家兔脊髓向延髓外侧网状核投射的体部定位——HRP顺行法研究

本实验用HRP顺行传递法研究了家兔脊髓向外侧网状核的纤维投射,结果是: 1.颈、胸和腰髓都有少数的神经元发出纤维投射于双侧的三叉神经下亚核。 2.颈、胸和腰髓至外侧网状核的投射都是双侧性的,但颈髓以同测投射为主,腰髓以对侧投射为主,胸髓至双侧的投射无明显差别。 3.脊髓神经元主要投射于外侧网状核的尾侧半,有体部定位关系。颈髓投射于大细胞亚核的外侧3/5及相邻的部分小细胞亚核;胸髓投射于大细胞亚核的内侧3/5及相邻接的部分小细胞亚核;腰髓投射于小细胞亚核及相邻接的一部分大细胞亚核,相互间有部分重叠。     

猫网状脊髓束的起源和终止——HRP法研究

选猫10只,分别于颈膨大或腰膨大的一侧灰质或一侧后角内注射HRP,对网状脊髓束的起止进行了研究。发现网状脊髓束不仅起自延髓及脑桥内侧网状结构的大细胞部,还起于其外侧网状结构小细胞部,此外还有少量发自中脑网状结构。网状脊髓束不仅止于前角,还止于后角。网状脊髓束主要起自延髓及脑桥网状结构腹内侧区,其起源细胞在巨细胞网状核内为数最多,延髓中央核腹侧亚核次之,脑桥尾侧网状核更次之。在脑桥吻侧网状核,延髓旁正中网状核腹侧亚核、外侧旁巨细胞核及中脑楔形核内也有标记细胞。由以上核发出的纤维均投向脊髓两侧灰质。除楔形核只投向颈髓外,其余都投射到颈髓和腰髓。在延髓网状结构腹外侧及脑桥头端网状结构外侧各有一群标记细胞,其位置各与去甲肾上腺素能神经元A_1和A_7群相当。由脑干腹内侧网状结构发出的纤维大部分止于颈、腰膨大后角以前的灰质,但也有少量止于后角,这些联系为脑干网状结构内侧区提供了一条直接影响脊髓运动及感觉功能的通路。 Brodal用逆行细胞变性法证明旁正中网状核全部细胞投射到小脑“脊髓区”。我们在颈、腰膨大一侧灰质注射组的旁正中网状核腹侧亚核内也发现了一些标记细胞。可能这些细胞的轴突是分叉的,一支投射到小脑“脊髓区”,另一支投射到脊髓后角以前的灰质。这群细胞对脊髓与小脑的联系可能有特殊的作用。在一般认为是“接受区”的延桥网状结构背外侧区,相当于延髓中央核背侧亚核及小细胞网状核内,也发现了标记细胞,由此发出的纤维主要止于脊髓后角。推测此通路可能主要影响脊髓的感觉功能。因此,不应把脑干网状结构外侧区仅仅看成是网状结构的“接受区”。     

猫红核脊髓束的体部定位——HRP法研究

本实验用六只成年猫分别于其颈、腰膨大和胸髓的右侧灰质内注入 HRP 溶液,观察红核脊髓束的投射。猫的红核脊髓束绝大部分是交叉的,有明确的体部定位,即红核的背内侧部投射于颈膨大,腹外侧部投射于腰膨大,两者之间的神经原投射于胸髓。在颈、腰膨大的注射例中还在同侧红核内观察到少数标记细胞,即红核还发出少数纤维投射于同侧的颈、腰膨大。胸髓注射例在同侧红核内未见到标记细胞。红核脊髓束在成年猫至少可达腰_6节段。     

猫下脑干至脊髓颈膨大和腰膨大的纤维投射——HRP法研究

用猫10只,分别干其颈膨大或腰膨大的一侧全灰质或一侧后角内注射HRP,研究下脑干到脊髓颈、腰膨大的投射。我们发现下列核群有细胞发出纤维投射到脊髓: 1.网状结构:巨细胞核、延髓中央核腹侧亚核、脑桥尾侧网状核和头侧网状核有较多脊髓投射细胞。延髓中央核背侧亚核、小细胞网状核、外侧旁巨细胞核、旁正中网状核腹侧亚核及中脑楔形核也向脊髓发出少量投射。除延髓中央核和小细胞网状核主要投至后角外, 其余核主要投射到后角以前灰质。 2.中缝核:大中缝核、苍白中缝核、隐中缝核向颈、腰膨大发出投射。背侧中缝核仅投射到颈膨大后角以前灰质。 3.薄束核及楔束核:向同侧颈、腰膨大发出部分重叠的定位投射。 4.脑神经核:E-W核、动眼神经主核、三叉神经脊束核、孤束核及前庭内侧核、外侧核、脊核和上核,前庭核ι细胞群均有细胞向脊髓发出投射。在前庭外侧核内,标记细胞有体部定位排列。 5.蓝斑、蓝斑下核、旁结合臂外侧核及内侧核、Kolliker-Fuse核、疑后核;投射至两侧脊髓。 6.红核:大量标记细胞出现在对侧红核内。红核的腹外侧部细胞投射至腰膨大,背内侧部投射到颈膨大。 7.上丘及中脑水管旁灰质投射到颈膨大后角以前的灰质。     

中脑导水管周围灰质和E-W核中SP和CCK样神经元至脊髓的投射——HRP与免疫细胞化学结合法研究

本研究用HRP逆行追踪和免疫细胞化学结合法,研究了大白鼠中脑导水管周围灰质(PAG)以及Edinger-Westphal(E-W)核至脊髓的SP能和CCK能神经投射。结果表明,PAG腹外侧区至脊髓颈、胸、腰段双侧均有少量投射,但以同侧为主。在这些下行投射神经元中,约有48％为SP样免疫反应阳性。E-W核至脊髓的颈、胸、腰段均有广泛投射,其中约有70％为SP样免疫反应阳性,73％为CCK样免疫反应阳性。提示至少有一部分E-W核的脊髓投射神经元含有SP和CCK两种神经递质。     

大白鼠脑干至腰骶髓投射的生后发育——HRP法研究

本实验用生后1、3、5、7至35天的大白鼠18只,将50％的HRP液注入右侧脊髓腰膨大内。HRP标记细胞见于下列核团:1.中脑:红核、黑质和中缝背核。2.脑桥:脑桥吻侧网状核、脑桥尾侧网状核、蓝斑、蓝斑下核、中缝大核、前庭神经外侧核和前庭神经内侧核。3.延髓:中缝隐核、中缝苍白核、腹侧网状核、巨细胞网状核、网状外侧核、三叉神经脊束核、Cajal连合核、前置核和薄束核。各核团标记细胞数随动物的生后发育逐渐增多。表明大白鼠脑干至腰骶髓投射有一生后发育过程。红核脊髓束和蓝斑脊髓投射较网状脊髓束和前庭脊髓束成熟得晚一些。脑干至腰骶髓的投射约于生后1个月完成。     

猫前庭外侧核向脊髓的投射——HRP法研究

本文用HRP法研究了猫前庭外侧核到脊髓各段的定位投射,发现核内投射到脊髓颈、腰段的细胞存于核的全长,但有相对的集中区,即核的尾、中1/3段背外侧部主要投射到腰髓;投射到颈髓的细胞则集中核的吻、中段;而投射到胸髓的细胞集中在尾、中段背部,似乎混在于腰髓的投射细胞区内。前庭外侧核投射到脊髓各段的细胞数以腰髓最多,颈髓次之,胸髓最少。     

家兔脊髓与孤束核间的相互联系

分别于14只家兔之颈、胸或腰髓一侧灰质内注射HRP或WGA-HRP,在孤束核中观察逆行标记细胞及顺行标记终支。标记细胞见于核之尾侧部,颈、胸注射例标记细胞的数量超过腰髓例。各例均以闩附近平面最为密集,主要分布于孤束之腹内侧;邻孤束之腹侧、腹外侧、外侧、内侧也各有一些。孤束核内侧之标记细胞主要分布于其腹侧部,迷走神经运动背核之背侧;小细胞亚核中无标记细胞。胸髓注射例,在孤束之背外侧还有一群标记细胞。此处在颈、腰髓注射例仅有少数标记。标记终支的分布大体上同标记细胞,因此脊髓孤束核投射很可能与孤束核中脊髓投射细胞之间有直接突触联系。在闩平面附近,沿核之背外侧缘有一狭标记终支带,其中偶见个别标记细胞。此带可能与心脏活动有关。     

家兔前庭核与脊髓的联系——HRP法研究

将HRP注入家兔颈、胸或腰髓的一侧灰质内,追踪前庭四核内的逆行标记细胞和顺行标记终支。发现同侧外侧核内标记细胞数量甚多,且具有体部定位规律。内侧核及降核的尾段标记细胞也较多,内侧核者甚为密集,它们投射到双侧脊髓的颈、胸、腰段,对侧多于同侧,无体部定位关系。降核的头段及在此平面的内侧核内也有一定数量的标记细胞,也投射到颈、胸、腰髓,同侧为主,无体部定位关系。上核内只有极少量标记细胞,主要投射到对侧颈髓。顺行标记终支于降核、内侧核的见端小范围内及外侧核的尾端背面较为恒定,颈、腰注射例在降核和内侧核的尾端尤为密集。     

猫脊髓脑干投射.HRP顺行法研究

用成年猫8只,在颈髓或腰髓内注射HRP,用HRP顺行法追踪了脊髓脑干投射。脑干内标记终末分枝最为密集的部位是同侧的后索核及外侧网状核,对侧的内侧及背侧副橄榄核及两侧的桥延体及桥核的背外侧部。在网状结构及一些核团内也有数量不等的标记。最远在丘脑下部见到微量标记。本研究还发现背侧副橄榄核可进一步分为尾、吻两部,尾部的细胞较小。副橄榄核中的标记终枝,在数量上腰髓注射例多于颈髓注射例。在背侧副撖榄核内有明确的体部定位关系。外侧网状核之标记主要见于颈髓注射例,分布于其大细胞亚核及小细胞亚核之侧翼中。颈髓及腰髓注射例在桥延体及桥核背外侧部内标记终枝的数量上无明显差别。本文对下橄榄核、外侧网状核、桥延体及桥核内的终止情况进行了讨论。     

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?     

Patterns of projection and branching of reticulospinal neurons

Extracellular microelectrodes were used to record the activity of reticulospinal neurons within the medial ponto-medullary reticular formation in the cat. In one series of experiments reticulospinal neurons were activated from electrodes in the ventro-medial reticulospinal tract (RSTm) and in the ipsi- and contralateral lateral reticulospinal tracts (RSTi, RSTc) at spinal levels C1--2, C4, Th1 and L1. RSTm neurons were found primarily in n.r. pontis caudalis and the rostro-dorsal part of n.r. gigantocellularis. 71% of these neurons projected as far as the lumbar spinal cord. RSTi neurons projecting to C4 and beyond were clustered in the caudo-ventral part of n.r. gigantocellularis, but those RSTi neurons projecting to the first three cervical segments were located more rostro-dorsally. In all, 63% of the RSTi neurons projected to the lumbar spinal cord. RSTc neurons, which comprised only 5% of the reticulospinal population, were found throughout n.r. gigantocellularis. RSTm neurons had a median conduction velocity of 101 m/sec whereas RSTi and RSTc had median conduction velocities on the order of 70 m/sec. In a second series of experiments microstimulation was used to activate branches of reticulospinal neurons within the gray matter of the cervical enlargement. Twenty-two of thirty-three neurons found to project to the cerivcal ventral horn were branching neurons that also sent axons to the lumbar spinal cord. Thus much of the teticulospinal activity reaching the cervical enlargement also acts at one or more other spinal levels. Detailed investigation of the course of reticulospinal axons within the cervical gray matter indicated that a single axon may traverse wide areas of the ventral horn including regions on both sides of the spinal cord.     

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?     

Segmental and propriospinal projection systems of frog lumbar interneurons

 Spinal interneuronal networks have been implicated in the coordination of reflex behaviors and limb postures in the spinal frog. As a first step in defining these networks, retrograde transport of horseradish peroxidase (HRP) was used to examine the anatomical organization of interneuronal circuitry in the lumbar spinal cord of the frog. Following neuronal degeneration induced by spinal transection and section of the dorsal and ventral roots, HRP was placed at different locations in the spinal cord and the positions of labeled neuronal cell bodies plotted using a Eutectics Neuron Tracing System. We describe four spinal interneuronal systems, three with cell bodies located in the lumbar cord and one with descending projections to the lumbar cord. Interneurons with cell bodies located in the lumbar cord include: (1) Lumbar neurons projecting rostrally. Those projecting to thoracic segments tended to be located in the lateral and ventrolateral gray and in the lower two-thirds of the dorsal horn, with projections that were predominantly uncrossed. Those projecting to the brachial plexus and beyond were located in the dorsal part of the dorsal horn (uncrossed) and in the lateral, ventrolateral, and ventromedial gray (crossed). (2) Lumbar neurons with segmental projections within the lumbar cord. These neurons, which were by far the most numerous, had both uncrossed and crossed projections and were distributed throughout the dorsal, lateral, ventrolateral, and ventromedial gray matter. (3) Lumbar neurons projecting to the sacral cord. This population, which arose mainly from the dorsal horn and lateral or ventrolateral gray, was much smaller than in the other systems. Neuronal density of some of these populations of lumbar interneurons appeared to vary with rostrocaudal level. Finally, a population of neurons with cell bodies in the brachial and thoracic segments that projects to the lumbar cord is described. The most rostral of these neurons were multipolar cells with uncrossed projections, while those with crossed projections were confined almost exclusively to the ventral half of the cord. The distribution of spinal interneurons reported here will provide guidance for future studies of the role of interneuronal networks in the control of movements using the spinal frog as a model system. Received: 11 June 1996 / Accepted: 26 February 1997     

Jaw-muscle spindle afferent feedback to the cervical spinal cord in the rat

Putative synaptic contacts between masticatory-muscle spindle afferents and brainstem neurons which project to the cervical spinal cord were studied in rats by combining retrograde and intracellular neuronal labeling. Spinal cord projecting neurons were retrogradely labeled via injection of horseradish peroxidase unilaterally or bilaterally into cervical spinal cord segments C2 through C5. Twenty-four hours after the injection of horseradish peroxidase, one to five jaw-muscle spindle afferent axons were physiologically identified and intracellularly stained with biotinamide on each side of the brainstem. Horseradish-peroxidase-labeled neurons were found bilaterally in the supratrigeminal region, trigeminal principal sensory nucleus, parvicellular reticular nucleus including its alpha division, spinal trigeminal subnuclei oralis and interpolaris and the medullary reticular formation. Retrogradely labeled neurons were most numerous in the spinal trigeminal subnucleus oralis, parvicellular reticular formation and the ventral part of the spinal trigeminal subnucleus interpolaris. A small number of horseradish-peroxidase-labeled neurons were also present in the trigeminal mesencephalic nucleus and spinal trigeminal subnucleus caudalis. Appositions between jaw-muscle spindle afferent boutons and spinal projecting neurons were found in the supratrigeminal region, dorsomedial portions of the trigeminal principal sensory nucleus and spinal trigeminal subnuclei oralis and interpolaris, and the parvicellular reticular formation including its alpha division. Putative synaptic contacts were most frequent in the parvicellular reticular formation and the dorsomedial portion of the trigeminal subnucleus oralis. These results indicate that some orofacial proprioceptive feedback transmitted via the mesencephalic trigeminal nucleus reaches the cervical spinal cord directly and suggests that jaw-muscle spindle afferent feedback reaches the cervical spinal cord predominately via relays in the dorsomedial part of the spinal trigeminal subnucleus oralis and the parvicellular reticular formation. It is hypothesized that these pathways are primarily involved in the coordination of jaw and neck movement during mastication and biting. Materials and methods 27 January 1999 / Accepted: 9 May 1999     

Evidence that dopamine‐beta‐hydroxylase immunoreactive neurons in the lateral reticular nucleus project to the spinal cord in the rat

The existence of noradrenergic projections from the lateral reticular nucleus (LRt) to the dorsal quadrant of cervical, thoracic, or lumbar spinal cord was investigated using a combined method of WGA‐apo‐HRP‐gold retrograde tracing and dopamine‐beta‐hydroxylase (DBH) immunocytochemistry. Preliminary retrograde tracing studies indicated that LRt neurons projecting to cervical, thoracic, or lumbar spinal cord were characteristically located near the perimeter of the LRt. Double‐labeling experiments demonstrated that a portion of these peripherally‐located, spinal‐projecting neurons were DBH‐immunoreactive. Double‐labeled neurons were also located at the parvocellular division of the contralateral LRt in the thoracic injection cases. Double‐labeled neurons were not observed at the subtrigeminal division in cervical, thoracic, or lumbar injection case. The results suggest the possibility that the noradrenergic LRt‐spinal pathway might be involved in a variety of pain processing and cardiovascular regulatory functions in the rat. Anat Rec 263:269–279, 2001. © 2001 Wiley‐Liss, Inc.     

Evidence that dopamine-beta-hydroxylase immunoreactive neurons in the lateral reticular nucleus project to the spinal cord in the rat.

The existence of noradrenergic projections from the lateral reticular nucleus (LRt) to the dorsal quadrant of cervical, thoracic, or lumbar spinal cord was investigated using a combined method of WGA-apo-HRP-gold retrograde tracing and dopamine-beta-hydroxylase (DBH) immunocytochemistry. Preliminary retrograde tracing studies indicated that LRt neurons projecting to cervical, thoracic, or lumbar spinal cord were characteristically located near the perimeter of the LRt. Double-labeling experiments demonstrated that a portion of these peripherally-located, spinal-projecting neurons were DBH-immunoreactive. Double-labeled neurons were also located at the parvocellular division of the contralateral LRt in the thoracic injection cases. Double-labeled neurons were not observed at the subtrigeminal division in cervical, thoracic, or lumbar injection case. The results suggest the possibility that the noradrenergic LRt-spinal pathway might be involved in a variety of pain processing and cardiovascular regulatory functions in the rat.