微量海人酸注入大鼠延髓网状背侧亚核诱导的Fos表达及其与NADPH-d的共存

目的:研究大鼠网状背侧亚核的功能传出通路及该通路上NADPH-d的分布.方法:将微量海人酸注入大鼠延髓网状背侧亚核,2 h后灌注,脑片进行NADPH-d组织化学和Fos免疫组化染色.结果:Fos阳性细胞主要分布于中缝背核(DR)、中缝大核(NRM)、蓝斑(LC)、中脑导水管周围灰质腹外侧(vlPAG)和下丘脑室旁核.Fos/NADPH-d双标细胞主要分布于巨细胞网状核、下丘脑室旁核和中缝大核.结论:大鼠延髓网状背侧亚核与脊髓上中枢存在广泛的功能联系,而且在延髓网状背侧亚核的功能传出通路上有一氧化氮合酶的分布.     

皮下注射多聚甲醛诱导大鼠脊髓和三叉神经脊束核向延髓网状背侧亚核传入投射的fos表达

目的：研究外周伤害性刺激下大鼠脊髓和三叉神经脊束核向延髓网状背侧亚核传入投射的神经元中的Fos表达。方法：采用荧光金逆行追踪及Fos免疫组结合的方法。结果：脊髓和三叉神经脊束核尾侧亚核均有神经元投射延髓网状背侧亚核。在颈髓背角浅层FG／Fos双标神经元占FG阳性神经元和Fos双标神经元的9．3％和7．5％；在三叉神经脊束核尾侧亚核浅层，FG／Fos双标神经元分别占FG阳性神经元和Fos双标神经元的9．5％和14．2％，结论：在颈髓背角浅层和三叉神经脊束核尾侧亚核浅层向延髓网状背侧亚核传入投射的神经元中，部分神经元可能与伤害性刺激有关。     

延髓内脏带至杏仁核投射通路参与迷走神经刺激抑制癫痫发作的研究

目的 观察迷走神经→延髓内脏带(MVZ)→杏仁中央核的儿茶酚胺能通路是否参与了迷走神经刺激(vagus nerve stimulation,VNS)抑制癫痫的调节；是否存在由迷走神经→延髓内脏带→海马的直接投射参与抑痫。方法 将逆行追踪剂WGA—HRP注入大鼠—侧杏仁中央核或腹侧海马，48h后，给予迷走神经刺激，观察MVZ内WGA—HRP逆行标记的细胞、Fos蛋白、TH阳性神经元的表达及分布。结果 杏仁核注射组大鼠MVZ内可见HPR／Fos／TH二重标记的细胞；海马注射组MVZ内未见HRP逆标神经元，但HRP逆行标记与Fos阳性双重标记细胞出现存隔区和下丘脑室旁该。结论 提示迷走神经→延髓内脏带→杏仁中央核的投射通路直接参与VNS抑痫过程，而且与儿茶酚胺能神经元有关；迷走神经→延髓内脏带→隔区、下丘脑室旁核中继至海马的间接通路也参与了抑痫。     

皮下注射多聚甲醛诱导大鼠脊髓和三叉神经脊束核向延髓网状背侧亚核传入投射的fos表达

目的:研究外周伤害性刺激下大鼠脊髓和三叉神经脊束核尾侧亚核向延髓网状背侧亚核传入投射的神经元中的Fos表达.方法:采用荧光金逆行追踪及Fos免疫组化染色相结合的方法.结果:脊髓和三叉神经脊束核尾侧亚核均有神经元投射到延髓网状背侧亚核.在颈髓背角浅层,FG/Fos双标神经元分别占FG阳性神经元和Fos阳性神经元的9.3%和7.5%;在三叉神经脊束核尾侧亚核浅层,FG/Fos双标神经元分别占FG阳性神经元和Fos阳性神经元的9.5%和14.2%.结论:在颈髓背角浅层和三叉神经脊束核尾侧亚核浅层向延髓网状背侧亚核传入投射的神经元中,部分神经元可能与伤害性刺激有关.     

模拟失重大鼠延髓内脏带向下丘脑室旁核投射的儿茶酚胺能神经元表达Fos

确定延髓内脏带向下丘脑室旁核（PVN）投射通路是否参与对模拟失重的反应,用HRP逆行追踪结合抗Fos和抗栈氨酸羟化酶（TH）的免疫组织化学三重标记技术。观察4周模拟失重大鼠延髓内脏带向PVN投射的儿茶酚胺能神元Fos表达情况。发现有7种不同的标记细胞：HRP,Fos,TH单标细胞;Fos/HRP,Fos/TH,HRP/TH双标细胞;Fos/HRP/TH三标细胞,主要分布于延髓内脏带即延髓中尾段的孤束核和腹外侧区以及两者之间的网状结构。向PVN投射的神经元中有15.3%为Fos阳性细胞,即对失重起反应,而这些神经元中有62.6%为儿茶酚胺能神经元。结果显示,延髓内脏带投射至PVN的儿茶酚胺能神经元有些参与对失重的心血管反应。     

大鼠延髓内脏带与下丘脑室旁核、视上核往返投射通路参与高渗调节反应的研究

目的探讨延髓内脏带(MVZ)与下丘脑室旁核(PVN)和视上核(SON)之间是否存在往返渗透压投射通路。方法通过给予大鼠饮用3%氯化钠的方法制作高渗刺激模型,并用WGA-HRP逆行追踪、抗Fos、抗酪氨酸羟化酶(TH)或加压素(VP)及胶质纤维酸性蛋白(GFAP)免疫组织化学相结合的四重标记方法,观察MVZ、PVN和SON中WGA-HRP、Fos、TH、VP和GFAP阳性分布及表达状况。结果高渗刺激后MVZ、PVN和SON内Fos阳性细胞明显增多;GFAP阳性结构也明显增多,其分布与Fos阳性细胞分布基本一致,表现为胞体肥大、突起粗长。星形胶质细胞(AST)紧密包绕在神经元周围形成神经元-AST复合体(N-ASC)。结论神经元和AST以N-ASC的形式共同参与渗透压调节反应,体内存在MVZ和SON或PVN之间往返的渗透压调节通路。     

中枢神经系统对大鼠颈部食管的神经支配：假狂犬病毒跨突触标记研究

为研究中枢神经对颈部食管的神经支配及调控，用免疫组化方法研究了假狂犬病毒注射颈部食管后跨突触标记细胞在脑中的分布。将假狂犬病毒（PRV）注射于大鼠颈部食管，存活不同时间（48，56，62，66，72，80，96或102小时）后，进行免疫组化或免疫荧光研究。脑内PRV阳性标记细胞的分布部位随着存活期的延长而增多。食管注射PRV后48小时，仅在两侧疑核致密部中出现阳性标记细胞。存活56小时后，PRV跨突触感染的第二级神经元可见于孤束核的中央亚核。存活62～72小时后，在孤束核周围的延困中央网状核、中缝大核、最后区、中缝苍白核、中缝隐核、三叉旁核、外侧网状核、蓝斑核、臂旁核、AS细胞群和脑桥网状核尾侧部、下丘脑室旁核及外侧区中出现标记细胞。存活80～96小时后，除延髓和脑桥外，中脑的中央灰质和中缝背核，间脑和大脑的下丘脑室旁核和外侧区、弓状核、终纹床核、杏仁核、斜角带核、血管终板器和无颗粒型岛对皮质后区等可见较多的阳性细胞。存活102小时的动物，标记细胞的分布和存活与96小时类似，但数量更多。推测中枢神经系统对颈部食管运动机能的神经支配和调控与脑内许多部位有关。     

Merlin在大鼠脑的分布

目的：对正常成年大鼠脑中NF2基因表达产物Merlin的分布进行了观察。方法：运用免疫组化ABC法。结果：（1）Merlin阳性反应较强的脑区和核团有大脑皮质，杏仁核，丘脑前核群，丘脑内侧核群，丘脑板内核群，丘脑中线核群，脑干前庭内侧核以及小脑皮质颗粒层等。（2）中等阳性免疫反应的结构有海马结构，隔外侧核，隔内侧核，下丘脑室周核，下丘脑室旁核，蜗神经背侧核，蜗神经腹侧核，前庭内侧核等。（3）阳性免疫反应较弱的脑区和核团有尾壳核，屏状核，苍白球，下丘脑外侧前核，下丘脑背侧核，三叉神经脊束核，巨细胞网状核等。结论：Merlin在大鼠脑中有广泛的表达，但在不同的脑区和核团其表达强度不同。     

下丘脑前核：参与褪黑素对血压影响的中枢部位

在大鼠用微量注射技术研究褪黑素在下丘脑前核对心血管活动的作用 ,以及用辣根过氧化物酶神经传导通路追踪技术研究下丘脑前核参与心血管活动交感传出的纤维投射。结果表明 ,下丘脑前核微量注射褪黑素可使血压呈剂量依赖性降低 ,下丘脑前核有大量纤维投射到室旁核、正中隆起、下丘脑腹内侧核、弓状核、中脑导水管周围灰质 ,有少量纤维投射到延髓腹外侧区、中缝隐核。因此 ,褪黑素可能为一种降压因子 ,下丘脑前核是褪黑素调节心血管活动的重要中枢部位之一 ,而且下丘脑前核可能通过下丘脑腹内侧核、弓状核、中脑导水管周围灰质、延髓腹外侧区和中缝隐核来影响心血管交感传出活动     

下丘脑前核:参与褪黑素对血压影响的中枢部位

在大鼠用微量注射技术研究褪黑素在下丘脑前核对心血管活动的作用,以及用辣根过氧化物酶神经传导通路追踪技术研究下丘脑前核参与心血管活动交感传出的纤维投射.结果表明,下丘脑前核微量注射褪黑素可使血压呈剂量依赖性降低,下丘脑前核有大量纤维投射到室旁核、正中隆起、下丘脑腹内侧核、弓状核、中脑导水管周围灰质,有少量纤维投射到延髓腹外侧区、中缝隐核.因此,褪黑素可能为一种降压因子,下丘脑前核是褪黑素调节心血管活动的重要中枢部位之一,而且下丘脑前核可能通过下丘脑腹内侧核、弓状核、中脑导水管周围灰质、延髓腹外侧区和中缝隐核来影响心血管交感传出活动.     

Lower brainstem afferents to the cat posterior hypothalamus: a double-labeling study

Using a double-immunostaining technique with cholera toxin (CT) as a retrograde tracer, the authors examined the cells of origin and the histochemical nature of lower brainstem afferents to the cat posterior hypothalamus. The posterior hypothalamus, in particular the lateral hypothalamic area, receives substantial afferent projections from: substantia nigra, peripeduncular nucleus, ventral tegmental area, periaqueductal grey, mesencephalic reticular formation, peribrachial region including the locus coeruleus complex, rostral raphe nuclei and the rostral part of the nucleus magnus. In addition, a moderate number of retrogradely labeled neurons was found in: Edinger-Westphal nucleus, nucleus reticularis pontis oralis, nucleus reticularis magnocellularis, caudal lateral bulbar reticular formation around the nucleus ambiguus and lateral reticular nucleus and the nucleus of the solitary tract. The posterior hypothalamus receives: 1) dopaminergic inputs from A8, A9 and A10 cell groups; 2) noradrenergic inputs from A6 and A7 pontine, as well as A1 and A2 bulbar cell groups; 3) adrenergic inputs from C1 cell group in the caudal medulla; 4) serotoninergic inputs from the rostral raphe nuclei (B6, B7 and B8 cell groups); 5) cholinergic inputs from the peribrachial region of the dorsal pontine tegmentum as well as from the nucleus reticularis magnocellularis of the medulla; 6) peptidergic inputs such as methionine-enkephalin, substance P, corticotropin-releasing factor and galanin that originate mainly in the mesencephalic periaqueductal grey, the dorsal raphe nucleus and the peribrachial region of the dorsal pontine tegmentum.     

Fos induction in selective hypothalamic neuroendocrine and medullary nuclei by intravenous injection of urocortin and corticotropin-releasing factor in rats

CRF and urocortin, administrated systemically, exert peripheral biological actions which may be mediated by brain pathways. We identified brain neuronal activation induced by intravenous (i.v.) injection of CRF and urocortin in conscious rats by monitoring Fos expression 60 min later. Both peptides (850 pmol/kg, i.v.) increased the number of Fos immunoreactive cells in the paraventricular nucleus of the hypothalamus, supraoptic nucleus, central amygdala, nucleus tractus solitarius and area postrema compared with vehicle injection. Urocortin induced a 4-fold increase in the number of Fos-positive cells in the supraoptic nucleus and a 3.4-fold increase in the lateral magnocellular part of the paraventricular nucleus compared with CRF. Urocortin also elicited Fos expression in the accessory hypothalamic neurosecretory nuclei, ependyma lining the ventricles and choroid plexus which was not observed after CRF. The intensity and pattern of the Fos response were dose-related (85, 255 and 850 pmol/kg, i.v.) and urocortin was more potent than CRF. Neither CRF nor urocortin induced Fos expression in the lateral septal nucleus, Edinger-Westphal nucleus, dorsal raphe nucleus, locus coeruleus, or hypoglossal nucleus. These results show that urocortin, and less potently CRF, injected into the circulation at picomolar doses activate selective brain nuclei involved in the modulation of autonomic/endocrine function; in addition, urocortin induces a distinct activation of hypothalamic neuroendocrine neurons.     

The origin of descending pathways in the dorsolateral funiculus of the spinal cord of the cat and rat: further studies on the anatomy of pain modulation.

There is considerable evidence that the dorsolateral funiculus (DLF) of the spinal cord contains descending pathways critical for both opiate and brainstem stimulation-produced analgesia. To obtain a comprehensive map of brainstem neurons projecting to the spinal cord via the DLF, large injections of horseradish peroxidase (HRP) were made into the lumbosacral spinal cord of cat and rat. These injections were made caudal to midthoracic lesions which spared only a single DLF or ventral quadrant (VQ); thus only those neurons whose axons descended in the spared funiculus would be labelled. Cells with descending axons in the VQ were concentrated in the medullary nucleus raphe pallidus and obscurus, nucleus retroambiguus and in various subregions of the reticular formation including the nucleus reticularis ventralis, gigantocellularis, magnocellularis, pontis caudalis and pontis oralis. Significant numbers of neurons were also found in medial and lateral vestibular nuclei and in several presumed catecholamine-containing neurons of the dorsolateral pons. In the rat, but not in the cat, considerable numbers of cells are present in the mesencephalic reticular formation just lateral to the periaqueductal gray. In both species, some cells were found in the paraventricular nucleus of the hypothalamus. Brainstem cells projecting in the DLF were concentrated in the nucleus raphe magnus and in the adjacent nucleus reticularis magnocellularis, ipsilateral to the spared funiculus. Significant numbers of cells were found in the dorsolateral pons, differing somewhat in their distribution from those projecting in the VQ. DLF-projecting cells were also present in the ipsilateral Edinger-Westphal nucleus and periaqueductal grey contralateral red nucleus of the midbrain and in the ipsilateral hypothalamus. Smaller projections from other sites are described. These results are discussed in terms of the differential contribution of several brainstem neuronal groups, including the serotonergic nucleus, raphe magnus, the ventromedial reticular formation of the medulla, and various catecholamine-containing neurons of the dorsolateral pontine tegmentum to the analgesia produced by opiates and electrical brain stimulation.     

The distribution and morphological characteristics of serotonergic cells in the brain of monotremes

The distribution and cellular morphology of serotonergic neurons in the brain of two species of monotremes are described. Three clusters of serotonergic neurons were found: a hypothalamic cluster, a cluster in the rostral brainstem and a cluster in the caudal brainstem. Those in the hypothalamus consisted of two groups, the periventricular hypothalamic organ and the infundibular recess, that were intimately associated with the ependymal wall of the third ventricle. Within the rostral brainstem cluster, three distinct divisions were found: the dorsal raphe nucleus (with four subdivisions), the median raphe nucleus and the cells of the supralemniscal region. The dorsal raphe was within and adjacent to the periaqueductal gray matter, the median raphe was associated with the midline ventral to the dorsal raphe, and the cells of the supralemniscal region were in the tegmentum lateral to the median raphe and ventral to the dorsal raphe. The caudal cluster consisted of three divisions: the raphe obscurus nucleus, the raphe pallidus nucleus and the raphe magnus nucleus. The raphe obscurus nucleus was associated with the dorsal midline at the caudal-most part of the medulla oblongata. The raphe pallidus nucleus was found at the ventral midline of the medulla around the inferior olive. Raphe magnus was associated with the midline of the medulla and was found rostral to both the raphe obscurus and raphe pallidus. The results of our study are compared in an evolutionary context with those reported for other mammals and reptiles.     

Hypothalamic projections to the ventral medulla oblongata in the rat, with special reference to the nucleus raphe pallidus: a study using autoradiographic and HRP techniques

Hypothalamic descending projections to the medullary ventral surface were studied autoradiographically in the rat. A small amount of [3H]leucine was injected unilaterally into various parts of the hypothalamus by air pressure. Abundant and characteristic terminal labelings were observed bilaterally in the nucleus raphe pallidus, the ventral surface of the pyramidal tract and the nucleus interfascicularis hypoglossi, after injections into the dorsal posterior hypothalamic area caudal to the paraventricular hypothalamic nucleus. Conspicuous, but less numerous labelings were observed in the nucleus raphe obscurus and the ipsilateral raphe magnus. After an injection of [3H]leucine into the hypothalamus and injections of horseradish peroxidase (HRP) into the spinal cord in the same animal, silver grains were densely distributed around HRP-labeled neurons in the nucleus raphe pallidus including the nucleus interfascicularis hypoglossi. The present results suggest that the dorsal posterior hypothalamic area projects directly to the spinal-projecting neurons of the nucleus raphe pallidus.     

大鼠内脏伤害性刺激后脑内70kDa热休克蛋白和c—Fos表达

不同的内脏伤害性刺激动物模型上研究脑内ｃ－ｆｏｓ样蛋白（Ｆｏｓ）表达的研究己有报道，而具有分子伴侣功能的７０ｋＤ热休克蛋自（ｈｓｐ７０）的表达是否有改变尚未见报道。本工作以大鼠内脏大神经电刺激作为伤害性刺激动物模型用免疫组化方法观察脑内ｈｓｐ７００和Ｆｏｓ表达的变化。结果显示：在内脏大神经电刺激后１２－１８ｈ于大脑新皮质，内嗅皮层，尾核，丘脑外侧核后部，下丘脑外侧核，下丘脑弓状核，巨细胞网状外侧核等结构观察到ｈｓｐ７０免疫阳性细胞；Ｆｏｓ在蓝斑，中脑导水管周围灰质，中缝大核，背核，下丘脑弓状核，隔核，伏隔核，新皮质等部位于刺激后２ｈ表达增加，４ｈ后减少。对照组脑内ｈｓｐ７０和ｆｏｓ阳性染色很少。这提示：ｈｓｐ７０和Ｆｏｓ表达可能都参与神经系统对内脏伤害性刺激的反应并发挥不同的功能。     

Raphespinal projections in the north american opossum: Evidence for connectional heterogeneity

Retrograde transport studies revealed that the nuclei pallidus, obscurus, and magnus raphae as well as the adjacent reticular formation innervate the spinal cord in the opossum. HRP-lesion experiments showed that a relatively large number of neurons within the nucleus obscurus raphae and closely adjacent areas of the nucleus reticularis gigantocellularis project through the ventrolateral white matter and that many cells within the nucleus magnus raphae, the nucleus reticularis gigantocellularis pars ventralis, and the nucleus reticularis pontis pars ventralis contribute axons to the dorsal half of the lateral funiculi. Neurons within the rostral pole of the nucleus magnus raphae and the adjacent nucleus reticularis pontis pars ventralis may project exclusively through the latter route. Each of the above-mentioned raphe and reticular nuclei contain nonindolaminergic as well as indolaminergic neurons (Crutcher and Humbertson, 1978). When True-Blue was injected into the spinal cord and the brain processed for monoamine histofluorescence evidence for True-Blue was found in neurons of both types. Injections of ³H-leucine centered within the nuclei pallidus and obscurus raphae and/or the closely adjacent nucleus reticularis gigantocellularis labeled axons within autonomic nuclei and laminae IV-X. Labeled axons were particularly numerous within the intermediolateral cell column and within laminae IX and X. Injections of the caudoventral part of the nucleus magnus raphae or the adjacent nucleus reticualris gigantocellularis pars ventralis labeled axons in the same areas as well as within laminae I-III. When the injection was placed within the rostal part of the nucleus magnus raphae or the adjacent nucleus reticularis pontis pars ventralis axons were labeled within laminae I-III and external zones of laminae IV-VII, but not within lamina IX. The immunohistofluorescence method revealed evidence for indolaminergic axons in each of the spinal areas labeled by injections of ³H-leucine into the raphe and adjacent reticular formation. They were particularly abundant within the intermediolateral cell column and within laminae IX and X. These data indicate that raphe spinal systems are chemically and connectionally heterogeneous.     

Metabolic mapping of the brain in pregnant, parturient and lactating rats using Fos immunohistochemistry

The present study was designed to investigate Fos-positive neurons of the female rat brain at various reproductive states in order to analyze the metabolic map connected with pregnancy, parturition and lactation. The number of Fos-positive neurons in each brain nucleus was analyzed with a quantitative immunohistochemical method in virgin, pregnant, parturient, lactating and arrested lactating rats. In parturient rats, a significant number of Fos-positive neurons was observed as compared to virgin or pregnant females in the following brain regions; the bed nucleus of the stria terminalis (BST), lateral septal nucleus (LS), medial preoptic area (MPA), periventricular hypothalamic nucleus (Pe), parvocellular paraventricular hypothalamic nucleus (PaPVN), magnocellular paraventricular hypothalamic nucleus (MaPVN), supraoptic nucleus (SON), paraventricular thalamic nucleus (PV), anterior hypothalamic area (AHA), lateral hypothalamic area (LH), amygdaloid nucleus (AM), supramammillary nucleus (SuM), substantia nigra (SN), central grey (CG), microcellular tegmental nucleus (MiTg), subparafascicular thalamic nucleus (SPF), posterior hypothalamic area (PH), dorsal raphe nucleus (DR), locus coeruleus (LC), dorsal parabrachial nucleus (DPB), nucleus of solitary tract (Sol), and ventrolateral medulla (VLM). Significant differences were found in the number of Fos-positive neurons between parturient and lactating females, although localization of Fos-positive neurons in lactating females was quite similar to parturient ones. Between parturient and lactating rats: (1) In the MPA, PaPVN, AHA, arcuate hypothalamic nucleus (Arc), ventromedial hypothalamic nucleus (VMH), mesencephalic lateral tegmentum (MLT), and genual nucleus (Ge), the number of Fos-positive neurons of lactating females were significantly higher than those of parturient ones; (2) In the LS, Pe, PV, LH, AM, SuM, CG, MiTg, SPF, PH, DR, LC, and VLM, there was no significant differences in the number of Fos-positive neurons; (3) In the BST, MaPVN, SON, SN, DPB and Sol, the number of Fos-positive neurons of lactating rats were significantly lower than those of parturient ones. These different patterns of Fos expression among many brain regions may be owing to the functional differences in each region. Fos expression in lactating rats was apparently induced by suckling stimulation because the removal of their litters immediately after parturition completely eliminated expression of Fos protein in each nucleus. These results suggest that the localization of Fos-positive neurons in a number of neural populations throughout the brain may be revealing the neural circuits in response to parturition or lactation.     

Somatodendritic and axonal anatomy of intracellularly labeled serotonergic neurons in the rat medulla

A knowledge of the anatomy of medullary serotonergic cells is critical to understanding local and brainstem circuits in which these cells participate. Serotonergic neurons (n = 16) were identified, as previously described (Mason [1997] J. Neurophysiol. 77:1087–1098) by their slow and steady background discharge in halothane anesthetized rats. Neurons were then intracellularly labeled with Neurobiotin and visualized with 3,3'diaminobenzidine. The validity of the physiological identification of serotonergic cells was confirmed by processing two neurons that were physiologically characterized as serotonergic for serotonin immunoreactivity; both tested cells contained immunoreactive serotonin. The dendrites and axon of each labeled cell were reconstructed by using a three-dimensional computerized system. Somata were small or medium in size and had fusiform, triangular, or multipolar shapes. The dendritic arbor was constricted with most dendrites extending for less than 500 μm from the soma. All labeled axons projected caudally and travelled in the ventrolateral medulla, either dorsal or ventral to the lateral reticular nucleus. Most cells had collaterals and/or dense axonal swellings in the nucleus reticularis gigantocellularis, nucleus reticularis magnocellularis, raphe magnus, and the ventrolateral medulla. Non-local collaterals and swellings were also observed in the nucleus reticularis gigantocellularis and in the ventrolateral medulla at all medullary levels. The results demonstrate that 1) the dendrites of serotonergic cells are restricted to raphe magnus and the ventral part of nucleus reticularis magnocellularis; and 2) serotonergic cells project to medullary nuclei that contain bulbospinal cells which project to dorsal, intermediate, and ventral horns. Serotonergic cell projections to brainstem sites may mediate the integration of sensory, autonomic, and motor modulation at the brainstem level. J. Comp. Neurol. 389:309–328, 1997. © 1997 Wiley-Liss, Inc.     

A comparative study of the immunohistochemical localization of a presumptive proctolin-like peptide, thyrotropin-releasing hormone and 5-hydroxytryptamine in the rat central nervous system

A proctolin (PROC)-like peptide was studied immunohistochemically in the hypothalamus, lower brainstem and spinal cord of the rat using an antiserum against PROC conjugated to thyroglobulin. Neuronal cell bodies containing PROC-like immunoreactivity (PROC-LI) were observed in the dorsomedial, paraventricular and supraoptic nuclei of the hypothalamus and in the nucleus raphe magnus, nucleus raphe pallidus, nucleus raphe obscurus and nucleus interfascicularis nervi hypoglossi in the medulla oblongata. Fibers containing PROC-LI were seen in the median eminence and in other hypothalamic nuclei, and in the lower brainstem in cranial motor nuclei including the dorsal motor nucleus of the vagus nerve, the motor trigeminal nucleus, the facial nucleus and nucleus ambiguous, and in lower numbers in the nucleus of the solitary tract and locus coeruleus. Fibers containing PROC-LI were also located in the spinal cord, in the intermediolateral cell column at thoracic levels and in the ventral horns at all levels of the spinal cord. After transection of the spinal cord, all PROC-immunoreactive fibers below the lesion disappeared. Following injection of Fast blue into the thoracic spinal cord, retrogradely labeled cells in the nuclei raphe pallidus, obscurus and magnus and nucleus interfasciculari nervi hypoglossi were seen to contain PROC-LI. PROC-LI had a similar distribution as thyrotropin-releasing hormone (TRH)-LI in the above-mentioned areas and coexistence of TRH-LI and PROC-LI was shown in cell bodies in the hypothalamus and medulla oblongata. PROC-LI could also be shown to coexist with 5-hydroxytryptamine (5-HT)-LI in neuronal cell bodies in the lower brainstem. The results demonstrate the occurrence of a PROC-like peptide in the mammalian nervous system, and these neurons seem to be at least largely identical to previously described TRH systems. A possible involvement of the PROC-like peptide in spinal motor control is discussed in relation to the well-established role of PROC in control of motor behavior in insects and invertebrates.