bluuebunny/crossref_metadata_2025_split huggingface dataset:
The astrocyte as a locus of carbonic anhydrase in the brains of normal and dysmyelinating mutant mice
Authors: Cammer Wendy , Tasey Francine A. 
Published: January 2005

AbstractThere is some controversy in the literature whether carbonic anhydrase occurs in astrocytes, as well as in oligodendrocytes and myelin, in the mammalian brain. In the present study this issue was addressed by double immunostaining for carbonic anhydrase and two astrocytic “markers” in the brains of normal mice and two dysmyelinating mutants, jimpy and shiverer. In the brains of young mice, carbonic anhydrase and glutamine synthetase were colocalized in astrocytes in the cortical gray matter. In gray matter of the adult mouse brain, it was possible to immunostain both carbonic anhydrase and glial fibrillary acidic protein (GFAP) in the same cells. However, in contrast to the findings in gray matter, in and near subcortical white matter carbonic anhydrase could be detected only in oligodendrocytes and myelinated fibers. In the brains of jimpy mice, virtually all the carbonic‐anhydrase‐positive cells were also GFAP positive, even in regions normally occupied by white matter. In the brains of young and adult shiverer mice, carbonic anhydrase was localized in astrocytes in the gray matter, but in and near the tracts normally occupied by white matter carbonic anhydrase could be detected only in oligodendrocytes and their abundant process. The findings confirmed the oligodendrocyte‐myelin unit to be the primary locus of carbonic anhydrase in the normal mouse brain and showed the astrocytes in gray matter normally to be a secondary locus of carbonic anhydrase. The immunostaining in the jimpy mouse brain suggested further that reactive astrocytes, in particular, might be rich in carbonic anhydrase.
Cholinergic neurons in the brain of a teleost fish (Porichthys notatus) located with a monoclonal antibody to choline acetyltransferase
Authors: Brantley Richard K. , Bass Andrew H. 
Published: January 2005

AbstractA monoclonal antibody (Ab8) to choline acetyltransferase (ChAT) was used to locate structures showing ChAT‐like immunoreactivity (ChAT‐IR) in the brain of a teleost fish, the midshipman (Porichthys notatus). ChAT is the synthetic enzyme for acetylcholine found in neurons using that neurotransmitter; thus ChAT‐IR may be interpreted as indicating putative cholinergic activity. Robust staining is seen in all cranial nerve motor nuclei. In addition, the brainstem of Porichthys is distinguished by two other expansive ChAT‐IR zones: a sonic motor nucleus, which innervates swimbladder “drum” muscles, and an octavolateralis efferent nucleus, which innervates acoustic, vestibular, and lateral line end organs. Scattered labeled cells are found in several cranial sensory nuclei–the vagal lobe, and the main and descending trigeminal nuclei. ChAT‐IR cells form restricted subpopulations in other noncranial nerve nuclei, including the granule cell layer of the cerebellum; superior, medial, and inferior divisions of the reticular formation; the stratum periventriculare of the midbrain's optic tectum; and the nucleus isthmi in the midbrain tegmentum. In the telencephalon, a dense population of ChAT‐IR cells is found in the ventral nucleus of area ventralis; terminals and fine fibers are found in the dorsal, medial, and central nuclei of area dorsalis. Together, the data represent the first complete report of ChAT‐IR cell bodies in the brain of any nonmammal with the monoclonal antibody Ab8, which has already been extensively used on a variety of vertebrate brains. The results are thus discussed from a comparative viewpoint, considering reports of ChAT‐IR in different taxa.
Onset and development of intersegmental projections in the chick embryo spinal cord
Authors: Oppenheim Ronald W. , Shneiderman Amiram , Shimizu Iwao , Yaginuma Hiroyuki 
Published: January 2005

AbstractThe ontogeny of intersegmental (propriospinal) projections was studied in the chick embryo spinal cord between embryonic day 2.5 and day 6. Our goals were (1) to determine the earliest projections of intersegmental interneurons between specific spinal regions and to establish the cell types involved; and (2) to follow the ontogeny of these projections during the early formative stages of spinal cord development. Studies were carried out in vitro by using an isolated spinal cord/brainstem preparation. Horseradish peroxidase injections were made either uni‐ or bilaterally at various levels of the spinal cord along the rostrocaudal axis of the embryo. HRP histochemistry was done on Vibratome sections with diaminobenzidine as the chromogen.Following unilateral injections at day 2.5, labelled commissural interneurons were found contralaterally and were confined to the injected segment. Subsequently, labelled cells were found progressively further away from the injected segment. By day 4.5 reciprocal projections extended between lumbar and brachial regions. Interneurons with intersegmental axonal projections were often undifferentiated, consisting of primitive unipolar or bipolar cells with little, if any, dendritic development. In some cases migrating interneurons could be retrogradely labelled from two or three segments away from the location of their translocating cell body. Anterograde Golgi‐like labelling of early undifferentiated cells revealed growing axons, axonal terminals, and growth cones. Five or six reasonably distinct classes of intersegmental interneurons were identified based on their location, axonal projections, and morphology of dendritic arbors. These appeared to be segmentally and bilaterally arranged along the rostrocaudal axis of the spinal cord. The axons of some of these types of interneurons exhibited preferences in their longitudinal projections within the ventral and ventrolateral marginal zone at the very onset of pathway formation. From the present observations it can be concluded that intersegmental connectivity precedes the development of ascending and descending supraspinal, as well as primary afferent connections in the chick embryo spinal cord.
Neuronal surface changes in the dorsal vagal motor nucleus of the guinea pig in response to axotomy
Authors: Engel Andreas K. , Kreutzberg Georg W. 
Published: January 2005

AbstractUltrastructural changes occurring in the dorsal motor nucleus of the vagus of the guinea pig after nerve transection were investigated. Two neuronal populations could be distinguished. Large neurons corresponding to the vagal motoneurons showed chromatolysis. They were found to develop complex changes in cell surface, which appeared either as a folding up and formation of flaplike processes or as invagination of adjacent neuronal or glial elements. Large processes often covered part of the plasmalemma and formed stacks of several neuronal lamellae. Smaller processes were mostly seen to extend into the neuropil, where they intermingled and adopted a budlike shape. These changes occurred in the cell somata within the first week after axotomy. The dendrites were affected after a short delay. The changes persisted for several months in most of the neurons, including the ones that showed signs of recovery from chromatolysis. The newly formed cellular extensions had a growth‐cone‐like internal structure, containing numerous smooth‐surfaced vesicles or cisternae, a feltwork of filamentous material, dense‐cored vesicles, and occasionally free polyribosomes. These surface changes did not occur in the second neuronal cell type of this nucleus, which had a smaller perikaryon characterized by a scanty cytoplasm. These cells did not show a retrograde degeneration and thus are probably interneurons. Acetylcholinesterase was used as a cytochemical marker of neuronal membranes. Surprisingly, the vagal motoneurons did not show a loss of enzymatic activity after nerve transection. Rather, a redistribution seemed to occur with intensified staining of the plasmalemma. The newly formed processes were consistently found to be acetylcholinesterase positive. It is suggested that the morphological changes observed correspond to an asyetunobserved growth process in the adult central nervous system, which involves perikarya and dendrites of regenerating guinea pig vagal motoneurons.
Development of the rat thalamus: III. Time and site of origin and settling pattern of neurons of the reticular nucleus
Authors: Altman Joseph , Bayer Shirley A. 
Published: January 2005

AbstractShort‐survival, sequential, and long‐survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, settling pattern, migratory route, and site of origin of neurons of the reticular nuclear complex of the thalamus. On the basis of its chronoarchitectonics, the reticular nucleus was divided into a central, medial, and lateral subnucleus. The central subnucleus is the earliest produced component of the entire thalamus with over 50% of its neurons being generated on day E13 and another 40% on day E14. Peak production of neurons of the lateral and medial subnuclei is on day E14. There is a lateral (earlier) to medial (later) neurogenetic gradient between these two components of the reticular complex: only about 12% of the lateral subnucleus neurons, but close to 30% of the medial subnucleus neurons, are generated on day E15. Because the lateral and medial subnuclei display the typical outside‐in gradient found in the thalamus, they are considered to constitute a single cytogenetic sector; the early generated central subnucleus, which violates this order, is considered to constitute a separate cytogenetic sector.Observations are presented that neurons of the central reticular subnucleus originate in a unique neuroepithelial region, the reticular protuberance. The migration of heavily labeled cells was traced from this region in rats labeled with 3H‐thymidine on day E13 and killed on the subsequent days. The neurons of the lateral and medial reticular subnuclei originate in the reticular lobule of the thalamic neuroepithelium. The migration of heavily labeled, spindle‐shaped cells was traced from this region in rats labeled with 3H‐thymidine on days E14 and E15 and killed at daily intervals thereafter. The neurogenetic gradient of the reticula thalamic complex seen in postnatal rats is established before birth.
Neuronal cell proliferation and ocular enlargement in black moor goldfish
Authors: Raymond Pamela A. , Hitchcock Peter F. , Palopoli Michae F. 
Published: January 2005

AbstractThe mechanisms that control cell proliferation in the developing nervous system are not well understood. In larval and adult goldfish addition of new retinal neurons continues as the eye grows, but the factors that modulate the rate of cell proliferation are unknown. The eyes of Black Moors grow excessively during postembryonic life, probably as a direct result of abnormally elevated intraocular pressure. Ocular growth must be partly autonomous in Black Moors because in some individuals the two eyes are very different in size. To determine whether cell proliferation and neuronal cell number in the retina were correlated with size of the eye, we counted dividing neuronal progenitor cells (rod precursors) and mature retinal neurons (ganglion cells) in the retinas of ocularly asymmetric fish. Rod Precursors, which are scattered across the retina in the outer nuclear layer, were labeled with 3H‐thymidine and counted on histological sections processed for autoradiography. Ganglion cells were counted in retinal whole mounts. We found that the total population of dividing rod precursors and the total number of ganglion cells were systematically greater in the large eye compared to the small eye of individual fish. We conclude that control of the rate of neuronal proliferation in the teleost retina is intrinsic to the eye and is probably regulated by the same factors that control ocular growth.
Anatomic organization of basoventral and mediodorsal visual recipient prefrontal regions in the rhesus monkey
Authors: Barbas H. 
Published: January 2005

AbstractThe sources of ipsilateral cortical afferent projections to basoventral and mediodorsal prefrontal cortices that receive some visual input were studied with retrograde tracers (horseradish peroxidase or fluorescent dyes) in eight rhesus monkeys. The basoventral regions injected with tracers included basal (orbital) areas 11 and 12, lateral area 12, and ventral area 46. The mediodorsal regions included portions of medial area 32 and the caudal part of dorsal area 8. These sites represent areas within basoventral and mediodorsal prefrontal cortices that show a gradual increase in architectonic differentiation in a direction from the least differentiated orbital and medial limbic cortices toward the most differentiated cortices in the arcuate concavity. The results showed that the visual input to basoventral and mediodorsal prefrontal cortices originated largely in topographically distinct visual areas. Thus, basoventral sites received most of their visual cortical projections from the inferior temporal cortex. The rostral inferior temporal region was the predominant source of visual projections to orbital prefrontal sites, whereas lateral area 12 and ventral area 46 also received projections which were found more caudally. In contrast, mediodorsal prefrontal sites received most of their visual projections from dorsolateral and dorsomedial visual areas. The cells of origin were located in rostromedial visual cortices after injection of retrograde tracers in area 32 and in more caudal medial and dorsolateral visual areas after injection in caudal area 8. The latter also received substantial projections from visuomotor regions in the caudal portion of the lateral bank of the intraparietal sulcus. These results suggest that the basoventral prefrontal cortices are connected with ventral visual areas implicated in pattern recognition and discrimination, whereas the mediodorsal cortices are connected with medial and dorsolateral occipital and parietal areas associated with visuospatial functions. In addition, the prefrontal areas studied received projections from auditory and/or somatosensory cortices, from areas associated with more than one modality, and from limbic regions. Orbital area 12 seemed to be a major target of projections from somatosensory cortices and the rostral portion of medial area 32 received substantial projections from auditory cortices. The least architectonically differentiated areas (orbital area 11 and medial area 32) had more widespread corticocortical connections, including strong links with limbic cortices. In contrast, areas which showed the highest degree of architectonic differentiation within the basoventral (area 46) and the mediodorsal (area 8) prefrontal cortices had restricted corticocortical connections.
Retinal ganglion cell topography in teleosts: A comparison between nissl‐stained material and retrograde labelling from the optic nerve
Authors: Collin Shaun P. , Pettigrew John D. 
Published: January 2005

AbstractThe retinal topography of cells within the ganglion cell layer of three teleost species is examined in Nissl‐stained material in which all neuronal elements containing Nissl substance in the cytoplasm are counted. A topographic comparison is made with retrogradely labelled ganglion cells to differentiate the proportion of nonganglion cells not possessing an axon joining the optic nerve. In the three species studied 92%, 80%, and 66% were found to be the maximum proportion of true ganglion cells in the area centralis, horizontal streak, and periphery, respectively. The proportion of nonganglion cells in the total population of cells counted was 24%. The major contribution to this discrepancy is from peripheral nonspecialized regions of the retina. There is little difference in both topography and peak densities of retinal ganglion cells between the two techniques. The soma areas of both populations are analysed, with the homogeneous nonganglion cell population possessing cells between 5 and 15 μm2 and the heterogeneous ganglion cell soma between 5 and 68 μm2, increasing in size with eccentricity.
Evidence for direct projections from the nucleus of the solitary tract onto medullary adrenaline cells
Authors: Hancock M. B. 
Published: January 2005

AbstractThe anatomic relationships between projections from the intermediate portion of the nucleus of the solitary tract (NTS) and phenylethanolamine N‐methyl transferaselike‐immunoreactive (PNMT‐LI) cells in the medulla oblongata were analyzed in Sprague‐Dawley rats by using two‐color immunoperoxidase staining combined with the anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA‐L). PHA‐L was iontophoretically deposited in the intermediate region of the NTS and the subjacent dorsal motor nucleus of the vagus (DMX) at the level of the middle of the area postrema. Blackstained PHA‐L‐immunoreactive (PHA‐LI) fibers and terminals were present throughout the length of the ipsilateral NTS, where many were seen in close apposition to amber‐stained PNMT‐LI cells belonging to the C2 cell group. Less profuse PHA‐LI projections were present in the contralateral NTS, especially at the level of the PHA‐L deposit. Bundles of smooth fibers emerged from the lateral edge of the DMX and could be followed to the ventrolateral surface of the medulla; these were likely vagal efferent fibers. PHA‐LI terminal arborizations were prominent in the region of the nucleus ambiguus (NA) and amongst PNMT‐LI cells in the lateral C1 cell group ventral to NA. Multiple sites of contiguity between PHA‐LI varicose fibers or boutons and PNMT‐LI cells in C1 were observed frequently and probably represent sites of functional connection.Medullary PNMT‐LI cells project to the intermediolateral cell columns of the spinal cord and to the hypothalamus and have been implicated in cardiovascular regulation. Based on the observations in this study, it is concluded that certain medullary PNMT‐LI cells in the C1 and C2 cell groups receive direct input from the intermediate NTS and thus play a role in baroreceptor‐mediated changes in cardiovascular activity.
Projections from the medial cortex in the brain of lizards: Correlation of anterograde and retrograde transport of horseradish peroxidase with timm staining
Authors: Olucha F. , Martinez‐Garcia F. , Poch L. , Schwerdtfeger W. K. , Lopez‐Garcia C. 
Published: January 2005

AbstractEfferent projections of the medial cortex of the lizards Podarcis hispanica and Gallotia stehlinii were studied by examining the transport of horseradish peroxidase; results were correlated with those from Timm‐stained sections. Two efferent systems were found. The first reaches the distal part of the outer plexiform layer in the medial, dorsomedial, and dorsal cortices, i.e., zones that are negative to Timm staining, and possibly originates from horizontal fusiform neurons. The second reaches the Timm‐positive zones in the cortex and septum and is topographically arranged: the vertical portion of the intermediate and caudal medial cortex and the entire rostral medial cortex project to the inner two‐thirds of the outer plexiform layer of the dorsomedial cortex and of the medial subfield of the dorsal cortex; to the paraventricular zone of the inner plexiform layer of the medial cortex; and bilaterally to the dorsal part of the dorsal precommissural septum. The dorsal part of the intermediate and caudal medial cortex and the ventralmost folded part of its caudal edge project rostrally to the juxtasomatic zone of the outer plexiform layer and the entire inner plexiform layer of the intermediate and lateral subfields of the dorsal cortex and to the ventral part of the dorsal septum. In its intense Timm reaction and its ultrastructural properties, as reported in earlier studies, the Timm‐positive fiber system of the lizard brain shows a close resemblance to the mossy fiber system of the mammalian hippocampus.
Organization of calcitonin gene‐related peptide‐immunoreactive terminals in the primate dorsal horn
Authors: Carlton S. M. , McNeill D. L. , Chung K. , Coggeshall R. E. 
Published: January 2005

AbstractThe present paper is concerned with the arrangement of axons and synaptic terminals immunostained for calcitonin gene‐related peptide (CGRP), a primary afferent marker, in the primate (Macaca fascicularis) dorsal horn. The CGRP axons and terminals are uniformly distributed in laminae I and II outer (o) but they are concentrated laterally and distributed intermittently in the reticulated region of lamina V. A prominent bundle of labeled axons is seen in the sacral cord dorsal to the central canal. Emphasis is given to the relation of CGRP‐immunoreactive terminals to other terminals, both labeled and unlabeled, in laminae I and IIo. In this regard, adjacent CGRP‐immunoreactive terminals are often united by puncta adhaerentia. Of particular interest is the observation that CGRP‐immunoreactive terminals can be found presynaptic to other terminals which sometimes resemble central primary afferent endings. In addition CGRP‐immunoreactive terminals end on other CGRP terminals. Both findings suggest that primary afferent terminals interact synaptically with other primary afferent terminals.
Morphogenesis of the brain in the harbour porpoise
Authors: Buhl Eberhard H. , Oelschläger Helmut A. 
Published: January 2005

AbstractMorphogenesis of the brain in a cetacean species has been investigated by means of reconstructions from serial sections of successive prenatal stages of the harbour porpoise (Phocoena phocoena). Four specimens ranging from 10 to 46 mm crown‐rump length (CRL) were selected and three‐dimensional reconstructions of the developing brains were obtained with the plate model method. External and internal characteristics, established as criteria for staging embryonic development of primates and rodents, revealed that a common ontogenetic plan regarding the chronological sequence of morphogenetic events exists in mammalian orders as different as primates and odontocetes. Comparison of the 10‐mm and 11.5‐mm CRL harbour porpoise brains with those in other mammalian embryos of a similar ontogenetic stage (stages 16 and 17) showed a high degree of correspondence in morphological features. This ontogenetic age group therefore might still be considered as a generalized mammalian one. However, during succeeding morphogenesis of the Phocoena brain, qualititative and quantitative divergences from other mammalian groups became manifest, such as those found in the 24‐mm CRL specimen (corresponding to mammalian stages 20, 21). Early foetuses of the harbour porpoise (46 and 65 mm CRL) already exhibited a variety of typical odontocete brain features, such as absence of olfactory bulb, thick cochlear nerve, and strong progression of brainstem structures. Morphogenesis of the harbour porpoise brain is discussed from a comparative perspective, incorporating the literature on the development of mammalian brains. Part of this study has been published in abstract form (Buhl and Oelschläger: Acta Anat. (Basel) 120:15–16 (Abstract), '84.