bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective lectin binding of the developing mouse retina
Authors: Blanks Janet C. , Johnson Lincoln V. 
Published: May 2005

AbstractA battery of eight lectins with different carbohydrate specificities was used to study changes in glycoconjugate expression during cell differentiation in the mouse retina. The lectins tested included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SB A), peanut agglutinin (PNA), Ulex europaeus agglutinin (UEA), Ricinus communis agglutinin I (RCA), Dolichos biflorus agglutinin (DBA), and Limulus polyphemus agglutinin (LPA). Unfixed frozen sections of adult and early postnatal mouse retina were treated with fluorescein isothiocyanate‐conjugated lectins and examined by fluorescence microscopy.The results showed selective lectin binding in both cellular and synaptic retinal layers of the adult mouse and throughout postnatal development. In general, an increase in intensity of fluorescent lectin staining during retinal development was observed for Con A, WGA, DBA, LPA, RCA, and PNA. This suggests an increase in the expression or accessibility of carbohydrate moieties during development. SBA and UEA showed little to no binding to adult or neonatal retina. Retinal vasculature was intensely stained by RCA, both during development and in the adult. All lectins binding to adult or neonatal retinal layers showed some degree of reactivity with the inner segment region of photoreceptor cells. However, only Con A, PNA and WGA bound to photoreceptor outer segments, suggesting significant differences in the glycosylated components of inner and outer segment membranes. PNA bound specifically to a subpopulation of photoreceptor cells and to discrete regions within the outer synaptic layer. The pattern of PNA binding suggests that this lectin binds preferentially to cone photoreceptor inner and outer segments and cone synaptic pedicles rather than to rod photoreceptor cells. This marked specificity of PNA binding suggests that it may provide a basis for the physical separation of cone and rod photoreceptor cells.
Kindled seizure‐induced reduction of muscarinic cholinergic receptors in rat hippocampal formation: Evidence for localization to dentate granule cells
Authors: Savage Daniel D. , Dasheiff Richard M. , McNamara James O. 
Published: May 2005

AbstractThe binding of [3H] quinuclidinyl benzilate ([3H] QNB) to muscarinic cholinergic receptors in dentate gyrus of rat hippocampal formation was analyzed by membrane binding assay and in vitro autoradiography. The destruction of dentate granule cells, either by neonatal irradiation or colchicine injection, resulted in nearly complete elimination of [3H] QNB binding sites in the molecular and granule cell layers. By contrast, neither perforant path transection nor destruction of the septal‐hippocampal cholinergic afferents caused a decline of [3H] QNB binding sites. Amygdala kindled seizures resulted in a 30% reduction of [3H] QNB binding sites which was distributed uniformly across the entire molecular and granule cell layers. Thus, most, if not all, of the muscarinic cholinergic receptors present in dentate gyrus appear to reside on the somata and dendritic trees of the dentate granule cells. We propose that this kindled seizure‐induced decline of muscarinic receptors represents an endogenous compensatory mechanism designed to stabilize granule cell excitability.
Accuracy of regeneration of vagal parasympathetic axons
Authors: Taylor Barbara , Finger Thomas E. , D'Arcy Genet , Roper Stephen D. 
Published: May 2005

AbstractThe degree of accuracy with which regenerating preganglionic parasympathetic fibers can restore their original connections was examined in the frog, Rana pipiens. The normal motor pool of the vagus nerve was determined by labeling the vagal cardiac branch fibers with horseradish peroxidase (HRP). Cardiac neurons form a relatively compact subgroup within the rostral half of the vagal motor column and represent less than 5% of the total vagal motor pool.Five to 14 weeks after crushing the vagus nerve, HRP labeling revealed that a more extensive population of vagal motor neurons has reinnervated the cardiac branch. The regenerated cardiac motor neuron pool is about twice as numerous as normal but is still centered in the rostral half of the vagal motor column.These experiments show that regeneration of the cardiac branch of the vagus nerve is neither a random process nor one which is completely accurate. Some degree of accuracy is maintained during regeneration following a crush lesion. Neurons nearer the original cardiac motor pool are more likely to reinnervate the cardiac branch than are vagal motor neurons located at some distance from the original cardiac pool.
Central neuronal projections and neuromuscular organization of the basal region of the shore crab leg
Authors: Bévengut M. , Simmers A. J. , Clarac F. 
Published: May 2005

AbstractThe musculature and associated skeleton, peripheral nervous system, and central projections of motor and sensory neurones of the two basal (thoracic and coxal) segments of the shore crab leg (fifth pereiopod, P5) were examined in vivo and with methylene blue or cobalt staining.Each of the four main basal muscles, promotor/remotor, levator/depressor, controlling the thoracico‐coxal (T‐C) and coxo basal (C‐B) limb joints, respectively, comprises several more or less discrete fibre bundles (total 14), with little morphological segregation of different functional groups.The innervation to the basal leg region is carried in two nerve roots arising from the thoracic ganglion. The anterior Th‐Cx root carries both sensory and motor axons, while the posterior Th‐Cx root is purely motor. Three previously undescribed sensory branches (two “epidermal” nerves and an “accessory” branch), in addition to that innervating the coxobasal chordotonal receptor, have been found in the distal part of the anterior Th‐Cx root. Two clusters of 10 to 15 multipolar somata (diam. 30–125 μm) are located proximally at the bifurcation of the accessory nerve and distally where the latter enters the basipodite.The cell bodies (diameter 20–80 μm) of basal leg motoneurones (total ca. 30) lie in the dorsal cortex of the ganglion, with somata of functionally related motoneurones tending to form discrete structural groups. The morphology of individual motoneurones conforms to the general arthropod pattern. All are confined to the ipsilateral hemiganglion and their main neuropilar processes run parallel and in close apposition to each other with overlapping dendritic structures. Sensory projections arising from the CB chordotonal organ also ramify in the region of the neuropile invaded by motoneurones. The possible physiological significance of such structural associations within the CNS is discussed, as are the functional implications of basal limb anatomy in general.
A morphological analysis of vasoactive intestinal polypeptide (VIP)‐like immunoreactive neurons in the area dentata of the rat brain
Authors: Köhler Christer 
Published: May 2005

AbstractThe general distribution and morphology of vasoactive intestinal polypeptide‐like immunoreactive (VIP‐LI) neurons in the area dentata (AD) have been studied using immunohistochemical methods on thick (70–120 μm) sections from the rat brain. The long (≥ 72 hours) incubation of free‐floating sections in combination with a sensitive immunoperoxidase method resulted in extensive labeling of VIP‐positive cell bodies, along with their dendritic and axonal processes in the hippocampal formation, including the area dentata. The VIP‐positive cells are found in all parts of the area dentata, and plots of the distribution of individual cells showed that there is a preferential clustering of these neurons within, or in close proximity to, the granule cell layer, while the deep zones in the hilus are almost completely devoid of VIP‐LI immunoreactive neurons. Throughout the long axis of the AD the number and relative position of the VIP‐LI neurons remains rather constant. Analysis of the size and shape of the VIP‐positive neurons in the AD shows a remarkable morphological heterogeneity, with the soma ranging from small (long axis: ˜ 10 μm) ovoid or round, to large (long axis: ˜ 25 μm) stellate or multipolar; of these the small to medium sized cells predominate.Comparisons between the morphology of neurons visualized with the VIP antibody and sections stained by the rapid Golgi method allow a rather conclusive classification of some of the VIP‐stained neurons, while the classification of a majority of the VIP nerons remains tentative, perhaps because of the selective visualization by the rapid Golgi method of only certain cell types in the AD. On the basis of this comparison, several displaced granule cells in the molecular layer, as well as granule cells, small ovoid cells, and pyramidal basket cells in the granule cell layer have been identified as VIP‐positive as determined by their somatic shape, dendritic branching pattern, and axonal projections. In addition, several VIP‐positive neurons have been identified with less certainty. These include the dentate basket cell of Cajal, certain small cells in the molecular layer, and fusiform cells in the polymorph layer. Taken together the present results demonstrate the usefulness of “Golgi‐like” immunoperoxidase staining for detailed classification of chemically defined neurons. Furthermore, these studies provide evidence for a morphological heterogeneity of VIP cells in the area dentata, and suggest that although some of the VIP cells may project out of the AD (the granule cells) a majority of the VIP neurons are interneurons that lack extrinsic projections.
Central projections of the brachial nerve in bullfrogs: Muscle and cutaneous afferents project to different regions of the spinal cord
Authors: Jhaveri Sonal , Frank Eric 
Published: May 2005

AbstractThe central projections of muscle and cutaneous sensory neurons in the bullfrog were labeled by filling their peripheral axons in the forelimb with horseradish peroxidase (HRP). Muscle afferent fibers were found to project exclusively to the ventral neuropil of the brachial spinal cord in the intermediate gray zone. Cutaneous afferent axons had their arbors limited to the dorsal neuropil. There is therefore a topography in the central representation of two classes of sensory modalities.
Radial organization of the hippocampal dentate gyrus: A Golgi, ultrastructural, and immunocytochemical analysis in the developing rhesus monkey
Authors: Eckenhoff Maryellen F. , Rakic Pasko 
Published: May 2005

AbstractThe cytoarchitectonic organization of the dentate gyrus was analyzed in the rhesus monkey at various embryonic (E) and postnatal (P) ages with the rapid Golgi method, transmission electron microscopy (EM), and immunocytochemical localization of glial fibrillary acidic protein (GFAP). From the earliest ages (stage I, E38‐E83), immature granule cells were arranged radially along elongated fibers that extend from the ventricular zone to the pial surface. The glial nature of these radial fibers was confirmed by the presence of GFAP antigen in their cytoplasm detected clearly by E70. EM analysis at this age showed that granule cells situated within the dentate plate, as well as many neurons still migrating from the ventricular zone, were closely apposed to fascicles of radial glial fibers. The radial organization of the dentate plate was even more evident during stage II (E83‐E165). Thus, in E97 and E125 specimens, radially oriented immunoreactive glial processes emerged from somas situated either in the ventricular or subgranular zones, penetrated between columns of neurons in the granular layer, branched upon entering the molecular layer, and finally terminated at the pial surface. Palisades of glial processes delineated ontogenetic radial units which consisted of stacks of granule cell bodies in different stages of maturation. In a given radial unit, more mature cells were located superficially (closer to the pial surface) and less mature cells were located at progressively deeper levels. This radial organization of the dentate gyrus was maintained during stage III (P0‐P60) and stage IV (2 months‐adult). Furthermore, the number of GFAP‐positive proliferating cells in the subgranular zone increased from 1 to 5 months. In the mature brain, the radial organization of the dentate gyrus was less apparent although many glial fibers still penetrated the granule cell layer. The present results indicate that the developing dentate gyrus in primates consists of a series of ontogenetic radial units that resemble those described in the fetal neocortex (Rakic, '72). They further suggest that the development and maintenance of this radial columnar organization may be imposed by the orientation of glial scaffolding during development.
Ascending somatosensory projections to the dorsal accessory olive: An anatomical study in cats
Authors: Molinari Helen H. 
Published: May 2005

AbstractThe cells in the gracile nucleus that project to the dorsal accessory olive were identified in cats with retrograde tracing techniques. In the same animals, the retrograde labeling patterns in the lateral cervical nucleus and the lumbosacral spinal cord were also examined. Small injections of wheat germ agglutinin complexed to horseradish peroxidase were made in the ventrolateral portion of the dorsal accessory olive without involving the medial accessory olive and without damaging the medial lemniscus. The tissue was processed with tetramethyl benzidine.In each of the three relay nuclei, the neurons that project to the ventrolateral portion of the contralateral dorsal accessory olive are highly concentrated in small regions. In the gracile nucleus these cells are found almost exclusively in the transitional zone, just caudal to the obex and rostral to the clusters. In the lateral cervical nucleus they are concentrated in the dorsolateral tip. In the lumbosacral spinal cord in segments L5 and L6 the cells are found primarily in lamina V, while in segments L7 and S1 they are found along the ventromedial edge of the ventral horn. In the gracile and lateral cervical nuclei there is no segregation of neurons that project to the rostral and caudal portions of the dorsal accessory olive.Comparison of these results with physiological data suggests that each of the three sources of ascending somatic input conveys some distinct aspect of sensory information from the hindlimb to the dorsal accessory olive.
Relation of target encounter and neuronal death to nerve growth factor responsiveness in the developing mouse trigeminal ganglion
Authors: Davies Alun , Lumsden Andrew 
Published: May 2005

AbstractAn aim of this study was to define precisely the period in the developmental history of primary sensory neurons during which nerve growth factor (NGF) exerts its growth‐promoting effect. The mouse trigeminal ganglion and its peripheral projection were studied at closely staged intervals throughout development using light and electron microscopy, and the influence of NGF and anti‐NGF antiserum on neurite outgrowth from ganglion explants was investigated at corresponding stages in culture. By embryonic day 9.5 (E9.5) peripheral fibers were first visible and increased in number until E13. Throughout this period in vitro neurites grew in the presence of anti‐NGF. Peripheral fibers initially contacted the epithelium of the mandibular process by E10.5 and the maxillary process by E11. This coincided with the stage in vitro during which the magnitude of neurite outgrowth was significantly increased by NGF. The development of this response was independent of target encounter since it occurred in neurons which had not contacted their targets prior to explantation. There was an approximate one‐to‐one relationship between the number of neurons in the ganglion and peripheral fibers throughout development. A peak of some 44,400 fibers and 42,600 neurons was reached by E13 and fell to 20,800 and 19,000, respectively, by birth. Neurite outgrowth was elicited by NGF throughout the period of neuronal death. It is argued that the time course of the influence of NGF is consistent with a role as a selective maintenance factor but not as an agent directing initial outgrowth.
Retinotectal terminals in the superior colliculus of the rabbit: A light and electron microscopic analysis
Authors: Schönitzer Klaus , Holländer Horstmar 
Published: May 2005

AbstractThe projection from the retina to the contralateral superior colliculus was studied light and electron microscopically by means of anterogradely transported horseradish peroxidase and tetramethylbenzidine histochemistry as well as light microscopically by experimental degeneration and [3H]‐leucine autoradiography.Labeled boutons were found in stratum zonale (SZ) and in stratum griseum superficiale (SGS), but not in stratum opticum (SO). The number of boutons was maximal in a narrow zone in SZ about 25 to 100 μm below the surface. The labeled boutons contained numerous round vesicles and predominantly pale mitochondria. They usually formed asymmetrical synapses and contacted dendrites or boutons. Occasionally, labeled boutons were observed whose cytological features were different from those generally associated with retinotectal axons. In general, labled boutons in SZ contained fewer mitochondria than those from SGS.Labeled myelinated axons were found throughout SGS, in the lowest part of SZ, and in SO. In upper and middle SGS they were small while in lower SGS and SO also large fibers were found.
Somatostatin in the caudal spinal cord: An immunohistochemical study of the spinal centers involved in the innervation of pelvic organs
Authors: Schrøder Henrik Daa 
Published: May 2005

AbstractThe distribution of somatostatin in the rat spinal cord was studied immunohistochemically with particular reference to the localization in the caudal centers that innervate the pelvic organs. For detailed studies of the laminar distribution of somatostatin the combination of immunohistochemistry and acetylcholinesterase enzyme histochemistry was employed.Deafferentation experiments were carried out to shed light on the origin of the somatostatin‐containing axons. These experiments showed that the bulk of the spinal somatostatin has a spinal origin.The structures showing somatostatin immunoreactivity formed a distinct and detailed pattern. The marginal layer and particularly the substantia gelatinosa contained a dense immunoreactivity in terminallike structures. Such structures were also found in the reticular nucleus, along the medial border of the dorsal horn, and in the nucleus of the dorsolateral funiculus. In all of these regions somatostatin‐positive cell bodies were also observed.In the intermediate gray matter stained terminals were present around the central canal in a varying number. The most prominent stainability was found in the lumbosacral transition zone. Many terminals were also observed in the sacral parasympathetic intermediolateral nucleus. In contrast, very few appeared in the sympathetic nuclei. Immunoreactive somata were present in the surroundings of the central canal at all levels. Moreover, positive neurons were found in the intermediolateral nucleus of the sacral cord. By combined retrograde tracing and immunohistochemistry the existence of somatostatin‐containing parasympathetic visceromotoneurons was ascertained. Corresponding to this, somatostatin‐positive terminals were seen in the major pelvic ganglion.The ventral horn generally contained few terminals, and the density was particularly low in the motoneuron neuropil. However, a dense somatostatin network was found in the sixth lumbar segment in relation to the neurons in Onuf's nucleus X complex, the nucleus that innervates the small pelvic muscles including the striated sphincters.It is concluded that somatostatin, besides being involved in the processing of sensory input, serves an important motor task, that of taking part in the complex control of the pelvic organs and their associated striated muscles.
Axoaxonal synapse location and consequences for presynaptic inhibition in crustacean motor axon terminals
Authors: Atwood H. L. , Stevens J. K. , Marin L. 
Published: May 2005

AbstractSerial sections were made of several excitatory nerve terminals in the stretcher muscle of the spider crab, Hyas areneus, to document locations of inhibitory axoaxonal synapses responsible for physiologically powerful presynaptic inhibition. The excitatory terminals are varicose, often with small side branches joined to the main terminal by thin bottlenecks. Axoaxonal synapses occur predominantly on the varicosities, both primary and secondary, with a smaller number on bottlenecks. The distribution is often clustered at specific locations of the excitatory terminal.An electrical model was employed to ascertain the effectiveness of axoaxonal synapses at different locations on the terminal. The model plotted the potential distribution along the terminal with or without a synaptic conductance equivalent to one quantal unit of inhibitory transmitter action. It was assumed from recent work that terminal varicosities are not completely invaded by an action potential. The model predicts that large drops in potentials originating in the main axon occur in the terminals during inhibitory transmitter action, with the largest total drop produced by axoaxonal synapses on the terminal varicosities. The effectiveness of inhibitory action is critically dependent on the dimensions and internal resistance of the bottlenecks. Thus, the geometrical features of the excitatory terminal appear to play a key role in effectiveness of presynaptic inhibition.
Sizes, laminar and topographic origins of cortical projections to the major divisions of the red nucleus in the monkey
Authors: Humphrey D. R. , Gold R. , Reed D. J. 
Published: May 2005

AbstractThe retrograde transport of horseradish peroxidase was used to study the topographic and laminar origins of the cortical projections to the parvocellular and the magnocellular divisions of the red nucleus in Macaca mulatto and Macaca fascicularis. Approximately 90% of the corticorubral projection is directed to the parvocellular division of the nucleus. Corticoparvocellular division of the nucleus. Corticoparvocellular (CRp) neurons are pyramidally shaped, are smaller in size than corticospinal neurons, and are more numerous. They are found principally in sublamina Va of cytoarchitectonic areas 4 and 6, and in moderate quantities in sublamina Vb of posterior area 8 and area 5. In areas 4 and 6, the cells are grouped in clusters of three to 15 neurons each and are arranged in cellular bands of varying rostrocaudal thickness which course mediolaterally. With respect functionally define zones, CRp neurons are found through the supplementary motor area and the precentral motor cortex. In addition, they are found in parts of area 5, 6, and 24 that project to these cortical motor areas, and that are thought to have “premotor” or movement programmming functions.The corticomagnocellular (CRm) projection arises principally from cells in sublamina Vb of the precentral arm and leg areas (area 4), and from adjacent parts of posterior area 6. CRm cells are pyramidally shaped and their size distribution is bimodal, with peaks that correspond, respectively, to the modal diameters of CRp and of corticospinal neurons.These result and those of previous studies that CRm neurons are involved principally in the control of hand and foot movements, with little effect on proximal musculature. The massive CRp projection, however, is clearly part of a large cerebrocerebellar communications system, with motor and/or movement programming functions that have yet to be clearly defined.