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ACUTE EFFECTS OF AMITRAZ ON THE ACOUSTIC STARTLE RESPONSE AND MOTOR ACTIVITY
Citation:
Crofton, K., V. Boncek, AND L.W. Reiter. ACUTE EFFECTS OF AMITRAZ ON THE ACOUSTIC STARTLE RESPONSE AND MOTOR ACTIVITY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/468 (NTIS PB91115998), 1989.
Description:
To characterize further the behavioral toxicity of amitraz, comparisons were made between the effects of amitraz on motor activity, the acoustic startle response, body temperature, and body weight in male Long-Evans rats. cute dosage-effect and time-course determinations of motor activity were made using figure-eight mazes. osage-effect and time-course determinations for the acoustic startle response were measured using a 13 KHZ, 120 dB(A), 40 ms tone as the eliciting stimulus, at each of three background white-noise levels (45, 60 and 75 dB). mitraz (0, 25, 50, 100 or 200 mg kg-1) was administered orally in 1.0 ml kg-1 of the vehicle 90 by volume). mitraz produced a dosage- and time-dependent decrease in motor activity which lasted from to 4 to 96 h post-administration. he effects of amitraz on the acoustic startle response consisted of an increased latency and a decreased amplitude and sensitization. The time-course of effects on the acoustic startle response were more transient (4-24 h) than the effects on motor activity. mitraz-exposed animals had decreased body weight that did not return to control levels until 120 h (five days) post-administration. mitraz administration produced a transient (4 h) dosage-dependent decrease in body temperature. he highest dosage of amitraz administered, 200 mg kg-1, produced 65% mortality within 72 h; 100 mg kg-1 was the lowest dosage that produced mortality (8%). ignificant behavioral effects were seen at dosages as low as 25-50 mg kg-1. hese data provide quantitative measures of the acute effects of amitraz following oral administration on sensory/motor systems in the rat.