The influence of age on supraoptic nucleus neurons of the rat: morphometric and morphologic changes.

Neurosecretory neurons (NSNs) of the supraoptic nucleus of 2-year-old rats presented significantly greater nuclear volumes and nuclear perimeters than those of 3-month-old animals. In aged NSNs, membranous bodies (MBs) were observed in the cytoplasm and the cell nucleus. The possible origin and function of these MBs are discussed.     

Ultrastructural evidence of sexual dimorphism in supraoptic neurons: a morphometric study

Summary We have recently shown that in spite of the absence of receptors for gonadal steroids in the supraoptic nucleus (SON) of the rat hypothalamus, the volume of the nucleus and the size of its neurons are larger in males than in females, and that these differences between male and female rats are correlated with body weight and dependent on the vasopressinergic neurons. As supraoptic neurons and their organelles enlarge when they are engaged in active peptidergic secretion we have carried out a morphometric ultrastructural analysis to determine if cell structures involved in the synthesis and storage of neurosecretory material also display weight-dependent sex dimorphism. Groups of six male and six female rats aged 30,60 and 180 days were used. Nucleoli, rough endoplasmic reticulum and neurosecretory granules were analysed and we estimated their volume or surface densities and the total volume of nucleoli and rough endoplasmic reticulum, and total surface area of rough endoplasmic reticulum. We found that, with the exception of neurosecretory granules, the densities of the organelles did not differ among the groups studied, but total values were higher in males. These differences were found to be weight-dependent. Since the organelles studied are regarded as reliable indicators of the neurosecretory activity of supraoptic neurons, our data fully support the view that the weight-dependent sexual dimorphism observed in this nucleus reflects greater synthetic activity of its vasopressinergic neurons associated with the need to maintain water balance in larger bodies.     

Studies on functional connections between the supraoptic nucleus and the stomach in rats

The present study was to investigate whether there are functional connections between the hypothalamic supraoptic nucleus (SON) and the stomach, which is the case with the paraventricular nucleus. The rats were divided into four groups. Group I: the neuronal discharge was recorded extracellularly in the NTS, DMV or SON before and after cold physiological saline (4°C) was perfused into the stomach and effused from the duodenum. Group II: the rats were stimulated as for Group I and c-Fos expression in NTS, DMV and SON was examined. Group III: the control to Group II. Group IV: gastric motility was recorded continuously before and after microinjection of l-Glu into the SON. In Group I, the discharge frequency increased in all the three nuclei, while in Group II, Fos expression in NTS, DMV and SON was, respectively, greater than that of Group III. In Group IV, microinjection of l-Glu (5 nmol) into SON significantly inhibited gastric motility. These data suggest there are functional connections between SON and stomach.     

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。     

The sinusoidal barrier in rats with portacaval anastomosis: A morphometric study

Summary Shunting of portal blood in the rat leads to liver atrophy and to an increase in arterial blood flow with microcirculatory disturbances. The aim of this study was to investigate the effects of these disturbances on the liver sinusoidal barrier (endothelial and perisinusoidal cells) using morphometric techniques. Rats with portacaval anastomosis (PCA) and sham operated pair-fed controls were studied 3 months after the shunt. Sinusoidal volume density in PCA increased but not significantly and the volume density (V_v) of total endothelial (EC) and perisinusoidal cells (PSC) increased by 104.54% compared to sham operated pair-fed rats. The increase of EC V_v was not associated with an increase in surface density (S_v) suggesting a fall in the number of small fenestrations and an increase in cell thickness. This interpretation supports the morphological observations. The increase of PSC V_v was mainly related to the increase in their subendothelial processes V_v and not to that of the cell body V_v. Lipids V_v and RER S_v expressed per sinusoidal cells remained unchanged suggesting that the balance between the 2 hypothetical functions of the PSC, namely fibrogenesis and storage of vitamin A, was maintained.In conclusion, changes of EC and PSC after PCA result mainly in thickening of the sinusoidal barrier. This increase may impair exchanges between the sinusoidal lumen and Disse space and contribute to functional abnormalities.This work was supported by a grant from INSERM CRL n^o 807003     

Cholinergic input to the supraoptic nucleus increases Fos expression and body temperature in rats

To examine the role played by cholinergic input and processes in the supraoptic nucleus (SON) in the control of body temperature and water intake in rats, we used microdialysis to stimulate and analyze SON without disturbing the behavior of unanesthetized rats. After microdialysis, we also investigated immunoreactivity for c-Fos protein in the brain as an index of neuronal activation. Stimulation with neostigmine, an acetylcholine esterase inhibitor, through the microdialysis probe increased the extracellular concentration of acetylcholine in the SON. This cholinergic stimulation dose-dependently increased body temperature but did not significantly change the water intake. The stimulation markedly increased c-Fos-like immunoreactivity (Fos-IR) in the SON and certain hypothalamic areas, including the paraventricular nucleus (PVN) and median preoptic nucleus (MnPO). Fos-IR was also evident in certain regions of the pons and brainstem, including the locus ceruleus (LC), area postrema (AP), and nucleus of the solitary tract (NTS). Addition of atropine, a muscarinic receptor antagonist, to the dialysis medium containing neostigmine attenuated the increase of Fos-IR and suppressed the neostigmine-induced responses in body temperature. These results suggest that cholinergic input and activation of the muscarinic cholinoceptive neurons in the SON contribute to the regulation of body temperature. Activation of noradrenergic pathways in the brainstem including LC and NTS may be involved in the thermoregulation mechanism.     

高渗刺激诱导大鼠视上核与孤束核内神经元-星形胶质细胞复合体反应

目的 探讨大鼠接受高渗刺激后,视上核和孤束核内神经元-星形胶质细胞复合体(N-ASC)反应.方法 成年雄性SD大鼠50只,随机分为光镜组(n=40)和电镜组(n=10).采用多重免疫荧光标记法,在光镜下观察高渗刺激(9%氯化钠,5.5ml/kg尾静脉注射)后15、45、90和180 min,视上核内胶质纤维酸性蛋白(GFAP,标记星形胶质细胞)、催产素(OXT,标记视上核神经元)、Fos(标记神经元胞核)和孤束核内GFAP、酪胺酸羟化酶(TH,标记神经元)、Fos表达的时程变化.采用双重免疫电镜法,观察高渗刺激后视上核N-ASC内星形胶质细胞(用Cx43标记)与神经元(用Cx32标记)之间接触处的超微结构.结果光镜下在视上核和孤束核可分别观察到3种N-ASC,即:由 GFAP阳性星形胶质细胞与 OXT(或TH)阳性神经元形成的N-ASC;由GFAP阳性星形胶质细胞与Fos阳性神经元形成的N-ASC;由GFAP阳性星形胶质细胞与Fos和OXT(或TH)双阳性神经元形成的N-ASC.高渗刺激后 N-ASC的数量明显增加.抗Cx43和抗Cx32的双重免疫电镜显示,高渗刺激后Cx43阳性星形胶质细胞突起(即Cx43半通道)以及Cx32和Cx43形成的异型缝隙连接(HGJ)的数量明显增加.结论视上核和孤束核内的N-ASC参与渗透压调节反应.     

Dye coupling among immunocytochemically identified neurons in the supraoptic nucleus: increased incidence in lactating rats

The hypothesis that electrotonic spread among oxytocinergic neurons contributes to synchronized bursting in the lactating rat leads to the prediction that coupling among oxytocinergic neurons would be stronger and more abundant in lactating than in non-lactating animals. We tested this prediction using, as an index of electrical coupling, transfer among neurons of the fluorescent dye Lucifer Yellow CH, which crosses gap junctions. Intracellular injections (total of 159) of the dye were made in supraoptic nucleus neurons in hypothalamic slices from virgin female and lactating rats. In virgins, 86 injections resulted in 76 single, 8 coupled pairs and 2 triplets of dye-filled neurons. In contrast, 73 injections in lactators yielded 51 single, 16 coupled pairs and 6 triplets, (greater than 100% increase) a difference significant at P less than 0.001. Immunocytochemical identification of the dye-filled cells revealed that there was an increase over virgins in coupling among both oxytocinergic and vasopressinergic neurons. These results are consistent with the hypothesis that electrical coupling is involved in synchronizing oxytocin cell bursting in lactators. They are also consistent with published data indicating that vasopressin neurons are metabolically activated (show increased glucose uptake) during suckling and may show correlated activity.     

Vasopressinergic neurons of the supraoptic nucleus in perinatal rats: reaction to osmotic stimulation and its regulation

Osmotic stimulation (OS) of vasopressin (VP) neurons of the supraoptic nucleus (SON) promotes VP secretion and tyrosine hydroxylase (TH) expression in adult mammals. VP secretion is under a noradrenaline control, whereas the regulation of TH expression remains uncertain. This study was aimed to determine at what period of ontogenesis: (1) VP neurons begin to react to OS by modifying simultaneously VP and TH gene expression and synthesis, (2) the noradrenergic control of VP neurons is established. Rats on the 21st embryonic day (E), third postnatal day (P), P13 were salt loaded or salt loaded and treated with an antagonist (prazosin) or agonist (phenylephrine) of α1-adrenoreceptors. According to our immunocytochemical and in situ hybridization data, OS resulted in an increased amount of VP mRNA in each age group and of VP on E21 and P3. TH gene and synthesis was initially expressed under OS on P3. The number of TH-expressing neurons diminished by threefold in salt loaded rats from P3 to P13. OS combined with prazosin administration resulted in an increased level of VP mRNA on P3 and P13, but not on E21 suggesting the onset of the noradrenaline inhibitory control after birth. OS together with prazosin treatment stimulated TH expression on P3 and P13, whereas phenylephrine provided an opposite effect. Thus, VP neurons begin to react to OS by an increased VP synthesis at the end of fetal life and by the onset of TH expression shortly after birth; the expression of both substances appears to be under the inhibitory control of noradrenaline.     

Anatomy of the human nucleus accumbens: a combined morphometric study

Purpose  

The human nucleus accumbens (NA), which belongs to the basal ganglia of the brain, is the main part of the ventral striatum. The purpose of our clinically oriented anatomical-radiologic study was to provide anatomical and imaging data of the human NA, primarily useful to neurosurgeons.     

不同月龄大鼠视上核血管加压素分泌的比较研究

我们应用光电镜技术、免疫细胞化学技术和图象分析技术对不同月龄大鼠视上核神经元ＡＶＰ的分泌进行了比较研究。结果：电镜下老龄组神经元胞质内脂褐素较多;ＰＡＰ法显示成龄组ＡＶＰ阳性细胞染色呈深棕色;数据经统计学处理有显著性差异,提示成龄组分泌功能较强而老龄组分泌功能减弱。     

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。     

Neuronal development in the trigeminal mesencephalic nucleus of the duck under normal and hypothyroid states: I. A light microscopic morphometric analysis

Light microscopic morphometric procedures were used in order to examine the effects of propylthiouracil (PTU) on the development of the mesencephalic nucleus of the trigeminal nerve in the duck. A single vascular injection of a 0.2% solution of PTU was administered at a dosage of 2 microliter/gm embryo weight on embryonic day nine (E9). Control embryos received a similar dose of Ringer's solution. The following parameters of cytodifferentiation of cells of the mesencephalic nucleus of V were studied: somal area profiles, nuclear area, and nuclear cytoplasmic ratios. In addition, the frequency of beak clapping was recorded from E16. Significant differences were observed in somal area profiles in the experimental group at E16 and E18 and in nuclear area profiles from E16 through hatching. Beak activity in the experimental embryos was drastically reduced. It is concluded that PTU induces a retardation in the differentiation of cells of the mesencephalic nucleus of V which may lead to behavior deficits as evidenced by reduction of beak activity. These observations provide a basis for the study of interactions between thyroid hormone and specific neuronal systems in the emergence of an adaptive function.     

Cell formation in the motor nucleus and mesencephalic nucleus of the trigeminal nerve of rats made hypothyroid by propylthiouracil

Summary Neurogenesis in the motor and mesencephalic nuclei of the trigeminal nerve was examined using autoradiographic techniques. Two groups of pregnant rats (control and experimental) were injected with two successive daily doses of 3H thymidine in an overlapping series starting from day nine of gestation in order to label in their progeny, the dividing precursor of neurons of the motor nucleus and mesencephalic nucleus of the trigeminal nerve. Control group of rats was raised on a standard diet, while the experimental group was made hypothyroid by propylthiouracil (PTU). At postnatal ages ranging between 20–30 days in the pups of both the control group and experimental group, the percentage of cells labelled and the proportion of cells added during each embryonic day were determined quantitatively throughout the rostro-caudal extent for both motor and mesencephalic nuclei. The neurons of the mesencephalic nucleus undergo their final cell divisions between gestational days 9 and 10 (E9 and E10). More than 80% of the population is generated by E10. The neurons of the motor nucleus undergo their final cell divisions between E9 and E11, and nearly 88% of the cells is generated by E11. In the thyroid deficient rats, in both nuclear centers, only 61% of the cells is generated by E12, and labelled cells are observed even as late as E18 and E19. In the hypothyroid state, there is a significant lengthening of the proliferative period. On the basis of absolute datings and duration of neuron production, it is postulated that in normal development, thyroid hormone determines the duration of the proliferative period, and push cells into the differentiative phase by taking them out of the proliferative phase.     

Different pharmacological anatomy in the paraventricular hypothalamic nucleus,supraoptic nucleus,and suprachiasmatic nucleus of rats: Quantitative autoradiography on angiotensin II receptor binding sites

Angiotensin II (AII) and vasopressin (VP) play important roles in cardiovascular function. Using ¹²⁵I-[Sar¹, Ile⁸]-angiotensin II (¹²⁵I-SI-AII), a potent AII antagonist, AII receptor binding sites were autoradiographically localized in three VP-producing areas of the hypothalamus and compared in hypertensive and normotensive rats. Within three major VP-producing areas, AII receptor binding was highest in the paraventricular hypothalamic nucleus and lowest in the supraoptic nucleus, suggesting that a differential AII regulation of separate VP systems exists in the brainstem. No statistical difference in ¹²⁵I-SI-AII receptor binding was found between WKY and SHR rats in each of the three major VP-producing nuclei studied. These results are consistent with a role of AII receptors in a subtle and complicated regulation of VP in cardiovascular function.