bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genesis of resting microglia in the gray matter of mouse hippocampus
Authors: Kitamura Tadahisa , Miyake Toshihiko , Fujita Setsuya 
Published: January 2005

AbstractThe genesis of resting microglia in the gray matter of mouse hippocampus was studied by 3H‐thymidine autoradiography in combination with electron microscopy. Newborn mice were injected with 3H‐thymidine singly or repeatedly at different postnatal stages, and killed shortly after the injection or after various intervals. Tissue specimens of the hippocampus at CA1 and CA2 were processed for light and electron microscopic autoradiography. The results showed that at least 91% of glial cells in the stratum radiatum of the hippocampus are produced after birth. About three‐fourths of astroglia in this area are produced before the sixth postnatal day, and a larger part of resting microglia are formed after the ninth postnatal day. Morphological transition can be traced from either proliferating cells in the stratum radiatum at late postnatal days to resting microglia or from those in early postnatal days to astroglia. A continuous morphological transition was observed between the proliferating cells at the late postnatal days (microglial production period) and those at the early postnatal days (astroglial production period). The latter retain some fine structural characteristics similar to small glioblasts in the subependymal layer. These findings strongly suggest that resting microglia, as well as astroglia, are derived from glioblasts, and are of neurectodermal origin.
The motor nuclei and primary projections of the IXth, Xth, XIth, and XIIth cranial nerves in the monitor lizard, Varanus exanthematicus
Authors: Barbas‐Henry Heleen A. , Lohman Anthony H. M. 
Published: January 2005

AbstractThe motor nuclei and sensory connections of the IXth, Xth, XIth, and XIIth cranial nerves of the reptile Varanus exanthematicus were studied with the methods of anterograde degeneration and anterograde and retrograde axonal transport. The motor nuclei of nerve IX are located ventrally in the rhombencephalon and are constituted medially by the large‐celled glossopharyngeal part of the nucleus ambiguus and laterally by the small‐celled nucleus salivatorius inferior. The motor nuclei of nerve X consist of the dorsomedially located dorsal motor nucleus of the vagus and the laterally located vagal part of the nucleus ambiguus. The rostral portion of the latter cell group contains smaller cells than its caudal portion and is rostrally continuous with the nucleus salivatorius inferior of nerve IX. The efferent axons of nerves IX and X arising from the ventrolateral medulla first course dorsomedially, form genua beneath the IVth ventricle, and then exit the brainstem. All primary afferent fibers of nerve IX and the majority of those of nerve X enter the solitary tract. Terminations of vagal fibers were observed in the postvagal portion of the nucleus of the solitary tract, the dorsal motor nucleus of the vagus, and the nucleus of the commissura infima. A small contingent of vagal fibers courses caudally just dorsolateral to the descending trigeminal tract. A separate spinal component of nerve XI could not be found. The bulbar component of this nerve forms part of nerve X and takes its main origin from a detached caudal element of the nucleus ambiguus. The motor nuclear complex of nerve XII consists of a large dorsal nucleus and a small ventral nucleus that extend from the medulla oblongata into the first segment of the cervical spinal cord.
The subnuclear distribution of substance P, cholecystokinin, vasoactive intestinal peptide, somatostatin, leu‐enkephalin, dopamine‐β‐hydroxylase, and serotonin in the rat interpeduncular nucleus
Authors: Hamill Geoffrey S. , Olschowka John A. , Lenn Nicholas J. , Jacobowitz David M. 
Published: January 2005

AbstractThe distribution of immunofluorescent somata and processes within the interpeduncular nucleus (IPN) containing substance P (SP), cholecystokinin (CCK), vasoactive intestinal peptide (VIP), somatostatin (SST), leu‐enkephalin (L‐ENK), dopamine β hydroxylase (DBH), and serotonin (5HT) was examined in male rats treated with colchicine 48 hours prior to perfusion. Serial sections were examined for immunofluorescence and variations in the density of fluorescence rated 1+ (sparse) to 4+ (dense).The rostral subnucleus contained SP, SST, and L‐ENK‐positive somata and processes. Substance P and VIP processes were present throughout the rostral subnucleus but were concentrated in two ovoid areas located dorsally in the caudal region of this subnucleus. Cholecystokinin and L‐ENK processes surrounded these ovoid areas. The entire width of the central subnucleus was crossed by SP and L‐ENK processes oriented horizontally in narrow bands. Substance P processes were also aligned into vertical columns adjacent to the lateral margins of the central subnucleus. Leu‐enkephalin and 5HT processes were distributed throughout this subnucleus, while VIP processes were present only caudally. Dopamine β hydroxylase processes were evenly distributed but were restricted from the vertical columns laterally.The intermediate subnuclei contained a sparse density of SP and 5HT processes that were present in proximity to the major blood vessels penetrating this subnucleus. Only DBH processes were evenly distributed.The lateral subnuclei contained a dense concentration of SP processes. The medial edges of this subnucleus were distinguished by VIP, CCK, L‐ENK, and 5HT processes.The dorsal subnucleus contained 5HT, L‐ENK, and SST‐positive somata and processes. Substance P, VIP, CCK., and DBH processes were also present. Dorsal‐lateral subnuclei contained SP, SST, L‐ENK, and DBH processes. Interstitial subnuclei contained SP, CCK, L‐ENK, 5HT, and DBH processes.This study demonstrates that perikarya and processes containing peptides and monoamines are distributed within subnuclei of IPN in a topographic and heterogeneous pattern. New features of IPN organization are revealed.
The distribution and synaptic organization of serotoninergic elements in the inferior olivary complex of the opossum
Authors: King James S. , Ho Raymond H. , Burry Richard W. 
Published: January 2005

AbstractImmunohistochemistry and high‐resolution autoradiography were used to analyze the distribution and synaptic organization of serotonin (5HT) ‐containing elements in the inferior olivary complex of the opossum. Immunoreactive beaded varicosities are present throughout the olivary complex. The densest 5HT immunostaining is present in subnucleus b of the caudal medial accessory nucleus. The rostral principal olive is sparsely populated with immunoreactive elements.Fine beaded fibers arborize throughout the neuropil of all the olivary nuclei except in subnucleus b of the caudal medial accessory nucleus where they also circumscribe neuronal cell bodies. In addition, a distinct population of large beaded fibers are occasionally encountered in the neuropil of the medial accessory nucleus. Ultrastructurally, labeled profiles that correspond in size to the smaller beads (< 1 μm) contain tubulovesicular elements, large dense‐cored vesicles, and clear vesicles. In contrast, larger profiles (> 2 μm) are characterized by numerous clear synaptic vesicles. Synaptic junctions were encountered in only 2% of the labeled elements. The majority of the labeled profiles were in juxtaposition to small‐diameter dendrites (< 2 μm) except in the caudal medial accessory nucleus, where they also were found in apposition to olivary cell bodies.Our results, when compared with other accounts, indicate that rather than major differences in the nuclear distribution of serotonin between species, there are differences in the density of serotoninergic elements in specific nuclei of the mammalian inferior olive. Based on the size of the labeled profiles and the distinct vesicle populations, our data suggest there are at least two populations of 5HT varicosities that are in juxtaposition to olivary neurons. Further, boutons containing 5HT primarily interact with the distal dendrites of olivary neurons except in the caudal medial accessory nucleus where cell bodies are in apposition to 5HT varicosities.
Distribution of tyrosine‐hydroxylase‐immunoreactive neurons in the hypothalamus of rats
Authors: Chan‐Palay Victoria , Záborszky László , Köhler Christer , Goldstein Menek , Palay Sanford L. 
Published: January 2005

AbstractThe distribution and morphology of cells containing tyrosine hydroxylase (TH) immunoreactivity in the hypothalamus of rats were studied by using a modified immunoperoxidase technique. The TH cell system is more complexly organized than was previously thought. On the basis of their clustering patterns, hypothalamic TH neurons could be subdivided into two groups: dorsal and ventral. The ventral group consists of a prominent aggregate of cells located in the caudal part of the arcuate nucleus. From here, cells extend around the caudal part of the ventromedial and dorsomedial nuclei and the base of the diencephalon. Tyrosine hydroxylase‐positive cells are present throughout the arcuate nucleus, except in its ventromedial part. Anteriorly, immunoreactive cells appear in the suprachiasmatic and supraoptic nuclei, in the retrochiasmatic area, and in the ventral part of the anterior hypothalamic nucleus. The dorsal group has its main concentration of cells in the medial part of the zona incerta, from which two clusters of cells, one medial and one lateral, extend rostralward. The medial group comprises cells in the medial part of the dorsomedial, paraventricular, and anterior hypothalamic nuclei. These cells adjoin the periventricular cells. The lateral group of cells emanating from the zona incerta occupies the lateral part of the dorsomedial and anterior hypothalamic nuclei and the dorsal hypothalamic area. The dorsal and ventral TH cell groups are in continuity medially in the periventricular layer, and laterally through the cells that surround the ventromedial nucleus.Although the cells vary widely in size, shape, and dendritic arborization pattern, there are two main cell types. Small (21 × 11 μm), round to fusiform cells, with two or three dendrites arborizing simply, were frequently seen in the arcuate, suprachiasmatic, periventricular, supramammillary nuclei and at the borders of the ventromedial nucleus. The other cell type is larger (40 × 15 μm) and multipolar, with three to five frequently branching dendrites. The dendritic field is large and the cells are intensely TH‐immunoreactive. Although the larger cells occur occasionally in every hypothalamic nucleus, their principal locations are in the dorsal parts of the dorsomedial, posterior hypothalamic nuclei and the dorsal and lateral parts of the zona incerta, and in the areas dorsal and medial to the mammillothalamic tract at caudal hypothalamic levels. In this paper we give a detailed description of TH‐immunoreactive fibers and terminals in the hypothalamus and a comparison with previous studies of catecholamine cells in the hypothalamus.
Intraocular grafts of fresh and freeze‐stored rat hippocampal tissue: A comparison of survivability and histological and connective organization
Authors: Jensen Steen , Sørensen Torben , Møller Anders G. , Zimmer Jens 
Published: January 2005

AbstractIntraocular grafts of rat hippocampal tissue, grafted either directly from the immature donor brains (fresh) or after storage in liquid nitrogen at –196°C (freeze‐stored), were compared with regard to survivability and histological and connective organization. For direct grafting, pieces of hippocampal tissue from rat embryos (embryonic day 19, E21) and newborn rats (PO) were placed in the anterior eye chamber of adult rats immediately after dissection. For grafting after deep‐freeze storage, pieces of hippocampal tissue were taken from rat embryos (E16–E21) and newborn rats (PO), frozen at a cooling rate of 1°C/min in CO2 or N2 vapours after addition of the cryoprotective agent dimethylsolfoxide (DMSO), and stored in liquid nitrogen for 1 to 33 days before thawing and intraocular grafting. From 20 to 68 days after grafting, the recipient rats were sacrificed, their eyes sectioned, and the sections stained with thionine for cell bodies, Timm's sulphide silver method for hippocampal fiber systems and terminal fields, and acetylcholinesterase (AChE) for cholinergic fibers and AChE‐positive neurons.When examining the 101 grafted eyes (34 grafted with fresh and 67 with freeze‐stored tissue) a significantly lower survival rate of the freeze‐stored tissue was found (28 vs. 88%). The survivability of the freeze‐stored tissue was age‐dependent with no survival at donor ages E16 and PO, while tissue from E18–E21 had a 50% survival rate. The grafts of the freeze‐stored tissue were also smaller and showed an increased tendency for fragmentation. When evaluating the structure of the grafts, the deep‐freeze storage was found primarily to have been harmful to the dentate granule cells and their precursors. The organization of intrinsic fiber connections followed the pattern known from lesion and intracerebral transplant studies. While demonstrating that immature brain tissue can survive deep‐freeze storage and subsequent intraocular grafting, the study also indicates that different schemes may have to be used to get optimal survival of different neuronal populations.
Elasmobranch oculomotor organization: Anatomical and theoretical aspects of the phylogenetic development of vestibulo‐oculomotor connectivity
Authors: Graf W. , Brunken W. J. 
Published: January 2005

AbstractThe oculomotor organization of two elasmobranch species, smooth dogfish (Mustelus canis) and little skate (Raja erinacea), was studied by investigating the extraocular muscle apparatus and the oculomotor motoneuron distribution.The macroscopic appearance of the eye muscles was similar to any lateral‐eyed vertebrate species (e.g., goldfish, rabbit). The size of extraocular muscles was expressed by counting single muscle fibers and comparing cross‐sectional areas of the extraocular muscles. There were significant differences in the number of fibers in the six extraocular muscles in dogfish, but not in skate. Fiber sizes varied considerably; thus, the number of fibers did not relate to cross‐sectional areas. In the dogfish, no one pair of agonist‐antagonist extraocular muscles was larger than the others, suggesting that there was no preference for eye movements in a particular plane of space. However, the lateral rectus was more than twice the size of most of the other muscles. In the skate, cross‐sectional areas of the horizontal eye muscles were smaller than those of the vertical eye movers. This may indicate a reduced utilization of horizontal eye muscles, which may reflect the bottom‐dwelling habitat and mode of locomotion of the skate.The distribution of the extraocular motoneurons was determined by injecting horseradish peroxidase (HRP) into single eye muscles. Medial rectus, superior rectus, and superior oblique motoneuron populations were located contralateral to their respective muscles. Lateral rectus, inferior rectus, and inferior oblique motoneurons were located ipsilateral to their muscles. This distribution is in contrast to almost all other vertebrates studied thus far, where medial rectus motoneurons are located ipsilateral to the muscle which they innervate. The oculomotor arrangement in elasmobranchs is likely to have consequences for the circuitry responsible for the production of conjugate compensatory eye movements in the horizontal plane.We hypothesize that, in contrast to other vertebrates, the basic elasmobranch vestibulo‐ocular reflex pathway consists of three identically structured three‐neuron‐arcs connecting the three semicircular canals to their respective extraocular muscles. This innervation pattern may constitute a special feature of the elasmobranch brain or a phylogenetically older arrangement of eye movement pathways.
Autonomic nervous system innervation of thymic‐related lymphoid tissue in wildtype and nude mice
Authors: Bulloch Karen , Pomerantz William 
Published: January 2005

AbstractA study was undertaken to determine the source and terminal distribution of the autonomic nervous system (ANS) innervation of lymphoid tissue in the mediastinum of male and female B10 and Balb/c wildtype and syngeneic nude (nu/nu) mice. Acetylcholinesterase (AChE) histochemistry was used to localize this hydrolytic enzyme in neural tissue and glyoxylic acid fluorescent histochemistry was used to characterize catecholaminergic (CA) innervation. The thymus was innervated by AChE‐positive fibers of the vagus, the recurrent laryngeal, and the phrenic nerves. Catecholaminergic innervation was derived from the stellate ganglia and other small ganglia of the thoracic sympathetic nervous system chain. Whereas intrinsic AChE‐positive innervation of the thymus was evident at the cortico‐medullary boundaries and under the capsule, CA innervation was observed along the trabeculae with perivascular plexuses at the cortico‐medullary boundaries and interlobular septa. Free CA fibers were noted in the medulla and in the cortex, where they were often proximal to cortical autofluorescent (CAF) cells. The rudimentary thymus of the adult nude mouse received limited ANS innervation. Only a few CA or AChE‐positive fibers were evident, with the majority of fibers associated with the acinar cells of the gland. Mediastinal lymph nodes in male and female wildtype mice varied in their distribution and were frequently found clustered around nerves and ganglia. The intrinsic innervation of lymph nodes by AChE‐positive fibers was confined to the subcapsular marginal sinus, with a few vascular‐associated fibers in the parenchyma. Catecholaminergic perivascular plexuses were present in the hilar zone, whereas some free fibers were noted under the capsule and in the parenchyma. The mediastinal lymph nodes of male and female nude mice when compared to the lymph nodes of male and female wildtype mouse were found to be increased in number and in distribution. Clusters of these lymph nodes were found in close proximity to ANS tissue. The intrinsic innervation of the nude mediastinal lymph nodes was comparable to that present in the wildtype mouse tissue. The functional implication of these data is discussed with regard to nervous: immune system interactions.
Segmental variation in the arborization of identified neurons in the leech central nervous system
Authors: Gillon Jean W. , Wallace Bruce G. 
Published: January 2005

AbstractMechanosensory and motor neurons in the central nervous system of the leech have been examined by intracellular injection of horseradish peroxidase and electrophysiological mapping of their peripheral fields to determine how the arborizations of homologous cells are influenced by their segmental position. The branching patterns of annulus erector (AE) motoneurons in ganglia near the head and tail were found to be more extensive than those of cells in midbody ganglia. As in midbody ganglia, the peripheral fields of AE motoneurons in adjacent ganglia near the head and tail overlapped extensively, but the subfields innervated by individual branches of a single AE motoneuron showed little or no overlap. No AE motoneurons were found in the head ganglion or in the 20th and 21st free segmental ganglia. The branching pattern of touch‐sensitive mechanosensory cells showed a similar segmental variation; touch cells in ganglia near the head and tail had more extensive arborizations than those in midbody ganglia. The rostrocaudal position along the cord at which the branching pattern changed from that characteristic of midbody ganglia to one with a more extensive arborization differed for different types of neurons. These findings demonstrate that a cell's pattern of arborization is not determined by a simple segmental difference between ganglia and suggest that during development neurons respond individually to cues that vary along the length of the cord.
The interconnections of the inferior colliculi through their commissure
Authors: Aitkin L. M. , Phillips S. C. 
Published: January 2005

AbstractMuch is known of the sources and manner of termination of ascending and descending input to the inferior colliculus (IC) but its commissural connections are less well understood. Most studies of the commissure have utilized small lesions or tracer deposits; while all agree that commissural axons terminating in the IC do so in its superficial and dorsomedial sectors, it is not clear where projecting cell bodies are located in the IC.The present study attempted total infiltration of the commissure of the cat IC with horseradish peroxidase (HRP) in an effort to label all neuronal somas whose axons cross in the commissure. The distribution of labeled cells after the brachium of the IC (BIC) was cut unilaterally and infiltrated with HRP was also examined to enable comparison of the locations and approximate proportions of cells projecting to the contralateral IC and medial geniculate body (MGB).The cells giving rise to commissural axons form an array tilted dorsally from caudal to rostral that spreads mediolaterally through the central nucleus into the external nucleus of the IC, but largely excludes the dorsomedial sector at posterior levels. A similar distribution of labeled cells, but with reduced numbers, is found when large HRP deposits are made in the contralateral BIC. These results, in conjunction with those from studies of the terminations of commissural axons made by others, suggest that the interconnections of the inferior colliculi through their commissure are complementary, rather than reciprocal.
Cerebellar efferents in the lizard Varanus exanthematicus. I. Corticonuclear projections
Authors: Bangma G. C. , Donkelaar H. J. Ten 
Published: January 2005

AbstractThe organization of the cerebellar corticonuclear projections, i.e., the projections from the Purkinje cell layer to the cerebellar nuclei and the vestibular nuclear complex, was investigated with the horseradish peroxidase (HRP) technique in the lizard Varanus exanthematicus. After HRP slowrelease gels were implanted in the cerebellar nuclei or various parts of the vestibular nuclear complex, the following longitudinally oriented zones of labeled Purkinje cells could be distinguished: (1) a medial zone projecting to the medial cerebellar nucleus; (2) an intermediate zone projecting to the vestibular nuclear complex, especially the ventrolateral vestibular nucleus, but probably also the dorsolateral vestibular nucleus; (3) a caudolaterally located area of the cerebellar cortex projecting to the lateral cerebellar nucleus; and (4) the flocculus and the adjacent lateral part of the Purkinje cell layer with projections to the middle and caudal parts of the vestibular nuclear complex, i.e., the descending and ventromedial vestibular nuclei. All projections of the Purkinje cells appeared to be strictly ipsilateral. It can be concluded that in reptiles a longitudinal organization of cerebellar corticonuclear projections exists, which may be basic for terrestrial vertebrates.
The postnatal development of the tract of lissauer in the rat
Authors: Chung Kyungsoon , Coggeshall Richard E. 
Published: January 2005

AbstractThis study determined the numbers of axons in the tract of Lissauer of the S2 segment of rat spinal cord during postnatal development. One day after birth there were an average of 39 myelinated and 9,520 unmyelinated axons in this pathway. These numbers changed steadily to the 722 myelinated and 2,759 unmyelinated axons that characterize the adult. Thus there was a 20‐fold increase in myelinated axons but a threefold decrease in total axons in this pathway from birth to adulthood. The axonal changes occurred so long after the changes in the number of cells that give rise to these axons that the axonal changes were almost certainly not due to the death of their parent neurons. We do not yet understand the mechanisms that control axonal numbers in this pathway, but in our opinion these mechanisms are as important as those that control neuronal numbers in considerations of the development of the nervous system.