When new learning occurs against the background of established prior knowledge, relevant information can be assimilated into a schema and thereby expand knowledge base. An animal model this important component memory consolidation reveals that systems very fast. In experiments with rats, we found hippocampal-dependent paired associates is associated striking up-regulation immediate early genes in prelimbic region medial prefrontal cortex, pharmacological interventions targeted at area...

In 2011, a joint World Health Organization (WHO) and United Nations Environment Programme (UNEP) expert consultation took place, during which the possible inclusion of brominated analogues dioxin-like compounds in WHO Toxicity Equivalency Factor (TEF) scheme was evaluated. The panel concluded that polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), some biphenyls (dl-PBBs) may contribute significantly daily human background exposure to total dioxin toxic equivalencies (TEQs)....

The epidermis (containing primarily keratinocytes and melanocytes) overlies the dermis fibroblasts) of human skin. We previously reported that dickkopf 1 (DKK1) secreted by fibroblasts in elicits hypopigmented phenotype palmoplantar skin due to suppression melanocyte function growth via regulation two important signaling factors, microphthalmia-associated transcription factor (MITF) beta-catenin. now report treatment with DKK1 increases their proliferation decreases uptake melanin...

There are large inter- and intraspecies differences in susceptibility to dioxin-induced toxicities. A critical question risk assessment of dioxin related compounds is whether humans sensitive or resistant their The diverse responses mammals strongly influenced by functional polymorphisms the arylhydrocarbon receptor (AHR). To characterize mediated human AHR (hAHR), we generated a mouse possessing hAHR instead AHR. Responses these mice 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD)...

Bisphenol‐A Affects Spermatogenesis in the Adult Rat Even at a Low Dose: Motoharu Sakaue, et al. Environmental Health Sciences Division, National Institute for Studies— (BPA), xenobiotic estrogenic compound widely used as plastics monomer, has been suspected to have so‐called low dose effect on reproductive system when administered transplacentally. In present study, we investigated possible low‐dose effects of BPA spermatogenesis adult rats. Male rats (13 weeks old; W13) were administrated...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an extremely toxic, persistent environmental contaminant that disrupts normal development in laboratory animals. In our earlier study, we found exposure of preimplantation embryos to TCDD markedly induced cytochrome P4501A1 mRNA at the blastocyst stage. present determine whether affects fetal growth, exposed from 1-cell stage and then transferred them unexposed recipient mice. On Embryonic Day 14, fetuses during weighed less than control group....

A single-antibody radioimmunoassay for determining nanogram quantities of rat metallothionein has been developed. This assay advantages over the double-antibody metallothioneins in terms accuracy and expedition. Metallothionein obtained from liver, human kidney even rabbit liver completely cross-reacted with antiserum, whereas crab hepatopancreas did not show any cross-reactivity. With use this was detected plasma urine rats exposed to 5 mumol CdCl2/kg/day, days a week up 15 weeks. The...

Neonicotinoid, a widely-used pesticide group designed to selectively bind insect nicotinic acetylcholine receptors, were considered be relatively safe for mammalian species. However, it has been found activate vertebrate receptors than ever anticipated, and could toxic the brain. In present study, we evaluated developmental neurotoxicity of acetamiprid (ACE), one most-widely used neonicotinoid, in C57BL/6J mice whose mothers administered ACE via gavage at doses either 0 mg/kg (control), 1.0...

Neonicotinoid insecticides that have been on the market since 1992 used globally including in Japan. Because they are sprayed over forests and agricultural areas, inadvertent toxicity nontarget insects (especially honey bees) humans is a matter of public concern. However, information exposure levels potential health impacts neonicotinoids children living around areas scarce. Thus, we determined neonicotinoid communities where thiacloprid was to control pine wilt disease. A total 46 (23 males...

To assess the health risks associated with exposure to 2,3,7,8-tetrachlorodebenzo-p-dioxin (TCDD), we studied effects of a relatively low dose TCDD on male reproductive system rats, using experimental protocol T. A. Mably et al. (1992, Toxicol. Appl. Pharmacol. 114, 97–107, 108–117, 118–126), and searched for most sensitive reliable among several indices toxicity. Pregnant Holtzman rats were given single oral 0, 12.5, 50, 200, or 800 ng TCDD/kg body weight gestational day (GD) 15, offspring...

Metallothionein (MT) is a low molecular mass protein inducible by heavy metals such as cadmium (Cd), zinc, and copper, having high affinity for these metals. In the present study, we investigated immunohistological localization of MT in brains rats mice. adult rat brain, almost no immunostaining was observed, whereas mouse brain strong found ependymal cells, some glial arachnoid, pia mater. No detected neurons endothelial cells. younger (1-3 weeks old), observed choroid plexus epithelium,...

Metallothionein (MT) is a cysteine-rich, low molecular weight protein inducible by heavy metal ions and various endogenous factors. Using an indirect immunofluorescent technique, we studied the localization of MT in developing rat tissues (kidney, small intestine, liver). In kidney neonate fetus, was found both cytoplasm nucleus renal tubular epithelia. Localization changed with shift zonation cortex during development. mainly inner zone but not tubules neogenic on Day 4. Until 18, cells...

Epidemiological and laboratory studies suggested that exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects glucose homeostasis increases the incidence of type 2 diabetes mellitus. To evaluate effects TCDD on insulin secretion from islets Langerhans (islets), we designed in vivo, ex vivo vitro experiments. For experiment, male C57BL/6J aryl hydrocarbon receptor (AhR)-null mice were injected intraperitoneally with (10 microg kg(-1) b.w.), fasted for 12 h administered 24...

An increasing prevalence of mental health problems has been partly ascribed to abnormal brain development that is induced upon exposure environmental chemicals. However, it extremely difficult detect and assess such causality particularly at low levels. To address this question, we here investigated higher function in mice exposed dioxin utero via lactation by using our recently developed automated behavioral flexibility test immunohistochemistry neuronal activation markers Arc, the 14...

Although di(n-butyl) phthalate (DBP), a suspected endocrine disruptor, induces testicular atrophy in prepubertal male rats, whether it exerts estrogenic activity vivo remains matter of debate. In the present study, we explored potency DBP using 3-week-old and then examined relationship between estrogen-induced spermatogenic cell apoptosis steroidogenesis. Daily exposure to for 7 days caused due loss cells, whereas steroidogenesis was almost same with control values. A single decreased...

Bisphenol A (BPA), a widely used raw component of polycarbonate plastics and epoxy resins, has been reported to induce developmental neurotoxicity in offspring born dams exposed low doses BPA; however, the toxicity mechanism remains elusive. To study effects utero BPA exposure on neuronal morphology, we studied spine density dendritic growth hippocampal CA1 aged mice developing prenatally BPA. Pregnant were orally administered at dose 0, 40, or 400 μg/kg body weight/day gestational days...

Rodent models have been widely used to investigate the impact of early life stress on adult health and behavior. However, social dimension has rarely incorporated into analysis due methodological limitations. This study characterized effects neonatal isolation (early deprivation, ED) C57BL/6 mouse behavior in a context using our recently developed behavioral test protocols for group-housed mice. During first two postnatal weeks, half pups per dam were separated from their littermates 3 h day...

Aryl hydrocarbon receptor (AhR), a member of the basic helix-loop-helix-Per-Arnt-Sim transcription factor family, plays critical role in developing nervous system invertebrates and vertebrates. Dioxin, ubiquitous environmental pollutant, avidly binds to this receptor, maternal exposure dioxin has been shown impair higher brain functions dendritic morphogenesis, possibly via an AhR-dependent mechanism. However, there is little information on AhR expression mammalian brain. To address issue,...