Effect of 17β-estradiol on striatal dopaminergic transmission induced by permethrin in early childhood rats.

A positive effect of estrogen treatment has been observed in neurodegenerative diseases such as Parkinson's disease. Since 17β-estradiol can modulate positively dopaminergic system, here we sought to evaluate the effect of 17β-estradiol supplementation on an animal model developing dopaminergic alterations on nucleus of striatum after neonatal exposure to permethrin pesticide. The goal of the study was to verify if the co-treatment with 17β-estradiol could protect against the damage induced by pesticide exposure in early life. Permethrin treated rats showed a decrease of dopamine and Nurr1 gene expression in striatum, while a more pronounced decrease of dopamine was observed in rats co-administered with permethrin+17β-estradiol. No difference between control and permethrin treated rats was observed in both mRNA of ERα and ERβ, whereas the rats co-administered with permethrin+17β-estradiol showed a down-regulation of ERα expression. The in vitro studies showed that permethrin, at high concentration may have an antagonist effect on ERα and even more pronounced in ERβ, thus suggesting that permethrin may block the estrogen neuroprotective effects. In conclusion, in male rats, the administration of estrogen further enhanced the impairment of dopaminergic transmission due to exposure to permethrin.