bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vasoactive intestinal polypeptide cerebrospinal fluid‐contacting neurons of the monkey and cat spinal central canal
Authors: Lamotte Carole C. 
Published: January 2005

AbstractNeurons immediately adjacent to the central canal were demonstrated in the cat and monkey to be immunoreactive for the peptide vasoactive intestinal polypeptide (VIP), by means of the peroxidase antiperoxidase method. Most of the cells were found in the thoracic and sacral segments, although a few were present at each level. The thoracic neurons were multipolar and either ependymal or subependymal; they usually had a large, thick dendrite that was oriented radially toward the center of the central canal; this dendrite penetrated through the ependymal layer and ended as a large, fringed podlike process (4–5‐μm diameter) along the canal surface in contact with the cerebrospinal fluid (CSF). From the basal surface of the thoracic cell arose several small dendrites and a varicose axon. A few of the thoracic VIP neurons also contained two nuclei. In the sacral cord, the VIP neurons that lie along the central canal were of several types. They were round or multipolar and were either subependymal, within the ependyma, or supraependymal. Many had long dendrites and thin varicose axons stretching for long distances parallel to the cord surface. Other VIP neurons were smaller cells with short, highly branched, varicose processes. Most prominent in the sacral cord of the cat was a massive intricate network of intensely labelled processes extending in parallel along the canal surface. This network contained thick dendrites, highly varicose axons, and small neurons. Electron microscopy demonstrated VIP axons and varicosities containing small round clear vesicles and dense core vesicles. These processes were in desmosomal contact with ependymal cells and in direct contact with the CSF space. VIP processes were also found along the pial surface of the spinal cord at each level. In some cases single axons and bundles of axons arising from the area around the central canal could be traced to terminal fields along the ventral median fissure and the ventral and ventral lateral surface. In summary, the cat and monkey spinal canal is richly innervated by VIP neurons with elaborate processes in contact with the cerebrospinal fluid; further, some of these neurons may also extend axons to the ventral surface of the spinal cord. In these aspects, these cells resemble CSF‐containing neurons previously described in lower species.
Identification of acetylcholinesterase‐reactive neurons and neuropil in neostriatal transplants
Authors: Walker Paul D. , Chovanes George I. , McAllister James P. 
Published: January 2005

AbstractTo identify and describe neurons in neostriatal transplants that synthesize acetylcholinesterase (AChE), the present study has utilized the irreversible AChE inhibitor diisopropylfluorophosphate (DFP) combined with AChE histochemistry. Dissociated suspensions of tissue taken from the striatal ridge of embryos at 14 days of gestation were transplanted into the neostriatum of adult rats 5 days after intrastriatal kainic acid lesions.Two types of AChE neurons have been identified in transplants treated with DFP. One type resembled the large intensely reactive AChE neuron that is thought to be a cholinergic interneuron of the normal neostriatum. The other type resembled smaller, less reactive AChE neurons of the neostriatum, as well as medium‐sized, lightly reactive AChE neurons of the globus pallidus. Qualitative observations suggest that these less reactive AChE neurons were more numerous in transplants compared to the normal neostriatum. Both AChE neuronal types were found in segregated clusters throughout the grafts. Transplants processed for AChE histochemistry without DFP treatment contained two types of AChE neuropil. Dark areas of AChE neuropil similar in intensity to the normal neostriatum were found between larger areas of lighter AChE neuropil.These results demonstrate that neostriatal transplants contain AChE neurons and suggest that these neurons contribute to the AChE reactivity within the graft.
Classes of neurons in relation to the laminar organization of the lateral geniculate nucleus in the tree shrew, Tupaia belangeri
Authors: Saini K. , Kretz R. , Rager G. 
Published: January 2005

AbstractWe used the rapid Golgi and horseradish peroxidase (HRP) techniques to study the dendritic spread of relay neurons in functionally distinct laminae of the tree shrew dorsal lateral geniculate nucleus (LGNd). On the basis of their dendritic spread in relation to laminar and interlaminar zones, we describe three classes of relay neurons. (1) Unilaminar neurons with multipolar radiate, bitufted, and intermediate types of dendrites. Dendrites of these neurons are confined to one lamina only, but also can have some of their segments in adjacent interlaminar zones. (2) Multilaminar neurons with multipolar radiate, bitufted, and intermediate types of dendrites. Independent of the site of their cell bodies in a laminar or interlaminar zone, these neurons spread their dendrites over two or more laminae. (3) Interlaminar neurons whose cell bodies and dendrites are confined to a single interlaminar zone.Unilaminar neurons are found in all the laminae. In the medial three laminae, they are more of the radiate type, whereas in laminae 4 and 5 their dendrites tend to be more of a tufted nature. Lamina 6 shows a preponderance of the elongated bitufted type. Multilaminar neurons, although less common as compared to the unilaminar, are also observed in all the laminae. Some neurons have their dendrites confined to an interlaminar zone. By retrograde transport of HRP injected into the visual cortex, we have shown that these neurons are, in fact, relay neurons. In addition to relay neurons, there are small interneurons with “axoniform” dendrites and an unmyelinated axon whose arborization is confined within the limits of the neuron's dendritic spread. Neurons of this type are not labeled with HRP injected into the visual cortex.We conclude that although each lamina is functionally specialized by input from ipsilateral or contralateral retina and by segregation of neurons responding to on or off stimuli, some multilaminar neurons can be found in each lamina. Thus, laminar as well as interlaminar zones contain a class of neurons that could provide a cross‐talk between the functionally specialized laminae. Most relay neurons in all the laminae, however, confine their dendrites to their home lamina. Thus, the dendritic architecture of relay neurons allows for processing of information both within channels and between channels.
Noradrenergic innervation of serotoninergic neurons in the myenteric plexus
Authors: Gershon Michael D. , Sherman Diane L. 
Published: January 2005

AbstractThe monoaminergic innervation of the guinea pig small intestine was investigated to determine if there is an anatomical basis for the hypothesis that serotoninergic and noradrenergic neurons physiologically interact in the enteric nervous system. Initial rates of uptake of tritiated 5‐hydroxy‐tryptamine (3H‐5‐HT) or norepinephrine (3H‐NE) by segments of guinea pig small intestine were measured in order to estimate the regional density of the serotoninergic and noradrenergic innervation. No change was found in the uptake of 3H‐5‐HT as a function of distance between duodenum and ileum, whereas the relative uptake of 3H‐NE declined. The pattern of serotoninergic elements demonstrated radioautographically was compared with that obtained by visualizing 5‐HT immunoreactivity. Both methods revealed that a small number of serotoninergic neurons, located in 35.3% ± 1.5% of myenteric ganglia, give rise to many fibers that form thick bundles in interganglionic connectives. Moreover, there was a pronounced heterogeneity in the serotoninergic innervation of individual myenteric neurons and ganglia. In material fixed with aldehydes and postfixed with NaMnO4, noradrenergic axon terminals were identified by their characteristic small dense‐cored vesicles. Following incubation with 3H‐NE only terminals with small dense‐cored vesicles were radioautographically labeled, confirming that these terminals are noradrenergic. When 3H‐5‐HT was substituted for 3H‐NE, noradrenergic terminals were not labeled, showing that nonspecific uptake of 3H‐5‐HT into noradrenergic axons did not occur in the presence of 5‐hydroxydopamine. The combination of aldehyde‐NaMnO4 fixation with the radioautographic localization of 3H‐5‐HT thus permitted the simultaneous identification of serotoninergic and noradrenergic neural elements. Serotoninergic varicosities were found to differ from noradrenergic varicosities in the size, appearance, and packing density of their synaptic vesicles. In addition, recognizable but rudimentary pre‐ and postsynaptic membrane specializations were associated with serotoninergic but not noradrenergic varicosities. Most serotoninergic neuronal cell bodies were contacted both by serotoninergic synapses and noradrenergic varicosities. Similar appositions of noradrenergic varicosities with nonserotoninergic neurons appeared to be rare. In view of earlier observations that sympathetic nerves affect the release of 5‐HT from stimulated enteric serotoninergic neurons, it seems likely that the noradrenergic appositions with serotoninergic neurons are the anatomical substrate for this effect. The strategic and possibly unique innervation of serotoninergic neurons by noradrenergic sympathetic postganglionic fibers is consistent with the hypothesis that the regulation of the activity of serotoninergic neurons is involved in central modulation of intestinal motility.
Choline acetyltransferase‐immunoreactive neurons and terminals in the rat septal complex: A combined light and electron microscopic study
Authors: Bialowas Jacek , Frotscher Michael 
Published: January 2005

AbstractA monoclonal antibody against choline acetyltransferase (ChAT), the acetylcholine synthesizing enzyme, was used to determine the morphological characteristics of cholinergic neurons and axon terminals within the rat septum. Light microscopy revealed numerous large fusiform or multipolar ChAT‐immunoreactive neurons in the medial septal nucleus/diagonal band complex (MSDB). In contrast, virtually no immunostained cells were found in the lateral septum (Nc. septalis dorsalis and Nc. septalis lateralis). Fine immunostained fibers were most abundant close to the midline in the MSDB mainly following an ascending course. A few thin ChAT‐immunoreactive fibers and terminallike pericellular punctate stuctures were observed in the inner part of the dorsal septal nucleus.Electron microscopy of ChAT‐immunoreactive neurons revealed large cell bodies rich in cytoplasmic organelles. The cell nuclei regularly exhibited multiple invaginations of the nuclear membrane. Only rarely were terminals found that established synaptic contacts on the cell bodies of immunostained neurons. In contrast, numerous terminals formed synaptic contacts on immunoreactive dendrites.ChAT‐immunopositive terminals were studied in thin sections from the MSDB and from the dorsal septal nucleus. In both regions they appeared as heavily immunostained vesicle‐filled boutons that established symmetric and asymmetric synaptic contacts. In the dorsal septal nucleus immunostained terminals often showed a basketlike arrangement around immunonegative cell bodies.Our fine structural study provides evidence that cholinergic neurons in the MSDB are similar to cholinergic neurons in the basal nucleus and neostriatum, which have been described by other investigators. The presence of cholinergic synopses in the septal complex indicates that this region not only contains cholinergic projection neurons, but receives a cholinergic input itself.
Descending projections from the superior olivary complex to the cochlear nucleus of the cat
Authors: Spangler Kevin M. , Cant Nell B. , Henkel Craig K. , Farley Glenn R. , Warr W. Bruce 
Published: January 2005

AbstractSubdivisions of the cochlear nuclear complex give rise to a number of discrete projections to certain cell groups of the superior olivary complex and also received substantial descending projections from the periolivary nuclei. In the present study, we sought to determine by means of retrograde transport of horseradish peroxidase (HRP), and anterograde transport of radiolabeled protein, if the periolivary nuclei give rise to discrete projections to the various subdivisions of the cochlear nuclear complex. Following medium to large injections of HRP into the cochlear nucleus, irrespective of location, labeled cells were found in all periolivary nuclei bilaterally. In every case more than 40% of the labeled cells were found in the lateral nucleus of the trapezoid body on the same side and the ventral nucleus of the trapezoid body of both sides. Other periolivary nuclei contributing more than 5% of the total number of cells in individual cases were the contralateral lateral nucleus of the trapezoid body and the ipsilateral anterolateral and dorsal periolivary nuclei. Injections of tritiated leucine into periolivary nuclei gave rise to axonal labeling to the trapezoid body and the dorsal acoustic stria, usually bilaterally, and to terminal labeling that was widely distributed within the cochlear nuclear complex. In several cases with small injections, particularly in the lateral nucleus of the trapezoid body, the projections from the periolivary nuclei to the anteroventral and dorsal cochlear nuclei connected areas described as having similar best‐frequency representation. The autoradiographic data corroborated the main results from the HRP experiments and provided additional information permitting these conclusions: (1) the projections from the periolivary nuclei to the cochlear nuclear complex are organized tonotopically, at least in part; (2) each periolivary nucleus (and perhaps individual cells), projects widely throughout the cochlear nuclear complex; (3) the pattern of termination of projections from different periolivary nuclei to a given region of the cochlear nuclear complex are similar, as seen in autoradiograms, and (4) the lateral and dorsal periolivary nuclei project mainly ipsilaterally, while the medial periolivary nuclei project bilaterally with a contralateral bias. The magnitude of these projections and their widespread distribution within the cochlear nuclear complex would suggest an important role for the descending projections in the normal functioning of the cochlear nucleus.
Development of brainstem and cerebellar projections to the diencephalon with notes on thalamocortical projections: Studies in the north american opossum
Authors: Martin G. F. , Cabana T. , Hazlett J. C. , Ho R. , Waltzer R. 
Published: January 2005

AbstractThe North American opossum is born in a very immature state, 12 days after conception, and climbs into an external pouch where it remains attached to a nipple for an extended period of time. We have taken advantage of the opossum's embryology to study the development of brainstem and cerebellar projections to the diencephalon as well as the timing of diencephalic projections to somatosensory motor areas of neocortex. The techniques employed included immunocytochemistry for serotonin, the retrograde and orthograde transport of wheat germ agglutinin conjugated to horseradish peroxidase, and the selective impregnation of degenerating axons. Our results suggest that serotoninergic axons, presumably from the dorsal raphe and superior central nuclei, are present in the diencephalon at birth. Axons from the bulbar reticular formation, the vestibular complex, the trigeminal sensory nuclei, and the dorsal column nuclei reach at least mesencephalic (and probably diencephalic) levels by postnatal day (PND) 3, whereas those from the cerebellar nuclei may not grow into comparable levels until PND 5. The dorsal column and cerebellar nuclei innervate the ventral nuclei of the thalamus by estimated postnatal day (EPND) 17 and all of the diencephalic nuclei supplied in the adult animal by EPND 26. Diencephalic axons enter ventrolateral (face) areas of presumptive somatosensory motor cortex by PND 12, but do not reach dorsomedial (limb) regions until EPND 21. At both ages, diencephalic axons are limited to the cortical subplate and marginal zone; they do not innervate an identifiable internal granular layer until considerably later. Our results suggest that axons from the brainstem and cerebellum grow into the diencephalon early in development, but that they do not influence the cerebral cortex until relatively late. When the results of the present study are compared with those reported previously on the development of ascending spinal (Martin et al., '83) and corticofugal (Martin et al., '80; Cabana and Martin, '85b, c) projections, it appears that specific components of major somatosensory and motor circuits develop according to different timetables.
Somatotopic alignment between climbing fiber input and nuclear output of the cat intermediate cerebellum
Authors: Gibson A. R. , Robinson F. R. , Alam J. , Houk J. C. 
Published: January 2005

AbstractThe rostral dorsal accessory olive (rDAO) contains a detailed somatosensory map of the entire contralateral body surface. The rDAO projects to the anterior interpositus nucleus (NIA) directly as well as indirectly by way of Purkinje cells in cerebellar cortex. NIA maintains a topographic relation to different levels of the spinal cord through a relay in the magnocellular red nucleus (RNm) and, thus, contains a motor somatotopy. By using bidirectional transport of WGA‐HRP, we demonstrate that the sensory somatotopy of rDAO aligns with the motor somatotopy of NIA. It is likely that rDAO information supplied to the cerebellum from a specific part of the body is used to influence movements restricted to that same body part.
Short axon cells of the rat olfactory bulb display NADPH‐diaphorase activity, neuropeptide Y‐like immunoreactivity, and somatostatin‐like immunoreactivity
Authors: Scott John W. , McDonald John K. , Pemberton Janice L. 
Published: January 2005

AbstractSeveral types of short axon cells of the mammalian olfactory bulb have been described after Golgi impregnation. Two of these types have been observed in our material after treatment with the NADPH‐diaphorase procedure or after immunohistochemistry for neuropeptide‐Y (NPY). The cells stained by the two procedures have similar morphologies and distributions. A less extensive series of observations confirms that similar cells also display somatostatin (SS)‐like immunoreactivity. One of these cell types corresponds to the superficial short axon cell of Golgi and electron microscopic studies. The dendrites of this cell lie within the periglomerular region and in the superficial external plexiform layer (EPL), generally lying parallel to the glomerular layer. In some cases the axon has been traced across the EPL into the granule cell layer (GCL). This cell may provide another route of interaction between the periglomerular region and the granule cells in addition to the influences conducted by basal dendrites and axon collaterals of some mitral and tufted cells. A type of deep short axon cell is also visible with these two procedures. It lies deep in the granule cell layer, frequently near the ventricular layer and its dendrites lie parallel to that layer. This deep short axon cell is stained with much greater frequency by the NADPH‐diaphorase and NPY procedures than is the superficial short axon cell. It corresponds most closely to the Blanes or Golgi cells of the Golgi impregnation literature, but it appears to differ from these cells in the position and orientation of its dendrites. No spines have been observed on either the superficial or deep cells in this series. Many glomeruli are also stained by the NADPH‐diaphorase procedure, but are not NPY or SS immunoreactive. This may provide additional evidence for functional differences between glomeruli in local regions of the olfactory bulb.
Morphological properties of respiratory intercostal motoneurons in cats as revealed by intracellular injection of horseradish peroxidase
Authors: Lipski J. , Martin‐body R. L. 
Published: January 2005

AbstractThis study was undertaken to describe details of the location and cellular morphology of functionally identified (inspiratory or expiratory) external and internal intercostal motoneurons on the basis of intracellular injection of horseradish peroxidase (HRP). Sixty HRP‐labeled motoneurons were examined; 44 in transverse, 16 in sagittal sections. In the upper thoracic segments ( T3T4), there was only a small overlap in the location of inspiratory external and internal intercostal motoneurons; the inspiratory external motoneurons were generally found more ventromedially within the ventral horn than either inspiratory or expiratory internal intercostal motoneurons. No major morphological differences were observed between the types of motoneurons studied. The number of primary dendrites ranged from 6 to 10. The dendrites projected mainly along the medial or the lateral border of the ventral horn, and rostrocaudally up to 1,760 μm from the cell body. The paths taken by dendrites to fill the territory occupied by the dendritic trees appeared to depend upon location of the cell body. Few dendrites penetrated the white matter. Axon diameters varied from 1.1 to 6.7 μm (mean 3.6 ± 1.3 μm, n = 55). Collateral branches were identified in 78% of axons. The number of branches arising from a given axon varied from 1 to 4. It is concluded that the respiratory intercostal motoneurons form a morphologically homogeneous population, in spite of their functional differences.
Early development of photoreceptors in the ventral retina of the zebrafish embryo
Authors: Kljavin Ivar J. 
Published: January 2005

AbstractThe first photoreceptor outer segments in the retina of the zebrafish Brachydanio rerio appear in the embryo 2.5 days after fertilization, as revealed by scanning and transmission electron microscopy. These outer segments arise in a small region ventral to the exit of the optic nerve. Ultrastructural features of the developing photoreceptor cells, especially those that distinguish the rods and cones, are described. By 3 days after fertilization, the time of hatching, photoreceptor outer segments are widespread in the retina. However, at this time and in the young larva the early developing ventral region remains distinctive because of its conspicuous population of rods.