Oxytocin Influences Male Sexual Activity via Non-synaptic Axonal Release in the Spinal Cord

Oxytocinergic neurons in the paraventricular nucleus of the hypothalamus that project to extrahypothalamic brain areas and the lumbar spinal cord play an important role in the control of erectile function and male sexual behavior in mammals. The gastrin-releasing peptide (GRP) system in the lumbosacral spinal cord is an important component of the neural circuits that control penile reflexes in rats, circuits that are commonly referred to as the “spinal ejaculation generator (SEG).” We have examined the functional interaction between the SEG neurons and the hypothalamo-spinal oxytocin system in rats. Here, we show that SEG/GRP neurons express oxytocin receptors and are activated by oxytocin during male sexual behavior. Intrathecal injection of oxytocin receptor antagonist not only attenuates ejaculation but also affects pre-ejaculatory behavior during normal sexual activity. Electron microscopy of potassium-stimulated acute slices of the lumbar cord showed that oxytocin-neurophysin-immunoreactivity was detected in large numbers of neurosecretory dense-cored vesicles, many of which are located close to the plasmalemma of axonal varicosities in which no electron-lucent microvesicles or synaptic membrane thickenings were visible. These results suggested that, in rats, release of oxytocin in the lumbar spinal cord is not limited to conventional synapses but occurs by exocytosis of the dense-cored vesicles from axonal varicosities and acts by diffusion—a localized volume transmission—to reach oxytocin receptors on GRP neurons and facilitate male sexual function

Effects of mild calorie restriction and high-intensity interval walking in middle-aged and older overweight Japanese

We investigated whether a combination of mild calorie restriction (MCR) and high-intensity interval walking (HIW) improved physical fitness more than HIW alone in middle-aged and older overweight Japanese (40-69 years old, BMI >= 23.6 kg/m(2)). Forty-seven women and 16 men were divided into MCR + HIW and HIW groups. All subjects performed HIW: >= 5 sets of 3-min low-intensity walking (40% peak aerobic capacity for walking, VO2peak) and 3-min high-intensity walking (>= 70% VO2peak) per day, >= 4 days per week, for 16 weeks while energy expenditure was monitored with a tri-axial accelerometer. The MCR + HIW group consumed meal replacement formula (240 kcal): a mixture of low-carbohydrates and -fat and high-protein, for either lunch or dinner everyday and therefore, had similar to 87% of the energy intake of the HIW group during the intervention period. Although the HIW group showed improvements in BMI, blood pressure, and several blood chemicals, the MCR + HIW group had greater improvement. Moreover, the medical expenditure for the 6 months including the intervention period was 59% lower in the MCR + HIW group than in the HIW group. Our strategy of a short-term combination of MCR and HIW may thus prevent lifestyle-associated diseases and improve health in middle-aged and older overweight Japanese.ArticleEXPERIMENTAL GERONTOLOGY. 44(10):666-675 (2009)journal articl

Language activity promoting the development of competence in reading reflectively.

言語活動の充実が求められている現在,言語の本質的機能を見失った,言語活動そのものが目的化された問題状況があり,言語活動のあり方を問い直すことが求められている。本研究では一貫して「読みとその変容を自覚化させる」ことを目標としてきたが,この目標の内実としては次の三点を挙げた。①自分の読み(一人読み)が自覚できる。②自らの読みと他者の読みの違いが自覚できる。③自らの読みの変容が自覚できる。これらの目標を達成するための手段として言語活動をとらえ,授業づくりのあり方を実践的に追究した。一貫した目標を掲げつつも,具体的には,物語,戯曲,説明文という様々なジャンルの文章と,低・中・高学年に渡る発達段階を考慮して仮説を立て,計画し,児童の実態に応じて授業実践し,考察した。その成果としては,無意識的につないでいる論理関係を自覚的に認識させたり,登場人物の行動と心情とを自覚的にとらえさせたり,学習者自身と他者との読みの差異や自身の読みの変容を自覚させたりする,具体的な授業のあり方を提案することができた。今後は,自覚化のための手立てや言語活動を,体系化,構造化することを目指し,考究を深めたい