bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and control of the head retractor muscle in a turtle, Pseudemys (trachemys) scripta: I. Architecture and histochemistry of single muscle fibers
Authors: Callister R. J. , Callister R. , Peterson E. H. 
Published: January 2005

AbstractWe are using the head retractor muscle (RCCQ) of a turtle, Pseudemys scripta, to analyze the neuromuscular mechanisms by which organisms vary the force and timing of muscle contraction. Previously we demonstrated that RCCQ comprises three histochemically defined fiber types: fast glycolytic (Fg), fast oxidative glycolytic (FOG), and slow oxidative (SO). In the present paper we report the 1) architectural features of single muscle fibers in RCCQ, including their lengths, diameters, and taper characteristics, 2) histochemical profiles of single muscle fibers, and 3) quantitative relations between our architectural and histochemical variables.Single fibers in RCCQ exhibit an order of magnitude variation in length (4–60 mm). Approximately 40% span the full muscle. The remaining fibers generally attach to bone or tendon at one end, and the other end tapers intramuscularly; rarely a fiber may taper at both ends. The maximum (untapering) diameters of single fibers are bimodally distributed, forming two diameter classes. Fibers also vary in the percentage of their total length that tapers and in the shape of the tapering region. Large diameter muscle fibers generally are longer and have shorter, more blunted tapers than small diameter fibers. The large diameter fibers are almost all Fg types; these fibers have a median diameter of 59.3 m̈m, and they account for approximately 60% of total fibers in RCCQ. FOG and SO fibers generally have small diameters (median: 32.5 m̈m and 35.8 m̈m), and they typically account for 30% and 10% of total fibers. We use these relations to draw inferences about the attachments and architecture of glycolytic (Fg) and oxidative (FOG, SO) fiber types.Taken together, our data suggest that single muscle fibers in RCCQ may be architecturally as well as histochemically specialized to perform different roles in head retraction. In the accompanying paper we report the efferent innervation of these fibers and consider some of the neural control problems posed by these diverse fiber types. © 1992 Wiley‐Liss, Inc.
Variation in form and axonal termination in the nucleus of the optic tract of the rat: The medial terminal nucleus input on neurons projecting to the inferior olive
Authors: Van Der Togt Chris , Van Der Want Johannes 
Published: January 2005

AbstractThe nucleus of the optic tract (NOT) and the medial terminal nucleus (MTN) are two primary visual nuclei that take part in circuits sustaining the optokinetic reflex, The morphology of rat NOT cells projecting to the inferior olive (NOT‐IO neurons) and their terminal input, specifically terminals originating from the MTN, have been studied in the rat at the light and electron microscopical level. This has been done by means of combined retrograde tracing from the inferior olive and anterograde tracing from the MTN to the NOT. The area containing MTN terminal fibers and the area occupied by NOT‐IO neurons has been found to match. This matched distribution provides a more detailed description of the NOT, with possible functional implications. Identified NOT‐IO neurons demonstrate considerable variability in their dendritic branching pattern and have been found to include all neuronal cell types described for the NOT. The dendritic branching pattern of NOT‐IO cells could be related to the orientation and distribution of the NOT's major afferent fiber systems. NOT‐IO neurons receive a variable MTN and retinal input onto their somata, comparable to other cells in the NOT. With exception of the superficial part of the NOT, NOT‐IO neurons with the most MTN terminals were found dorsally in areas containing large numbers of MTN terminals. In conclusion, although NOT‐IO neurons are uniform with respect to their receptive field properties, they vary considerably with respect to the shape of the cell body, dendritic branching pattern, and terminal input. This means that morphological characteristics of NOT‐IO neurons have no predictive value with regard to their receptive field properties. © 1992 Wiley‐Liss, Inc.
Immunohistochemical study on development of serotonin‐, substance P‐, and enkephalin‐positive fibers in the rat spinal motor nucleus
Authors: Ozaki Shigeru , Kudo Norio , Okado Nobuo 
Published: January 2005

AbstractDevelopmental changes in the coexistence of serotonin and substance P/enkephalin within single fibers of lamina IX of the rat lumbar spinal cord were examined by the use of a double‐labelling immunohistochemical technique. On postnatal day (P) 0, 65.0% of immunoreactive varicosities contained only serotonin, and 21.3% of them had both serotonin and substance P. The coexistent ratio of serotonin and substance P in single fibers increased with development: 61.9% of serotonin positive varicosities co‐contained substance P on P28, similar to the ratio found in adult animals (67.4%). The ratios of varicosities containing only substance P remained the same from PO to adult stage (about 15%). Enkephalin positive immunoreactivity was not co‐localized with serotonin positive varicosities at any stage of development.Although numerous serotonin positive fibers were found in lamina IX, only a few substance P and enkephalin positive fibers were observed in the same area on P0. The density of serotonin positive varicosities increased slightly by P28, whereas substance P and enkephalin positive fibers increased considerably by this age. Between P28 and the adult stage, the density of serotonin positive fibers decreased by about 50%.The cross sectional area of axonal varicosities containing serotonin‐ and substance P‐like immunoreactivity was similar in both P0 and adult animals, whereas that of enkephalin positive fibers was different.We also examined the coexistence of serotonin and substance P within single neurons of the caudal raphe nuclei in P7 and adult animals, and found that the coexistent ratio significantly increased with development. © 1992 Wiley‐Liss, Inc.
Monoaminergic systems in the brainstem and spinal cord of the turtle Pseudemys scripta elegans as revealed by antibodies against serotonin and tyrosine hydroxylase
Authors: Kiehn Ole , Rostrup Egill , Møller Morten 
Published: January 2005

AbstractWith the aim of gaining more insight into the monoaminergic regulation of spinal motor systems in the turtle, we have studied the distribution of 5‐HT (5‐HTir) and tyrosine hydroxylase immunoreactivity (THir) in the brainstem and spinal cord of Pseudemys scripta elegans. 5‐HTir cell bodies were located in the midline in nucleus raphe inferior, nucleus raphe superior, and laterally in nuclei reticularis superior and inferior and nucleus reticularis isthmi. THir cell bodies were located in the commissural nucleus, nucleus tractus solitarii, the locus coeruleus‐subcoeruleus complex, nuclei reticularis superior and inferior, the pretectal area, and substantia nigra, 5‐HTir and THir tracts were found in lateral and ventral bundles superficially in the brainstem.5‐HTir fibers in the spinal cord were located in a large dorsolateral and a smaller ventrolateral tract. In the gray matter, a high concentration of 5‐HTir fibers were observed in areas I–IV and in the lateral motor column of cervical and lumbar enlargements. Areas V–VIII and area X were less intensively innervated, with the lowest fibre concentration in areas VII–VIII and area X. Throughout the spinal cord, THir nerve fibres were located in the same areas but with a lower density. Small bipolar 5‐HTir and THir cell bodies were found ventromedially to the central canal especially in cervical and lumbosacral segments. Large THir cells were found in area IX in the caudal sacral and coccygeal spinal cord. THir cerebrospinal fluid‐contacting cells were also found in the most caudal part of the brainstem and the upper cervical spinal cord.The well developed spinal 5‐HT system and the less developed THir system provides an anatomical explanation for the monoaminergic modulation of turtle motoneuron membrane properties, which has been observed in electrophysiological experiments. © 1992 Wiley‐Liss, Inc.
Cellular localization of the neural cell adhesion molecule L1 in adult rat neuroendocrine and endocrine tissues: Comparisons with NCAM
Authors: Grant Nancy J. , Leon Catherine , Aunis Dominique , Langley Keith 
Published: January 2005

AbstractThe tissue distribution and cellular localization of the neural cell adhesion molecule L1 was determined by immunocytochemistry at the optical and ultrastructural levels in adult rat neuroendocrine tissues and pancreatic endocrine cells. L1 was found to be abundant in the neurohypophysis but undetectable in the rest of the pituitary gland. It was barely detectable in the normal rat endocrine pancreas, but a rat pancreatic insulinoma cell line was found by immunofluorescence to express low levels of L1. In the adrenal medulla, it was present on a sub‐population of chromaffin cells and its density appeared to be lower on surfaces exposed to the extracellular matrix. Double immunolabelling showed this sub‐population to consist of noradrenergic chromaffin cells. Adrenergic chromaffin cells were found not to express L1. In addition, the tissue distribution and cellular localization of NCAM mRNAs was determined by in situ hybridization, extending our previous studies on the cellular expression of NCAM proteins in endocrine and neuroendocrine tissues. This confirmed that the NCAM message has a wider cellular distribution than L1 within the hypophysis and the adrenal gland. In addition to secretory cells, L1 immunoreactivity was detected in glial cells, in particular in the pituicytes of the neurohypophysis, which further distinguishes them from astrocytes, their counterparts in the central nervous system. These data are discussed in terms of the different embryological origins of the various endocrine tissues examined and also in terms of the specific design constraints imposed on these tissues during their development. © 1992 Wiley‐Liss, Inc.
Distribution of modulatory inputs to the stomatogastric ganglion of the crab, Cancer borealis
Authors: Coleman Melissa J. , Nusbaum Michael P. , Cournil Isabelle , Claiborne Brenda J. 
Published: January 2005

AbstractThe pyloric and gastric mill neural networks in the crustacean stomatogastric ganglion receive modulatory inputs from more anteriorly located ganglia via the stomatogastric nerve. In this study we employed biocytin backfilling and immunostaining, as well as electron microscopy, to determine the origin of these inputs in the crab, Cancer borealis. Fiber counts from electron micrographs of sections through the stomatogastric nerve showed that this nerve contains 55–60 medium to large diameter fibers (1–13 m̈m). These fibers were individually wrapped by several layers of membrane, presumably glial in origin. There was also a single cluster of jointly wrapped, small diameter (< 1 m̈m) fibers that may originate from peripheral sensory somata. Biocytin backfills revealed that approximately two thirds of the individually wrapped fibers in this nerve originate from somata in the other three ganglia of the stomatogastric nervous system, including the paired commissural ganglia and the single oesophageal ganglion. There were approximately 20 biocytin‐labeled somata in each commissural ganglion and 3 somata in the oesophageal ganglion. An additional ten somata were localized to the stomatogastric ganglion itself. This accounts for nearly all of the medium to large diameter fibers in the stomatogastric nerve. We used double‐labeling with backfills and immunocytochemistry to determine that there are two proctolin‐immunoreactive neurons and four FMRFamide‐like immunoreactive neurons among the biocytin‐labeled neurons in each commissural ganglion. Both peptides modulate neural network activity in the stomatogastric ganglion. Thus, our results demonstrate that most inputs to the stomatogastric ganglion originate from somata in the commissural ganglia, and that at least one third of these neurons contain a peptide known to modulate network activity in the stomatogastric ganglion. © 1992 Wiley‐Liss, Inc.
Immunocytochemical localization of kynurenine aminotransferase in the rat striatum: A light and electron microscopic study
Authors: Roberts Rosalinda C. , Du Fu , McCarthy Kathleen E. , Okuno Etsuo , Schwarcz Robert 
Published: January 2005

AbstractKynurenine aminotransferase is the biosynthetic enzyme for kynurenic acid, an antagonist of excitatory amino acid receptors. Because of the possible role of kynurenic acid in basal ganglia diseases, the distribution of kynurenine aminotransferase immunoreactivity was examined in the adult rat striatum at the light and electron microscopic levels. Kynurenine aminotransferase immunoreactivity was detected in glial cells and in neurons. The preadsorption control vastly reduced or eliminated specific staining at both the light and electron microscopic levels. Kynurenine aminotransferase positive glial cells were abundant and contained a robust and homogeneous distribution of reaction product in both the nucleus and cytoplasm. The majority of neurons, both medium and large, were immunostained and exhibited granular kynurenine aminotransferase immunoreactivity in the cytoplasm of somata and proximal dendrites. At the ultrastructural level, kynurenine aminotransfease immunoreactive astrocytic processes were apparent throughout the neuropil where they often encircled capillaries and surrounded axospinous synapses. Reaction product was associated with the cytoplasmic matrix, filaments, rough endoplasmic reticulum, and the nucleus. In neurons, the majority of label occurred in round membrane‐bound cytoplasmic organelles located adjacent to the Golgi apparatus, rough endoplasmic reticulum, and the cell or nuclear membranes. Cisternae and vesicles were identifiable in some of the labeled profiles. Polyribosomes and rough endoplasmic reticulum were also labeled. These data provide an anatomical basis for biochemical studies that have suggested the presence of striatal kynurenine aminotransferase in both astrocytes and neurons. © 1992 Wiley‐Liss, Inc.
Development of callosal connections in the sensorimotor cortex of the hamster
Authors: Norris Carolyn R. , Kalil Katherine 
Published: January 2005

AbstractTo investigate the development of corpus callosal connectivity in the hamster sensorimotor cortex, we have used the sensitive axonal tracer 1,1 dioctadecyl‐3,3,3′,3′, tetramethylindocarbocyanine perchlorate (DiI), which was injected either in vivo or in fixed brains of animals 3‐6 days postnatal. First, to study changes in the overall distribution of developing callosal afferents we made large injections of DiI into the corpus callosal tract. We found that the anterogradely labeled callosal axons formed a patchy distribution in the contralateral sensorimotor cortex, which was similar to the pattern of adult connectivity described in earlier studies of the rodent corpus callosum. This result stands in contrast to previous retrograde studies of developing callosal connectivity which showed that the distribution of callosal neurons early in development is homogeneous and that the mature, patchy distribution arises later, primarily as a result of the retraction of exuberant axons. The initial patchy distribution of callosal axon growth into the sensorimotor cortex described in the present study suggests that exuberant axons destined to be eliminated do not enter the cortex. In addition, small injections of DiI into developing cortex resulted in homotopic patterns of callosal topography in which reciprocal regions of sensorimotor cortex are connected, as has been shown in the adult.Second, to study the radial growth of callosal afferents we followed the extension of individual callosal axons into the developing cortex. We found that callosal axons began to invade the contralateral cortex on about postnatal day 3, with little or no waiting period in the callosal tract. Callosal afferents then advanced steadily through the cortex, never actually invading the cortical plate but extending into layers on the first day that they could be distinguished from the cortical plate. The majority of callosal axons grew radially through the cortex and did not exhibit substantial branching until postnatal day 8, the age when the cortical plate disappears and callosal afferents reach the outer layer of cortex. This mode of radial growth through cortex prior to axon branching could serve to align callosal afferents with their radial or columnar targets before arborizing laterally. © 1992 Wiley‐Liss, Inc.
Sympathetic nerves in adult rats regenerate normally and restore pilomotor function during an anti‐NGF treatment that prevents their collateral sprouting
Authors: Gloster Andrew , Diamond Jack 
Published: January 2005

AbstractWe have used nerve growth factor (NGF) administration to study the NGF dependency of the reinnervation of denervated skin by sympathetic nerves inthe adult rat. Sympathetic pilomotor fields were revealed by electrical stimulation of selected dorsal cutaneous nerves; the affected skin rapidly assumed a “gooseflesh” appearance, sharply demarcated from surrounding unstimulated skin. Examined 2‐5 days after section of neighboring nerves, the “isolated” pilomotor field of the spared nerve was found to be coextensive with an area of amine‐fluorescent fibers that were associated with pilomotor muscles and blood vessels. After its isolation, a pilomotor field begins to expand into the surrounding deprived territory, reaching a maximum size at approximately 40 days. Fluorescence studies confirmed that new sympathetic fiber growth had occurred into the expanded regions of such fields. Daily injections of polyclonal anti‐NGF serum completely prevented these pilomotor field expansions. Following termination of the anti‐NGF treatment, expansion proceeded normally. Finally, if the onset of anti‐NGF treatment was delayed until pilomotor field expansion had already commenced, further expansion was halted. Regeneration of sympathetic fibers wasevoked by crushing a selected nerve. Recovery of pilomotor function in the totally denervated skin was first detected at about 20 days postcrush, and the field progressively enlarged over the next 40 days. Although the imposed NGF deprivation is known to cause a demonstrable shrinkage, and presumably atrophy, of sympathetic ganglia, the anti‐NGF treatment appeared to impair neither the restoration of a pilomotor field after nerve crush, nor its continued expansion into skin regions well beyond that originally supplied by the nerve, i.e., into territory whose invasion by collateral sprouts would have been totally prevented by the treatment. During such NGF deprivation, fluorescent regenerating fibers were visualized in the nerve trunk. We conclude that even though the regenerating and collaterally sprouting sympathetic fibers probably utilise the same degenerating dermal pathways to reach and functionally reinnervate the same denervated targets, only the collateral sprouting of the uninjured axons is dependent upon endogenous NGF. These findings extend the results described earlier for nociceptive fibers, andsuggest that the contrasting dependencies upon growth factors of sproutingand regeneration might apply throughout the adult nervous system. © 1992 Wiley‐Liss, Inc.
Translaminar deficits in the retinae of albinos
Authors: Jeffery Glen , Kinsella Brian 
Published: January 2005

AbstractThe central retina in albino mammals is poorly developed. There is a general reduction in ganglion cell density compared with the normal animal, and there are irregularities in the center to periphery gradient in ganglion cell density. It is not known whether, and if so to what extent, this abnormality is associated with deficits in other retinal layers.In this study the distribution of cells in the ganglion cell layer has been determined in horizontally sectioned eyes from pigmented and albino ferrets. This was undertaken to define the location of the region of highest cell density and the relative cell gradients around it. Detailed counts and measurements were then undertaken to determine the cell density within, and thickness of, the inner and the outer nuclear layers in these animals.All the albino animals had an abnormal distribution of cells in the ganglion cell layer in the central retina when compared with pigmented animals. The extent of this abnormality was variable. No differences between pigmented and albino animals could be found in the packing density of cells within the inner or the outer nuclear layer. However, in the pigmented animals there was a clear increase in the thickness of these layers associated with the region of highest density in the ganglion cell layer. This feature was absent in the albino animals, where the gradient in layer thickness was less marked and frequently contained irregularities. These abnormalities were most obvious in the outer nuclear layer. © 1992 Wiley‐Liss, Inc.
Electron microscopic immunocytochemical study of the distribution of parvalbumin‐containing neurons and axon terminals in the primate dentate Gyrus and Ammon's horn
Authors: Ribak Charles E. , Seress László , Leranth Csaba 
Published: January 2005

AbstractFive green monkeys were examined with light and electron microscopic preparations to explore the regional differences in the distribution of parvalbumin (PV)‐positive neurons and axon terminals in the primate hippocampus. PV‐positive neurons were mainly found in the hilus of the dentate gyrus and the strata oriens and pyramidale of Ammon's horn. In electron microscopic preparations, the PV‐positive cells displayed nuclear infoldings, intranuclear rods, a large rim of perikaryal cytoplasm with numerous organelles and both asymmetric and symmetric axosomatic synapses. One prominent PV‐positive cell type in CA1 was a large multipolar neuron that resembled the large basket cells of the neocortex. Although most PV‐positive dendrites were aspiny and postsynaptic to numerous axon terminals, some PV‐positive dendrites in the molecular layer of the dentate gyrus displayed filipodia‐like appendages with no synapses or spines that were postsynaptic to multiple axon terminals. The PV‐positive dendrites in the hilus and stratum oriens were apposed at specialized junctions that resembled gap junctions. PV‐positive axons were concentrated in the principal cell layers, and formed axosomatic, axodendritic, and axon initial segment synapses. In cases where these axons were observed to appose the surface of granule cells for a long length, only one axosomatic symmetric synapse per cell was found. In the hilus, PV‐positive axon terminals formed synapses onto thorny excrescences of spiny cells. Both semithin sections and electron microscopic preparations indicated that more PV‐positive axon terminals formed symmetric axosomatic synapses with pyramidal cells in CA2 than in CA1 and CA3. Also, CA2 displayed a unique plexus of PV‐positive axon terminals in stratum lacunosum moleculare.These results indicate that the PV‐positive hippocampal cells form a subset of GABAergic local circuit neurons, including the basket and chandelier cells. The ubiquitous finding of PV‐positive dendrites linked by gap junctions throughout the dentate gyrus and Ammon's horn adds further data to indicate that this subset of GABAergic neurons is linked electrotonically. The synaptic organization of PV‐positive neurons in the hippocampus suggests their participation in both feedback and feedforward inhibition. The PV‐positive neurons in the hippocampus are only a proportion of the basket and chandelier cells, whereas virtually all of these cells in neocortex are PV‐positive. © 1993 Wiley‐Liss, Inc.