Dynamics of Central and Peripheral Evoked Electrical Activity in the Nervous System of Rats Exposed to Xenobiotics

András Papp, László Pecze, and Tünde Vezér

Department of Public Health, University of Szeged Faculty of Medicine, Szeged, Hungary

Corresponding author: András Papp
    Department of Public Health
    University of Szeged Faculty of Medicine
    Dóm tér 10.
    H-6720 Szeged, Hungary
    Telephone: +36-62-545-119
    Fax number: +36-62-545-120
    E-mail: ppp@puhe.szote.u-szeged.hu

CEJOEM 2004, Vol.10. No.1.: 52–59

Key words:
Cortical evoked potential, nerve action potential, heavy metals, rat

Abstract:
The complex chemical pollution of our environment results in mass human exposure to a number of proved or supposed neurotoxicants. In most cases, there are no overt symptoms of nervous system damage, thus new sensitive indicators of the resulting functional alterations still need to be worked out. Various forms of evoked electrical activity of the central and peripheral nervous system are routinely recorded in experimental animals and in humans, and are known to be sensitive to damaging influences. In the present work, male Wistar rats (300–350 g body weight) were acutely or subchronically treated with various neurotoxic heavy metals and dynamic alterations in different forms of evoked activity (somatosensory cortical evoked potentials and peripheral nerve action potential) were observed.
A series of 50 stimuli was applied and the first and last five evoked responses were averaged. The changes in the amplitude and latency of the responses over the series (last 5 vs. first 5) and the dependence of this difference on the frequency of stimulation were calculated. It was found that several of these variables, e.g., the amplitude of the cortical evoked response, were sensitive and dose-dependent indicators of the nervous system damage caused by the heavy metal exposure. On the basis of our results, new, easy to use functional tests for detection and follow-up of nervous system damage of environmental origin could be developed.

Received: 19 September 2003
Accepted: 1 December 2003

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