ERG Measurement in Toxicity Studies in Beagles

Abstract

In order to study their use in toxicity studies, electroretinograms (ERGs) were measured in conscious beagles treated orally with ethambutol at a dosage of 500 mg/kg/day (250 mg/kg b.i.d.) for 7 days. The tapetum lucidum was discolored and ERGs showed slightly lowered amplitude or prolonged peak latency in the a-wave and b-wave. No remarkable changes were observed in behavior suggesting disorder of visual function. Tapetal discoloration did not change but the changes in the ERG recovered 4 weeks after withdrawal. To measure the ERG in conscious beagles it is necessary to keep the animals quiet because of interruption by the noise from moving eyes or legs. Our results indicated the possiblity of using ERGs in toxicity studies and the necessity of accumlating background data.