[Visual evoked potentials (FVEP) after the prenatal exposure to heavy metals--experimentals studies].

PURPOSE

To find out, if any and how deep alterations in visual tract are due to prenatal intoxication by heavy metals such as: cadmium (Cd), lead (Pb), mercury (Hg) and manganese (Mn). The measure of these alterations were the changes in flash visual evoked potentials after prenatal intoxication.

MATERIAL AND METHODS

The experiments were carried out on 55 white newborns Wistar rats, which were divided into 5 groups: control group (14 rats), Cd group (12), Pb (6), Hg (14) and Mn (9). The method of the FVEP study was described by Pojda et al.

RESULTS

The latencies of the peaks N1 and P1 were prolonged in the Mn group till 113-118% (p< 0.05). Slight prolongation of N1 latencies about 1% in Cd and Hg groups and of 4% in Pb group were not statistically significant. The differences of P1 latencies were not statistically significant in these groups, compared to the control group. The amplitude of N1 wave decreased in Cd group about 63% and in Mn group of 32% compared to the control (p<0.05). In Hg intoxicated group the N1 amplitude decreased to 56% (p< 0.01). The amplitude of P1 decreased in all intoxicated groups (Hg of 56%, Cd 55%, Mn 49%) statistically significant, except the Pb one, in which even 21% decrease was not significant.

CONCLUSIONS

The heavy metals prolonged the latencies and diminished the amplitudes of flash visual evoked potentials, so may be, they are not only neurotoxic but also "ophthalmotoxic" factors.