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Ethological methods to study the effects of maternal exposure to estrogenic endocrine disrupters: A study with methoxychlor
No full textThere has been increasing interest, both at the scientific and regulatory level, in the use of ethological methods for evaluating neural effects of endocrine disrupters. We present a series of ethological studies on the effects of maternal exposure to low, environmentally relevant doses (0.02, 0.2, and 2 μg/g mother bw/day) of the estrogenic pesticide methoxychlor (MXC) on behavior. From gestation day 11 to 17, female mice spontaneously drank oil with or without MXC; their maternal behavior was examined from postpartum days 2 to 15. MXC treatment during pregnancy produced slight changes in the expression of maternal behavior: females fed the lower MXC dose spent less time nursing the pups as compared to control dams. Their maternally exposed offspring were subjected to a series of behavioral tests at different ages. Maternal exposure to MXC affected behavioral responses to novelty in both sexes at periadolescence. The onset of male intrasex aggression was delayed in males prenatally exposed to low doses of MXC, since exposed males showed low levels of aggressive interactions during early adolescence but not after they reached adulthood. When adults, MXC-exposed females, but not males showed increased exploration in an unfamiliar open-field. While a sex difference was observed in the control group, with males being significantly more active in the open field than females, prenatal treatment with some MXC doses tended to decrease the sexual dimorphism in activity levels in the novel environment. Ethology, as the evolutionary study of behavior, may provide a framework for integrating a functional perspective (i.e., evolutionary significance) to studies on proximate mechanisms that can account for behavioral alterations induced by developmental exposure to endocrine disrupters. © 2002 Elsevier Science Inc. All rights reserved
Etho-toxicology: an evolutionary approach to the study of environmental endocrine disrupting chemicals.
No full textExposure to very low doses of Endocrine Disrupting Chemicals(EDCs) during fetal life permanently alters brain development and behavior in animals and humans
No full textSelective allocation of parental and infanticidal responses in rodents: a review of mechanisms.
No full textSex-biased impact of endocrine disrupting chemicals on behavioral development and vulnerability to disease: Of mice and children
No full textSex is a fundamental biological characteristic that influences many aspects of an organism's phenotype, including neurobiological functions and behavior as a result of species-specific evolutionary pressures. Sex differences have strong implications for vulnerability to disease and susceptibility to environmental perturbations. Endocrine disrupting chemicals (EDCs) have the potential to interfere with sex hormones functioning and influence development in a sex specific manner. Here we present an updated descriptive review of findings from animal models and human studies regarding the current evidence for altered sex-differences in behavioral development in response to early exposure to EDCs, with a focus on bisphenol A and phthalates. Overall, we show that animal and human studies have a good degree of consistency and that there is strong evidence demonstrating that EDCs exposure during critical periods of development affect sex differences in emotional and cognitive behaviors. Results are more heterogeneous when social, sexual and parental behaviors are considered. In order to pinpoint sex differences in environmentally-driven disease vulnerabilities, researchers need to consider sex-biased developmental effects of EDCs
Effects of prenatal exposure to low doses of the estrogenic chemicals diethylstilbestrol and o',p DDT on aggressive behavior of male and female house mice
No full textExposure to a low dose of Bisphenol A during fetal life or in adulthood alters maternal behavior in mice
No full textMaternal behavior in mammals is the result of a complex interaction between the lactating dam
and her developing offspring. Slight perturbations of any of the components of the mother–infant
interaction may result in alterations of the behavior of the mother and/or of the offspring. We
studied the effects of exposure of female CD-1 mice to the estrogenic chemical bisphenol A (BPA)
during fetal life and/or in adulthood during the last part of pregnancy on subsequent maternal
behavior. Pregnant females were fed daily doses of corn oil (controls) or 10 μg/kg body weight
BPA during gestation days 14–18. As adults, the prenatally treated female offspring were timemated
and again fed either corn oil (controls) or the same doses of BPA on gestation days 14–18,
resulting in four treatment groups: controls, prenatal BPA exposure, adult BPA exposure, and
both prenatal and adult BPA exposure. Maternal behavior was then observed on postnatal days
2–15 and reflex responses were examined in the offspring. Dams exposed to BPA either as fetuses
or in adulthood spent less time nursing their pups and more time out of the nest compared with
the control group. Females exposed to BPA both as fetuses and in adulthood did not significantly
differ from controls. No alterations in postnatal reflex development were observed in the offspring
of the females exposed to BPA. The changes seen in maternal behavior may be the result of
a direct effect of BPA on the neuroendocrine substrates underlying the initiation of maternal
behavior. Key words: development, endocrine disruptors, house mice, maternal behavior, nongenomic
transmission. Environ Health Perspect 110(suppl 3):415–422 (2002)
The effect of bisphenol A on emotional behavior depend upon the timing of exposure, age and gender in mice
No full textAbstract
Experimental evidence suggests that endocrine-disrupting chemicals (EDCs) can permanently disrupt the development of sexually dimorphic behaviors and the structure of sexually dimorphic areas of the brain. EDC exposure has different effects depending on diverse factors, such as the timing and dose of the exposure, the maternal environment and the individual's age and sex. Among EDCs, bisphenol A (BPA) is one of the most studied because of its extensive use, which ranges from dentistry to food/drink packaging. In the present study, we aimed to investigate the behavioral effects of developmental exposure to a low dose of BPA with respect to the timing of the exposure, maternal environment, sex and age at testing. Starting from the last week of pregnancy to the first postpartum week, dams spontaneously drank either corn oil (control group) or a solution containing BPA (10 μg/kg bw/day). At birth, the litters were cross-fostered to different dams to differentiate among the effects of pre- and postnatal exposure. Pre- and postnatally exposed offspring underwent three diverse experimental paradigms for anxiety-related behaviors: as juveniles, a novelty test and at adulthood, both the free exploratory open field and elevated plus maze tests. At both testing ages, pre- and postnatally exposed females showed evidence of increased anxiety and were less prone to explore a novel environment relative to the control females, showing a behavioral profile more similar to control males than females. In this study, the direction of the behavioral changes was affected similarly by the pre- and postnatal exposures, resulting in a disruption of these sexually dimorphic behaviors, although with a greater effect associated with postnatal exposure primarily in females. Our findings indicate that non-reproductive, sexually dimorphic behaviors are sensitive to endocrine disruption during critical developmental periods-particularly the highly critical early neonatal stage. Combined with previous research, our study provides further evidence of the potential risks that even low doses of EDCs may pose to humans, with fetuses and infants being highly vulnerabl
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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