activity and a dose- and time-dependent reduction of grooming behaviour. The electrophysiological data showed that each investigated parameter changed in a dose- and time-dependent manner: increased mean ECoG frequencies accompanied by decreased mean amplitudes, lengthened latencies and durations of evoked potentials, decreased conduction velocity and increased refractory periods were observed. By the end of the 12-week treatment period, changes were significant in the highest, or in the two higher dose groups. The results suggest that the subchronic, low-level exposure by lead has, after a 4 to 12-week treatment, clear effects on behaviour as well as on spontaneous and evoked electrical activity of the rats’ nervous system.
Received: 25 July 1997
Accepted: 11 August 1997

Posted: 25 November 1997

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