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。     

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。     

Estradiol-concentrating neurons: topography in the hypothalamus by dry-mount autoradiography

Serial section autoradiograms were prepared of different planes of the hypothalamus and diencephalon of immature female, immature male, and ovariectomized mature rats injected with 6,7-(3)H-estradiol-17 beta. Known causes of diffusion and redistribution of the label, such as fixation, embedding, and thawing, were eliminated by the use of an autoradiographic technique based on the dry-mounting of freeze-dried sections. Neurons that concentrate estradiol exist in distinct and definable anatomical areas that are independent of the sex and hormonal state of the animals. Distribution of these neurons follows known terminations of the stria terminalis, which supports the concept of an endocrine amygdaloid-hypothalamic-hypophysial axis.     

Steroid-sensitive single neurons in rat hypothalamus and midbrain: identification by microelectrophoresis

Minute amounts of Na-dexamethasone-21-phosphate administered by microelectrophoresis to the immediate extracellular environment promptly suppressed electrical activity of 15 out of 115 hypothalamic and mesencephalic neurons, the effect being readily reversible. Such neurons marked with fast green were found to lie in circumscribed areas of the periventricular gray of the third ventricle and aqueduct, and may represent a site of action of adrenocortical steroids in the regulation of corticotrophin releasing factor and/or adrenocortico-tropin secretion by negative feedback.     

雌二醇和孕酮对山羊子宫雌二醇受体的调节

将１２只卵巢摘除山羊随机分为４组，用孕酮（Ｐ＿４）和雌二醇（Ｅ＿２）按２×２因子实验进行发情周期的人工模拟，然后测定子宫内膜胞浆中的Ｅ＿２受体（ＲＥ＿２），Ｐ４组、空白组、Ｐ＿４＋Ｅ＿２组和Ｅ＿２组的ＲＥ＿２水平分别为８．９，１８．３，３３．８和６７．９ｆｍｏｌ·ｍｇ￣（－１）．除空白组与Ｐ＿４＋Ｅ＿２组之间ＲＥ＿２水平的差异显著外（Ｐ＜０．０５），其余组之间均为极显著（Ｐ＜０．０１）。结果表明，山羊子宫内膜胞浆ＲＥ＿２水平处于Ｐ＿４和Ｅ＿２的共同调节之中，Ｐ＿４具有极显著的降调节作用，而Ｅ＿２则具有极显著的升调节作用。     

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.     

苯甲酸雌二醇在奶牛体内的药物动力学

分析苯甲酸雌二醇在奶牛体内的药物代谢动力学过程.试验前对奶牛进行摘除卵巢手术,术后30 d单剂量肌肉注射不孕奶牛催乳注射液(苯甲酸雌二醇+黄体酮),216 h内不同时间17次颈静脉采血,用放射免疫法(RIA)测定血清中雌二醇浓度.结果表明,雌二醇在奶牛体内的药物动力学配置符合有吸收因素的二室开放模型,其药时曲线最佳方程为:C=283.773e-0.0326t+136.748e-0.0133t-420.521e-0.0770t.消除半衰期(t1/2)为(52.232±1.383) h;药时曲线下面积(AUC)为(13525.940±288.114) pg/(mL·h);达峰时间(Tp)为(22.025±0.427) h,达峰浓度(Cp)为(165.385±3.120) pg/mL.试验结果显示,苯甲酸雌二醇在奶牛体内分布广泛,吸收和消除较慢.     

Estradiol shortens the period of hamster circadian rhythms

Continuous administration of estradiol benzoate by means of subcutaneously implanted capsules shortened the free-running circadian period of locomotor activity of blind hamsters (Mesocricetus auratus) that had had their ovaries removed. Estradiol also advanced the phase of the wheel running of sighted female hamsters without ovaries that were entrained to a photoperiod with 12 hours of light and 12 of darkness. These results, and findings from hamsters undergoing natural estrous cycles, indicate that endogenous estradiol is involved in the regulation of circadian periodicity.     

溴化十六烷基三甲铵存在时伏安法测定雌二醇含量

雌二醇在用裸玻碳电极进行伏安法测定时的电活性极低。但雌二醇在有阳离子表面活性剂溴化十六烷基三甲铵 (CTMAB)存在时 ,使用Nafion修饰的玻碳电极 ,则可于 0 .35V处有一灵敏的响应。据此 ,建立了雌二醇的线性扫描伏安测定法。适宜条件下 ,线性范围为1× 1 0 - 8mol/L8× 1 0 - 5 mol/L ,检测限为 5× 1 0 - 9mol/L。     

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。     

除草剂阿特拉津对大白鼠血清中雌二醇(E2)浓度的影响

SD大白鼠120只 ,随机分成4组 ,3个处理组 ,1个对照组 ,分别按每千克体重200mg,100mg,10mg,0mg阿特拉津灌胃 ,并于喂药15d和30d采样测定大白鼠血清中雌二醇的含量。结果表明 ,除草剂阿特拉津对雌性和雄性大白鼠血清中雌二醇的含量均有影响。阿特拉津对雄性大白鼠雌二醇的含量的影响出现较早 ,说明雄性动物对阿特拉津的作用较为敏感 ;阿特拉津可使雌性大白鼠血清中雌二醇含量增加 ,虽然这种现象出现较晚 ,但各组差异较大 ,尤其是对照组和剂量组之间 ,差异极显著(p<0.01)。血液中雌激素含量的变化直接影响到成鼠的生殖功能及雄鼠的性征变化。由此推测 ,体内因富集阿特拉津所导致血清中雌二醇浓度变化的大白鼠可能出现一定的生殖缺陷 ,以致影响到种族的繁衍。     

"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.     

Protein tyrosine kinase Wee1B is essential for metaphase II exit in mouse oocytes

Waves of cyclin synthesis and degradation regulate the activity of Cdc2 protein kinase during the cell cycle. Cdc2 inactivation by Wee1B-mediated phosphorylation is necessary for arrest of the oocyte at G2-prophase, but it is unclear whether this regulation functions later during the metaphase-to-anaphase transition. We show that reactivation of a Wee1B pathway triggers the decrease in Cdc2 activity during egg activation. When Wee1B is down-regulated, oocytes fail to form a pronucleus in response to Ca(2+) signals. Calcium-calmodulin-dependent kinase II (CaMKII) activates Wee1B, and CaMKII-driven exit from metaphase II is inhibited by Wee1B down-regulation, demonstrating that exit from metaphase requires not only a proteolytic degradation of cyclin B but also the inhibitory phosphorylation of Cdc2 by Wee1B.     

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.     

内源性和外源性雌二醇对绵羊黄体溶解的作用

20只绵羊随机按双因子试验设计分为4个处理组,双因子为X-射线照射卵巢选择性破坏卵泡和埋植雌二醇。X-射线照射使发情周期黄体期延长,雌二醇使这种作用逆转。子宫内膜催产素受体浓度决定于黄体溶解发生的时间,即黄体溶解较早发生羊只子宫内膜催产素受体浓度低于黄体溶解发生较晚或尚未发生的羊只。催产素和PGFM均呈现明显的分泌波。雌二醇处理缩短PGFM峰值间隔时间、延长催产素峰值间隔时间,可能存在一种不依赖于催产素的PGF_(2α)释放;雌二醇对这种不依赖于催产素的PGF_(2α)释放有着重要作用。     

Electrical activity of the hypothalamus effects of intraventricular catecholamines

The injection of epinephrine into the third ventricle of the rat brain causes a biphasic elevation and depression in the integrated multiple-unit electrical activity of the median eminence. Activity in the arcuate nucleus decreases after the injection of the catecholamines. These changes in the integrated multiple-unit electrical activity may be related to the secretion of hormones by the anterior pituitary gland.     

Lectins mimic insulin in the induction of tyrosine aminotransferase

Various lectins were found to induce tyrosine aminotransferase in H-35 rat hepatoma cells grown in monolayer culture. Wheat germ agglutinin gave a maximal induction of tyrosine aminotransferase 6 hours after its addition. The induction time course was similar to that elicited by insulin. Fourteen micrograms of wheat germ agglutinin per milliliter gave half-maximal enzyme induction and 50 micrograms per milliliter gave the maximal response. The induction of tyrosine aminotransferase by wheat germ agglutinin was additive with the induction by either dexamethasone or dibutyryl adenosine 3',5'-monophosphate, but was not additive with the tyrosine amino transferase induction by insulin. Wheat germ agglutinin also mimicked insulin in the inhibition of cellular protein degradation in the absence of serum. The insulin-like effects of lectins should be considered in lectin-mediated manipulations such as agglutination.     

Adenosine 3',5'-monophosphate is localized in cerebellar neurons: immunofluorescence evidence

Adenosine 3',5'-monophosphate is localized in specific cerebellar neurons, as shown by fluorescence immunocytochemistry with a specific rabbit immunoglobulin. Positive staining is exhibited by Purkinje neurons and granule cells. The increase in concentration of cyclic adenosine monophosphate in the cerebellum, which is known to follow decapitation, is represented by greatly increased fluorescence of Purkinje neurons only. These immunofluorescence data provide the first evidence for localization of cyclic adenosine monophosphate in specific neurons and may permit further exploration into the role of this cyclic nucleotide in neuronal function.     

Innate immunity in Caenorhabditis elegans is regulated by neurons expressing NPR-1/GPCR

A large body of evidence indicates that metazoan innate immunity is regulated by the nervous system, but the mechanisms involved in the process and the biological importance of such control remain unclear. We show that a neural circuit involving npr-1, which encodes a G protein-coupled receptor (GPCR) related to mammalian neuropeptide Y receptors, functions to suppress innate immune responses. The immune inhibitory function requires a guanosine 3',5'-monophosphate-gated ion channel encoded by tax-2 and tax-4 as well as the soluble guanylate cyclase GCY-35. Furthermore, we show that npr-1- and gcy-35-expressing sensory neurons actively suppress immune responses of nonneuronal tissues. A full-genome microarray analysis on animals with altered neural function due to mutation in npr-1 shows an enrichment in genes that are markers of innate immune responses, including those regulated by a conserved PMK-1/p38 mitogen-activated protein kinase signaling pathway. These results present evidence that neurons directly control innate immunity in C. elegans, suggesting that GPCRs may participate in neural circuits that receive inputs from either pathogens or infected sites and integrate them to coordinate appropriate immune responses.