Yoshiaki Kumamoto

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In vivo microdialysis was employed to measure the extracellular concentrations of dopamine (DA) in the medial preoptic area (MPOA) of rats during male sexual activity to look for a correlation with sexual activity. During copulation, the concentration of DA in the MPOA was significantly increased. A significant difference was detected in changes of DA(More)
The effects of long-term psychological stress on sexual behavior and brain catecholamines were investigated in rats. Stress was applied using the communication box developed by Ogawa and Kuwabara (1996), and a psychological stress group (n = 12), a physical stress group (n = 5), and a control group (n = 5) were established. Stress was applied for 1 hour(More)
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited To the Editor Chlamydia trachomatis (CT) infection in pregnancy can cause maternal disease, adverse pregnancy outcomes, and neonatal(More)
As you know, for penile erection, a sufficient amount of testosterone-induced nitric oxide is needed in the smooth muscle of the penile arterial wall. With aging, LOH syndrome and so on, the serum testosterone level decreases, resulting in a decline of penile erectile function. Furthermore, it is known that the enzyme PDE5 in the penile artery wall also(More)
It is reported that some elderly males exhibit both hypospermatogenesis and intratesticular arterial changes. These arterial changes are thought to contribute to spermatogenic damage. In this study the process of the damage to spermatogenesis induced by such changes was evaluated using stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP showed a(More)
The relationship between sexual behavior and long-term stress in male Wistar rats was investigated. Rats were divided into two groups, one of which exposed to electrical foot shock for 1 hour a day for 10 weeks to create physical stress. The other group was exposed to the rats receiving shock to create psychological stress. Rats in both groups were placed(More)
We have reported that sexual behavior of male rats is impaired by long-term psychological stress. We measured dopamine (DA) and its metabolites (3,4-dihydroxyphenylacetic acid, DOPAC, and homovanillic acid, HVA) in the brain of rats which were exposed to the long-term stress. Our experiment was focused on the medial preoptic area (MPOA), which is perhaps(More)
Nocturnal LH pulse was analyzed in 4 prepubertal, 3 early pubertal and 2 midpubertal boys by measuring serum LH concentrations. Blood samples were taken every 30 minutes while awake, and every 20 minutes after subjects had gone to sleep. Serum LH was measured by using immunofluorometric assay (IFMA) with a lower detection limit of 0.02mIU/ml. Pulsatile LH(More)
After an exposure of 24 h to synthetic LHRH (100 ng/ml) in vitro, the anterior pituitaries of 4-day-old rats show a notable loss of immunoreactive material in most LH cells in males, but not in females. When radioimmunoassayed without incubation, the pituitary LH content of 4-day-old female rats is 2.8 times higher than that of males of the same age. LHRH(More)