bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential development of the dual serotoninergic fiber system in the cerebral cortex of the cat
Authors: Vu Dzung H. , Törk Istvan 
Published: January 2005

AbstractThe changes in distribution and density of the serotoninergic innervation of the cerebral cortex were studied in kittens from birth (PO) to 60 days of age (P59). Three cortical areas were sampled: prefrontal, primary auditory, and primary visual areas. Two systems of serotoninergic axons were demonstrated by immunocytochemical techniques: the fine axon system characterized by small fusiform varicosities up to 1 μm in diameter, and the beaded axon system, the fibers of which have round varicosities up to 5 μm in diameter. The density of the two types of fibers across the cortical layers at different ages was measured with a semiautomatic computerized system. In all three areas, the density of fine axons increased steadily from birth, although the pattern of innervation changed from an even distribution at PO to a distinct concentration of the fibers in layers I–III by week 2 in the prefrontal cortex and by week 3 in auditory and visual cortices. By contrast, the beaded axons first appeared in the cortex at week 2 for the prefrontal cortex, at week 3 in auditory and visual areas. Initially, these fibers were distributed throughout all cortical layers and were of much lower density than the fine axons. At later ages the beaded axons became confined to layers I–III where they gradually increased in number, and from week 4, they formed pericellular arrays which were only observed in the prefrontal and auditory cortices, not in visual cortex.These findings provide further evidence for the existence of two parallel subsystems of serotoninergic axons which are different not only in their morphology and nuclear origin, but also in their development. Our finding that the two serotoninergic fiber systems arrive in the cortex in two different stages suggests that they have differential roles in development. The late formation of the pericellular arrays indicates that the formation of the specific connections made by the beaded fibers could be dependent on a certain degree of maturity of the target neurons.
Neonatal enucleation induces correlated modification in sensory responsive areas and pial angioarchitecture of the parietal and occipital cortex of albino rats
Authors: Wolff Joachim R. , Toldi József , Siklós László , Fehér Ottó , Joó Ferenc 
Published: January 2005

AbstractThis study was carried out to investigate whether correlations existing in normal adult rats (Ambach et al., '86) between functional characteristics of neocortical areas and their pial angioarchitechture can be correspondingly modified under pathological conditions. The right eyes of albino rats were enucleated on the 1st, 8th, 15th and 30th day after birth, respectively. At the age of 3 to 4 months, the responsiveness of the parieto‐occipital cortex to sensory stimuli was studied in enucleated animals and age matched controls. After the mapping of visually and somatosensorily evoked potentials, the vascular system was filled with dye. Monocular enucleation at birth induced bilateral modifications in sensory responsiveness and corresponding changes in pial angioarchitecture, especially in the venous drainage fields. In comparison with the controls, a considerable expansion was observed in the overlapping zone between visually and somatosensorily responsive areas. In contrast, borders of the visual cortex toward the auditory and retrosplenial areas were essentially stable. Corresponding changes were found in the pial distribution patterns of cerebral veins but not of arteries. The major effect of neonatal enucleation on angioarchitecture was a change in the subdivision of the parietooccipital veins drainage fields. This was due to a significant enlargement of the anterior accessory occipital (O3) vein, which compressed the drainage fields of the parietal and occipital veins and completely separated them from one another. The results suggest that during ontogenesis: (1) alterations in the formation of sensory input may interfere with neocortical angiogenesis, especially the structuring of veins, (2) after monocular enucleation this influence is prominent in parietal and occipital cerebral veins, and (3) these angiogenetic processes are vulnerable only during the perinatal and early postnatal period.
Secondary vestibular cholinergic projection to the cerebellum of rabbit and rat as revealed by choline acetyltransferase immunohistochemistry, retrograde and orthograde tracers
Authors: Barmack N. H. , Baughman R. W. , Eckenstein F. P. , Shojaku H. 
Published: January 2005

AbstractPreviously we have shown that four regions of the cerebellum, the uvula‐nodulus, flocculus, ventral paraflocculus, and anterior lobe 1, receive extensive, but not exclusive, cholinergic mossy fiber projections. In the present experiment we have studied the origin of three of these projections in the rat and rabbit (uvula‐nodulus, flocculus, ventral paraflocculus), using choline acetyltransferase (ChAT) immunohistochemistry in combination with a double label, retrogradely transported horseradish peroxidase (HRP).We have demonstrated that in both the rat and rabbit the caudal medial vestibular nucleus (MVN) and to a lesser extent the nucleus prepositus hypoglossus (NPH) contain ChAT‐positive neurons. Neurons of the caudal MVN are double‐labeled following HRP injections into the uvula‐nodulus. HRP injections into the uvula‐nodulus also labeled less than 5% of the neurons in the cholinergic vestibular efferent complex.Fewer ChAT‐positive neurons in the MVN and some ChAT‐positive neurons in the NPH are double‐labeled following HRP injections into the flocculus. Almost no ChAT‐positive neurons in the MVN and some ChAT‐positive neurons in the NPH are double‐labeled following HRP injections into the ventral paraflocculus.Injections of Phaseolus leucoagglutinin (PHA‐L) into the caudal MVN of both the rat and rabbit demonstrated projection patterns to the uvula‐nodulus and flocculus that were qualitatively similar to those observed using ChAT immunohistochemistry.We conclude that the cholinergic mossy fiber pathway to the cerebellum in general and the uvula‐nodulus in particular is likely to mediate secondary vestibular information related to postural adjustments.
Galanin‐like innervation of rat submandibular and sublingual salivary glands: Origin and effect on acinar cell membranes
Authors: Konopka L. M. , May V. , Forehand C. J. 
Published: January 2005

AbstractThe distribution and source of a galanin‐like innervation of rat salivary glands has been examined. Additionally, submandibular and sublingual acinar cell membrane responses to galanin or a cholinergic agonist were studied. Galanin‐immunoreactive fibers were observed throughout the submandibular and sublingual glands in association with ducts and acini. A subset of submandibular ganglion cells expresses galanin immunoreactivity. Parasympathectomy resulted in a marked decrease in galanin immunoreactivity in the glands. Sympathectomy resulted in marked reduction of dopamine β‐hydroxylase immunoreactivity with no appreciable change in galanin immunoreactivity. Retrograde labeling experiments demonstrated that galanin‐immunoreactive sensory neurons in the trigeminal ganglion do not innervate the submandibular or sublingual gland. These results indicate that the galanin‐like innervation of rat salivary glands is derived from parasympathetic nerves to the glands.Since rat sublingual glands contain largely mucous acini while rat submandibular gland acini are seromucous, electrophysiological responses to galanin and the muscarinic agonist, bethanechol, were compared. Agonist‐induced voltage shifts varied between the two glands. The galanin‐induced response at the level of the resting membrane potential in submandibular acinar cells was a hyperpolarization, while that in sublingual acinar cells was a depolarization. There was also a greater voltage dependence to the galanin‐induced submandibular response than to the sublingual response. Differences were also noted in the acinar cell response to cholinergic stimulation between these glands.These results demonstrate the existence of a galanin‐like innervation to salivary glands that may be functionally relevant. Moreover, the results challenge the idea that agonist‐induced membrane responses are similar among acinar cells of different glands.
Anatomical organization of the hypophysiotrophic systems in the electric fish, Apteronotus leptorhynchus
Authors: Johnston Sheila A. , Maler L. 
Published: January 2005

AbstractThe organization of afferents to the pituitary was investigated by applying DiI crystals to the pituitary or pituitary stalk of the gymnotiform electric fish, Apteronotus leptorhynchus. Most hypophysiotrophic cells were found in the hypothalamus and were distributed throughout its rostrocaudal extent: nucleus preopticus periventricularis, pars anterior and posterior; suprachiasmatic nucleus; anterior, dorsal, ventral, lateral, and caudal hypothalamic nuclei; and nucleus tuberis lateralis, pars anterior and posterior. In addition a small number of retrogradely labeled cells were found in the ventral telencephalon (area ventralis, pars ventralis) and, most surprisingly, in a thalamic nucleus (nucleus centralis posterioris). The nucleus preopticus periventricularis pars posterior and the anterior hypothalamic nucleus appear to correspond to the parvicellular and magnocellular divisions of the nucleus preopticus of other teleosts. Integration of these results with immunohistochemical localization of monoamines and neuropeptides in the apteronotid brain suggests many homologies between the hypophysiotrophic nuclei of teleosts and other vertebrates, including mammals.Apteronotus communicates electrically during agonistic and sexual interactions. There are numerous anatomical links between the hypophysiotrophic systems and the brain areas related to electrocommunication.
Organization of the superior olivary complex in the guinea pig: II. Patterns of projection from the periolivary nuclei to the inferior colliculus
Authors: Schofield Brett R. , Cant Nell B. 
Published: January 2005

AbstractThe superior olivary complex is a major source of auditory projections to the inferior colliculus. Although the projections from the medial and lateral superior olivary nuclei have been well characterized, projections from the surrounding periolivary nuclei have received relatively little attention. In the guinea pig, cytoarchitectonic criteria can be used to distinguish 11 periolivary nuclei that can be divided into four groups. These are: (1) a lateral group that comprises the anterolateral and posteroventral periolivary nuclei and the lateral nucleus of the trapezoid body; (2) a dorsal group that comprises the dorsal and dorsolateral periolivary nuclei; (3) a ventral group that comprises the rostral, ventromedial, and anteroventral periolivary nuclei and the ventral nucleus of the trapezoid body; and (4) a medial group that comprises the superior paraolivary nucleus and the medial nucleus of the trapezoid body.In the present study we used horseradish peroxidase and fluorescent tracers to identify olivocollicular cells in each of the periolivary nuclei. The lateral, dorsal, and medial periolivary groups project bilaterally, and the ventral periolivary group projects ipsilaterally. Within groups, individual nuclei contain different numbers of olivocollicular cells. The posteroventral periolivary nucleus is the only periolivary nucleus that does not project to the inferior colliculus. The superior paraolivary nucleus is the only periolivary nucleus that contains significant numbers of individual cells that project to both inferior colliculi. The remaining periolivary nuclei project only ipsilaterally or contain separate populations of cells that project to the two inferior colliculi.
Serotoninergic, noradrenergic, and peptidergic innervation of Onuf's nucleus of normal and transected spinal cords of baboons (papio papio)
Authors: Rajaofetra N. , Passagia J.‐G. , Marlier L. , Poulat P. , Pellas F. , Sandillon F. , Verschuere B. , Gouy D. , Geffard M. , Privat A. 
Published: January 2005

AbstractWe have investigated with light and electron microscope immunocytochemistry the aminergic and peptidergic innervation of Onuf's nucleus in adult baboons. This nucleus, located in the ventrolateral part of the sacral spinal cord (S2 and S3), is considered to control urethral and anal sphincters and penile muscles. By comparison of intact and transected spinal cords, we have found that serotoninergic innervation has two origins: first, supraspinal, innervating the whole nucleus, with a possible predominance in the dorsal half; and second, intraspinal, corresponding to the ventral half of the nucleus. Thyrotropin‐releasing hormone innervation appears largely coincident with serotonin, both in intact and transected spinal cords. Noradrenaline is exclusively of supraspinal origin, as attested by its disappearance below the level of the section. Substance P, calcitonin genex‐related peptide, and Leux‐ and Metx‐enkephalin, which profusely innervate Onuf's nucleus, are on the contrary not affected by the transection. They most likely originate from the cord itself or the dorsal root ganglia. Thus, Onuf's nucleus innervation in the baboon arises both from supraspinal and intraspinal sources.The present study provides an anatomical basis for both voluntary and reflex controls of excretory and sexual functions in a primate. The same neurotransmitter (serotonin) according to its cell origin and discrete topography could exert different influences upon the same effector system.
Distribution of vasopressin and oxytocin cells and fibres in the hypothalamus of the domestic pig (Sus scrofa)
Authors: Van Eerdenburg Frank J. C. M. , Swaab Dick F. , Van Leeuwen Fred W. 
Published: January 2005

AbstractThe distribution of vasopressin and oxytocin cells and fibres was studied in the pig hypothalamus by means of monoclonal antibodies, in order to prevent the non‐specific staining that is characteristic for the pig. The nucleus circularis is described for the first time in the pig hypothalamus and consists of both oxytocin and vasopressin containing cell bodies. A cell group, characteristic for the pig and horse, lateral and caudal from the vascular organ of the lamina terminals, was found to be continuous with the supraoptic nucleus. It contained only oxytocin and it is proposed that this group be called pars dorsomedialis of the supraoptic nucleus. In this study, vasopressin has been demonstrated for the first time in the suprachiasmatic nucleus of the pig. The discussion focusses on how our findings in the pig differ from vasopressin and oxytocin systems identified in other mammalian species.
A light and electron microscopic study of intracellularly HRP‐labeled lumbar motoneurons after intramedullary axotomy in the adult cat
Authors: Lindå H. , Cullheim S. , Risling M. 
Published: January 2005

AbstractIn contrast to many other neurons in the central nervous system, spinal motoneurons in adult cats have been shown to regenerate their axons after an axotomy accomplished within the CNS compartment. This regenerative capacity may be the result of extrinsic influences, or intrinsic properties of the motoneurons themselves, or interactions between extrinsic and intrinsic factors. As part of the effort to establish circumstances of importance for this central regeneration, a detailed analysis of the morphology of lumbar motoneurons was performed 3–11 weeks following a ventral funiculus axotomy. Fourteen large neurons considered to be intramedullarly axotomized alpha motoneurons were labeled intracellularly with horseradish peroxidase.Twelve out of the fourteen analyzed neurons had an axonlike regenerating process. These twelve neurons could, in turn, be separated into two groups, based on the proximity of the axonal lesion and the proximal morphology of the regenerating process. Thus, after a comparatively proximal axotomy, new axons were produced, originating either from the cell soma or from a distal dendritic branch. After a more distal axotomy, but still intramedullarly, it seemed as if the proximal part of the original axon always persisted and subsequently regenerated.Analysis of the relation between the cell soma diameter and the diameter and number of its stem dendrites revealed that dendrites become thinner and also decrease in number after an intramedullary axotomy. In this way, it may be calculated that the total dendritic surface area of lesioned motoneurons will decrease by approximately half. In four neurons, most dendrites had an abnormal appearance in the light microscope with increasing diameter of distal branches. Ultrastructural analysis revealed that such dendrites were surrounded by myelin sheaths.Small filopodia in close relation to axon terminals were found to emerge from the cell membrane of the lesioned motoneurons. Their function may be to establish contact with presynaptic elements and then retract them to the cell membrane.We interpret the morphological changes of the motoneurons as signs of a large capacity for axonal regeneration, even after axotomy in the central nervous system.
Independent mosaics of large inner‐ and outer‐stratified ganglion cells in the goldfish retina
Authors: Cook Jeremy E. , Becker David L. , Kapila Rakesh 
Published: January 2005

AbstractGoldfish retinal ganglion cells were filled with horseradish peroxidase and studied in flatmounts. Two regular mosaics of large neurons with many of the properties of mammalian alpha ganglion cells were found, differing from each other in spacing, size, and dendritic stratification. The existence of biplexiform ganglion cells with additional dendrites in the outer plexiform layer was also confirmed.One of the two alpha‐like mosaics consisted of giant ganglion cells with thick primary dendrites and large, sparsely branched dendritic trees in the outer sublamina of the inner plexiform layer (IPL). In fish 55–65 mm long, about 300 formed a tessellated array across each retina. Their somata (mean area 277 ± 6 μm2) were displaced to varying degrees into the IPL, neighbours in the mosaic often occupying different levels. Their dendrites ramified in one stratum near the inner nuclear layer, at a mean depth of 70.8 ± 0.5% of the IPL.The other alpha‐like mosaic comprised about 900 large ganglion cells, with slightly smaller somata (mean area 193 ± 4 μm2) in the ganglion cell layer. Most of their dendrites lay in a narrow stratum at 41.9 ± 0.5% of the depth of the IPL. However, deviations (usually into more vitread strata) were common, which was not true for similar cells in the distantly related cichlid fish Oreochromis. Measurements of nearest neighbour distance (NND) for 4 outer and 4 inner mosaics showed that they were at least as regular as the alpha cell mosaics of mammals: the ratio of the mean NND to the standard deviation ranged from 4.03 for the least regular outer mosaic to 6.47 for the most regular inner mosaic.The wide phylogenetic distribution of these paired, regular mosaics points to a fundamental role in vision. The presence of some variability in dendritic stratification even within the exceptionally regular inner‐stratified mosaic suggests that classifications based entirely on the detailed morphology of individual neurons may not always correlate well with their primary functional roles. Where possible, neuronal morphology and spatial distribution should be studied together.
Rapid growth of astrocytic processes in N. Magnocellularis following cochlea removal
Authors: Rubel Edwin W. , MacDonald Glen H. 
Published: January 2005

AbstractRemoval of the cochlea or pharmacological blockade of eighth nerve activity in young postnatal chickens results in rapid transneuronal cell death and atrophy in neurons of n. magnocellularis. The present experiments were designed to examine the influence of afferent input on astrocyte structure in n. magnocellularis. Young chickens were subjected to unilateral cochlea removal. At times ranging from 5 minuses to 72 hours later, the brainstems were histologically processed with a polyclonal antibody against glial fibrillary acidic protein (GFAP). A second group of chick brainstems was impregnated by a Golgi method 6 hours after unilateral cochlea removal and impregnated three‐dimensional reconstructions were made of glial cells in n. magnocellularis (NM).Analyses of GFAP positive processes in NM revealed an observable increase in the number of astrocytic processes at the borders of the nucleus within 30 minutes of cochlea removal and a twofold increase in GFAP + glial processes by 6 hours. A secondary increase in the number and density of GFAP + processes occurred between 24 and 72 hours following cochlea removal, during the period of axonal degeneration, and transneuronal cell atrophy and death.Analyses of astrocytes impregnated by the Golgi method revealed that individual glial cells had increased their total process length and the number of processes by approximately twofold by 6 hours after cochlea removal.These results suggest that the structure of astrocytes is rapidly and dramatically influenced by the level of excitatory activity in a neuronal system. Furthermore, the similarity of results obtained with GFAP immunohistochemistry and three‐dimensional reconstruction of astrocytes provides evidence that the short‐term changes observed following cochlea removal represent the actual growth of glial processes. We speculate that modulations in glial processes as a function of afferent activity may act to influence synaptic efficacy.
Frequency tuning properties of neurons in the inferior colliculus of an FM bat
Authors: Casseday J. H. , Covey E. 
Published: January 2005

AbstractWe examined frequency tuning characteristics of single neurons in the inferior colliculus of the echolocating bat, Eptesicus fuscus, in order to determine whether there are different classes of spectral selectivity at this level and to relate frequency tuning properties to the design of the echolocation signal. In unanesthetized but tranquilized animals, we recorded responses from 363 single units to pure tones, frequency‐modulated (FM) sweeps, or broad‐band noise. Most units were selective for stimulus type; 50% responded only to pure tones, 14% responded only to FM sweeps, and 5% responded only to noise. The remainder responded to two or more types of stimuli. Tuning curves could be classified as follows: 1) V‐shaped tuning curves (57%) were the most common type; 2) closed tuning curves (20%) had thresholds at both low and high sound levels; 3) narrow filters (14%) had Q values above 20 at 10 dB and 30 dB above threshold or 10 dB and 40 dB above threshold; 4) frequency‐opponent tuning (6%) was found in units with high spontaneous activity; within a center range of frequencies, firing rate increased above spontaneous level, but at higher or lower frequencies, firing rate decreased below spontaneous level; 5) double‐tuned units (3%) had two best frequencies (BF). The most clear evidence of topographic distribution was seen for filter units, which were only found in the dorsal part of the 20–30 kHz isofrequency contour. Filter units were also the most clearly related to the echolocation signal of the bat. Their BFs were all within the range of the dominant frequency (˜20–30 kHz) that Eptesicus uses during the searching phase of echolocation. © 1992 Wiley‐Liss, Inc.