Article

Effect of estradiol and progesterone on rat striatal dopamine uptake sites.

School of Pharmacy, Laval University, Québec, Québec, Canada.
Brain Research Bulletin (Impact Factor: 2.97). 10/1990; 25(3):419-22. DOI: 10.1016/0361-9230(90)90231-N
Source: PubMed

ABSTRACT Striatal dopamine (DA) uptake sites labelled with [3H]GBR-12935 binding were investigated in ovariectomized (OVX) rats acutely treated with 17 beta-estradiol (E2) or progesterone (P). One injection of E2 (100 ng, SC) to OVX rats increased plasma levels of this steroid after 15 min while plasma prolactin (PRL) levels remained unchanged. The E2 injection left striatal [3H]GBR-12935 binding affinity unchanged while the maximum density increased 15 and 30 min after the injection (+24% and +18%, respectively). One injection of P (110 micrograms, SC) to OVX rats increased this steroid plasma level from 15 to 120 min while plasma PRL levels remained unchanged. [3H]GBR-12935 binding density and affinity remained unchanged up to 120 min after the injection. Thus, acutely, E2 but not P, modulated striatal DA uptake sites in OVX rats. The effect of E2 appeared in coincidence with the peak of this steroid plasma concentration. This increase was rapid and is probably nongenomic and suggests a causal effect relationship as well as a presynaptic site of action of E2.

0 Bookmarks
 · 
43 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Chemosphere 10/2014; 112C:496-502. DOI:10.1016/j.chemosphere.2014.05.035 · 3.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Women and female rodents are more responsive to the subjective effects of psychostimulant drugs of abuse compared to males. A growing body of literature supports a role for estradiol as a mechanism underlying these sex differences. However, little is known about the influence of acute elevations in levels of estradiol on drug conditioned behaviors. The aim of the present study was to evaluate the influence of an acute increase in systemic estradiol levels on the expression of cocaine conditioned place preference (CPP). Using a six day conditioning procedure, ovariectomized (OVX) female rats were conditioned with one of four doses of cocaine (2.5, 5, 10, or 15 mg/kg) to associate one of two large chambers of a CPP apparatus with cocaine or saline. Thirty minutes prior to the start of the CPP preference test, rats were pretreated with either 5 μg estradiol benzoate (EB) or peanut oil (PO). PO-treated rats expressed a significant preference for only the mid-range conditioning doses of cocaine (5 and 10 mg/kg). However, acute EB treatment resulted in a rightward shift in the cocaine dose-response curve; rats demonstrated a significant preference at only the moderate and high conditioning doses of cocaine (10 and 15 mg/kg). These findings demonstrate that acute elevations in estradiol may dampen the expression of conditioned responses to cocaine's secondary rewards at lower conditioning doses of the drug and facilitate CPP at higher doses while estradiol deficiency decreases the threshold dose of cocaine necessary to induce CPP.
    Brain research bulletin 04/2014; DOI:10.1016/j.brainresbull.2014.02.002 · 2.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A large number of chemical pollutants including phthalates, alkylphenolic compounds and organochlorine pesticides have the ability to disrupt endocrine function in animals, and alter cog-nitive function. Because hormone mediated events play an important role in central nervous system development and function, the changes in cognitive function seem to be mediated by the endocrine-like action of these chemicals. The present study therefore was designed to investigate effect of bisphenol A (BPA), an endocrine disrupting chemical on neuro-behavial patterns, and expression of estrogen receptors and tyrosine hydroxylase, a limiting enzyme of dopamine synthesis pathway. BPA was treated orally for 3 weeks into 3 week old mice, and then the neuro-behavial patterns (stereo-type behaviors such as jumping rearing and forepaw tremor, climbing behavior, tail flick, rotarod and locomotor activity), and the expression of estrogen receptors and tyrosine hydroxylase were deter-mined every 3 week for 9 weeks. During the treatment of BPA, the food uptake and body weight increase were not significantly changed. BPA resulted in the increased stereotype behaviors (jump-ing, rearing and forepaw tremor) 6 or 9 weeks after treatment. The time response to tail flick and locomotor activity were decreased by the treatment of BPA, whereas the time for rotarod was increased by the treatment of BPA. The expression of estrogen receptor alpha and beta was increased in the brain and pituitary gland. Maximum expression was found in the brain after 9 week of 100 mg/kg BPA treatment and in the pituitary gland after 6 week of 100 mg/kg BPA treatment. Tyrosine hydroxylase was increased in dose and time dependent manners in the brain but no change was found in the pituitary gland. The present data show that exposure of BPA in the young mice could alter expression of estrogen receptors and dopamine synthesis pathway, thereby modulate neuro-behavial patterns (increase of stereotype behaviors but decrease locomotor activity).
    01/2004; 20(3).