Electron-microscopic autoradiography of rat hypothalamus after intraventricular h3-norepinephrine

Tritiated norepinephrine was injected into the lateral ventricles of rats, and its localization in the hypothalamus was determined by light and electron-microscopic autoradiography. Eighty percent of the autoradiographic grains were located over nerve endings and unmyelinated axons. Large, dense synaptic vesicles were present in most of the endings and axons with activity. Grains were rarely seen over myelinated axons, glia, or blood vessels.     

Single unit activity of anterior hypothalamus during local heating

There are heat-sensitive units in the anterior hypothalamus which respond with an increase of discharge frequency to a rise in hypothalamic temperature of less than 1 degrees C. The increase of unit discharge occurred in advance of the onset of polypnea , and the unit has little phasic response or after discharge, and shows little adaptation.     

Electrical phenomena associated with the activity of the membrane-bound acetylcholinesterase

Treatment of isolated electroplax with physiological solutions supplemented with either 1 molar sodium chloride, 2 molar urea, or 2 molar sucrose renders the cell insensitive to carbamylcholine, phenyltrimethylammonium, or decamethonium even at high concentrations. The treated cells have a residual resting potential of -20 +/- 10 millivolts (negative inside) and are depolarized by acetylcholine at concentrations larger than 10(-3) mole per liter. This response is not affected by d-tubocurarine but is blocked by physostigmine, diisopropylphosphorofluoridate, or strong buffers and thus depends on the catalytic activity of the membrane-bound acetylcholinesterase.     

Somatomedin-C mediates growth hormone negative feedback by effects on both the hypothalamus and the pituitary

Somatomedin-C stimulates somatostatin release to a maximum of 390 percent of basal release during short-term (20-minute) incubation of rat hypothalamus. It has no effect on basal or stimulated growth hormone release from primary cultures of rat adenohypophyseal cells during a 4-hour incubation, but inhibits stimulated release by more that 90 percent after 24 hours. These findings suggest that somatomedin-C participates in the growth hormone negative feedback loop with an immediate effect on hypothalamic somatostatin and a delayed effect on the anterior pituitary.     

Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.     

Unexpected adrenergic effects of chlorpromazine: eating elicited by injection into rat hypothalamus

Although chlorpromazine is believed to block adrenergic transmission, injection of this drug into the hypothalamus of satiated rats does not block norepinephrine-elicited eating, but instead mimics norepinephrine by eliciting eating. The amount of eating elicited by norepinephrine and by chlorpromazine is reliably correlated. These results suggest that endogenous norepinephrine mediates eating elicited by centrally injected chlorpromazine.     

Self-stimulation in the ventromedial hypothalamus

Male Sprague-Dawley rats pressed a bar for electrical stimulation of the ventromedial hypothalamus. The threshold for such behavior correlated positively with the threshold to stop feeding and the threshold to escape from prolonged stimulation at the same electrode site. The results again open the question of the role that the ventromedial area is playing in positively reinforcing and punishment systems.     

皮下埋植大豆黄酮对猪下丘脑阿片肽受体水平的影响

动物下丘脑—垂体—性腺轴分泌受到相互制约调节 ,性腺类固醇激素可通过与下丘脑和垂体受体结合反馈性地影响垂体ＬＨ分泌 ;而高级神经中枢存在的阿片肽受体水平的变化 ,亦可以通过ＧｎＲＨ途径 ,参与或控制ＬＨ分泌过程[1 ,2 ] 。大豆黄酮是一种具有多种生物活性的植物雌激素 ,体内外试验表明 ,它可以影响垂体ＬＨ分泌[3～5] ,但对其作用机理仍在探索中。本试验研究大豆黄酮皮下埋植去卵巢母猪后下丘脑阿片肽受体水平的变化 ,探讨大豆黄酮的作用通路 ,以帮助阐明相应的作用机理。1　材料和方法1 1　动物及处理　　格丁根小母猪 6头 ,4～ 5…     

Interleukin-1 immunoreactive innervation of the human hypothalamus

Interleukin-1 (IL-1) is a cytokine that mediates the acute phase reaction. Many of the actions of IL-1 involve direct effects on the central nervous system. However, IL-1 has not previously been identified as an intrinsic component within the brain, except in glial cells. An antiserum directed against human IL-1 beta was used to stain the human brain immunohistochemically for IL-1 beta-like immunoreactive neural elements. IL-1 beta-immunoreactive fibers were found innervating the key endocrine and autonomic cell groups that control the central components of the acute phase reaction. These results indicate that IL-1 may be an intrinsic neuromodulator in central nervous system pathways that mediate various metabolic functions of the acute phase reaction, including the body temperature changes that produce the febrile response.     

猪下丘脑开胃素 A的分布定位

用免疫组织化学方法研究了5头苏钟猪下丘脑内开胃素(orexin)A的分布。结果表明,在猪下丘脑内,开胃素A免疫阳性神经元分布于下丘脑的视前内侧区、室周核、室旁核、视上核、背内侧核、穹隆周核、乳头体核、前区、外侧区和后区等部位,以下丘脑外侧区、乳头体核和视上核出现的免疫阳性神经元最多,以室周核的最少。这一结果与在其他动物上获得的基本相似。     

Behavior of free-ranging macaques after intraventricular 6-hydroxydopamine

Macaques (Macaca mulatta) observed in a free-ranging colony on Guayacan Island, Puerto Rico, were significantly different in their social interactions, initiatives, facial expressions, and postures after intraventricular 6-hydroxydopamine compared with sham-treated and field controls. This study extends the known effects of 6-hydroxydopamine and catecholamine depletion to the social interactions of a higher primate species under free-ranging conditions.     

Barometric pressure fluctuations: effects on the activity of laboratory mice

Fluctuations in naturally occurring levels of barometric pressure appear to be an important determinant of activity in laboratory mice. In three experiments, activity was higher after increases in barometric pressure than it was after decreases. When the barometric pressure remained relatively stable, intermediate levels of activity were observed.     

神经元在动物下丘脑中分布的研究进展

对近年来研究较多的神经元在动物下丘脑各个神经核中的分布情况作了介绍,指出神经元在下丘脑各个神经核均有分布,甚至有几种神经元同时分布在某些神经核中,视上核(SON)、室旁核(PVN)及弓状核(ARC)是多种神经元集中分布的主要神经核,为进一步研究下丘脑的生理功能提供了形态学资料。     

Relationship between feeding and satiation centers of the hypothalamus

Electrodes were implanted in the hypothalamus of five goats in which an alimentary instrumental conditioned reflex had been previously established. Electrical stimulation of the ventromedial hypothalamus inhibited the conditioned movements and food intake in hungry goats. This also occurred in those satiated goats in which eating and conditioned movements were elicited by stimulation of the lateral hypothalamic area. Withdrawal of the stimulation of the medial hypothalamus evoked a short aftereffect in the form of a recovery or increase in the trained movements and food intake.     

Role of myocardial catecholamines in cardiac contractility

In cats bilateral sympathectomy or administration of reserpine results in a marked reduction in concentration of myocardial catecholamines. The contractility of papillary muscles from such animals is significantly less than that of muscles from untreated animals. These findings demonstrate the importance of normal levels of myocardial catecholamines in the maintenance of normal cardiac contractility.     

Olfactory input to the hypothalamus: electrophysiological evidence

Electrical stimulation of the rat's olfactory bulb or lateral olfactory tract elicited unit discharges in the region of the medial forebrain bundle of the lateral hypothalamus, with latencies of 4 to 25 milliseconds. Unit responses in this area were driven by odors in preparations that were paralyzed to prevent breathing artifacts.     

"Copulation-reward site" in the posterior hypothalamus

Posterior hypothalamic selfstimulation of male rats, in which monopolar,platinum electrodes had been belaterally implanted, increased after systdmic injection of testosterone. constant stimulation to the same site elicited immediate copulation with estrous female rats. During constant stimulation males would press a bar to open a door for access to females. Even after ejaculation, males continued to open the door and to display sexual activity until stimulation terminated. Posterior hypothalamic stimulation is like normal sexual stimulation; it is rewarding, the reward varies with the amount of the sex hormone, and it elicits motivated copulation.     

蛋鸡下丘脑中生长抑素神经原发育的研究

应用免疫组织化学技术显示蛋鸡生长发育过程中下丘脑中生长抑素（ＳＳ）免疫阳性神经原的分布。发现蛋鸡在生长早期（１周龄和３周龄）ＳＳ神经原数量较多，６周龄时暂时降低，到９周龄又回升；在生长晚期（６１周龄）呈显著下降趋势。尽管公鸡和母鸡ＳＳ神经原数量没有显著差异，但母鸡的ＳＳ神经原数量从第３周到第６周明显下降，第９周时显著上升，表明ＳＳ神经原的发育具有性别差异。研究结果表明，蛋鸡下丘脑中ＳＳ神经原数量与血浆中ＧＨ水平呈负相关，下丘脑中ＳＳ控制着脑垂体中ＧＨ的分泌。     

森林经营对土壤酶活性影响的研究进展

为探讨土壤质量酶指标研究的新思路,把有关森林经营对土壤酶活性影响的研究资料进行了归纳总结。结果发现:林地利用方式的改变、人工林的培育模式、森林抚育措施以及林地施肥管理等各种森林生态系统经营过程,都显著改变着土壤酶活性。酶是反映森林土壤质量高低的重要生物学指标,在一定程度上也可反映森林经营措施的实施效果。今后在森林土壤酶的研究中,应重视水解酶的种类、酶指标的敏感性以及酶变化机理的探索。