大鼠前庭核向脑干呕吐区的间接投射

前庭信息调节内脏活动的神经通路是产生运动病的结构基础,但至今尚未明了。本研究旨在探讨接受初级前庭传入信息的前庭核到脑干呕吐中枢的神经通路。向大鼠前庭内侧核和前庭下核内注入顺行追踪剂生物素化葡聚糖胺(BDA),向脑干呕吐区注入逆行追踪剂荧光金(FG),用荧光组织化学方法显示BDA顺行标记纤维和终末,在荧光显微镜下观察BDA顺行标记纤维和终末与荧光金逆行标记细胞的重叠区域。结果发现在延髓背侧巨细胞旁核(DPGi)、巨细胞网状核(Gi)和小细胞网状核(PCRt)有顺行标记纤维与逆行标记细胞的重叠。表明前庭核可能经DPGi、Gi和PCRt向呕吐区有间接投射,此结果为进一步揭示前庭信号引发恶心、呕吐的神经机制提供了形态学依据。     

大鼠前庭核向迷走神经背侧复合体的间接投射

目的：研究大鼠前庭核向迷走神经背侧复合体的间接投射,探索前庭信息向脑干呕吐区传递的神经通路。方法：向前庭神经下核和前庭神经内侧核注入顺行追踪剂菜豆凝集素（PHA-L）,向迷走神经背侧复合体注入逆行追踪剂荧光金（FG）,用免疫荧光组织化学方法显示PHA-L顺行标记纤维和终末,在荧光显微镜下观察顺行标记PHA-L的纤维和终末与FG逆行标记的细胞重叠区域。结果：在延髓外侧巨细胞旁核和腹外侧区有顺行纤维和终末与逆行标记细胞的重叠。结论：前庭核团可能经外侧巨细胞旁核和腹外侧区向迷走神经背侧复合体有间接投射,为进一步揭示前庭核团与呕吐相关的内脏反应区之间的功能关系提供了形态学基础。     

大鼠三叉神经节细胞向三叉神经脊束核各亚核的分枝投射

本文应用荧光素双标记与免疫荧光结合方法研究了单个含ＳＰ或ＣＧＲＰ的三叉神经节细胞向三叉神经脊束核的尾侧亚核、极间亚核和吻侧亚核的分枝投射。将ＤｉａｍｉｄｉｎｏＹｅｌｌｏｗ（ＤＹ）注入尾侧亚核，ＦａｓｔＢｌｕｅ（ＦＢ）分别注入吻侧亚核或极间亚核，发现ＤＹ／ＦＢ双标细胞占同侧三叉神经节内标记细胞总数的１３．２％（ＦＢ注入吻侧亚核例）和２．３％（ＦＢ注入极间亚核例）；双标细胞中含ＳＰ者分别为７４．４％和６９．６％；含ＣＧＲＰ者分别为７２．１％和６４．３％。将ＤＹ注入极间亚核，ＦＢ注入吻侧亚核时，ＤＹ／ＦＢ双标细胞占同侧三叉神经节标记细胞总数的１．６％，双标细胞中有６７．９％为ＳＰ阳性，７３．９％为ＣＧＲＰ阳性。多数的双标且呈ＳＰ或ＣＧＲＰ阳性的三叉神经节细胞直径约为２５～５０μｍ，为中、小型节神经元，而直径大于５０μｍ的大型细胞较少见。以上结果提示，三叉神经初级传入纤维进入脑干后的下降支分枝投射向三叉神经脊束核的各亚核，它们可能与面口部的痛信息传递有关。ＳＰ和ＣＧＲＰ是这些分支投射神经元的重要神经活性物质。     

大鼠三叉神经脊束核尾侧亚核和脊髓向丘脑和臂旁核的谷氨酸能投射

本研究用荧光金逆行追踪与免疫荧光组比技术相结合的方法,对大鼠三叉神经脊束核尾侧亚核和脊髓向丘脑和臂旁核的谷氨酸能投射进行了观察。磷酸激活的谷氨酸胺酶（PAG）是谷氨酸能神经元的特异性标识物。PAG样阳性胞体主要位于三叉神经脊束核尾侧亚核和颈髓背角的Ⅰ层,少量PAG样阳性胞体也见于它们的Ⅱ层外侧部及外侧网状核。将荧光金注入丘脑腹基底复合体后．荧光金逆标神经元主要见于对侧三叉神经脊束核尾侧亚核和颈髓背角的Ⅰ层及外侧网状核;将荧光金注入臂旁核后,荧光金逆标神经元也主要见于对侧三叉神经脊束核尾侧亚核和颈髓背角的Ⅰ层及外侧网状核。三叉神经脊束核尾侧亚核向丘脑腹基底复合体投射神经元的12．4％,向臂旁核投射神经元的13．2％呈PAG样阳性;颈髓背角浅层向丘脑瓜基底复合体投射神经元的12．7％,向臂旁核投射神经元的14．3％呈PAG样阳性。向丘脑腹基底复合体和臂旁核投射的PAG／荧光金双标神经元分别占三叉神经脊束核尾侧亚核浅层内PAG样阳性神经元总数的13％和24．6％,向丘脑腹基底复合体和臂旁核投射的PAG／荧光金双标神经元分别占颈髓背角浅层内PAG样阳性神经元总数的11．6％和30．1％。外侧网状核内的部分PAG样阳性神经元也向丘脑腹基底复合体或臂旁核投射。Ⅰ层内的双?     

大鼠展神经核和前庭神经核内GABA反应神经元向动眼神经核的投射

用辣根过氧化物酶(horseradish peroxidase,HRP)逆行标记结合γ-氨基丁酸(γ-amino-butyric acid,GABA)的免疫组织化学双标技术观察大鼠的展神经核和前庭神经核内GABA阳性神经元的分布,以及其向动眼神经核的投射。结果表明:注射HRP于大鼠动眼神经核内直肌亚核后,在对侧展神经核区以及前庭神经核、脑桥旁正中网状结构中发现HRP单标记细胞;在前庭神经核内,可见HRP单标记、GABA阳性和HRP/GABA双标记三类神经元,其中HRP/GABA双标记细胞占HRP标记细胞总数的47.1%。结果表明GABA在前庭神经核向动眼神经核的抑制性投射中起一定作用,而在展神经核向动眼神经核投射的核间通路中,可能不是起主要作用的抑制性神经递质。     

大鼠三叉神经节神经元向三叉神经脊束核尾侧亚核和孤束核的分支投射

为研究三叉神经节神经元向三叉神经脊束核尾侧亚核（ＶＣ）和孤束核（ＮＴＳ）的分支投射，用荧光素逆行追踪双标记方法，Ｆａｓｔｂｌｕｅ（ＦＢ）和Ｎｕｃｌｅａｒｙｅｌｏｗ（ＮＹ）分别注射入三叉神经脊束核尾侧亚核和孤束核后，荧光显微镜（３６０ｎｍ激发波长）下可见三叉神经节内的多种逆行标记神经元。ＦＢ显示明亮的蓝色标记胞浆，而ＮＹ标记则为黄绿色的圆形胞核。虽大多数神经元为单标记，但部分也呈黄色胞核，蓝色胞浆的双标记细胞。双标记细胞多为直径３０μｍ以下的中、小型，鲜见大型细胞。分支投射神经元可能扩散传递口、舌伤害性痛觉信息并在ＶＣ和ＮＴＳ内与其他来源的内脏、躯体感觉传入信息相互影响。     

大鼠三叉神经脊束核吻侧亚核背内侧部向三叉神经中脑核的回返投射

既往的研究证明,由支配咬肌的三叉神经中脑核神经元到丘脑腹后内侧核存在着一条由四级神经元组成的传递本体觉信号的中枢通路．此通路的第二级神经元位于三叉神经脊束核吻测亚核背内侧部和邻接的小细胞网状核的一部分,第三级神经元存在于沿三又神经感觉主核内缘伸延的“带状区”。本研究将ＰＨＡ－Ｌ注入第二级神经元所在区域,不仅在“带状区”发现有很多标记终末,而且在三叉神经中脑核区域内也发现较密集的ＰＨＡ－Ｌ阳性终末,许多终末与中脑核神经无形成密切接触．对这种材料又向咬肌神经内注入ＨＲＰ,观察到有一些ＨＲＰ标记的中脑核神经元与ＰＨＡ－Ｌ标记终末接触．本研究结果提示,在三叉神经本体感觉通路中,由第二级神经元的核区向初级传入神经元发出有回返投射,并对其机能意义进行了讨论．     

大鼠三叉神经脊束核尾侧亚核和脊髓向丘脑和臂旁核的强啡肽能和一氧化氮能投射

本文用荧光金逆行追踪与免疫荧光组化染色相结合的方法，对大鼠三叉神经脊束核尾侧亚核和颈髓背角浅层向丘脑腹基底复合体和臂旁核的强啡肽能和NO能投射进行了研究．强啡肽原前体样阳性胞体主要位于尾侧亚核和颈髓背角的Ⅰ层和Ⅱ层外侧部；NOS样阳性胞体主要位于尾侧亚核和颈够背角Ⅱ层，Ⅰ层较少。将荧光金注入丘脑腹基底复合体后，荧光金逆标神经元主要见于对侧尾侧亚核、颈髓背角的Ⅰ层和外侧网状核，Ⅱ层偶见；将荧光金注入臂旁核后，逆标神经元主要见于同侧尾侧亚核和颈髓背角的Ⅰ、Ⅱ层，少量位于外侧网状核。尾侧亚核向丘脑瓜基底复合体投射神经元的16．6％，向臂旁核投射神经元的24．8％呈强啡肽原前体样阳性；颈髓背角浅层向丘脑腹基底复合体投射神经元的19．2％，向臂旁核投射神经元的272％呈强啡肽原前体样阳性。向丘脑腹基底复合体和臂旁核投射的强啡肽原前体／荧光金双标神经元分别占尾侧亚核浅层内强啡肽原前体样阳性神经元总数的7％和18％，分别占颈髓背角浅层内强啡肽原前体样阳性神经元总数的8．1％和21．9％。这些双标神经元多呈大梭形及中等大圆形和梨形。由昆侧亚核向丘脑腹基底复合体投射神经元的5．1％呈NOS阳性，向臂旁核投射神经元的11．8％呈NOS阳性。由颈髓背角浅层向丘脑版?     

大鼠颈髓中央核向前庭神经外侧核的定位纤维投射

目的　探讨大鼠颈髓中央核向前庭神经外侧核的定位投射。方法　本实验通过向脊髓内单侧注射菜豆—白细胞凝集素 ,在不同节段上对由脊髓向前庭神经核的纤维投射做顺行示踪。结果　在颈髓颈 2和颈 3节段包括颈髓中央核单侧注射示踪剂后 ,应用免疫组织化学法在对侧前庭神经下核以及前庭神经内侧核的大型细胞、小型细胞部和尾部内可见大量标记终末。在对侧前庭神经外侧核由头部至尾部整个范围内 ,标记物数量最多 ;在颈膨大处单侧注射示踪剂后 ,在对侧前庭神经内侧核的大型细胞部见很多标记轴突和终末 ,但在前庭神经外侧核和前庭神经下核内 ,仅见少量标记轴突和终末。在颈膨大以下脊髓节段注射示踪剂后 ,在前庭神经内侧核的大型细胞部、前庭神经下核及前庭神经外侧核的尾部标记纤维和终末仅零星存在。结论　颈部初级传入纤维经过颈中央核中继后 ,可直接投射到对侧前庭神经外侧核 ,同时 ,研究结果亦提示颈髓中央核可能是颈部传入冲动的中继和整合之处     

大鼠中脑导水管周围灰质向三叉神经脊束核尾侧亚核的5-羟色胺能投射

大鼠中脑导水管周围灰质(PAG)向三又神经脊束核尾侧亚核(Sp 5 C)投射的起源细胞在其吻、中、尾三个部分的分布不同,且由尾段向吻段有从腹侧向背侧移行的趋势。尾段的HRP逆标细胞主要位于PAG的腹外侧区、内侧区腹侧部;中段的标记细胞较多,主要见于腹外侧区、背侧区和背外侧区腹侧部,尚可见一些顺行标记的终末;吻段的标记细胞主要位于背外侧区,在上丘深层、Cajal氏中介核、Darkschewitsch氏核内,也可见标记细胞。标记细胞和终末均主要位于注射侧的PAG内。PAG向Sp 5 C投射的5-羟色胺(5-HT)样神经元主要位于PAG的中、尾段的腹外侧区和内侧区腹侧部。中段的双标细胞占全部双标细胞数的57％,尾段占41％,吻段占2％。在背中缝核(DR)内,亦可见到一些双标细胞。PAG内的双标细胞占其HRP标记细胞总数的37％,但仅占5-HT样阳性细胞总数的4.5％。标记细胞主要为中型(20—30μm)梭形及三角形,小型(<20μm)梭形和大型(>30μm)多角形细胞较少见。     

Direct projections from vestibular nuclei to facial nucleus in cats

Postsynaptic potentials were recorded from motoneurons in the facial nucleus in response to stimulation of the vestibular and trigeminal nerves. The motoneurons were identified by antidromic activation from their peripheral axons. Disynaptic excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) and mixed EPSP/IPSPs were recorded in response to vestibular nerve stimulation, ranging in latency from 0.9 to 2.1 ms, with most at 1.5 ms. Activity in secondary vestibular axons recorded within the facial nucleus occurred at a latency of 0.7-1.1 ms. The amplitudes of the vestibular postsynaptic potentials were small, generally less than a millivolt, but double shocks produced marked summation. The average time to peak of ipsilateral vestibular EPSPs, 1.1 ms, was faster than that of either ipsilateral IPSPs, 1.6 ms, or contralateral EPSPs, 1.4 ms. The double-spiked vestibular activity was detectable in double-peaked PSPs. Disynaptic EPSPs, ranging in latency from 2.0 to 3.0 ms, were recorded in response to trigeminal nerve stimulation. The average time to peak was 1.3 ms. The multiple-spiked activity of the trigeminal neurons was detectable in multipeaked EPSPs. Inhibitory ipsilateral effects (Vi IPSPs) were recorded twice as often as excitatory ipsilateral effects (Vi EPSPs), being found in 29% versus 15% of the motoneurons. Contralateral effects were found in 13% of the motoneurons studied, and almost all were excitatory. Analysis of synaptic potential shapes suggested that the excitatory and inhibitory vestibular synapses probably contact distal dendrites preferentially, with the excitatory connections being somewhat closer to the soma. The trigeminal inputs probably contact the facial motoneurons more extensively near the soma. Horseradish peroxidase was injected into the facial nucleus, and retrograde uptake by vestibular neurons was studied. The majority of filled vestibular neurons was ipsilateral to the injection site, especially in the medial vestibular nucleus, ventral y group, and supravestibular nucleus. On the contralateral side, filled vestibular cells were found almost exclusively in the medial nucleus. Filled cells were also noted in the trigeminal nucleus, predominantly ipsilaterally at all rostrocaudal levels. We have demonstrated monosynaptic projections to facial motoneurons from both vestibular and trigeminal nuclei. The trigeminal input is likely to be involved in facial reflexes, especially blinking and grimacing. The afferent vestibular population overlaps that going to the oculomotor and cervical motoneurons; these projections may be collaterals of single vestibular neurons.4+.     

大鼠前庭神经核群向腰髓投射特征——BDA法逆行研究

目的　研究大鼠前庭神经核群向脊髓的投射纤维特征。方法　在 7例SD大鼠采用结合生物素的葡聚糖胺(BDA)逆行法观察大鼠前庭核群向脊髓的投射。结果　除前庭神经上核 (SVN)外的其余各前庭核均有向大鼠腰髓的投射 ,单侧注射的实验动物中 ,前庭神经内侧核 (MVN)、外侧核 (LVN)和降核 (DVN)的标记神经元可见于双侧 ,其中MVN和LVN的标记神经元以注射同侧占优势 ,而DVN标记神经元两侧数量基本一致。结论　大鼠前庭脊髓尾侧束发出纤维投向脊髓腰段     

A cerebellar projection onto the pontine nuclei in the albino rat

Summary Following removal of a significant part of the dentate nucleus and most of the interpositus nucleus in the rat cerebellum degenerated cerebellopontine fibres are shown to end in three fairly restricted regions in the contralateral pontine gray: in the paramedian position, in the middle and in the lateral third. The three regions are arranged in rostro-caudal longitudinal columns in the caudal three-quarters of the pons and these columns are continuous with one another by regions of scattered degeneration. The fibres appear to end in relation to distal dendrites of the pontine cells.This article has not been published in any journal before. The guiding principles in the care and use of animals approved by the American Physiological Society have been followed     

The projection from nucleus raphe magnus and other brainstem nuclei to the spinal cord in the rat: a study using the HRP blue-reaction

Horseradish peroxidase injections, or solid HRP placements, were made into the dorsolateral quadrant of the spinal cord in ten adult rats, processed according to the blue-reaction (benzidine dihydrochloride) protocol [6]. When the interventions involved the dorsal lateral funiculus (DLF) HRP-labelled somata were observed primarily in the ipsilateral nucleus raphe magnus (NRM), with an occasional cell in nucleus raphe obscurus (NRO) and pallidus (NRP). Other brainstem raphe nuclei consistently lacked labelled neurons. The red nucleus and paralemniscal reticular formation of the rostal pons also contained appreciable numbers of HRP back-filled perikarya. The direct NRM-spinal projection in the rat, involved in the modulation of pain transmission in the spinal cord dorsal horn, originates primarily from the expanded region of the nucleus in the rostralmost medulla.     

A projection from nucleus reticularis tegmenti pontis of Bechterew to the medial vestibular nucleus in rabbits

This study documents a bilateral projection from nucleus reticularis tegmenti pontis (NRTP) to the rostral aspect of the medial vestibular nucleus (MVN) in rabbits. Horseradish peroxidase injections in rostral MVN produced retrogradely labeled neurons in the caudal half of NRTP; caudal MVN injections produced negative results. This supports the hypothesis that NRTP relays visual input to the vestibular nuclei via an extracerebellar pathway (Precht and Strata 1980), and indicates the importance of examining the contributions of both direct and cerebellar-mediated visual pathways to oculomotor physiology.     

A direct projection from the medial vestibular nucleus to the cervical spinal dorsal horn of the rat, as demonstrated by anterograde and retrograde tracing

Summary Phaseolus vulgaris leucoagglutinin and wheat germ agglutinin-horseradish peroxidase were iontophoretically injected into different parts of the vestibular nuclear complex (VNC) of the rat. Injections centered into the caudal part of the medial vestibular nucleus revealed a vestibulospinal projection predominantly to the dorsal horn of the cervical spinal cord, besides the expected projection to the intermediate zone (IZ) and ventral horn (VH). While most of the anterogradely labelled fibres could be localized in laminae III to V, some scattered fibres were also seen in laminae I and VI. Lamina II remained free of labelling. The dorsal horn (DH) area with detectable anterograde labelling showed a rostrocaudal extension from C₁-C₆. Injections into other parts of the VNC labelled fibres and terminals in the IZ and VH while the DH remained almost free of labelling. Additionally, fluorogold and wheat germ agglutininhorseradish peroxidase were pressure- or iontophoretically injected at different levels into the spinal cord to confirm the projection to the dorsal horn by means of retrograde tracing. Labelled neurons in the area of the medial vestibular nucleus (MVN), from which anterograde labelling in the DH was obtained, were only detectable after fluorogold and wheat germ agglutinin-horseradish peroxidase injections into the cervical spinal cord, in particular its DH. This projection from the caudal medial vestibular nucleus to the dorsal horn of the cervical spinal cord probably enables the VNC to influence sensory processing in the DH, in addition to its well-established influence on posture and locomotion via projections to the intermediate zone and ventral horn.Abbreviations BSA bovine serum albumin - CuN cuneate nucleus - CCN central cervical nucleus - cMVN caudal medial vestibular nucleus - cVST caudal vestibulospinal tract - DAB diaminobenzidine - DH dorsal horn - DRG dorsal root ganglia - DVN descending vestibular nucleus - ECN external cuneate nucleus - FCS fetal calf serum - FG fluorogold - HRP horseradish peroxidase - icp inferior cerebellar peduncle - In intercalated nucleus - IZ intermediate zone - LVN lateral vestibular nucleus - LVST lateral vestibulospinal tract - mlf medial longitudinal fasciculus - MVN medial vestibular nucleus - MVST medial vestibulospinal tract - PHA-L Phaseolus vulgaris leucoagglutinin - PrH praepositus hypoglossi nucleus - rMVN rostral medial vestibular nucleus - Ro Roller's nucleus - SVN superior vestibular nucleus - TMB tetramethylbenzidine - VH ventral horn - VNC vestibular nuclear complex - WGAHRP wheat germ agglutinin-horseradish peroxidase - 12 hypoglossal nucleus Dedicated to Prof. J.W. Rohen on the occasion of his 70th birthday     

GABAergic projection from the arcuate nucleus to the supraoptic nucleus in the rat

Electrical stimulation of the neurones in the hypothalamic arcuate nucleus results in a transient inhibition followed by a marked post-stimulus excitation of magnocellular neurones of the supraoptic nucleus. Microdialysis administration of the gamma-aminobutyric acid agonist (GABA(A)), muscimol, directly into the supraoptic nucleus inhibited both oxytocin and vasopressin neurones and these actions were fully reversed by the GABA(A) antagonist bicuculline. In addition, bicuculline administration blocked the inhibition induced by arcuate stimulation, but had no effect on the post-stimulus excitation. Thus, part of the inhibitory pathway arising from or passing through the arcuate nucleus to the supraoptic nucleus is mediated by the neurotransmitter GABA. However, the post-inhibitory excitation induced by arcuate stimulation is not a rebound response, but appears to involve an independent excitatory pathway.     

Polysynaptic pathways from the vestibular nuclei to the lateral mammillary nucleus of the rat: substrates for vestibular input to head direction cells

The activity of some neurons in the lateral mammillary nucleus (LMN) of the rat corresponds with the animals current head direction (HD). HD cells have been studied extensively but the circuitry responsible for the generation and maintenance of the HD signal has not been established. The present study tested the hypothesis that a polysynaptic pathway connects the vestibular nuclei with the LMN via one or more relay nuclei. This circuitry could provide a substrate for the integration of sensory input necessary for HD cell activity. This hypothesis is based upon the prior demonstration that labyrinthectomy abolishes HD selectivity in thalamic neurons. Viral transneuronal tracing with pseudorabies virus (PRV) was used to test this hypothesis. We injected recombinants of PRV into the LMN and surrounding nuclei of adult male rats and defined the patterns of retrograde transneuronal infection at survival intervals of 60 and 72 h. Infected medial vestibular neurons (MVN) were only observed at the longest postinoculation interval in animals in which the injection site was localized largely to the LMN. Robust infection of the dorsal tegmental nucleus (DTN) and nucleus prepositus hypoglossi (PH) in these cases, but not in controls, at both survival intervals identified these nuclei as potential relays of vestibular input to the LMN. These data are consistent with the conclusion that vestibular information that contributes to the LMN HD cell activity is relayed to this caudal hypothalamic cell group via a polysynaptic brainstem circuit.