bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal changes in vasopressin in the brain of the garden dormouse (Eliomys quercinus L.)
Authors: Hermes M. C. H. J. , Buijs R. M. , Masson‐Pévet M. , Pévet P. 
Published: January 2005

AbstractThe distribution of vasopressin in the brain of the garden dormouse (Eliomys quercinus L.) was examined by immunocytochemistry at different times of the year. In spring‐summer, sexual dimorphism in the density of vasopressin labeling was observed in several areas of the brain. In these regions, such as the lateral septum and the nucleus of the vertical limb of the diagonal band of Broca, male garden dormice showed more vasopressin immunoreactivity than their female counterparts. In autumn‐winter, at the time of hibernation, vasopressin was undetectable in the sexually dimorphically innervated brain regions in males as well as females. In early spring, there was large variation in vasopressin staining in the male brain, whereas the female brain was consistently lacking in vasopressin labeling. In brain regions that exhibited no sexually dimorphic innervation in the summer, vasopressin labeling remained the same throughout the year. The difference in the amount of vasopressin immunoreactivity in males in summer and winter correlated significantly with differences in testes weight. In early spring, because of interindividual variations in the start of sexual activation, testes size does not correlate with the density of vasopressin immunoreactivity.Similar seasonal variations in density of vasopressin labeling in the brain were also observed in the European hamster (Cricetus cricetus). In this animal, central vasopressin infusion during the winter prevents hibernation. The presence of a similar pattern of changing vasopressin content in another hibernator, the garden dormouse, suggests an important role for this neuropeptide in seasonal functions.In the garden dormouse, vasopressin fibres could be detected in a number of brain regions where, in other rodents, such fibres are undetectable, e.g., the interpeduncular complex and the lateral superior olive. It is suggested that the central vasopressin system in the rat and European hamster is essentially the same as in the garden dormouse, but more difficult to detect immunocytochemically.
Early development of retinal ganglion cell dendrites in the marsupial Setonix brachyurus, Quokka
Authors: Dunlop S. A. 
Published: January 2005

AbstractThe dendritic morphology of retinal ganglion cells was studied in flatmounted retinae of the marsupial Setonix brachyurus, quokka. In the adults, horseradish peroxidase (HRP) was applied to the vitread surface of flattened retinae. Wide‐, large‐, medium‐, and small‐field classes appeared to correspond to gamma, alpha, delta, and beta cells, respectively, in the cat (Boycott and Wässle, J. Physiol.249:397‐419, 1974).To reveal the early stages of dendritic development, HRP was placed on the optic nerve of isolated eye cups from the day of birth to postnatal day (P) 63 when the area centralis is beginning to form (Dunlop and Beazley, Dev. Brain Res.23:81‐90, 1985). Youngest cells lacked dendrites and had an elongate soma in the cytoblastic layer with an endfoot contacting the ventricular surface. Once in the ganglion cell layer, the soma was rounded and dendrites appeared as short, unbranched processes. Most cells were asymmetric or „polarised”︁ with the axon arising from the side nearest the optic disk and dendrites from the opposite side. Polarity was maintained in cells with longer, branched dendrites. A small proportion of cells exhibited a reversed polarity in which the axon arose from the side nearest the retinal edge and dendrites towards the disk. Cells appeared to acquire an approximately symmetric, adult‐like tree by the addition of new primary dendrites between the existing ones and the axon hillock. Wide‐, large‐, medium‐, and small‐field cells were evident from P6, P25, P31, and P40, respectively. Spines were observed on dendrites and axons during development but were rare in the adult. Some den‐dro‐axons were seen at all ages examined.The existence of an initial axodendritic polarity in retinal ganglion cells supports the hypothesis that the axon hillock is the determinant of dendritic geometry (Maffei and Perry, Dev. Brain Res. 41:185‐194, 1988). Polarity may also contribute to the establishment of „radial orientation”︁ in which the long axis of the elliptical dendritic tree of cells outside the area centralis points towards central retina and the weighted centre is displace towards the retinal periphery (Leventhal and Schall, J. Comp. Neurol. 220:465‐475, 1983).
Electron microscopic study of immunocytochemically labeled centrifugal fibers in the goldfish retina
Authors: Kawamata Kunihiko , Ohtsuka Teruya , Stell William K. 
Published: January 2005

AbstractThe centrifugal fibers innervating the goldfish retina were studied quantitatively by light and electron microscopy. These fibers originating from cell bodies in the olfactory bulb were labeled by antiserum to the tetrapeptide Phe‐Met‐Arg‐Phe‐NH2 (FMRFamide). The number of FMRFamide‐immunoreactive (ir) centrifugal fibers in each eye of the adult goldfish (body length: 12‐15 cm) was 65 + 14 (mean ± S. D., n = 7). All of these fibers in the optic nerve and the retina were unmyelinated. Each FMRFamide‐ir centrifugal fiber runs along the optic fiber layer and gives several terminal arborizations in the outermost layer (layer 1) of the inner plexiform layer. Layer 1 is, therefore, densely covered by a plexus of terminal arborizations. Along these terminal arborizations, we found output synapses characterized by a cluster of small clear vesicles (40 nm in diameter) at the presynaptic site and a thickened membrane in the apposed retinal cell processes. In a sample area of 2,000 üm2, such synapses occurred at a density of one per 105 üm2, or about 13,000 per centrifugal fiber. Thus, the FMRFamide‐ir centrifugal fibers are likely to modulate retinal cell activity through an estimated total of 840,000 output synapses per retina.
Quantitative fine structure of capillaries in subregions of the rat subfornical organ
Authors: Shaver Steven W. , Sposito Nadine M. , Gross Paul M. 
Published: January 2005

AbstractThe differentiated cytology across subregions of the rat subfornical organ (SFO) prompted our hypothesis that ultrastructural features of capillary endothelial cells would vary topographically and quantitatively within this small nucleus. We used electron microscopic and computer‐based morphometric methods to assess fine structural dimensions of the capillary endothelium in four distinct subregions of the SFO from Long‐Evans and homozygous Brattleboro rats. Three types of capillary were present. Type III capillaries (resembling those of endocrine glands) had an average wall thickness of 0.17 μm, 54% thinner than those of Type I and II capillaries. Pericapillary spaces around Type III capillaries measured 56 μm2, 100% larger than for Type I vessels (resembling those of skeletal muscle). Only Type III capillaries contained fenestrations (9 per μm2 of endothelial cell) and were the predominant type of capillary in central and caudal subregions of the SFO. Type I capillaries, prevalent in the transitional subregion between the central and rostral parts of the SFO, had 10 cytoplasmic vesicles per μm2 of endothelial cell area, a number not different from that of Type III capillaries but 3× the frequency found in Type II vessels. Type II capillaries (those typical of “blood‐brain barrier”endothelium) had low vesicular density (3 per μm2), no fenestrations, and no pericapillary spaces. Luminal diameters and the densities of mitochondria and intercellular junctions were not different among capillary types or subregions in the SFO. Furthermore, there were no morphometric differences for any capillary dimensions between Long‐Evans and Brattleboro rats. These studies reveal quantitative differences among capillary networks in four distinct compartments of the rat SFO and provide morphometric dimensions for the three types of capillary existing in this cerebral sensory nucleus.
Organization of retinopetal axons in the optic nerve of the cichlid fish, Herotilapia multispinosa
Authors: Rusoff Anne C. , Hapner Sharon J. 
Published: January 2005

AbstractWe have studied the position and numbers of retinopetal axons in the rainbow cichlid fish, Herotilapia multispinosa, to determine the response of related parts of the brain of fish to the continual addition of new neurons in the retina. The retinopetal axons were traced by using the retrograde tracers HRP and cobaltous lysine and an immunocytochemical probe, antibodies to FMRFamide, the molluscan cardioexcitatory peptide. One population of cells with retinopetal axons was found in the telencephalon (in the nucleus olfactoretinalis) and the other was scattered in the diencephalon. Some of the cells in the nucleus olfactoretinalis with retinopetal axons were FMRFamide positive; antibodies were used to trace the axons of these cells into the retina. All the retinopetal axons, from the nucleus olfactoretinalis and the diencephalon, were confined to the portion of the optic nerve that contains axons from the central retinal ganglion cells, that is, the oldest ganglion cells. Theis result suggests that the retinopetal axons grow into the optic nerve and retina early in the life of the fish, and no new ones are added later in life despite the extensive addition of cells in the retina. Counts of the cells in the nucleus olfactoretinalis that project to the retina in 3‐month‐old and adult fish support this interpretation. We conclude that retinopetal axons grow into the retina early in the life of the fish and respond to the formation of new retina by extending their arbors toward the new retina.
Development of retinopetal projections in the cichlid fish, Herotilapia multispinosa
Authors: Rusoff Anne C. , Hapner Sharon J. 
Published: January 2005

AbstractThis paper reports a study of the development of cells that project to the retina from the telencephalic nucleus olfactoretinalis and the diencephalon. Stell et al. (Proc. Natl. Acad. Sci. USA 81:940‐944,'84) have shown that the FMRFamide‐immunoreactive (FMRFamide‐ir) cells in the nucleus olfactoretinalis project to the retina. Therefore, we used immunocytochemistry to study the development of these cells in the nucleus olfactoretinalis. Twenty hours after fry hatched, FMRFamide‐ir cells were unambiguously seen in the nucleus olfactoretinalis. At this time the axons of these cells could be traced into the optic nerve. A few hours later the axons were visible in the retina and soon attained their adult position in the inner plexiform layer near the amacrine cells.In older fry, tracers were used to fill retinopetal cells in both the nucleus olfactoretinalis and the diencephalon. Counts of these cells demonstrated that over one‐third of the adult number of retinopetal cells in the nucleus olfactoretinalis are present and have axons in the retina when the fry is 9 days old, and the percentage grows to one‐half by the time the fry is 1 month old. Development of the retinopetal cells in the diencephalon lags behind that of the cells in the nucleus olfactoretinalis. However, about one‐third of the adult number extend their axons into the optic nerve by 1 month of age.These results support our suggestion that the retinopetal cells have axons in the old part of the optic nerve because these cells were born and extended axons early in the life of the fish.
Synapses formed by olivocochlear axon branches in the mouse cochlear nucleus
Authors: Benson T. E. , Brown M. C. 
Published: January 2005

AbstractCochlear nucleus branches of thick olivocochlear axons were labeled by injections of horseradish peroxidase into the spiral ganglion of the cochlear basal turn in mice. Six labeled axons were traced by light microscopy, and selected portions of seven branches were sectioned serially for electron microscopic examination. Axonal branches most frequently terminated near certain granule cell regions of the ventral cochlear nucleus. This article describes terminals, synapses, and postsynaptic elements of these olivocochlear branches.The olivocochlear branches had both terminal and en passant boutons that contained round vesicles and made asymmetric synapses with other neuronal processes. About a quarter of the synapses also possessed additional specializations, postsynaptic, or subjunctional bodies. Mossy terminals, a multisynaptic type of terminal commonly found in granule cell regions, were not found arising from any of the labeled branches. No somatic synapses were found, although contacts with cell bodies were occasionally observed.The predominant synaptic target of olivocochlear branches were what appeared to be dendrites of large diameter. At least some of these large dendrites received multiple synapses from a single labeled olivocochlear branch. The morphological characteristics of reconstructed dendrites suggest that multipolar cells might be predominant targets for the medial olivocochlear system in the cochlear nucleus. This was demonstrated in one case in which a large dendrite was followed to its cell body of origin.
Distribution of quinolinic acid phosphoribosyltransferase in the human hippocampal formation and parahippocampal gyrus
Authors: Du Fu , Okuno Etsuo , Whetsell William O. , Köhler Christer , Schwarcz Robert 
Published: January 2005

AbstractThe morphological distribution of quinolinic acid phosphoribosyltransferase (QPRT), the degradative enzyme of the endogenous excitotoxin quinolinic acid, was studied in the human hippocampal formation and parahippocampal gyrus by immunohistochemical techniques. In seven neurologically normal human brains obtained at autopsy, QPRT ‐ immunoreactivity (QPRT‐i) was found in both glial cells and neurons. Glial cells exhibiting QPRT‐i, sharing the morphological features of astrocytes, were observed in all hippocampal subfields. The polymorphic layer of the dentate gyrus contained the highest density of QPRT‐i glial cells. Numerous QPRT‐i glial cells were also found along both sides of the fused hippocampal fissure and in the white matter including the alveus of Ammon's horn, whereas only a few were observed in the granule cell layer and the stratum pyramidale. Neurons containing QPRT‐i were found mainly in the subiculum and in the strata oriens and pyramidale of CA1. They were mostly small and polymorphic or fusiform, thus indicating that they may belong to a subpopulation of interneurons. Moderate numbers of QPRT‐i glial cells and neurons were also observed throughout layers II‐VI of parahippocampal cortex. The localization of QPRT‐i in selected glial cells and neurons suggests that in the regions examined these cellular elements might play specific roles in the regulation of quinolinic acid function.
Target dependence of chick retinal ganglion cells during embryogenesis: Cell survival and dendritic development
Authors: Vanselow Jens , Dütting Dieter , Thanos Solon 
Published: January 2005

AbstractThe survival of retinal ganglion cells and the dendritic development were investigated (a) in normal chick embryos, (b) in embryos whose primordial optic lobes and adjacent areas were removed (target reduced embryos), and (c) in embryos whose optic nerves were transected (target deprived embryos) in order to study the influences of central targets on developing ganglion cells. The ganglion cells were stained postmortem with the carbocyanine dye DiI. Cell body and dendritic field diameters were measured in whole‐mounted retinae before and after the period of cell death at embryonic day 10 (E10) and E16. The cell densities within the ganglion cell layer were counted in cresyl violet/thionine stained retinae. The central retinal projection in target reduced embryos was studied with the anterogradely transported fluorescent marker rhodamine‐B‐isothiocyanate (RITC).In normal embryos, the earliest dendritic processes were observed at E6 in the central retina, whereas at E10 elabrate dendritic branching was found across the retina. Different morphological types of ganglion cells could be identified at E16. In both, target reduced embryos and target deprived embryos, the initial dendritic growth and pattern of ramification were indistinguishable from those of normal embryos up to E10. Cell body diameters, dendritic tree diameters, and cell densities were not significantly different. At the end of the naturally occurring cell death period (E16), the ganglion cell density was strongly reduced in both experimental groups compared to controls. In particular, when the optic nerve was transected, it resulted in the almost complete degeneration of ganglion cells. In target reduced embryos, a small population (about 5% of the normal number) of ganglion cells survived. The proportion of large cells was increased within the total population compared to normal retinae. Displaced ganglion cells were not affected by partial target removal but strongly affected by transection of the optic nerve. Anterograde labelling from the retina revealed that in target reduced embryos the remaining ganglion cells innervated non‐tectal primary visual nuclei.The present results suggest the following: (a) Before the onset of the cell death period, the growth and ramification of ganglion cell dendrites occur independently of central visual targets. (b) In target reduced embryos, a small population of ganglion cells survives, namely, those cells that project to remaining central areas. Complete disconnection from central targets by transecting the optic never leads to the degeneration of almost all ganglion cells. (c) The surviving ganglion cell population consists mainly of large ganglion cells.
Spatial organization of axons in turtle visual cortex: Intralamellar and interlamellar projections
Authors: Cosans Christopher E. , Ulinski Philip S. 
Published: January 2005

AbstractThe spatial pattern of projections within turtle visual cortex was studied by using focal injections of horseradish peroxidase into visual cortex in an in vitro wholebrain preparation. Injections anterogradely filled the axons of many layer 2 neurons, which could be followed for 200–500 μm from the injection sites. Axons were typically unbranched, relatively straight, and bore small varicosities at irregular intervals. They radiated from the injection sites in all directions, but showed some preference toward orientations along the lateral‐medial axis of the cortex. Earlier work ((Mulligan and Ulinski,'90)) had demonstrated that turtle visual cortex contains a series of isoazimuth lamellae, each representing an individual azimuth of visual space and oriented perpendicular to the rostral‐caudal axis of the cortex. The present study provides evidence for intrinsic projections both along isoazimuth lamellae and between adjacent lamellae. These projections may play roles in the elaboration of wide receptive fields of cortical neurons.
Endogenous peroxidatic activity in astrocytes after spinal cord injury
Authors: Noble L. J. , Cortez Selina C. , Ellison J. A. 
Published: January 2005

AbstractAfter spinal cord injury, endogenous peroxidatic‐like activity develops along the axis of the cord. At 2 weeks postinjury, this activity appears in cells whose processes are intimately associated with microvessels. The objectives of this study were to further characterize this response and to identify the cellular localization of endogenous peroxidatic‐like activity.After traumatic injury to the rat spinal cord, adjacent sections of spinal cord were processed in medium to visualize antiglial fibrillary acidic protein, endogenous peroxidatic activity, or cytochrome oxidase activity. In addition, certain sections, stained for endogenous peroxidatic‐like activity, were prepared for electron microscopy. To identify the nature of the activity, some sections were exposed to an incubation medium that included inhibitors of either catalase or heme protein activity.The distribution of prominent glial fibrillary acidic protein immunoreactivity in the dorsal columns corresponded to that of marked staining for endogenous peroxidatic‐like activity and cytochrome oxidase. At the ultrastructural level, endogenous peroxidatic‐like activity was identified in the cytoplasmic compartment of the astrocyte. This activity was abolished when potassium cyanide (an inhibitor of heme protein) was added to the incubation medium.Spinal cord injury elicited a pronounced cellular response along the axis of the cord that was characterized by enhanced staining for antiglial fibrillary acidic protein, cytochrome oxidase activity, and endogenous peroxidatic‐like activity. It is not clear whether pronounced cytochrome oxidase activity corresponded to astrocytes that also expressed prominent endogenous peroxidatic‐like activity. However, according to both light and ultrastructural findings, endogenous peroxidatic‐like activity was prominently associated with the astrocytic cytoplasm. The biochemical nature of the peroxidatic activity is unknown, but these results suggest that it is related to a heme‐containing protein.
Morphology of the human olfactory epithelium
Authors: Morrison Edward E. , Costanzo Richard M. 
Published: January 2005

AbstractThe human olfactory epithelium has been previously studied with scanning electron microscopy; however, most studies have been limited to examining the epithelial surface. In an attempt to examine structures below the surface, we scanned epithelial fractures that occurred during tissue preparation. This made it possible to obtain unique three‐dimensional images of cell profiles from the mucosal surface through the full depth of the epithelium. We examined supporting cells, olfactory neurons, basal cells, and a fourth cell type, the microvillar cell. Supporting cells had a microvillar surface and were in close contact with olfactory neurons and their processes. Olfactory neurons were primarily located in the middle and lower epithelial regions. Basal cells occurred alone or in clusters adjacent to the basal lamina. Microvillar cells were always observed in the upper epithelial region. They were flask‐ or pear‐shaped, had a tuft of microvilli that extended into the nasal cavity, and a thin axon‐like process that passed basally towards the lamina propria.This study represents the first comprehensive scanning electron microscopy examination of the human olfactory epithelium. Three‐dimensional images obtained for each epithelial cell type allowed us to examine cell processes and their close contacts, especially between supporting cells and olfactory neurons. These results also revealed the irregular and patchy distribution of olfactory receptors within the human nasal cavity. Further studies that examine the detailed morphology of the human olfactory epithelium should provide a better understanding of the physiological mechanism and clinical disorders that affect olfactory function in humans.