大鼠中缝背核及中缝正中核内的VIP、GABA样触液神经元

本文将ＣＢ－ＨＲＰ注入侧脑室，用ＣＢ－ＨＲＰ逆行迫踪与免疫细胞化学相结合的方法，对大鼠脑干内的中缝背核及中缝正中核的远位触液神经元进行了定性研究。结果表明：中缝背核内存在ＶＩＰ样、ＧＡＢＡ样免疫反应阳性的触液神经元；中缝正中核内亦存在少量ＶＩＰ样、ＧＡＢＡ样免疫反应阳性触液神经元。它们的形态和数量各异。本文首次报道中缝背核和中缝正中核内远位触液神经元的化学性质，为探索其机能意义提供了形态学依据。     

Organization of serotoninergic projections from the raphé nuclei to the anterior thalamic nuclei in the rat: a combined retrograde tracing and 5-HT immunohistochemical study

We combined retrograde transport of horseradish peroxidase (HRP) with 5-hydroxytryptamine (5-HT) immunohistochemistry to study serotoninergic projections to the anterior thalamic nuclei (ATN) of the rat. Small iontophoretic injections of HRP into the anterodorsal thalamic nucleus resulted in double-labelled neurons predominantly in the ventromedial and also in the ventrolateral part of the ipsilateral dorsal raphé (DR). A smaller number of double-labelled neurons was also found in the dorsomedial part of the nucleus, predominantly ipsilaterally, and in the median raphé nucleus (MnR), close to the midline. After injection into the medial subdivision of the anteroventral thalamic nucleus, the pattern of labelling in DR and MnR was similar to that detected following injections into the anterodorsal thalamic nucleus. However, injection into the posterior subdivision of the anteroventral thalamic nucleus resulted in bilateral retrograde labelling of a few 5-HT-containing neurons in the dorsolateral part of the DR. Labelling in the ventromedial, ventrolateral and dorsomedial regions of DR and MnR was similar to that detected after injections into the medial subdivision of the anteroventral thalamic nucleus. After all injections into the ATN, double-labelled cells were found throughout the rostrocaudal extent of MnR and throughout the rostral two-thirds of DR. The caudal extension of DR was devoid of double-labelled cells. Although double-labelled cells were observed bilaterally in the dorsolateral part of the DR, the projection from DR to ATN was predominantly ipsilateral. These results show that there is an internal organization within DR such that subnuclei of the DR can be defined on the basis of their efferent projections to specific subdivisions of the ATN.     

Comparative topography of dopamine- and tyrosine hydroxylase-immunoreactive neurons in the rat arcuate nucleus

The distribution of dopamine (DA)-immunoreactive (IR) cells is described in the rat arcuate nucleus of the hypothalamus and its adjacent areas and compared with that of tyrosine hydroxylase (TH)-IR cells. Small DA-IR cells were seen to be aggregated mainly in the dorsomedial part of the nucleus, but were hardly detectable in its ventrolateral portion and neighbouring periarcuate region which showed many larger TH-IR cells. This study reveals, for the first time, the differences in the respective topography of those neurons which actually contain detectable DA and those which contain TH, the initial synthesizing enzyme of catecholamine.     

The role of dopamine in the control of neuropeptide Y neurons in the rat arcuate nucleus

In order to determine the role of dopamine (DA) on neuropeptide Y (NPY) neurons in the arcuate nucleus of the rat hypothalamus, we evaluated the effects of alpha-methylparatyrosine (alpha-MPT), an inhibitor of catecholamines biosynthesis, and haloperidol, a dopaminergic antagonist, on NPY immunoreactive neurons. The two drugs used produced in the arcuate nucleus the appearance of a large number of NPY-containing neuronal bodies which are normally absent in control animals. The density of stained fibers were not significantly modified. These results suggest that DA can exert some negative regulation of NPY neurons activity in the arcuate nucleus.     

L-dopa-immunoreactive neurons in the rat hypothalamic tuberal region

The presence of L-DOPA-immunoreactivity is reported for the first time in the rat hypothalamic tuberal region. L-DOPA-immunoreactive neurons were demonstrated to be present in the ventrolateral part of the arcuate nucleus and periarcuate region just dorsal to the ventral surface of the brain (VLAR/PA). Weakly L-DOPA-immunostained neurons were found in the dorsomedial part of the arcuate nucleus and its neighboring periventricular nucleus (DMAR/PV). In contrast, dopamine (DA)-immunoreactive neurons were detected only in the DMAR/PV. These findings suggest that L-DOPA exists not only as a precursor of DA in neurons of the DMAR/PV, but also as an end-product in cells of the VLAR/PA.     

Isolated catecholaminergic projections from substantia nigra and locus coeruleus to caudate,hippocampus and cerebral cortex formed by intraocular sequential double brain grafts

Summary Sequential intraocular grafting of defined areas from fetal rat brain to adult host rats was used to explore the possibility that such double grafts would become interconnected. Norepinephrine- containing neurons of the locus coeruleus were grafted together with either parietal cerebral cortex, hippocampus, or the caudate nucleus. Dopamine-containing neurons of the substantia nigra were transplanted together with either parietal cerebral cortex or the caudate nucleus. The brainstem grafts showed good survival and development in oculo, using both histochemical and electrophysiological criteria. Locus coeruleus neurons were found to innervate cerebral cortex, hippocampus, and the caudate nucleus. Substantia nigra neurons invaded cerebral cortex abundantly, with a terminal distribution typical of cortical DA terminals in situ. The innervation of the caudate nucleus from substantia nigra transplants was variable, but areas of dense confluent terminals were observed.We conclude that sequential brain grafting in oculo permits generation of isolated yet defined catecholaminergic projections, which are suitable for electrophysiological, pharmacological, and histochemical studies.     

Serotonergic innervation of mesencephalic trigeminal nucleus neurons: a light and electron microscopic study in the rat

Neurons of the mesencephalic trigeminal nucleus (MTN) are considered to be homologous to mechanosensitive neurons in the sensory ganglia. The sites of origin of serotonin (5HT)-immunoreactive axons on neuronal cell bodies in the MTN were studied in the rat by combining immunofluorescence histochemical techniques with retrograde tracing of Fluoro-Gold (FG) and anterograde tracing of biotin-conjugated dextran amine (BDA). The tracing studies, which were combined with multiple-labeling immunohistochemistry and confocal microscopy, indicated that 5HT-immunoreactive axon terminals on the cell bodies of MTN neurons originated from the medullary raphe nuclei, such as the nucleus raphes magmus (RMg), alpha part of the nucleus reticularis gigantocellularis (GiA) and nucleus raphes obscurus (ROb), as well as from the mesopontine raphe nuclei, such as the nucleus raphes dorsalis (DR), nucleus raphes pontis (PnR) and nucleus raphes medianus (MnR); mainly from the RMg, GiA and DR, and additionally from the ROb, PnR and MnR. The cell bodies in close apposition to 5HT-immunoreactive axon terminals were found through the whole rostrocaudal extent of the MTN. Electron microscopically a number of axon terminals that were labeled with BDA injected into the raphe nuclei were confirmed to be in asymmetric synaptic contact with the cell bodies of MTN neurons. It was also indicated that substance P existed in some of the 5HT-containing axosomatic terminals arising from the ROb, RMg and GiA. The present results indicated that proprioceptive sensory signals from the muscle spindles or periodontal ligament might be modulated at the level of the primary afferent cell bodies in the MTN by 5HT-containing axons from the mesopontine and medullary raphe nuclei including the GiA.     

Distribution of dopamine-immunoreactive cell bodies in the guinea-pig brain

The distribution of dopamine (DA)-containing neurons in the guinea-pig brain was investigated immunohistochemically using antibodies raised against glutaraldehyde-conjugated DA. Light microscopical studies revealed the presence of nearly 50,000 DA-immunoreactive cells, localized throughout the hypothalamus and the midbrain. With a few exceptions the dopaminergic cell groups identified by different (immuno)histochemical techniques in the rat were also demonstrated in the guinea-pig brain. These include tyrosine hydroxylase-immunoreactive positive, dopamine-beta-hydroxylase-immunoreactive negative cells in the medial hypothalamus, the ventral tegmental area, the substantia nigra and the dorsal raphe nucleus. A group of dopaminergic cell bodies, not present in the rat, was found to extend from the nucleus retrochiasmaticus into the rostral part of the eminentia mediana. Also at variance with the rat, the guinea-pig lacked DA-immunoreactive cells in a number of homologous areas corresponding to the A15- and A8 cell groups and partly, the A14- and A10 cell groups. However, in general, the localization of dopaminergic cell bodies in the guinea-pig brain appeared similar to that in the rat brain.     

Degeneration of dopaminergic neurons triggers an expression of individual enzymes of dopamine synthesis in non-dopaminergic neurons of the arcuate nucleus in adult rats

Non-dopaminergic neurons expressing individual complementary enzymes dopamine (DA) synthesis were shown to produce DA in cooperation [Ugrumov, M., Melnikova, V., Ershov, P., Balan, I., Calas A., 2002. Tyrosine hydroxylase- and/or aromatic L-amino acid decarboxylase-expressing neurons in the rat arcuate nucleus: ontogenesis and functional significance. Psychoneuroendocrinology 27, 533-548; Ugrumov, M.V., Melnikova, V.I., Lavrentyeva, A.V., Kudrin, V.S., Rayevsky, K.S., 2004. Dopamine synthesis by non-dopaminergic neurons expressing individual complementary enzymes of the dopamine synthetic pathway in the arcuate nucleus of fetal rats. Neuroscience 124, 629-635]. This study was aimed at testing our hypothesis that the cooperative synthesis of DA in non-dopaminergic neurons is an adaptive reaction under functional insufficiency of the dopaminergic system. Functional insufficiency of the tuberoinfundibular dopaminergic system was provoked by 6-OHDA-induced degeneration of dopaminergic neurons in the arcuate nucleus in adult rats. Bienzymatic (dopaminergic) neurons and monoenzymatic neurons expressing tyrosine hydroxylase (TH) or aromatic L-amino acid decarboxylase (AADC) were detected with a double-immunofluorescent technique on cryostat sections. The 6-OHDA-induced degeneration of dopaminergic neurons was accompanied by a significant increase of the number of monoenzymatic TH neurons and AADC neurons that appears to support our hypothesis. The reaction of bienzymatic and monoenzymatic neuron populations to the 6-OHDA administration occurred to be region-specific. The former disappeared in the dorsomedial region of the arcuate nucleus while the latter increased in the ventrolateral region. Thus, degeneration of dopaminergic neurons in the arcuate nucleus of adult rats is accompanied by the expression of individual enzymes of DA synthesis in non-dopaminergic neurons that may be an adaptive reaction.     

Increased utilization of dopamine in the nucleus accumbens but not in the cerebral cortex after dorsal raphe lesion in the rat

Dihydroxyphenylacetic acid (DOPAC) and dopamine (DA) levels were estimated in the frontal cortex, the nucleus accumbens and the striatum of the rat after electrolytical lesion of the dorsal raphe nucleus. The efficiency of this lesion was tested by measuring the decline in serotonin (5-HT) levels in the striatum. 5-HT levels were reduced by 90% when compared to those of sham-operated rats 11 days after the lesion. As revealed both by the increase in DOPAC levels and in the DOPAC/DA ratio, the rate of DA utilization was markedly increased in the nucleus accumbens, slightly enhanced in the striatum and in contrast remained unaffected in the frontal cerebral cortex 4 days after the lesion. Changes in DOPAC levels in the nucleus accumbens were also seen 11 and 30 days after the lesion but they were less pronounced than those observed at 4 days. These results suggest that neurons originating from the dorsal raphe and projecting to the ventro-tegmental area are regulating the activity of the meso-nucleus accumbens dopaminergic neurons but not that of the meso-cortical dopaminergic neurons.     

Tyrosine hydroxylase- and/or aromatic l-amino acid decarboxylase-containing cells in the suprachiasmatic nucleus of the Syrian hamster (Mesocricetus auratus)

Catecholamines, including dopamine (DA), affect the activity of cells in the suprachiasmatic nucleus (SCN) of the hypothalamus, the principal circadian clock in mammals. This study examined the distribution of dopaminergic cells in the SCN of the male Syrian hamster, using both single- and double-label immunocytochemistry for tyrosine hydroxylase (TH), the rate-limiting enzyme in DA synthesis and for aromatic

Full-size image

-amino acid decarboxylase (AADC), the second enzyme needed to produce DA. Some neurons immunopositive for TH (TH+) were found in the SCN, but most of the TH+ cells of the region were located just outside the borders of the nucleus, as defined by pyronin Y staining. In the SCN, 91% of these cells were also immunopositive for AADC and thus, likely to be dopaminergic. Cells positive for AADC, many of which were not TH+, were found throughout the SCN, with the highest concentration seen in the ventral aspects of the nucleus. Cells containing AADC, but lacking TH may synthesize products other than DA, such as trace amines. These anatomical observations suggest that local neurons that produce DA and perhaps trace amines, may play a role in SCN function and in the neural control of circadian rhythms.     

含Calbindin-D28K mRNA的神经元在大鼠脑干中的分布—原位杂交组织化学法观察

用原位杂交组织化学技术,对含Calbindin-D28K mRNA的神经元在大鼠脑干中的分布进行全了面观察。发现不同脑区或核团中所含阳性神经元的数量及其标记强度各不相同。其中含强阳性杂交信号的区域有:小脑皮质、外侧丘系核、斜方体核、下橄榄核及臂旁核;含中等强度杂交信号的区域包括:脚间核、黑质致密部、耳蜗核和最后区。而在其它大部分脑区中杂交信号呈弱阳性,如:上丘、顶盖前区、红核、三叉神经感觉核簇、后索核、下丘、前庭核群、孤束核、中央灰质和网状结构中的部分核团。含Calbindin-D28KmRNA的神经元在脑干中的这种区域特异性分布特点提示在神经系统的某些生理功能中,Calbindin-D28K可能起重要的作用。     

Morphology and distribution of neurons expressing serotonin 5-HT1A receptors in the rat hypothalamus and the surrounding diencephalic and telencephalic areas

Disorders of serotonergic neurotransmission are involved in disturbances of numerous hypothalamic functions including circadian rhythm, mood, neuroendocrine functions, sleep and feeding. Among the serotonin receptors currently recognized, 5-HT_1A receptors have received considerable attention due to their importance in the etiology of mood disorders. While previous studies have shown the presence of 5-HT_1A receptors in several regions of the rat brain, there is no detailed map of the cellular distribution of 5-HT_1A receptors in the rat diencephalon.In order to characterize the distribution and morphology of the neurons containing 5-HT_1A receptors in the diencephalon and the adjacent telencephalic areas, single label immunohistochemistry was utilized. Large, multipolar, 5-HT_1A-immunoreactive (IR) neurons were mainly detected in the magnocellular preoptic nucleus and in the nucleus of diagonal band of Broca, while the supraoptic nucleus contained mainly fusiform neurons. Medium-sized 5-HT_1A-IR neurons with triangular or round-shaped somata were widely distributed in the diencephalon, populating the zona incerta, lateral hypothalamic area, anterior hypothalamic nucleus, substantia innominata, dorsomedial and premamillary nuclei, paraventricular nucleus and bed nucleus of stria terminalis.The present study provides schematic mapping of 5-HT_1A-IR neurons in the rat diencephalon. In addition, the morphology of the detected 5-HT_1A-IR neural elements is also described. Since rat is a widely used laboratory animal in pharmacological models of altered serotoninergic neurotransmission, detailed mapping of 5-HT_1A-IR structures is pivotal for the neurochemical characterization of the neurons containing 5-HT_1A receptors.     

Projections from the raphe nuclei to the suprachiasmatic nucleus of the rat

The presence of serotonergic afferents in the hypothalamic suprachiasmatic nucleus (SCN) is well documented and several functional roles of serotonin (5-HT) in circadian function are well established. However, there is some controversy about the precise location of the serotonergic neurones from where this input arises. Discrete injection of the tracer Cholera toxin, subunit B, (ChB) was centred in the rat SCN, and a few retrograde labelled neurones were distributed in the dorsal and median raphe nuclei (MnR) and in the rostral part of the raphe magnus (RMg), but no neurones were found in the raphe pallidus or raphe obscurus. In addition, a group of neurones was consistently found in the medial part of the pontine supra lemniscal nucleus but not including the serotonergic B₉ region. A combination of retrograde tracing with Fluoro-Gold together with 5-HT-immunolabelling, showed few double-labelled neurones in the dorsal, MnR and B₉. However, the majority of projecting neurones were not co-storing 5-HT immunoreactivity. Phaseolus vulgaris-leucoagglutinin (PHA-L) injections in the dorsal raphe resulted in faint labelling, whereas the MnR gave rise to several labelled fibres in the SCN. Individual delicate PHA-L nerve fibres were found in all compartments of the SCN both in terms of rostrocaudal, ventromedial and dorsomedial extent, without any sign of a topographical organisation of the MnR input to the SCN. PHA-L injections into RMg gave rise to labelling of a few processes within the SCN. In conclusion, the main serotonergic input to the rat SCN originates from a few neurones in the MnR.     

大鼠杏仁体基底外侧核中小白蛋白反应阳性神经元受抑制性神经网络支配(英文)

小白蛋白 (PV)神经元作为杏仁核簇基底外侧核 (BL)中局部神经环路成分 ,对杏仁核的情绪、学习和记忆过程等机能发挥重要作用。为探讨 BL中 PV中间神经元的突触形成状态 ,本研究用抗 PV抗体标示 PV神经元 ,以抗多巴胺 (DA)抗体标示多巴胺能轴突及末梢作为传入纤维的标志 ,对大鼠杏仁核做了免疫电镜双标记研究。结果表明 ,突触主要见于 PV免疫阳性神经元的树突结构上 ,包括从树突干到中间及小型树突的各级分支。其中 68%的突触由未标记的轴突终末形成 ,3 2 %分别由 DA(2 1% )和 PV(11% )免疫阳性轴突末梢形成。 PV免疫阳性神经元与未标记末梢所形成的突触大多数是对称性的 ,仅少数为非对称性。这些非对称性突触见于 PV神经元的树突小棘和连续性突触 ,即一个未标记轴突末梢与另一个未标记轴突末梢形成对称性突触 ,后者又与 PV免疫阳性神经元树突形成非对称性突触。 DA和 PV免疫阳性神经元轴突终末与 PV免疫阳性神经元树突之间的突触全部是对称性的。以上结果表明 ,大鼠杏仁核 BL 的 PV中间神经元受非对称性突触所构成的包括多巴胺系统在内的抑制性神经网络支配     

大鼠脑室触液神经元的分布及其在中缝核团与NADPH-d的共存

目的系统研究脑内接触脑脊液神经元的分布,并对远位触液神经元与一氧化氮合酶的共存进行研究。方法将霍乱毒素B(CTB)注入侧脑室,5d后将动物进行灌注,留取全脑切片,进行CTB免疫组化染色和NADPH鄄d组化染色,镜下观察免疫阳性细胞和纤维的分布。结果CTB标记的触液神经元的分布分为3个区:脑室壁周围、蛛网膜下及大脑皮质表层以及脑实质内。在中缝背核、中缝正中核和线形核等部位还可见NADPH鄄d阳性细胞以及CTB/NADPH鄄d双标细胞。结论侧脑室内触液神经元分布广泛;在中缝系统部分NADPH鄄d阳性细胞与远位触液神经元的共存,提示一氧化氮在脑鄄脑脊液之间的信息传递中有一定作用。     

Localization of neuroactive substances in the rat parabigeminal nucleus: an immunohistochemical study

The distribution of neurons and fibres that contain substance P, cholecystokinin-8, vasoactive intestinal polypeptide, corticotropin-releasing factor, calcitonin-gene-related peptide, choline acetyltransferase, tyrosine hydroxylase, somatostatin, leucine-enkephalin, and neuropeptide Y was examined in the parabigeminal nucleus of the rat by immunohistochemistry. Many choline acetyltransferase-like immunoreactive or calcitonin-gene-related peptide-like immunoreactive neurons were observed in the dorsal, middle and ventral subdivisions of the parabigeminal nucleus. A few corticotropin-releasing factor-like immunoreactive neurons were also seen in these three subdivisions. The double-immunostaining demonstrated that some choline acetyltransferase-like immunoreactive neurons in the dorsal and ventral subdivisions contained calcitonin-gene-related peptide. Fibres containing cholecystokinin-8, substance P or vasoactive intestinal polypeptide were abundant in the parabigeminal nucleus. Fibres containing cholecystokinin-8 were concentrated in the dorsal and ventral subdivisions, and the lateral margin of the middle subdivision, whereas many fibres containing substance P or vasoactive intestinal polypeptide existed in the lateral half of each subdivision. Fibres containing calcitonin-gene-related peptide or corticotropin-releasing factor were mostly observed around the immunoreactive neurons. Tyrosine hydroxylase-like immunoreactive fibres were scattered in the parabigeminal nucleus.     

Immunocytochemical visualization of D-glutamate in the rat brain

Using highly specific antisera directed against conjugated d-amino acids, the distribution of d-glutamate-, d-tryptophan-, d-cysteine-, d-tyrosine- and d-methionine-immunoreactive structures in the rat brain was studied. Cell bodies containing d-glutamate, but not d-glutamate-immunoreactive fibers, were found. Perikarya containing this d-amino acid were only found in the mesencephalon and thalamus of the rat CNS. Thus, the highest density of cell bodies containing d-glutamate was observed in the dorsal raphe nucleus, the ventral part of the mesencephalic central gray, the superior colliculus, above the posterior commissure, and in the subparafascicular thalamic nucleus. A moderate density of immunoreactive cell bodies was observed in the dorsal part of the mesencephalic central gray, above the rostral linear nucleus of the raphe, the nucleus of Darkschewitsch, and in the medial habenular nucleus, whereas a low density was found below the medial forebrain bundle and in the posterior thalamic nuclear group. Moreover, no immunoreactive fibers or cell bodies were visualized containing d-tryptophan, d-cysteine, d-tyrosine or d-methionine in the rat brain. The distribution of d-glutamate-immunoreactive cell bodies in the rat brain suggests that this d-amino acid could be involved in several physiological mechanisms. This work reports the first visualization and the morphological characteristics of conjugated d-glutamate-immunoreactive cell bodies in the rat CNS using an indirect immunoperoxidase technique. Our results suggest that the immunoreactive neurons observed have an uptake mechanism for d-glutamate.     

The distribution and ultrastructure of VIP-immunoreactivity in the central nucleus of the rat amygdala

Vasoactive intestinal polypeptide (VIP) neurons within the central nucleus of the rat amygdala were examined using light and electron microscopic immunocytochemical techniques. Vasoactive intestinal polypeptide-immunoreactive neurons were located in the ventral part and less frequently in the central part of the central nucleus. Vasoactive intestinal polypeptide positive terminals were distributed throughout the medial part of a cytoarchitectonically distinct central zone of the central nucleus. Three types of terminals formed synaptic contacts on VIP-immunoreactive neurons: type A containing round vesicles, type B containing many pleomorphic vesicles and type C containing fewer pleomorphic vesicles. All VIP-immunoreactive boutons observed were of type A variety, and made asymmetrical and symmetrical synaptic contacts on both VIP-immunoreactive and nonreactive neurons within the central nucleus.     

Detailed organization of nitric oxide synthase, vasopressin and oxytocin immunoreactive cell bodies in the supraoptic nucleus of the female rat

The anatomical distribution and quantitative relations of cell bodies containing neuronal nitric oxide synthase (nNOS), 8-arginine vasopressin (AVP) and oxytocin (OT) were examined throughout the supraoptic nucleus (SON) of the female rat by means of immunocytochemical and NADPH-diaphorase (NADPH-d) histochemical techniques using a triple labelling methodology. Seven chemically defined populations of neurons containing all combinations of either nNOS, AVP or OT were identified. nNOS-containing (NADPH-d positive) neurons, amounting to about 40% of all neurons counted, were most frequent in central and dorsal regions, and were evenly distributed along the rostro-caudal axis. Two small nNOS-positive neuronal populations were preferentially located dorso-centrally in the nucleus: nNOS-positive neurons containing both AVP- and OT-immunoreactivity, and neurons only containing nNOS. Slightly less than half of all nNOS-positive neurons contained AVP, and a similar share of nNOS-positive neurons contained OT. The occurrence of nNOS-positive/ AVP-containing neurons was highest in the caudal half, whereas that of nNOS-positive/OT-neurons was highest in the rostral half of SON. The data demonstrate new findings concerning the anatomical organization and co-localization patterns of nNOS-, AVP- and OT-containing neuronal populations in SON. We conclude that the absolute and relative occurrence of the identified neuronal populations vary markedly in different parts of SON. This is important to take into consideration when performing, and evaluating experimental investigations concerned with neurochemical changes in SON. Accepted: 29 December 2000