ABSTRACT
Pyrethroids are insecticides extensively used to control pests around houses as well as in agriculture. It has been suggested that type II pyrethroids may act on GABA receptors as benzodiazepine antagonists. Because benzodiazepines are used in anxiety, the present study was undertaken to investigate the possible anxiogenic effects of fenvalerate, a type II pyrethroid, in rats. Behavior in the open-field, social interaction, plus-maze behavior, and one-way passive avoidance were studied in rats orally treated with 1, 10, or 30 mg/kg fenvalerate. This pyrethroid reduced locomotion and rearing frequencies and increased immobility duration. Ten and 30 mg/kg of fenvalerate reduced social interaction, whereas the 1 mg/kg dose had no effect on this behavior. Fenvalerate administration did not change the plus-maze behavior of rats. Pretraining administration (1, 10, and 30 mg/kg) did not modify the behavior of rats during the training session of a passive avoidance task, while in the test session 10 mg/kg fenvalerate caused an increase in the crossing latency, and the 30 mg/kg dose reduced this parameter and increased the percent of animals crossing to the shock compartment. The behavioral alterations observed in this study suggest that fenvalerate has an anxiolytic effect on rats.
Subject(s)
Anxiety/chemically induced , Anxiety/psychology , Insecticides/pharmacology , Pyrethrins/pharmacology , Animals , Avoidance Learning/drug effects , Electroshock , Interpersonal Relations , Male , Motor Activity/drug effects , Nitriles , Rats , Rats, Wistar , Salivation/drug effects , Tremor/chemically induced , Tremor/psychologyABSTRACT
The effects of maternal exposure to fenvalerate during the prenatal and postnatal periods of sexual brain differentiation were studied in adult male offspring. Behavioral (open field, stereotyped, and sexual behaviors), physical (sexual maturation, body and organ weights), endocrine (testosterone levels), and neurochemical (striatal and hypothalamic monoamine and respective metabolite levels) data were assessed. The results showed that there was no change in the age of testis descent or testis weight, nor were there changes in monoamine levels or stereotyped behavior. However, there were significant reductions in ductus deferens and seminal vesicle weights and plasma testosterone concentrations. In addition, treated offspring showed decreased male sexual behavior and increased immobility in the open field. These results indicate that perinatal exposure to fenvalerate during the critical periods of male brain sexual differentiation has long-term effects on the reproductive physiology and behavior of male rats.