bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic organization of class II (inter)neurons in the dorsal lateral geniculate nucleus of the tree shrew: Observations based on Golgi, immunocytochemical, and biocytin methods
Authors: Conley Michael , Wilson Kristin F. 
Published: January 2005

AbstractIn this report we examine the dendritic organization of putative interneurons (class II cells) in different layers of the dorsal lateral geniculate nucleus of the tree shrew. The results show that there is considerable morphological diversity within this class, but that two broad groups can be identified: neurons whose dendrites remain within a layer or its adjacent interlaminar zones (intralaminar class II cells); and neurons whose dendrites cross into an adjacent layer(s) (interlaminar class II cells). The majority of class II cells in every layer have intralaminar dendrites, some of which are oriented along a particular axis, and others that are organized radially. The paired layers (1 and 2, 4 and 5) contain a particular group of intralaminar class II cells that have radially organized dendrites and elaborate claw‐like appendages. The dendrites of interlaminar class II cells are organized along lines of projection and extend across as many as four layers. These cells often reside close to or within the interlaminar zones. Overall, the organization of class II cells seems to follow a pattern similar to the class I (relay) cells identified previously. Most have intralaminar dendrites, which presumably underlie the fidelity of signals transmitted from the retina to a particular layer. However, there are also a number of other cells whose processes cross laminar borders, presumably to affect integrative functions within the nucleus. © 1992 Wiley‐Liss, Inc.
5B4‐CAM expression parallels neurite outgrowth and synaptogenesis in the developing rat brain
Authors: Alcantara Adriana A. , Pfenninger Karl H. , Greenough William T. 
Published: January 2005

AbstractIn order to study whether 5B4‐CAM expression parallels neurite outgrowth and synaptogenesis, a monoclonal antibody, 5B4, was used, which recognizes both fetal (185–250 kD) and adult (140 kD, 180 kD) forms of the neural cell adhesion molecule (N—CAM), to identify and localize the antigen in rat tissue during developmental ages P1 through P31 and in adults between P60 and 2 years of age. A ubiquitous pattern of intense immunolabelling was detected during the earliest stages of development. 5B4‐CAM expression paralleled process outgrowth and the early stages of synaptogenesis in the cerebral cortex, hippocampal formation, and cerebellum. In the adult, immunoreactivity was generally less intense, but the cerebral cortex and hippocampal and cerebellar molecular layers, all areas implicated in learning—associated plasticity, retained substantial immunoreactivity. The inner one–third of the dentate gyrus molecular layer, an area implicated in axonal sprouting and reactive synaptogenesis, was particularly intensely labelled. Evidence from this work suggests that 5B4‐CAM expression may be useful in monitoring neurite outgrowth and the early stages of synapse formation during development and possibly axonal sprouting and reactive synaptogenesis in the adult. © 1992 Wiley‐Liss, Inc.
A crustacean neuronal cytoskeletal protein with characteristics of neurofilaments and microtubule‐associated proteins
Authors: Weaver Debora J. , Viancour Terry A. 
Published: January 2005

AbstractThe purpose of this study was to characterize further a unique protein that is a component of the cytoskeleton of crayfish neurons. This protein, referred to as P600, is unique because it is unusually large (Mr > 600 kD), and because it has characteristics in common with both mammalian microtubule‐associated proteins and neurofilaments. Immunohistochemical techniques have shown that P600 colocalizes with microtubules and is a component of the fibrous side‐arms that extend from microtubules (Weaver and Viancour, Brain Res. 544:49, 1991). We have developed a method for obtaining purified P600 by using gel nitration techniques. When viewed by negative staining electron microscopy, P600 obtained by that method produced 11 nm‐wide beaded filaments. The number of filaments was strictly related to the P600 concentration in a column fraction. A small amount of P600 consistently copurified with taxol‐stabilized microtubules. The proportion copurifying with microtubules was increased by using apyrase to deplete ATP, or by using a nonhydrolyzable ATP analogue to compete with ATP. Immunogold labeling localized P600 near the ends of a subset of the fibrous side‐arms extending from endogenous axonal microtubules. Several polyclonal antibodies against mammalian microtubule‐associated proteins were tested for P600 labeling on immunoblots, and positive labeling was obtained with an antiserum directed against a region of microtubule‐associated protein 1B that has microtubule binding activity. Epitope homology between P600, mammalian microtubule‐associated protein 1B, and the mammalian mid‐molecular weight neurofilament subunit is discussed in the context of possible evolutionary relationships among these cytoskeletal proteins.
Development and birthdates of vasoactive intestinal peptide immunoreactive neurons in the chick proventriculus
Authors: Epstein Miles L. , Saffrey M. Jill , Poulsen Kristian T. 
Published: January 2005

AbstractTo gain insight into the mechanisms regulating expression of transmitter phenotypes in the enteric nervous system, we have studied the development and birthdate of vasoactive intestinal peptide immunoreactive (VIP‐IR) myenteric neurons in the chicken proventriculus (secretory portion of the avian stomach) by a combination of immunocytochemistry and radioautography. The appearance and numbers of VIP‐IR neurons in whole mounts of the myenteric plexus from chick embryos and chickens were examined. We found that VIP‐IR neurons first appeared at embryonic day (E) 5.5–6.5 in the distal part of the proventriculus. At E7.5, VIP‐IR neurons were found singly, in pairs, or in small groups, which together with unlabeled cells formed primitive myenteric ganglia. VIP‐IR fibers were found within the developing fiber tracts which connected the ganglia. The number of VIP‐IR neurons was found to be maximum in the E15.5 embryo and to decline to 68% of maximum in the 4 week old chicken.Birthdate studies were performed by application of either single pulses or cumulative doses of [3H]‐thymidine to embryos between E3 and E14. Whole mounts of the myenteric plexus from the proventriculus of these embryos were immunostained for VIP at E10 or E17. The whole mounts were subsequently sectioned and processed for radioautography. We found that VIP‐IR myenteric neurons were born between E3 and E10 with a peak at E7. Most cells underwent terminal division between E5 and E9. These data will be useful in determining the time and conditions when cells make decisions about transmitter phenotypes. © 1992 Wiley‐Liss, Inc.
A dopaminergic projection to the rat mammillary nuclei demonstrated by retrograde transport of wheat germ agglutinin–horseradish peroxidase and tyrosine hydroxylase immunohistochemistry
Authors: Gonzalo‐Ruiz A. , Alonso A. , Sanz J. M. , Llinás R. R. 
Published: January 2005

AbstractThe presence and distribution of dopaminergic neurons and terminals in the hypothalamus of the rat were studied by tyrosine hydroxylase (TH) immunohistochemistry.Strongly labelled TH‐immunoreactive neurons were seen in the dorsomedial hypothalamic nucleus, periventricular region, zona incerta, arcuate nucleus, and supramammillary nucleus. A few TH‐positive neurons were also identified in the dorsal and ventral premammillary nucleus, as well as the lateral hypothalamic area. TH‐immunoreactive fibres and terminals were unevenly distributed in the mammillary nuclei; small, weakly labelled terminals were scattered in the medial mammillary nucleus, while large, strongly labelled, varicose terminals were densely concentrated in the internal part of the lateral mammillary nucleus. A few dorsoventrally oriented TH‐positive axon bundles were also identified in the lateral mammillary nucleus.A dopaminergic projection to the mammillary nuclei from the supramammillary nucleus and lateral hypothalamic area was identified by double labelling with retrograde transport of wheat germ agglutinin‐horseradish peroxidase and TH‐immunohistochemistry. The lateral mammillary nucleus receives a weak dopaminergic projection from the medial, and stronger projections from the lateral, caudal supramammillary nucleus. The double‐labelled neurons in the lateral supramammillary nucleus appear to encapsulate the caudal end of the mammillary nuclei. The medial mammillary nucleus receives a very light dopaminergic projection from the caudal lateral hypothalamic area.These results suggest that the supramammillary nucleus is the principal source of the dopaminergic input to the mammillary nuclei, establishing a local TH‐pathway in the mammillary complex. The supramammillary cell groups are able to modulate the limbic system through its dopaminergic input to the mammillary nuclei as well as through its extensive dopaminergic projection to the lateral septal nucleus. © 1992 Wiley‐Liss, Inc.
Pathway from the zona incerta to the superior colliculus in the rat
Authors: Kim Uhnoh , Gregory E. , Hall William C. 
Published: January 2005

AbstractIn order to test the proposal that the zona incerta contributes to the generation of orienting movements, we examined the synaptic relationships between the incertotectal pathway and the cells of origin of the predorsal bundle. The predorsal bundle cells give rise to the major premotor pathway from the superior colliculus to the brainstem gaze centers. First, cytochrome oxidase histochemistry, gamma‐aminobutyric acid (GABA), and glutamic acid decarboxylase (GAD) immunocytochemistry, and the axonal transport of markers were used to define the borders of a ventral subdivision of the zona incerta. This subdivision projects topographically to the same sublamina of the intermediate grey layer of the superior colliculus that contains the vast majority of the predorsal bundle cells. Experiments in which incertotectal cells were labeled by both retrograde transport and immunocytochemistry showed that this pathway is GABAergic. Retrograde and anterograde experiments also showed that this pathway is reciprocated by a pathway from the intermediate grey layer of the superior colliculus to the same ventral subdivision of the zona incerta. Finally, experiments combining axonal transport and electron microscopic methods showed that the incertotectal pathway is the source of a monosynaptic GABAergic input to the cells of origin of the predorsal bundle. The ventral subdivision of the zona incerta is contrasted with a second source of GABAergic input to the predorsal bundle cells, the substantia nigra pars reticulata. © 1992 Wiley‐Liss, Inc.
Progressive morphological abnormalities observed in rat spinal motor neurons at extended intervals after axonal regeneration
Authors: Bowe Constance M. , Evans Nyle H. , Vlacha Vasoliki 
Published: January 2005

AbstractIt is generally accepted that mammalian spinal motor neurons return to normal after axotomy if their regenerated axons successfully reinnervate appropriate peripheral targets. However, morphological abnormalities, recently observed in spinal motor neurons examined 1 year after nerve crush injury, raise the possibility that delayed perikaryal changes occur after regeneration is complete. In order to distinguish between chronic and progressive alterations in neurons with long‐term regenerated axons, rat spinal motor neurons and dorsal root ganglion cells were examined at 5 and 10 months following unilateral sciatic nerve crush. Neurons with regenerated axons were identified by retrograde labelling with horseradish peroxidase. The structural properties of neurons ipsilateral to nerve injury were compared to those of neurons from the spinal cord and dorsal root ganglia on the contralateral side and from age‐matched control rats.At 5 months postcrush, the morphology of motor and sensory neurons ipsilateral to injury was comparable to that of control cells. However, several features of the motor neurons with regenerated axons distinguished them from control motor neurons at 10 months postcrush. Mean perikaryal area of ipsilateral spinal motor neurons was larger than the means for control motor neurons (p < 0.001). Ipsilateral spinal motor neurons also appeared clustered within the spinal cord and had thicker dendrites. Dorsal root ganglion cells with regenerated axons were slightly larger than control cells at 10 months postcrush but they exhibited no other morphological changes. The present findings indicate that spinal motor neurons are progressively altered after their regenerated axons have reestablished functional synapses with their peripheral targets. © 1992 Wiley‐Liss, Inc.
Substance P‐containing pyramidal neurons in the cat somatic sensory cortex
Authors: Conti Fiorenzo , de Biasi Silvia , Fabri Mara , Abdullah Lubna , Manzoni Tullio , Petrusz Peter 
Published: January 2005

AbstractLight and electron microscopic immunocytochemical methods were used to verify the possibility that neocortical pyramidal neurons in the first somatic sensory cortex of cats contain substance P.At the light microscopic level, substance P‐positive neurons accounted for about 3% of all cortical neurons, and the vast majority were nonpyramidal cells. However, 10% of substance P‐positive neurons had a large conical cell body, a prominent apical dendrite directed toward the pia, and basal dendrites, thus suggesting they are pyramidal neurons. These neurons were in layers III and V. At the electron microscopic level, the majority of immunoreactive axon terminals formed symmetric synapses, but some substance P‐positive axon terminals made asymmetric synapses. Labelled dendritic spines were also present.Combined retrograde transport‐immunocytochemical experiments were also carried out to study whether substance P‐positive neurons are projection neurons. Colloidal gold‐labelled wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase was injected either in the first somatic sensory cortex or in the dorsal column nuclei. In the somatic sensory cortex contralateral to the injection sites, a few substance P‐positive neurons in layers III and V also contained black granules, indicative of retrograde transport. This indicates that some substance P‐positive neurons project to cortical and subcortical targets.We have therefore identified a subpopulation of substance P‐positive neurons that have most of the features of pyramidal neurons, are the probable source of immunoreactive axon terminals forming asymmetric synapses on dendritic spines, and project to the contralateral somatic sensory cortex and dorsal column nuclei. These characteristics fulfill the criteria required for classifying a cortical neuron as pyramidal. © 1992 Wiley‐Liss, Inc.
Quantitative autoradiographic distribution of calcitonin gene‐related peptide (hCGRPα) binding sites in the rat and monkey spinal cord
Authors: Yashpal K. , Kar S. , Dennis T. , Quirion R. 
Published: January 2005

AbstractCalcitonin gene‐related peptide (CGRP) has been implicated in various spinal functions on the basis of its presence in the substantia gelatinosa and motoneurons and the biological effects induced by intrathecal CGRP injections. We investigated here the comparative distribution of [125I]hCGRPα binding sites in various segments of the rat and monkey spinal cord. The immunocytochemical localization of CGRP‐like material in rat spinal cord was also evaluated for comparison. In the rat spinal cord, high densities of [125I]hCGRPα binding sites were observed in lamina I, in a U‐shaped band that included lamina X and the medial parts of laminae III‐IV and in the intermediolateral and intermediomedial nuclei. The substantia gelatinosa (lamina II) contained relatively lower, but still significant, densities of [125I]hCGRPα binding sites, while the ventral horn showed low amounts of specific labeling. CGRP‐like immunoreactive fibers, on the other hand, were heavily concentrated in laminae I–II and in the reticulated portion of lamina V of the dorsal horn. Immunoreactivity to CGRP antiserum was also noted in fibers around the central canal and in a number of motoneurons of the ventral horn. In the monkey spinal cord, [125I]hCGRPα binding sites were present in lamina I in a U‐shaped band that included lamina X and the medial portions of laminae V–VI. Relatively low levels of [125I]hCGRPα binding were detected in laminae II to IV of the dorsal horn, while the ventral horn was more enriched with specific [125I]hCGRPα binding sites. Thus, it appears that the autoradiographic distribution of [125I]hCGRPα sites is species dependent in the spinal cord. Additionally, some differences are observed between the localization of [125I]hCGRPα binding sites and immunoreactive material in the rat spinal cord. These differences may be relevant to the purported roles of CGRP‐like peptides in spinal functions such as nociception, control of sympathetic output, and motor control. © 1992 Wiley‐Liss, Inc.
An aromatase‐associated cytoplasmic inclusion, the “stigmoid body”, in the rat brain: I. Distribution in the forebrain
Authors: Shinoda Koh , Mori Shiro , Ohtsuki Tsukasa , Osawa Yoshio 
Published: January 2005

AbstractAn aromatase‐containing neural system was examined in the rat forebrain, using a polyclonal antibody against aromatase‐associated human placental antigen X‐P2 (hPAX‐P2).Numerous dot‐like structures, which we have called stigmoid bodies, were immunostained in the preoptico‐hypothalamic region, the bed nucleus of the stria terminalis, the medial amygdala, the arcuate nucleus, the subfornical organ, and the area extending from the hypothalamic area to the central gray through the medial forebrain bundle and the periventricular fiber system of the posterior diencephalon. The stigmoid bodies were always found as inclusions in the neuronal cytoplasm. Their diameter was usually 1–3 μm, but exceptionally large forms, over 3 μm, were found in some brain regions, including the area extending from the median preoptic nucleus surrounding the organosum vasculosum laminae terminalis to the anterior medial preoptic nucleus, the periventricular nucleus of the preoptic area, and some parts of the medial preoptic nucleus. Most of these nuclei show sexual dimorphism. The distribution pattern of the hPAX‐P2 immunoreactive stigmoid bodies agreed well with that of aromatase activity previously reported in many biochemical studies. Brain regions where the stigmoid bodies were prominent largely coincide with steroid binding locations common to both androgen and estrogen, or regions where both sex steroid receptors are present. Although it still remains to be determined whether aromatase is localized within these stigmoid bodies, it appears likely that they are closely associated with the function of sex steroids at their target sites in the brain. © 1992 Wiley‐Liss, Inc.
The organization of the thalamocortical connections of the mediodorsal thalamic nucleus in the rat, related to the ventral forebrain–prefrontal cortex topography
Authors: Ray James P. , Price Joseph L. 
Published: January 2005

AbstractThe medial and central segments of the mediodorsal nucleus of the thalamus (MD) receive afferents from the ventral forebrain, including the piriform cortex, the ventral pallidum, and the amygdaloid complex. Because MD is reciprocally interconnected with prefrontal and agranular insular cortical areas, it provides a relay of ventral forebrain activity to these cortical areas. However, there are also direct projections from the piriform cortex and the amygdala to the prefrontal and agranular insular cortices.This study addresses whether this system has a “triangular” organization, such that structures in the ventral forebrain project to interconnected areas in MD and the prefrontal/insular cortex. The thalamocortical projections of MD have been studied in experiments with injections of retrograde tracers into prefrontal or agranular insular cortical areas. In many of the same experiments, projections from the ventral forebrain to MD and to the prefrontal/insular cortex have been demonstrated with anterograde axonal tracers.The connections of the piriform cortex (PC) with MD and the prefrontal/insular cortex form an organized triangular system. The PC projections to the central and medial segments of MD and to the lateral orbital cortex (LO) and the ventral and posterior agranular insular cortices (AIv and AIp) are topographically organized, such that more caudal parts of PC tend to project more medially in MD and more caudally within the orbital/insular cortex. The central and medial portions of MD also send matching, topographically organized projections to LO, AIv and AIp, with more medial parts of MD projecting further caudally. The anterior cortical nucleus of the amygdala (COa) also projects to the dorsal part of the medial segment of MD and to its cortical targets, the medial orbital area (MO) and AIp.The projections of the basal/accessory basal amygdaloid nuclei to MD and to prefrontal cortex, and from MD to amygdaloceptive parts of prefrontal cortex, are not as tightly organized. Amygdalothalamic afferents in MD are concentrated in the dorsal half of the medial segment. Cells in this part of the nucleus project to the amygdaloceptive prelimbic area (PL) and AIp. However, other amygdaloceptive prefrontal areas are connected to parts of MD that do not receive fibers from the amygdala.Ventral pallidal afferents are distributed to all parts of the central and medial segments of MD, overlapping with the fibers from the amygdala and piriform cortex. Fibers from other parts of the pallidum, or related areas such as the substantia nigra, pars reticulata, terminate in the lateral and ventral parts of MD, where they overlap with inputs from the superior colliculus and other brainstem structures. Thus, pallidal or pallidum‐related inputs overlap with other afferents in all parts of MD. © 1992 Wiley‐Liss, Inc.
Physiology and morphology of neurons in the dorsal motor nucleus of the vagus and the nucleus of the solitary tract that are sensitive to distension of the small intestine
Authors: Zhang Xueguo , Fogel Ronald , Renehan William E. 
Published: January 2005

AbstractWe have recently shown that distension‐sensitive vagal afferents are part of a neural circuit affecting absorption of water in the rat small intestine. Our results indicated that vagal afferent activity directly or indirectly influences the activity of neurons in the dorsal motor nucleus of the vagus (DMNV). In the present study we pursued this interaction by examining the structure and function of neurons in the DMNV and nucleus of the solitary tract (NST) that responded to moderate distension of the small intestine. Distension‐sensitive cells were filled by intracellular iontophoretic injection of horseradish peroxidase. A total of 43 distension‐sensitive brainstem neurons were successfully characterized and labeled. Sixteen of the 17 NST neurons were excited by distension of the small intestine. Ten of the seventeen were restricted to the ipsilateral NST. Only two NST neurons possessed axons that terminated in the subjacent DMNV. In contrast to the response profile of the NST neurons, 24 of 26 DMNV neurons were inhibited by intestinal distension. Fourteen of the DMNV neurons appeared to contribute to the vagus nerve and 15 extended dendrites into the overlying NST. We propose that distension‐induced inhibition of DMNV activity is accomplished by inhibitory NST neurons, which synapse on the dendrites of DMNV neurons in the NST. © 1992 Wiley‐Liss, Inc.