高渗刺激诱导大鼠下丘脑室核和视上核神经激肽B受体阳性神经？…

目的 研究神经激肽Ｂ受体与机体渗透压调节之间的可能关系。方法 用双重免疫组织化学染色技术，高渗刺激采用静脉内注射１．５ｍｏｌ／Ｌ ＮａＣｌ的方法，观察下丘脑室旁核和视上核ＮＫ３受体阳性神经元在高渗刺激下的Ｆｏｓ表达情况。结果 高渗盐水可诱导下丘脑室旁核和视上核内大量神经元表达Ｆｏｓ。     

高渗刺激诱导大鼠下丘脑室旁核和视上核神经激肽B受体阳性神经元表达Fos

目的研究神经激肽Ｂ受体（ＮＫ３受体）与机体渗透压调节之间的可能关系。方法用双重免疫组织化学染色技术,高渗刺激采用静脉内注射１．５ｍｏｌ／ＬＮａＣｌ的方法,观察了下丘脑室旁核和视上核内ＮＫ３受体阳性神经元在高渗刺激下的Ｆｏｓ表达情况。结果高渗盐水可诱导下丘脑室旁核和视上核内大量神经元表达Ｆｏｓ。在室旁核,双标细胞约占ＮＫ３受体阳性神经元的８８％,约占Ｆｏｓ阳性细胞的７１％;在视上核的主部,双标细胞约占ＮＫ３受体阳性神经元的７４％,约占Ｆｏｓ阳性细胞的４３％。结论室旁核和视上核内ＮＫ３受体阳性神经元可能参与大鼠渗透压调节过程。     

N-氨基-D-门冬氨酸诱导大鼠下丘脑视上核、室旁核和弓状核内c-fos基因表达

实验用foS蛋白免疫组织化学方法,研究了中枢神经系统兴奋性介质N-氨基-D-门冬氨酸诱导大鼠下丘脑内c-fos的表达.N-氨基-D-门冬氨酸注射大鼠皮下后,观察了fos阳性细胞在下丘脑内开始出现与消失的时程相关以及在下丘脑内的分布.结果表明:给N-氨基-D-门冬氨酸后30分开始出现fos阳性细胞,1～2小时达高峰,4～8小时消失.fos阳性细胞主要分布于视上核、室旁核和弓状核,视上核和室旁核中fos阳性细胞分别占细胞总数的57.8%和63.6%,在弓状核中占细胞总数的60.6%.     

中国树Qu下丘脑视上核和室旁核内加压素能神经元的形态和神 …

用抗加压素（ＶＰ）血清和免疫组化技术，观察了中国树Ｑｕ下丘脑视上核（ＳＯＮ）和室旁核（ＰＶＮ）内ＶＰ能神经元的形态和神经纤维的分布，ＶＰ能胞体的形态，在ＳＯＮ主部多呈梭形，少数呈多角形，在ＳＯＮ交叉后部，多呈多角形，少数呈梭形，在ＰＶＮ，以多角形为主，少数为梭形，ＶＰ能纤维的分布；在ＰＶＮ与ＳＯＮ主部之间，特别是与视交叉上区和视束背内侧区之间，纤维细而直，多平行分布。在ＰＶＮ后半外侧，可见部分纤维     

加压素在自发性高血压大鼠与正常大鼠下丘脑视上核、室旁核神经元内表达

目的观察加压素(AVP)在自发性高血压大鼠(SHR)与正常大鼠下丘脑视上核(SON)、室旁核(PVN)内的分布。方法应用光镜和免疫细胞化学技术。结果SHR的AVP阳性细胞内分泌颗粒密集呈棕黄色,正常大鼠组则染色较浅。SHR大鼠SON内AVP阳性神经元百分数(69.30±18.10%)明显多于正常大鼠(59.53±16.97%,P<0.05),而两组大鼠PVN内AVP的表达无明显差异。结论AVP在下丘脑的血压调节活动中起着重要的介导作用,中枢AVP含量的异常增加可能与高血压的发病有关。     

中国树下丘脑视上核和室旁核内加压素能神经元的形态和神经纤维的分布

用抗加压素（VP）血清和免疫组化技术，观察了中国树下丘脑视上核（SON）和室旁核（PVN）内VP能种经元的形态和神经纤维的分布。VP能胞体的形态，在SON主部多呈梭形，少数呈多角形；在SON交叉后部，多是多角形，少数是梭形；在PVN，以多角形为主，少数为梭形．VP能纤维的分布：在PVN与SON生部之间，特别是与视交叉上区和现柬背内侧区之间，纤维细而直，多平行分布．在PVN后半外侧，可见部分纤维呈内侧-背外侧向分布；在SON交叉后部的背外侧，纤维是朝向正中隆起处汇集的趋势，其中部分纤维呈串珠状；在正中隆起内带，纤维呈西外侧-内侧向和吻-屠向密集分布，有少数大小不等的免疫反应阳性的聚集体；在正中隆起外带，特别在会体门脉毛细血管排周围，有致密的、成群分布的免疫反应阳性点状结构；在漏斗柄和垂体神经部，可见致密的免疫反应阳性纤维和Herring体，在神经部内的窦状毛细血管周围有致富的、大小不等的免疫反应阳性点状结构．     

大鼠下丘脑室旁核和视上核内神经激光肽B受体和加压素的共？…

研究神经激肽Ｂ受体免疫反应产物在大鼠下丘脑旁室核和视上核的分布及其与加压素的共存。方法免疫组织化学染色，标本在光镜和电镜下观察。共存研究采用相邻切片染色法。结果致密的ＮＫ３受体阳性产物分布于室旁核的后大细胞部和视上核的主部。     

一氧化氮合酶在自发性高血压大鼠视上核及室旁核的分布

目的：探讨自发性高血压大鼠视上核及室旁核内一氧化氮合酶阳性神经元的改变。方法：用ＮＡＤＰＨ－ｄｉ－ａｐｈｏｒａｅ组织化学方法,观察和比较了一氧化氮合酶在自发性高血压大鼠和正常对照大鼠视上核和室旁核的分布间下观察下捕脑视上核及室旁核的一氧化氮合酶阳性细胞形态、分布并进行计数。用图像分析仪测其灰度显差异。视上核及室旁核内的一氧化氮合酶阳性细胞灰度值在高血压组均明显高于对照组。提示这两上核内一氧化氮合酶     

N—氨基—D—门冬氨酸诱导大鼠下丘脑视上核,室旁核和弓状核内c—fo…

实验用ｆｏｓ蛋白免疫组织化学方法，研究了中枢神经系统兴奋性介质Ｎ－氨基－Ｄ－门冬氨酸诱导大鼠下丘脑内ｃ－ｆｏｓ的表达。Ｎ－氨基－Ｄ－门冬氨酸注射大鼠皮下后，观察了ｆｏｓ阳性细胞在下丘脑内开始出现与消失的时程相关以及在下丘脑内的分布，结果表明：给Ｎ－氨基－Ｄ－门冬氨酸后３０发开始出现ｆｏｓ阳性细胞，１￣２小时达高峰，４￣８小时消失，ｆｏｓ阳性细胞主要分布于视上核、室旁核和弓状核，视上核和室旁核中ｆｏ     

腹腔注射2-脱氧-D-葡萄糖可诱发大鼠视上核和室旁核神经元表达Fos

目的 探讨腹腔注射2-脱氧-D-葡萄糖（2-DG）能否激活大鼠下丘脑视上核（SON）和室旁核（PVN）神经元而表达Fos。方法 健康雄性SD大鼠12只,随机分为腹腔注射2-DG组（6只）、生理盐水对照组（3只）及正常对照组（3只）。各自处理后,应用免疫组织化学方法,观察各组下丘脑SON和PVN内Fos表达及其与催产素（OT）和加压素（VP）的双标情况,同时采用ELISA方法对血清中OT和VP的含量进行检测。 结果与生理盐水对照组和正常对照组相比,2-DG引发的特异性Fos免疫阳性产物主要集中分布于下丘脑外侧区和穹隆周区,在SON、PVN也有密集表达。SON和PVN内的Fos表达与该区的特异性神经活性物质OT和VP有共存。OT/Fos双标细胞率（双标细胞占OT阳性细胞的百分率）在SON和PVN分别为87.10%、90.57%,明显高于VP/Fos在这两个核团的双标率（双标细胞占VP阳性细胞的百分率,68.42%、76.92%）,两者比较差异有统计学意义（P<0.05）。ELISA检测结果显示,2-DG组动物血清中OT和VP水平与对照组相比无明显变化。 结论 腹腔注射2-DG可激活大鼠下丘脑SON和PVN内OT和VP神经元表达Fos,SON和PVN可能参与2-DG诱导的急性应激反应。     

不同饥饿刺激对下丘脑穹隆周区orexin-A神经元的影响

目的:通过观察下丘脑穹窿周区orexin-A神经元对不同刺激方式的反应特性探索能够激活该系统的高效而适宜的方法。方法:采用禁食、腹腔注射胰岛素和2-DG三种饥饿刺激方式,利用免疫组织化学染色及ELISA检测相结合的方法对大鼠穹隆周区orexin-A神经元的Fos的表达,脑脊液中orexin-A的浓度进行了对比分析。27只SD大鼠随机分为六组,分别进行禁食2 d,腹腔注射胰岛素或生理盐水存活5 h,腹腔注射2-脱氧-D-葡萄糖(2-DG)或生理盐水存活2 h和正常对照处理,动物的饮水量保持正常。结果:三种饥饿刺激引发的Fos表达比较类似,主要集中于下丘脑背内侧核,下丘脑外侧区和下丘脑后区,2-DG组的Fos表达最为浓密。三种刺激对orexin-A神经元的数量无明显影响,但orexin-A/Fos双标细胞数占所有orexin-A阳性细胞数的比例以2-DG组最高,为26%;禁食2 d组次之为21%;胰岛素组最低为14%。禁食组和2-DG组的双标细胞率与胰岛素组相比差异具有统计学意义(P<0.05)。ELISA检测结果显示禁食组脑脊液中orexin-A的含量显著高于对照组23%,而其它两组与对照组相比没有差别。结论:本研究提示orexin-A的功能状态与刺激方式密切相关:急性刺激如2-DG注射适于研究神经元的激活状态,而慢性刺激如禁食适于研究激活后导致的orexin-A表达变化。     

大鼠视上核、室旁核肠三叶因子表达与实验性胃溃疡的关系

目的探讨大鼠实验性胃溃疡自愈期间肠三叶因子(ITF)在下丘脑视上核(SON)、室旁核(PVN)的表达及其与实验性胃溃疡愈合的关系。方法以免疫组织化学染色、酶联免疫吸附实验分别检测溃疡组(42只)和正常组(6只)大鼠下丘脑和血清及ITF的表达及含量变化,RT-PCR检测ITFmRNA的转录情况。结果 ITF免疫反应阳性物质主要位于视上核和室旁核大细胞部。溃疡1d视上核和室旁核ITF积分吸光度略增高,2d、4d和6d逐渐升高,6d达高峰(P0.01),10～23d均维持在较高水平(P0.05)。血清ITF的变化与免疫组织化学法结果相似;溃疡组ITF/3-磷酸甘油醛脱氢酶(GAPDH)吸光度比值在溃疡2～23d均高于正常组(P0.01,或P0.05)。结论胃溃疡自愈期间可能通过下丘脑和血清ITF的高表达参与溃疡愈合的调节。     

The functional plasticity of cells of the paraventricular nucleus of surviving sections of the hypothalamus

Stimulation of the supraoptic nucleus in surviving coronal sections of the hypothalamus elicited in the paraventricular nucleus the appearance of focal potentials reflecting the generation of action potentials of a population of cells. Repeat stimulation was accompanied by a decrease in the descending phase of the focal potentials. Tetanization of the supraoptic nucleus led to the appearance of an additional wave in the descending phase of the focal potentials which was maintained for 15 min. The data obtained attest to the functional plasticity of cells of the paraventricular nucleus of the hypothalamus.Translated from Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 78, No. 2, pp. 50–54, February, 1992.     

Intermittent activation of peripheral chemoreceptors in awake rats induces Fos expression in rostral ventrolateral medulla-projecting neurons in the paraventricular nucleus of the hypothalamus

Despite the well-established sympathoexcitation evoked by chemoreflex activation, the specific sub-regions of the CNS underlying such sympathetic responses remain to be fully characterized. In the present study we examined the effects of intermittent chemoreflex activation in awake rats on Fos-immunoreactivity (Fos-ir) in various subnuclei of the paraventricular nucleus of the hypothalamus (PVN), as well as in identified neurosecretory preautonomic PVN neurons. In response to intermittent chemoreflex activation, a significant increase in the number of Fos-ir cells was found in autonomic-related PVN subnuclei, including the posterior parvocellular, ventromedial parvocellular and dorsal-cap, but not in the neurosecretory magnocellular-containing lateral magnocellular subnucleus. No changes in Fos-ir following chemoreflex activation were observed in the anterior PVN subnucleus. Experiments combining Fos immunohistochemistry and neuronal tract tracing techniques showed a significant increase in Fos-ir in rostral ventrolateral medulla (RVLM)-projecting (PVN-RVLM), but not in nucleus of solitarii tract (NTS)-projecting PVN neurons. In summary, our results support the involvement of the PVN in the central neuronal circuitry activated in response to chemoreflex activation, and indicate that PVN-RVLM neurons constitute a neuronal substrate contributing to the sympathoexcitatory component of the chemoreflex.     

Activity-dependent synaptic plasticity in the supraoptic nucleus of the rat hypothalamus

Activity-dependent long-term synaptic changes were investigated at glutamatergic synapses in the supraoptic nucleus (SON) of the rat hypothalamus. In acute hypothalamic slices, high frequency stimulation (HFS) of afferent fibres caused long-term potentiation (LTP) of the amplitude of AMPA receptor-mediated excitatory postsynaptic currents (EPSCs) recorded with the whole-cell patch-clamp technique. LTP was also obtained in response to membrane depolarization paired with mild afferent stimulation. On the other hand, stimulating the inputs at 5 Hz for 3 min at resting membrane potential caused long-term depression (LTD) of excitatory transmission in the SON. These forms of synaptic plasticity required the activation of NMDA receptors since they were abolished in the presence of d -AP5 or ifenprodil, two selective blockers of these receptors. Analysis of paired-pulse facilitation and trial-to-trial variability indicated that LTP and LTD were not associated with changes in the probability of transmitter release, thereby suggesting that the locus of expression of these phenomena was postsynaptic. Using sharp microelectrode recordings in a hypothalamic explant preparation, we found that HFS also generates LTP at functionally defined glutamatergic synapses formed between the organum vasculosum lamina terminalis and SON neurons. Taken together, our findings indicate that glutamatergic synapses in the SON exhibit activity-dependent long-term synaptic changes similar to those prevailing in other brain areas. Such forms of plasticity could play an important role in the context of physiological responses, like dehydration or lactation, where the activity of presynaptic glutamatergic neurons is strongly increased.     

Effects of septal and hippocampal stimuli on paraventricular nucleus neurons

The electrical activity of 125 neurons within the hypothalamic paraventricular nucleus was recorded in urethan-anaesthetized male rats. Spontaneous activity of the cells and their responses following electrical stimuli delivered to the ipsilateral lateral septum and dorsal hippocampus were recorded. The mean firing rate of all the cells recorded was3.5 ± 0.4 Hz and the majority were located within the dorsal and medial components of the paraventricular nucleus. Forty-six percent of the cells were inhibited following stimulation of the lateral septum (onset,22.8 ± 6.7 ms; offset,195.1 ± 28.5 ms). Inhibitory responses to dorsal hippocampus stimulation were recorded from 44% of all cells (onset,28.1 ± 4.7ms; offset,180.7 ± 28.7ms). Stimulation of both sites caused excitation of equal proportions (26%) of the cells tested (lateral septum onset, 47.7 ± 4.5 ms; offset, 64.8 ± 6.6 ms; dorsal hippocampus onset,48.7 ± 5.6 ms; offset, 72.3 ± 8.8 ms). Of the sub-population of cells identified as projecting to the median eminence, inhibition was recorded from 50% following lateral septum stimulation and 43% following dorsal hippocampus stimulation, excitatory responses being recorded from only 9% of cells tested. The excitatory responses were only recorded from phasically firing, vasopressin-secreting cells identified as projecting to the median eminence, and also to the neurohypophysis. Following stimulation of either site, more phasic cells were excited whilst only few were inhibited. Continuously active cells, identified as projecting to the neurohypophysis, showed more mixed responses following stimulation.

The specificity of the response categories, according to cell-type, and the high degree of convergence of responses (79%;P < 0.05) appear to correlate with a variety of neuroendocrine studies concerning the regulation of anterior and posterior pituitary hormone secretion and the results are discussed in relation to such studies.     

Plasticity of secretory neurons in the supraoptic and paraventricular nuclei of the hypothalamus on exposure to light

Light and electron microscopic methods were used to analyze changes in secretory neurons in the supraoptic (SON) and paraventricular (PVN) nuclei in the hypothalamus in 100 adult male rats at time points from the first minutes to 180 days after 48 hours of full-time exposure to bright light. At the early time points after exposure, the cellular formulae of the SON and PVN shifted towards functionally active neurons with minimal quantities of secretory granules, large nuclei and nucleoli, low RNA contents, small numbers of rough endoplasmic reticulum cisterns, vacuoles, and lysosomes in the perikarya. The number of cells depositing secretion was greater than in controls at 24 h in the SON and PVN and at 10 days in the SON. Normalization of the cellular formula and the structural organization of the protein-synthesizing apparatus of PVN neurons occurred at 10–30 days, with normalization in the SON at 30–180 days. These data provide evidence that the range of plasticity of neurons in the PVN on exposure to full-time bright light was more significant than that in the SON. __________ Translated from Morfologiya, Vol. 127, No. 2, pp. 24–27, March–April, 2005.     

Food deprivation decreases vasopressin mRNA in the supraoptic and paraventricular nuclei of the hypothalamus in rats

We examined the effect of food deprivation for three days on hypothalamic arginine vasopressin (AVP) mRNA in rats. Simultaneously the effect of water deprivation for the same period was examined as a model of dehydration. Levels of AVP mRNA in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) were determined by semiquantitative in situ hybridization histochemistry. Water deprivation increased AVP mRNA in both nuclei as previously reported. In contrast, food deprivation decreased AVP mRNA in these nuclei. The changes in AVP mRNA levels in the PVN were observed in the magnocellular subdivision of the nucleus. Plasma levels of ACTH and corticosterone were greatly increased in both treated groups of rats. Plasma AVP and osmolality levels were significantly elevated in water-deprived rats but not in food-deprived rats. These observations indicated that both food deprivation and water deprivation stimulated the pituitary-adrenal axis and that a reduction in AVP mRNA levels in food-deprived rats was caused by food deprivation but not by glucocorticoid feedback suppression nor by altered plasma osmolality.