bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sexual differentiation of androgen accumulation within the zebra finch brain through selective cell loss and addition
Authors: Nordeen Ernest J. , Nordeen Kathy W. , Arnold Arthur P. 
Published: January 2005

AbstractIn zebra finches males, but not females, respond to gonadal androgens with the production of a stereotyped courtship song. Corresponding to this dimorphism in hormone sensitivity, two song‐related neural regions, magnocellular nucleus of the anterior neostriatum (MAN) and hyperstriatum ventralis pars caudalis (HVc), have more cells that accumulate androgens in males than in females. The early hormonal environment establishes these sex differences in the brain and behavior such that females treated with estradiol (E2) shortly after hatching have male‐typical levels of androgen accumulation in MAN and HVc, and respond to adult androgen stimulation with male‐typical song. Using autoradiographic procedures employing the androgen 3[H]‐dihydrotestosterone (DHT), the present study focused on whether E2 masculinizes androgen target cell numbers in MAN and HVc by inducing, or rather preserving, a male‐typical number of androgen target cells. First, it was demonstrated that E2 treatment of females as late as 20 days after hatching increases the number of MAN and HVc cells accumulating 3[H]‐DHT or its metabolites in adulthood to levels typical of males. Then the number of androgen target cells present within these nuclei in 20‐day‐old females was compared with the number present in adult females previously masculinized with E2 treatment on day 20. In MAN, E2 masculinizes androgen accumulation by preserving androgen target cell numbers in the face of massive overall cell loss, a result that suggests that E2 promotes the survival of androgen target cells during sexual differentiation. In HVc, however, E2 treatment on day 20 promotes an addition of androgen target cells, suggesting that during adolescence, E2 regulates the proliferation, migration, and/or survival of these cells.
In vivo ANTI‐NGF induces sprouting of sensory axons in dorsal roots
Authors: Hulsebosch C. E. , Perez‐Polo J. R. , Coggeshall R. E. 
Published: January 2005

AbstractNewborn rats were given subcutaneous injections of antibodies to mouse β ‐NGF (ANTI‐NGF) daily for 1 month. The number of neurons in T4‐T6 dorsal root ganglia (DRG) and the numbers of myelinated and unmyelinated axons in the dorsal roots of the same segments were counted in the ANTI‐NGF animals and in normal littermates. The ANTI‐NGF rats had 38% fewer neurons in thoracic ganglia but 17% more myelinated and 40% more unmyelinated fibers than their untreated littermates. Dorsal root ganglion cells also have a larger average size in the ANTI‐NGF animals, which we interpret as a disproportionate loss of small cells. These data are interpreted as showing that some dorsal root ganglion cells, principally small ones, die when endogenous NGF is inactivated, and that the remaining cells emit more processes than normal. Thus, removal of NGF has what appears to be a paradoxical effect, a reduction in dorsal root ganglion cell numbers but an increase in dorsal root axon numbers. The relation of myelin thickness to fiber diameter is also altered, with small fibers being more thinly myelinated in the ANTI‐NGF group. Thus, Schwann cell‐neuronal interactions are also affected by inactivation of NGF.
Cerebellocerebral projection from the fastigial nucleus onto the frontal eye field and anterior ectosylvian visual area in the cat
Authors: Kyuhou Shin‐Ichi , Kawaguchi Saburo 
Published: January 2005

AbstractThe fastigiocerebral projection in the cat was investigated electrophysiologically by recording field potentials and unit activities and also morphologically by anterograde and retrograde HRP methods. Three cortical areas mostly hidden in sulci, two in the frontal cortex and one in the insular cortex, were responsive to fastigial stimulation under pentobarbital anesthesia. The responsive areas in the frontal cortex were the ventral bank of the cruciate sulcus and the area surrounding the fundus of the presylvian sulcus; the latter area corresponds to a subregion of the frontal eye field. The responsive area in the insular cortex Was the ventral bank of the anterior ectosylvian sulcus, which overlaps largely with the “anterior ectosylvian visual area.” The response in the frontal cortex was a surface‐positive, depth‐negative wave, whereas the response in the insular cortex was a surface negative, depth‐positive wave. Anterogradely labeled terminals of the fastigiothalamic projection were most dense in the ventromedial (VM) nucleus in which retrogradely labeled neurons were numerous when WGA‐HRP was injected into any one of the three cortical areas. In agreement with the results of the HRP studies, units that responded orthodromically to fastigial stimulation and antidromically to cortical stimulation were located in the thalamic VM nucleus. There was a marked difference between the frontal and insular cortices in laminar distribution of terminals of the thalamocortical projection fibers. Anterogradely labeled terminals after injection of WGA‐HRP into the VM nucleus were distributed mainly in layers I and III in the frontal cortex, whereas they were distributed mainly in layer I in the insular cortex.
Topography and morphometry of capillaries in the rat subfornical organ
Authors: Sposito Nadine M. , Gross Paul M. 
Published: January 2005

AbstractA comprehensive stereological analysis was performed to define capillary dimensions in individual subregions of the subfornical organ in Long‐Evans, homozygous Brattleboro, and Sprague‐Dawley rats. Capillary density, volume fraction, length, surface area, and diameter were assessed in four regions in the sagittal plane (rostral, “transitional,” central, and caudal) and two zones in the coronal plane (dorsal and ventromedial). The ventromedial zones in the central and caudal regions correspond to areas of dense perikarya and neuropil containing neural afferent inputs to the subfornical organ (e.g., putative fiber terminals for angiotensin II), whereas the dorsal zones of these regions are apparently the predominant sites of perikarya having efferent projections directed outside of the organThe morphometric analysis revealed heterogeneous capillary density across subregions of the subfornical organ (range of 132 to 931 capillaries/mm2 in the three rat groups). Capillaries in the ventromedial zones of the central and caudal regions had significantly greater density, volume fraction, and surface area, but smaller diameters, than those in the adjacent dorsal zones and more rostral regions. Across all subregions within the dorsal zone, there was generally a consistent morphometric pattern in the three rat groups. No differences in capillary dimensions in any part of the subfornical organ were found between the Long‐Evans and Brattleboro rats.A qualitative electron microscopic investigation of endothelial cells in each subregion of the subfornical organ in Long‐Evans rats revealed at least three types of capillary oriented according to region: (1) in the rostral region were capillaries having no endothelial fenestrations or pericapillary spaces, and few vesicles, (2) in the “transitional” region between the rostral and central regions, capillaries having no endothelial fenestrations, substantial numbers of vesicles, and narrow but perceptible pericapillary spaces were found, and (3) in the central and caudal regions, capillaries having abundant endothelial fenestrations and vesicles, expansive pericapillary labyrinths, and relatively thin walls were present.These findings from light microscopic morphometry and electron microscopy in rats indicate a heterogeneity of capillary organization that shows topographical correspondence to the cytology and putative functions of the subfornical organ.
Somatostatin immunoreactive neurons in the human hippocampus and cortex shown by immunogold/silver intensification on vibratome sections: Coexistence with neuropeptide Y neurons, and effects alzheimer‐type dementia
Authors: Chan‐Palay V. 
Published: January 2005

AbstractThe distribution of somatostatinlike immunoreactivity was studied in the hippocampal formation, retrohippocampal region, and temporal cortex in the human brain. Tissues from surgical biopsy and postmortem cases were used, and the immunogold/silver method on vibratome sections was introduced for routine applications in conjunction with primary antisera that recognise somatostatin‐14 or somatostatin‐28. Somatostatin‐28 antisera readily stained numerous neurons, dendrites, and extensive axonal networks throughout the hippocampus and neighbouring cortex. Liquid phase absorption provided controls for specificity. The most prominent accumulations of Somatostatin immunoreactive neurons and axons occurred in the hilus of the area dentata, in CA1, and in the entorhinal and perirhinal cortices. Axonal plexuses occurred throughout the hippocampal subfields but were particularly dense in those regions rich in Somatostatin neurons. The distribution of Somatostatin immunoreactive neurons and fibers parallels the distribution of neuropeptide Y (NPY) neurons and fibers in the hippocampus and cerebral cortex to a remarkable extent. Double labelling experiments with antisera against neuropeptide Y and Somatostatin indicate a considerable frequency of coexistence of the two peptides in single neurons, particularly in large multipolar cortical neurons and also in the small bipolar white matter neurons. Regional variations exist in the amounts of coexistence found in the hippocampal subfields; somatostatin‐NPY coexistence is particularly high in the hilus of the area dentata, the subicular complex, and the deep layers of the entorhinal and perirhinal cortices.In the hippocampi and temporal cortices in cases of Alzheimer‐type dementia compared to those of age‐matched control brains, there is a significant to severe loss of Somatostatin immunoreactive neurons and axons. This loss is most severe in those regions with the highest indices of neurofibrillary tangles and neuritic plaques–the hilus of the area dentata, CA1, and the entorhinal and perirhinal cortices. Surviving Somatostatin neurons are distorted with short dendrites and truncated axons. Neuritic plaques identified on double label experiments with thioflavin include Somatostatin axons but not neurons.
Spinal cord projections from hindlimb muscle nerves in the rat studied by transganglionic transport of horseradish peroxidase, wheat germ agglutinin conjugated horseradish peroxidase, or horseradish peroxidase with dimethylsulfoxide
Authors: Molander C. , Grant G. 
Published: January 2005

AbstractThe spinal cord projections of four different groups of hindlimb muscle nerve branches–the medial and lateral gastrocnemius nerves, muscle branches of the deep peroneal nerve, muscle branches of the femoral nerve, and a nerve to the hamstring muscles–were studied with transganglionic transport of horseradish peroxidase (HRP), in the rat. The influence of varying the postoperative survival (3, 6, and 10 days) and of using wheat germ agglutinin‐HRP conjugate (WGA‐HRP), or HRP with dimethylsulfoxide (DMSO) instead of free HRP was studied for the gastrocnemius nerves. After 3 days' survival following application of HRP to the gastrocnemius nerves, fine granular labeling was found mainly in lamina V in L4–5, and coarse granular labeling was found in Clarke's column as far caudally as L2, and in laminae VI and VII predominantly in Th12–L2. After 6 or 10 days' survival, the fine labeling in lamina V was sparse or absent, whereas the coarse labeling appeared to remain or to be only slightly reduced in Clarke's column and in laminae VI and VII. No labeling suggestive of terminals was observed in laminae I‐III from the gastrocnemius nerves. Except for sparse labeling in lamina I in some of the cases and some minor differences rostro‐caudally, the spinal distribution of labeling was similar to that from the other nerves investigated. The distribution of labeling obtained after application of WGA‐KRP or HRP with DMSO to the gastrocnemius nerves was very similar to that obtained with free HRP after 3 days' survival.The results indicate that the spinal cord projections of hindlimb muscle nerves in the rat distribute mainly in the deep part of the dorsal horn and in the intermediate zone. Furthermore, the lack of labeling suggestive of terminals in laminae I–III from the gastrocnemius nerves suggests, in conflict with earlier findings in the cat, that primary afferent fibers from muscles do not necessarily terminate in these laminae in the rat. The results suggest, furthermore, that fine granular labeling found in lamina V represents fine‐calibered afferent fibers. Finally, the similar spinal projection patterns of the different muscle nerves investigated suggest either a less developed or an essentially different somatotopic organization for muscle afferents compared to cutaneous afferents, as revealed in earlier studies.
[125I] triiodothyronine in the rat brain: Evidence for neural localization and axonal transport derived from thaw‐mount film autoradiography
Authors: Dratman Mary B. , Crutchfield Floy L. , Futaesaku Yutaka , Goldberger Michael E. , Murray Marian 
Published: January 2005

AbstractPrevious thaw‐mount light microscopic autoradiographic studies have shown that intravenously administered [125I] triiodothyronine is saturably concentrated and retained for at least 10 hours in discrete neural systems in the rat brain. To survey the brain more completely and to gain information about the time course of labeling, serial thaw‐mount film autoradiograms were prepared from rat brains obtained at intervals through 48 hours after intravenous injection of high specific activity [125I] triiodothyronine. Parallel biochemical studies of whole brain homogenate extracts revealed that, at all time intervals, the label in the brain was mainly due to triiodothyronine itself (80%), or other organic iodocompounds (15%), but probably not due to free [125I] iodide (3%), which is rapidly transported out of the brain. The highly reproducible, well‐defined labeling patterns seen on film indicated a widespread but selective localization of the hormone. At early times after intravenous injection of [125I] triiodothyronine, label was nonuniformly and prominently concentrated in selected regions of gray matter; evidence for saturability of hormone processing was obtained in competition studies with unlabeled triiodothyronine. Discrete labeling of fiber tracts (usually after 10 hours) left some regions of white matter conspicuously unlabeled. At 48 hours, many originally labeled gray regions showed markedly diminished or virtually complete loss of radioactivity, whereas others became newly or more prominently labeled. At that time, certain fiber tracts were also conspicuously labeled. The observed changing profiles of regional labeling over time are best explained by movement of the hormone from original sites of saturable incorporation in specific nuclei, to terminal fields, through the mechanism of axonal transport.
Efferent projections of the subthalamic nucleus in the rat: Light and electron microscopic analysis with the PHA‐L method
Authors: Kita H. , Kitai S. T. 
Published: January 2005

AbstractEfferent projections of rat subthalamic nucleus were studied by use of the axonal transport of phaseolus vulgaris‐leucoagglutinin (PHA‐L), and the results were analyzed with light and electron microscopes. PHA‐L injections in the subthalamic nucleus (STH) resulted in heavy labeling of fiber plexus with en passant boutons and terminals in the pallidal complex, i.e., the entopeduncular nucleus (EP), the globus pallidus (GP) and the ventral pallidum (VP), and the substantia nigra pars reticulata (SNR). Labeling in GP was characterized by two distinct bands of labeled terminals oriented dorsoventrally, whereas labeling in SNR was patchy. STH efferents to the pallidum and SNR, displayed a mediolateral topographic organization. With regard to dorsoventral organization, projections to GP were inverted, but those to SNR were not. There were moderate projections to the neostriatum and sparse projections to the frontal cortex, substantia innominata, substantia nigra pars compacta (SNC), pedunculopontine tegmental nucleus, ventral part of the central gray matter including the dorsal raphe nucleus, and the mesencephalic and pontine reticular formation.PHA‐L injections in the zona incerta and the lateral hypothalamic area resulted in fiber and terminal labelings in many structures, including the basal forebrain, EP, SNC, and other brainstem areas that overlap with some of the terminal sites of STH projections.Ultrastructural observations of PHA‐L labeled processes in GP and SNR revealed that STH terminals in both structures contained small pleomorphic vesicles and formed asymmetrical contacts. These contacts were mainly on dendritic shafts, but some were on somata. It also was observed that the myelinated axons of STH neurons lost their myelin after reaching their target areas and the synaptic boutons arose from relatively thin unmyelinated axons.
Morphometric study of the anteroventral cochlear nucleus of two mouse models of presbycusis
Authors: Willott James F. , Jackson Leslie M. , Hunter Kelly Paris 
Published: January 2005

AbstractThe dimensions and volume of the anterior ventral cochlear nucleus (AVCN), the density and number of AVCN neurons, and the size of neuronal somata nuclei (in Nissl‐stained tissue) were determined in two mouse models of age‐related hearing loss: the C57BL/6J strain, which undergoes progressive chronic sensorineural hearing loss with onset during young adulthood, and the CBA/J, which demonstrates only moderate hearing loss with onset late in life. Frontal and horizontal AVCN sections, as well as cochleas, were analyzed in 4 C57 age‐groups (1, 7, 12, 19+ months) and in 3 CBA groups (1, 10, 22 months).Within each strain no significant changes in AVCN dimensions or volume occur with aging. In C57 mice, packing density and cell number decrease between 1 and 7 months, but remain stable thereafter, despite chronic severe hearing impairment. CBA mice show a reduction in AVCN cell number and packing density only during the second year of life. In aging C57 mice, the size of spherical and perhaps globular cells increases, whereas the size of multipolar cells tends to decrease slightly. In CBA mice, all three AVCN cell types tend to decrease in size with aging. The early cell loss and cell size increases in C57 mice are most consistent in the dorsal (high frequency) region of the AVCN. Likewise, loss of cochlear spiral ganglion cells is most pronounced in the base of the cochlea, which provides input to this region. The data indicate that aging is associated with rather different central effects, depending on AVCN cell type, cochleotopic organization, genotype, and/or the type of peripheral hearing loss involved.The C57 and CBA AVCNs also differ in several aspects irrespective of age. The volume of AVCN and number of AVCN neurons are significantly greater in C57 mice.
Localization of choline acetyltransferase‐like immunoreactivity in the embryonic chick retina
Authors: Spira Arthur W. , Millar Thomas J. , Ishimoto Ichiro , Epstein Miles L. , Johnson Carl D. , Dahl June L. , Morgan Ian G. 
Published: January 2005

AbstractPutative sites of acetylcholine synthesis in the retina of the embryonic and posthatched chick were localized immunohistochemically with antisera to choline acetyltransferase; the resultant choline acetyltransferase‐like immunoreactivity (ChAT‐IR) was compared to demonstrated sites of acetyltransferase (AChE) activity, and changes were followed in localization during development. The results confirmed the early and rapid course of development of the chick's retinal cholinergic system described in previous biochemical and morphological studies. Immunoreactivity was first detected at embryonic day 6.5 in cells close to the retina's vitreal surface. By 8 days it was present in cells in two juxtaposed rows; by the ninth day the two rows were separated and Immunoreactivity was evident in two sublaminae of the inner plexiform layer. On the tenth day distribution was like that in the posthatched chicken, in type I cholinergic cells in the inner nuclear layer and in type II cells in the ganglion cell layer (Millar et al.: Neurosci. Lett. 61:311–316, '85.), and similar to that of most vertebrates. Three days before hatching, a third population of weakly immunoreactive cells (type III cells) appeared within the inner nuclear layer. The onset of localizable ChAT‐IR occurred in amacrine cells and in their processes, before the period of synaptogenesis. Acetylcholinesterase activity was localized at an earlier age than ChAT‐IR, and at all ages was present in more cells. The results obtained support the view that “displaced” cholinergic amacrine cells begin to differentiate at the same time and in the same retinal region as type I cholinergic cells. Separation of the two groups is a consequence of the ramification of processes of amacrine and ganglion cells rather than a result of the secondary migration of cells between layers.
Distribution of neurotensin‐like immunoreactivity in the diencephalon of the Japanese monkey (Macaca fuscata)
Authors: Makino Shigeru , Okamura Hitoshi , Morimoto Nobumitsu , Abe Jun , Yanaihara Noboru , Ibata Yasuhiko 
Published: January 2005

AbstractThe distribution of neurotensin‐like immunoreactive (NT‐LI) neurons was examined in the thalamus and hypothalamus of the Japanese monkey (Macaca fuscata) by using the peroxidase‐antiperoxidase immunocytochemistry technique. In the thalamus, NT‐LI neuronal perikarya were distributed mainly in the midline nuclear group and the dorsomedial nucleus, and partially in the intralaminar nucleus: Immunoreactive fibers were mainly distributed in the midline nucleus, particularly in the nucleus rhomboidalis. Numerous immunoreactive fibers were also detected in the regions that contain the pathways to extrathalamic areas such as the stratum zonale and inferior thalamic peduncle. In the hypothalamus, many immunoreactive neuronal perikarya were distributed in the lateral hypothalamic area and in the arcuate nucleus. Immunoreactive fibers were disseminated throughout the hypothalamus, but they were dense in the preoptic area and sparse in the ventromedial nucleus. An accumulation of dense immunoreactive endings was also observed in the external layer of the median eminence. NT‐LI fibers in the extenal layer of the median eminence were considered to represent nerve endings near portal vessels. Functional roles of neurotensin in the thalamus and hypothalamus are discussed from the anatomical point of view.
Morphology of corticotectal cells in the primary visual cortex of hooded rats
Authors: Schofield Brett R. , Hallman L. Eric , Lin Chia‐Sheng 
Published: January 2005

AbstractIn primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V.