The method of conditioned reflexes in toxicology and its application for determining the toxicity of small quantities of pesticides

Effect of dieldrin on auditory detection behavior and central auditory mechanisms in sheep

“…Ammonia was found to be liberated in the brain prior to the onset and during convulsive seizure. Alpha-ketoglutarate, glutamate, pyru vate, and alanine are necessary in the binding mechanism of ammonia, there fore, the possible blockade of glutamine synthesis by the brain during diel drin intoxication has been suggested (Hathway and Mallinson, 1964 An investigation conducted to assess the influence of aldrin and dieldrin upon conditioned reflexes in cats has been reported (Medved e^ , 1964). They found disruption occurred early in intoxication, and following repetitive low level exposure cyclic disturbances in conditioned reflexes…”

The effect of exposure to dieldrin on avoidance response extinction and conditioned heart rate in sheep

“…That is, the high dosage groups, ran slowest. Medved, Spynu, and Kagan (1964) reported that investiga tions on the effect of Dieldrin on classically conditioned responses reveal a disruption in the latency of the CE. Some animals show an increased-latency, while others show a de creased latency.…”

Auditory detection behavior in parathion treated squirrel monkeys

“…It is important to know whether mental effects may precede more dis abling signs and symptoms of intoxication or whether such neurologic effects may take place in the complete absence of clinical toxicosis. Sev eral investigations reviewed by Medved et al (1964) have shown that changes in conditioned behavior become evident with a chronic 40-60 percent inhibition of serum and erythrocyte cholinesterases. The chronic lowering of brain cholinesterase concentration below a "critical level" of 60-65 percent of normal has been shown to markedly affect extinction of condi tioned avoidance behavior in male white rats (Russell £t , 1961).…”

“…The possibility that behavioral changes free from somatic symptoms may occur after prolonged low-level organophosphate exposure is expressed by Bignami and Gatti (1967), Medved et al (1964), and Lewis et al (1973).…”