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 HealthAlbert Szent-Györgyi Medical UniversityDóm tér 10, 6720 Szeged, HungaryTel: 36-62-455-119Fax: 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.