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EFFECTS OF CARBARYL ON THE MOTOR ACTIVITY OF SPONTANEOUSLY HYPERTENSIVE (SHR) AND NORMOTENSIVE (WKY) RATS.
Citation:
MacPhail, R C., J D. Farmer, K A. Jarema, L. Jackson, AND S. Padilla. EFFECTS OF CARBARYL ON THE MOTOR ACTIVITY OF SPONTANEOUSLY HYPERTENSIVE (SHR) AND NORMOTENSIVE (WKY) RATS. Presented at Society of Toxicology, Nashville, TN, March 17-21, 2002.
Description:
SHR rats have been widely used to investigate the etiology and mechanisms of hypertension. Recent evidence suggests SHR rats have an increased sensitivity to cholinesterase inhibitors. In an effort to develop animal models of susceptibility for use in risk assessment, this experiment compared the effects of the carbamate pesticide carbaryl on the motor activity of SHR and WKY rats. Adult male rats of each strain (N=18) were tested daily during 30-min sessions in a photocell device that separately recorded horizontal and vertical activity. Once activity levels stabilized, carbaryl (5-100 mg/kg) was administered p.o. in corn oil, once weekly, 60-min presession to all rats. Baseline motor activity was consistently higher in SHR than in WKY rats; SHR rats also showed no habituation of activity across initial test sessions, in contrast to the WKY rats. Carbaryl produced dose-related decreases in horizontal and vertical activity in SHR rats. Over the same dose range, carbaryl decreased vertical activity but had no effect on the horizontal activity of WKY rats. Determination of cholin-esterase activity in blood showed that activity was higher in SHR than WKY rats after vehicle, but carbaryl (15 mg/kg) produced a comparable degree of inhibition in both strains. Our behavioral results indicate that SHR rats are sensitive to carbaryl and WKY rats are remarkably insensitive to this pesticide.
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