实验性高血压大鼠室旁核加压素分泌的免疫细胞化学研究

精氨酸加压素（AVP）主要是由下丘脑室旁核（PVN）和视上核（SON）的加压素能神经元合成分泌。近年来的研究表明,AVP作为一种血管活性肽与高血压的发病有关。本文采用二肾一夹法制成高血压模型。应用光、电镜技术、免疫细胞化不技术和图象分析技术对实验性高血压大鼠PVN加压素神经元进行了研究,并与SON加压素神经元及正常大鼠进行比较,研究结果表明,实验性高血压大鼠PVN和SON内AVP阳性细胞中分泌颗粒密集呈棕黄色,正常大鼠组染色浅谈。图象分析检测两组PVN和SON中AVP阳性细胞平均灰度值,所得数据分别经统计学处理,实验组和正常组AVP神经元在PVN有显著性差异。在SON也有显著性差异。但在实验组内的PVN和SON之间无显著性差异,正常大鼠组PVN和SON之间亦无显著性差异。结果表明, 高血压大鼠在血压升高时,PVN和SON内加压素神经元的分泌增强。     

大鼠生后视上核加压素分泌的发育

血管加压素是下丘脑加压素能神经元分泌的九肽激素,我们应用光镜,免疫细胞化学和图像分析技术,对大鼠生后视大核加压素能神经元分泌加压素的发育变化进行了跟踪研究,结果表明,新生仔鼠已开始分泌加压素,数据经统计学处理,表明新生组与1周,3周与4周组存在显著性差异。     

实验性高血压大鼠与正常大鼠视上核加压素分泌的比较研究

近年来研究表明,精氨酸加压素（ＡＶＰ）作为一种血管活性肽与高血压发病有关。本文应用光镜、电镜技术、免疫细胞化学技术和图像分析技术对实验性高血压大鼠视上核加压素分泌神经元进行了研究,并与正常大鼠进行比较。我们采用二肾一夹法制成实验性高血压大鼠模型。本文的结果表明,实验性高血压大鼠视上核ＡＶＰ阳性细胞内分泌颗粒密集呈棕黄色。正常大鼠组则染色浅谈。图像分析技术检测两组ＡＶＰ阳性细胞平均灰度值。所得数据经统计学处理,结果表明,实验性高血压大鼠组ＡＶＰ分泌增加     

烫伤对大鼠下丘脑视上核、室旁核AVP神经元的影响──免疫电镜观察及形态计量分析

为研究加压素与应激的关系,我们曾应用免疫细胞化学（ＰＡＰ）方法结合图像分析技术观察到烫伤应激后２小时视上核、室旁核加压素神经元免疫反应阳性物质的总体积减小最明显。本文采用免疫电镜技术,进一步观察了烫伤后２小时视上核、室旁核加压素神经元超微结构的变化,并运用体视学方法定量分析了对照组及烫伤后２小时组视上核、室分校加压素神经元各２４０张照片的粗面内质网、高尔基复合体及线粒体的体积密度（Ｖｖ）、面积密度（Ｓｖ）、面数密度（Ｎａ）等。结果显示：烫伤后２小时组视上核、室旁核加压素神经元的粗面内质网的Ｖｖ．Ｓｖ显著增大,说明合成功能已开始增强,但是,高尔基复合体的Ｖｖ、Ｓｖ及阳性分泌颗粒却显著减少,因而引起总体积的缩小。从超微结构水平进一步证实加压素参与应激过程。     

雌雄子午沙鼠的认知行为及其神经内分泌水平的差异

本研究通过对雌雄子午沙鼠进行新物体识别和社会认知实验,运用免疫组化方法检测其相关脑区合成催产素（OT）、加压素（AVP）和多巴胺（DA）能的神经元数量,采用酶联免疫试验（ELISA）方法检测了其血清中OT、AVP的水平,探究了雌雄子午沙鼠的两性认知差异及其神经内分泌水平的差异。结果表明,雌雄子午沙鼠对新物体的探究时间均要显著高于旧物体,雌雄子午沙鼠的辨别指数无显著差异（P＞0.05）;雄性子午沙鼠随着探究次数的增加对重复刺激鼠a的探究时间不断减少,对陌生刺激鼠b的探究时间显著高于刺激鼠a（P＜0.05）;雌性子午沙鼠没有此趋势。雄性子午沙鼠OT能神经元数量在下丘脑室旁核(PVN)和视上核(SON)均要显著少于雌性（P＜0.05）;雄性个体DA能神经元数量在黑质显著高于雌性（P＜0.01）;然而雄性个体DA能神经元数量在腹侧被盖区显著少于雌性（P＜0.01）;雌雄子午沙鼠血清OT、AVP水平均无显著差异。综上所述,雌雄子午沙鼠对新物体的识别能力无显著差异,然而雄性子午沙鼠的社会认知能力强于雌性。在神经内分泌水平上,雌雄子午沙鼠PVN和SON中OT能神经元数量、黑质和腹侧背盖区的DA能神经元数量均呈现出了两性差异。     

Apelin与血管加压素在水平衡中的研究

Apelin受体与血管加压素Ⅱ型受体均属于G蛋白偶联受体,Apelin与血管加压素均由下丘脑大细胞AVP神经元分泌,Apelin受体与血管加压素Ⅱ型受体均在肾脏表达,本文就Apelin与血管加压素的分布及参与水平衡调节做简单的综述,为其参与水代谢疾病的发病机制提供理论依据。     

不同生长阶段长爪沙鼠血清中氧化与抗氧化物质含量变化

目的　探讨不同生长阶段长爪沙鼠血清中氧化与抗氧作用机制。方法　选择 1月龄、3月龄、2 4月龄的长爪沙鼠各 16只 (雌雄各半 ) ,测定长爪沙鼠血清中超氧化物歧化酶 (SOD)、丙二醛 (MDA)、谷胱甘肽过氧化物酶 (GsH -Px)。结果　丙二醛 (MDA)在 3月龄最低 ,谷胱甘肽过氧化物酶 (GsH -Px)在 3月龄最高 ;超氧化物歧化酶 (SOD)随着长爪沙鼠的月龄增长而升高。结论　在长爪沙鼠生长过程中谷胱甘肽过氧化物酶 (GsH -Px)的含量变化与丙二醛 (MDA)含量变化有直接关系 ,而超氧化物歧化酶 (SOD)含量变化与MDA含量变化没有直接关系。     

大鼠运动病敏感性性别差异与相关脑区AVP及其V1b受体表达的关系

目的：检测不同性别大鼠旋转刺激后脑内相关区域精氨酸加压素（AVP）含量及V1b受体表达的变化,探讨AVP及受体参与运动病的可能机制。方法：给予SD大鼠30 min绕水平轴的旋转刺激,然后采用放免法检测相关脑区AVP含量,并通过荧光免疫组化方法测定相应脑区V1b受体的表达情况。结果：①在雌性大鼠,旋转刺激组各脑区AVP含量无显著性改变;对于雄性大鼠,对照组各检测脑区AVP含量高于雌性,旋转刺激组小脑、延髓内AVP含量的变化无显著性意义,但前脑、间脑、脑桥内AVP含量较对照组明显降低（P〈0.05）。②雌性大鼠视上核AVP的V1b受体表达阳性神经元数量旋转刺激组显著低于对照组（P〈0.05）,而前庭核、最后区V1b受体表达阳性神经元数量明显多于对照组（P〈0.05）;在雄性大鼠,旋转刺激组视上核与前庭核V1b受体表达阳性神经元数量无显著性改变,而最后区V1b受体表达阳性神经元数量有所增加（P〈0.05）,但增加幅度没有雌性大鼠明显。结论：前脑、间脑、脑桥内AVP含量与前庭核和最后区V1b受体表达及对旋转刺激反应的差异可能与运动病敏感性性别差异有关,并且前庭核、最后区可能是AVP-V1受体拮抗剂抗运动病作用的靶点。     

精氨酸加压素与抑郁症的研究进展

抑郁症是目前最为常见的情感性精神障碍,以情绪及应激的行为反应失调为主要特征。迄今为止,抑郁症的病因及发病机制不明,但相关的神经生化假说很多。精氨酸加压素(Arginine vasopressin,AVP)作为一种神经肽,因其在抑郁症中改变明显而越来越受关注。加压素系统包括丘脑大细胞性神经元、丘脑视上核和室旁核小细胞性神经元、视交叉上核(Suprachiasmatic nucleus,SCN)及下丘脑外边缘脑区。AVP在大脑区域分布不同,对大脑功能的调节机制也不一样。本文从加压素系统及血浆AVP在抑郁症中的研究进展、AVP受体拮抗剂在抗抑郁治疗方面的研究现状进行综述。     

冷应激诱导的脾脏NK细胞活性下降和脑内c-fos表达

目的 :观察单一冷应激对大鼠脾脏NK细胞活性的影响以及脑内Fos表达。方法 :大鼠置于 4℃的冷室 4h。采用YAC 1细胞51Cr释放法测定脾脏NK细胞的活性。用免疫细胞化学观察脑内有关核团的Fos表达 ,以及PVN和LC中Fos表达阳性的神经元的性质。结果 :单一冷应激能使脾脏NK细胞活性明显下降 ,下丘脑室旁核 (PVN)和脑干蓝斑 (LC)出现明显的Fos表达。双染实验表明 ,PVN中有部分神经元同时表达精氨酸加压素 (AVP) ,LC中大多数神经元同时表达酪氨酸羟化酶 (TH)。结论 :PVN中的AVP能神经元和LC中的儿茶酚胺能神经元很可能参与冷应激诱发的脾脏NK细胞活性的下降     

BiP mRNA expression is upregulated by dehydration in vasopressin neurons in the hypothalamus in mice

The immunoglobulin heavy chain binding protein (BiP) is an endoplasmic reticulum (ER) chaperone that facilitates the proper folding of newly synthesized secretory and transmembrane proteins. Here we report that BiP mRNA was expressed in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus in wild-type mice under basal conditions. Dual in situ hybridization in the SON and PVN demonstrated that BiP mRNA was expressed in almost all the neurons of arginine vasopressin (AVP), an antidiuretic hormone. BiP mRNA expression levels were increased in proportion to AVP mRNA expression in the SON and PVN under dehydration. These data suggest that BiP is involved in the homeostasis of ER function in the AVP neurons in the SON and PVN.     

Oxytocin and vasopressin involved in restraint water-immersion stress mediated by oxytocin receptor and vasopressin 1b receptor in rat brain

Aims

Vasopressin (AVP) and oxytocin (OT) are considered to be related to gastric functions and the regulation of stress response. The present study was to study the role of vasopressinergic and oxytocinergic neurons during the restraint water-immersion stress.

Methods

Ten male Wistar rats were divided into two groups, control and RWIS for 1h. The brain sections were treated with a dual immunohistochemistry of Fos and oxytocin (OT) or vasopressin (AVP) or OT receptor or AVP 1b receptor (V_1bR).

Results

(1) Fos-immunoreactive (Fos-IR) neurons dramatically increased in the hypothalamic paraventricular nucleus (PVN), the supraoptic nucleus (SON), the neucleus of solitary tract (NTS) and motor nucleus of the vagus (DMV) in the RWIS rats; (2) OT-immunoreactive (OT-IR) neurons were mainly observed in the medial magnocellular part of the PVN and the dorsal portion of the SON, while AVP-immunoreactive (AVP-IR) neurons mainly distributed in the magnocellular part of the PVN and the ventral portion of the SON. In the RWIS rats, Fos-IR neurons were indentified in 31% of OT-IR neurons and 40% of AVP-IR neurons in the PVN, while in the SON it represented 28%, 53% respectively; (3) V_1bR-IR and OTR-IR neurons occupied all portions of the NTS and DMV. In the RWIS rats, more than 10% of OTR-IR and V_1bR-IR neurons were activated in the DMV, while lower ratio in the NTS.

Conclusion

RWIS activates both oxytocinergic and vasopressinergic neurons in the PVN and SON, which may project to the NTS or DMV mediating the activity of the neurons by OTR and V_1bR.     

Genomic Effects of Cold and Isolation Stress on Magnocellular Vasopressin mRNA-Containing Cells in the Hypothalamus of the Rat

We assessed the effects of cold and isolation stress on arginine vasopressin (AVP) mRNA in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. Vasopressin mRNA levels were determined by in situ hybridization histochemistry at the cellular level. In posterior magnocellular neurons of the PVN isolation stress for 7 or 14 days increased vasopressin mRNA levels 28 and 29%, respectively, compared to group-housed controls. No significant alterations in vasopressin gene expression were observed in the SON after 7 or 14 days of isolation stress. Scattered magnocellular AVP mRNA-expressing cells of the medial parvocellular PVN showed increases of 19 and 34% after 7 and 14 days of isolation, respectively. We also studied the effect of cold or combined cold and isolation stress on vasopressin gene expression in the PVN and SON. Cold stress for 3 h daily for 4 consecutive days increased AVP mRNA levels in the posterior magnocellular PVN by 15%. Cold-isolated animals showed an increase of 21%. No significant effect on AVP mRNA levels in the SON was observed. In contrast to the posterior magnocellular PVN, cold or cold-isolation stress increased AVP mRNA in magnocellular neurons of the medial parvocellular region of the PVN by 25 and 43%, respectively, relative to control rats. These results suggest that psychological and metabolic stress may be added to the list of stressors that activate the hypothalamo-neurohypophysial system.     

Locus Coeruleus Lesions Decrease Oxytocin and Vasopressin Release Induced by Hemorrhage

The role of the noradrenergic nucleus Locus Coeruleus (LC) on hemorrhage-induced vasopressin (AVP) and oxytocin (OT) secretion was examined. Rats with LC lesion were submitted to three 1-min hemorrhage sessions at 5-min intervals; 15% of the total blood volume was withdrawn in each session. OT and AVP were measured in plasma, paraventricular (PVN) and supraoptic (SON) nuclei and in posterior pituitary (PP). LC Lesion did not affect basal plasma AVP or OT levels, but partly blocked the increase in plasma AVP and OT induced by hemorrhage. Hemorrhage produced decreases in content of AVP and OT in the PVN and SON and increased levels in the PP. These responses were attenuated in the lesioned group, but only in the PVN and PP. Data suggest a stimulatory role of the inputs from LC to PVN neurons on hemorrhage-induced OT and AVP secretion and that, this pathway is critical in the hypo-volemic neuroendocrine reflex.Special Issue Dedicated to Miklós Palkovits.     

The Notch effector gene Hes1 regulates migration of hypothalamic neurons, neuropeptide content and axon targeting to the pituitary

Proper development of the hypothalamic-pituitary axis requires precise neuronal signaling to establish a network that regulates homeostasis. The developing hypothalamus and pituitary utilize similar signaling pathways for differentiation in embryonic development. The Notch signaling effector gene Hes1 is present in the developing hypothalamus and pituitary and is required for proper formation of the pituitary, which contains axons of arginine vasopressin (AVP) neurons from the hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON). We hypothesized that Hes1 is necessary for the generation, placement and projection of AVP neurons. We found that Hes1 null mice show no significant difference in cell proliferation or death in the developing diencephalon at embryonic day 10.5 (e10.5) or e11.5. By e16.5, AVP cell bodies are formed in the SON and PVN, but are abnormally placed, suggesting that Hes1 may be necessary for the migration of AVP neurons. GAD67 immunoreactivity is ectopically expressed in Hes1 null mice, which may contribute to cell body misplacement. Additionally, at e18.5 Hes1 null mice show continued misplacement of AVP cell bodies in the PVN and SON and additionally exhibit abnormal axonal projection. Using mass spectrometry to characterize peptide content, we found that Hes1 null pituitaries have aberrant somatostatin (SS) peptide, which correlates with abnormal SS cells in the pituitary and misplaced SS axon tracts at e18.5. Our results indicate that Notch signaling facilitates the migration and guidance of hypothalamic neurons, as well as neuropeptide content.     

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Running becomes a stress, termed running stress, if it persists above the lactate threshold (LT) and results in enhanced plasma ACTH level in humans. Although the exact underlying regulation mechanism is still uncertain, hypothalamic AVP has been shown to play a dominant role in running-induced ACTH release. It is still not known, however, whether running stress activates the hypothalamic AVP-containing neurons that are involved in the activation of the ACTH response. For this reason, we applied our rat running stress model, in which both plasma ACTH and osmolality levels increase just above LT running (supra-LT running), to delineate which hypothalamic AVP neurons were responsive to running stress. Rats were previously habituated to running and then subjected to a 30-min run either just below or above the LT. Plasma samples were collected from these animals to determine ACTH and osmolality levels. Brains were prepared for immunocytochemistry for both AVP/Fos in the hypothalamus and enzyme immunoassay for the stalk median eminence (SME) AVP content. Only supra-LT running resulted in an increase in the number of Fos/AVP-immunoreactive neurons in both the parvocellular paraventricular nucleus (pPVN) and the magnocellular supraoptic nucleus (SON) accompanied by increased ACTH and plasma osmolality levels. Similarly, running reduced the SME content of the AVP. We thus found that AVP-containing neurons located in both the pPVN and SON are responsive to running stress just above the LT.     

Oxytocin, but not arginine vasopressin is involving in the antinociceptive role of hypothalamic supraoptic nucleus

Our pervious study has demonstrated that the hypothalamic supraoptic nucleus (SON) plays a role in pain modulation. Oxytocin (OXT) and arginine vasopressin (AVP) are the important hormones synthesized and secreted by the SON. The experiment was designed to investigate which hormone was relating with the antinociceptive role of the SON in the rat. The results showed that (1) microinjection of l-glutamate sodium into the SON increased OXT and AVP concentrations in the SON perfusion liquid, (2) pain stimulation induces OXT, but not AVP release in the SON, and (3) intraventricular injection (pre-treatment) with OXT antiserum could inhibit the pain threshold increase induced by SON injection of l-glutamate sodium, but administration of AVP antiserum did not influence the antinociceptive role of SON stimulation. The data suggested that the antinociceptive role of the SON relates to OXT rather than AVP.     

Age-related changes in oxytocin-, arginine vasopressin- and nitric oxide synthase-expressing neurons in the supraoptic nucleus of the rat

Many histochemical investigations indicated that the oxytocin (OXY), the arginine vasopressin (AVP) and the nitric oxide synthase (NOS) have been synthesized in the supraoptic nucleus (SON) neurons. The objective of this study was to examine the age-related expression of the OXY, the AVP and the NOS in the SON of the young adult (2-month-old) and the aged (24-month-old) rats. The histochemistry for reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d; marker for the NOS) and the double labeling histochemistry for the OXY/NADPH-d or the AVP/NADPH-d were employed, and the quantitative analysis was performed with a computer-assisted image processing system. In comparison of the young adult and the aged group, the cell number, the cell size and the reactive density of the NOS-expressing neurons showed a significant increase along with age, and these evidences suggested the age-related increase of the nitric oxide (NO) production. The age-related significant increase was not detected in the number of the OXY/NOS-expressing neurons in the dorsal part, but was detected in the number of the AVP/NOS-expressing neurons in the ventral part. Based on our histochemical findings and reports demonstrated by other authors, we attempted to discuss the physiological role of NOS for the secretion of posterior pituitary hormones along with age.