Electrophysiological biomarkers of an organophosphorous pesticide, dichlorvos

The correlations between the relatively low level, chronic dichlorvos (DDVP ) treatment and the early electrophysiological changes were investigated in three series of experiments. In the first series, male Wistar rats were or ally given daily by gavage 0.98, 1.96 and 3.92 mg/kg of DDVP for 4, 8, or 1 2 weeks, and recordings were made at the end of each period. In the second one, the male and female rats of three consecutive generations were treated with the same doses, the investigated parameters were recorded at the age of 12 weeks of the male animals. In the third experiment, the doses were ad ministered in different stages of development: during pregnancy, pregnancy + lactation, pregnancy + lactation + postweaning, and the: electrophysiolog ical markers were recorded also at the age of 12 weeks of male offspring. T he analyzed elecrophysiological parameters were: electrocorticogram, sensor ic cortical evoked potentials, conduction velocity and refractory periods o f peripheral nerve. The data showed that the relatively low level dichlorvo s exposure caused dose-, duration-, generation-, developmental stage-depend ent and partly significant alterations in all the investigated electrophysi ological parameters. The analyzed functional parameters proved to be sensit ive biomarkers of the exposure as they were changed by the lower doses, whi le the brain cholinesterase activity was considerably inhibited only in the groups given the highest dose. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.