Publications by authors named "Sayaka Asai"

Hatano high- and low-avoidance (HAA and LAA) rats are separated by breeding from Sprague-Dawley rats by high versus low rates of avoidance responses in a shuttle-box task. In addition, compared to HAA rats, LAA rats show lower running-wheel activity, later sexual maturation, 5-day estrous cycling, lower sperm motility, more pronounced immunological reactions, and are generally less reactive to stress. The present study was designed to compare the effects of transmaternal exposure to genistein on these characteristics between HAA and LAA rats.

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Lipids are major structural component of the brain and play key roles in signaling functions in the central nervous system (CNS), such as the hippocampus. In particular, sulfatide is an abundant glycosphingolipid component of both the central and the peripheral nervous system and is an essential lipid component of myelin membranes. Lack of sulfatide is observed in myelin deformation and neurological deficits.

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Methods to study gene expression in live cells over time have been limited. One known method is the luciferase assay, which measures the luminescence of luciferase by coupling its expression to the promoter of a gene under study. This luminescence in cells can be measured over time by a luminometer.

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Article Synopsis
  • - Prolactin has been found to inhibit the development of stress-induced gastric ulcers, but the exact mechanism behind this effect remains unclear.
  • - A study comparing high-avoidance (HAA) and low-avoidance (LAA) rat strains showed that HAA rats had higher plasma levels of ACTH and gastric erosion after stress, while LAA rats had higher prolactin secretion and more prolactin receptor-positive cells in the brain.
  • - These findings suggest that HAA rats are more sensitive to stress and that differences in prolactin secretion and receptor expression may contribute to the varying levels of gastric ulceration between the two strains.
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Objective: To investigate the effects of N-methyl-D-aspartate (NMDA) receptor antagonists on restraint-induced release of prolactin (PRL) in male Wistar rats of different ages.

Design: Rats were implanted with a brain ventricular for icv injection, and with a jugular vein cannula for iv injection. Competitive NMDA receptor antagonist AP-5 and noncompetitive NMDA receptor blocker MK-801 was injected via brain cannula or vein cannula and was restrained for 3 hours.

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Inappropriate exposure to estrogens in the fetal and/or newborn period can exert irreversible influence, including carcinogenesis on the reproductive system in mammals. The present study was conducted to investigate uterine carcinogenesis in Donryu rats treated neonatally with a high-dose estrogenic compound, p-t-octylphenol (OP) for different exposure periods. Female Donryu rats were subcutaneously administered 100 mg/kg/day OP every other day for the first 5 postnatal days (PNDs 1-5) or the first 2 weeks (PNDs 1-15).

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The high- and low-avoidance animals (HAA and LAA rats) were originally selected from Sprague-Dawley rats for their shuttle-box task. Reproductive endocrinology during the estrous cycle was compared between HAA and LAA rats. All HAA rats showed a regular 4-d estrous cycle, whereas most LAA rats (70.

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