bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glial fibrillary acidic (GFA) protein in vertebrates: Immunofluorescence and immunoblotting study with monoclonal and polyclonal antibodies
Authors: Dahl D. , Crosby C. J. , Sethi J. S. , Bignami A. 
Published: May 2005

AbstractWe report a comparative immunofluorescence and immunoblotting study of GFA protein, the subunit of glial filaments, in nonmammalian vertebrates. The study was conducted with polyclonal antibodies raised to human and shark antigen and with monoclonal antibodies isolated from mice immunized with chicken and bovine antigen. With the exception of cyclostomes, glial filaments appeared remarkably conserved in vertebrate phylogeny, both with respect to the molecular weight and immunoreactivity of their protein subunit. In most species, the antibodies decorated a single band in brain, spinal cord, and optic nerve extracts by the immunoblotting procedure. This band had the same molecular weight in the different CNS regions. With the exception of the turtle, species differences in the molecular weight of the band were not greater than those observed among mammalian vertebrates (human, bovine, and rat). However, there were some exceptional findings in fish. In goldfish and trout brain and spinal cord extracts, the antibodies decorated with the same intensity two bands. In accordance with previous immunofluorescence findings, goldfish optic nerve extracts were negative by the immunoblotting procedure. In four fishes (sea bass, tautog, trout, and scup), optic nerves reacted with the antibodies. However, the band decorated by the antibodies was higher in molecular weight than that obtained from brain and spinal cord extracts. Glial fibers were demonstrated by immunofluorescence in the brain, spinal cord, optic nerve, and retina of most species studied. In amphibia immunofluorescent structures were comparatively few, probably accounting for the negative results by immunoblotting. A comparative immunohistological study of the cerebellum showed the presence of perpendicular glial fibers in the molecular layer of most species examined. Birds and amphibia were different in this respect. Bergmann glia in chicken were GFA negative. In the frog and the toad, immunofluorescent fibers in the molecular layer of the cerebellum were haphazardly oriented. Ependymal radial glia was GFA‐negative in the cerebellum of subavian vertebrates. Antisera raised in rabbit to shark GFA protein reacted with the same bovine GFA fragments recognized by polyclonal and monoclonal antibodies raised to human and bovine antigens, respectively, i.e., 30‐kDa N‐bromosuccinimide fragment (tryptophan cleavage); 35‐kDa 2‐nitro‐5‐thiocyanobenzoic acid fragment (cysteine cleavage); 18‐kDa cyanogen bromide fragment (methionine cleavage). Conversely, the chicken GFA monoclonal antibodies selected for this study only reacted with noncleaved protein.
A quantitative analysis of the geometry of cat motoneurons innervating neck and shoulder muscles
Authors: Rose P. K. , Keirstead S. A. , Vanner S. J. 
Published: May 2005

AbstractThe geometry of the somata and dendritic trees of motoneurons innervating neck and shoulder muscles was investigated by using intracellular injections of HRP. In general, these motoneurons did not belong to a homogeneous population of motoneurons. Differences in average primary dendritic diameter, number of primary dendrites, and other measures of dendritic tree size were found between different neck and shoulder motoneuron groups. Several indices of proximal dendritic tree size (number of primary dendrites, sum of dendritic diameters, Rall's dendritic trunk parameter, and the sum of dendritic holes) were weakly correlated with the diameter or surface area of the soma. Some of these correlations depended on the muscle supplied by the motoneuron.The total combined dendritic length ranged from 66,660 to 95,390 μm. There was a weak, but positive, correlation between the diameter of primary dendrites and combined dendritic length. This relationship varied from motoneuron to motoneuron.The diameters of all dendrites of three trapezius motoneurons were examined in detail. The total dendritic surface area examined ranged from 415,000 to 488,100 μm2 and represented approximately 99% of the total neuronal surface area. Last‐order dendrites showed a high degree (39.9%) of taper. Dendritic tapering, by itself, was a major factor in the decrease of the (sum of dendritic diameters)3/2 measured at progressively distal sites from the soma. Although few parent and daughter dendrites obeyed the “three‐halves law,” the average exponent was 1.57. The diameters of primary dendrites and dendritic surface area were weakly correlated. The correlation between dendritic diameter and combined dendritic length or surface area improved if the weighted average of the diameter of second‐order dendrites was used as a measure of dendrite size. Second‐order dendrites, whose branches terminated in different regions of the spinal cord, showed different relationships between dendritic diameter and combined dendritic length or surface area.Comparisons between the motoneurons examined in the present study and motoneurons innervating other muscles indicate that, although all spinal motoneurons share several common features (e.g., long dendrites, dendritic tapering), each motoneuron group has a set of unique features (e.g., soma shape, relationship between primary dendrite diameter and dendritic surface area). Thus, the rules governing motoneuron dendritic geometry are not fixed but depend on the species of the motoneuron.
Topography of the goldfish optic tracts: Implications for the chronological clustering model
Authors: Springer Alan D. , Mednick Adam S. 
Published: May 2005

AbstractBoth the dorsal and ventral optic tracts of goldfish have similar shapes when they are sectioned perpendicularly to their longitudinal axes. Each tract is pear‐shaped, consisting of a narrow and a deep apex, a wide mid‐span, and a progressively curved and tapered superficial base. The tracts differ in that the apex of the dorsal optic tract points caudally, while the apex of the ventral optic tract points medially. In addition, upon segregating from the main optic tract, the dorsal optic tract courses dorsally while the ventral optic tract courses caudally. Thus, the two optic tracts have similar shapes and are orthogonal to one another.The topography of the retinal fibers within the optic tracts was determined either by ablating part of the retina and subsequently filling the axons from the intact hemiretina with cobaltous‐lysine or by applying cobaltous‐lysine to a slit in the retina. Both optic tracts contain a similar arrangement of optic fibers. Axons of central retinal ganglion cells (RGCs) are in the apex of each tract and optic fibers of peripheral RGCs are located along the base of each tract. Axons of temporal RGCs are located dorsally in the ventral optic tract and laterally in the dorsal optic tract, while axons of nasal RGCs are located ventrally in the ventral optic tract and medially in the dorsal optic tract. These findings indicate that the optic axons are organised as laminae. Deeper laminae contain the axons of older annuli of RGCs and superficial laminae contain the axons of younger annuli of RGCs. This type of chronological organization appears to be consistent across vertebrates. Furthermore, the organization of the optic axons across laminae is constant. Temporal RGC axons are at one end, and nasal RGC axons are at the other end of each lamina. These results are consistent with those found in other nonmammalian vertebrates. Moreover, these findings preclude the possibility that the axons of a half‐annulus of RGCs in goldfish travel together as a fascicle in the optic tracts that is continuous with a fascicle in the stratum opticum of the tectum.The general position of the fibers from different retinal quadrants in the optic tracts may lead to a probabilistic determination as to which part of the tectum they innervate. Namely, temporal RGC axons, destined for the rostral tectum, are situated in the optic tracts so that they are close to the rostral tectum. Nasal RGC axons, destined for caudal tectum, are situated in the optic tracts so thay they are farthest from the rostral tectum. Thus, axons of nasal, RGCs have a lower probability of innervating the rostral tectum.
Observations on the afferent and efferent organization of the vagus nerve and the innervation of the stomach in the squirrel monkey
Authors: Gwyn D. G. , Leslie R. A. , Hopkins D. A. 
Published: May 2005

AbstractHorseradish peroxidase was injected into the cervical vagus nerve or stomach wall of adult squirrel monkeys. Following cervical vagus nerve injections, labelled afferent fibres were present in the tractus solitarius and labelled fibres and terminals were present in medial and lateral parts of the nucleus of the tractus solitarius (NTS) ipsilaterally. Afferent labelling was also seen in the ipsilateral commissural nucleus and in the area postrema. Labelling was present contralaterally in caudal levels of the medial parts of the NTS, in the commissural nucleus, and in the area postrema. Afferent projections to the ipsilateral pars interpolaris of the spinal trigeminal nucleus and to the substantia gelatinosa of the C1 segment of the spinal cord were also labelled. Following injections of HRP into the anterior and posterior stomach walls, the tractus solitarius was labelled bilaterally. Afferent labelling was concentrated bilaterally in the dorsal parts of the medial division of the NTS, i.e., in the subnucleus gelatinosus, and in the commissural nucleus. The regions of NTS immediately adjacent to the tractus solitarius were largely unlabelled.Injections of HRP into the cervical vagus nerve resulted in heavy retrograde labelling of neurons in the ipsilateral dorsal nucleus of the vagus (DMX) and in the nucleus ambiguus (NA). In addition a few neurons were labelled in the intermediate zone between these two nuclei. Retrogradely labelled neurons were also present in the nucleus dorsomedialis in the rostral cervical spinal cord and in the spinal nucleus of the accessory nerve. Injections of HRP into the left cricothyroid muscle in two cases resulted in heavy retrograde labelling of large neurons in the left NA. Following stomach wall injections of HRP retrograde labelling of neurons was seen throughout the rostrocaudal and mediolateral extent of the DMX; there was no apparent topographical organization of the projection. In these cases, a group of labelled smaller neurons was found lying ventrolateral to the main part of the NA through its rostral levels.This study in a primate indicates that a large vagal afferent projection originates in the stomach wall and terminates primarily in the subnucleus gelatinosus of the NTS and in the commissural nucleus with a distribution similar to that described previously in studies in several subprimate mammalian species. The present results and those of other studies suggest some degree of segregation of visceral input within different subnuclei of the NTS. In addition, the investigation shows that while the majority of neurons which supply the stomach are located in the DMX, a small number are found in the ambiguus complex.
Development of the trochlear nucleus in quail and comparative study of the trochlear nucleus, nerve, and innervation of the superior oblique muscle in quail, chick, and duck
Authors: Sohal G. S. , Knox T. S. , Allen J. C. , Arumugam T. , Campbell L. R. , Yamashita T. 
Published: May 2005

AbstractThe present study was undertaken to examine the development of the trochlear nucleus in quail and to compare the mature trochlear nucleus, nerve, and their sole target of innervation, the superior oblique muscle, in quail, chick, and duck. Study of the trochlear nucleus in quail from embryonic day 5 through hatching shows a maximum of 1,248 neurons on embryonic day 10 followed by spontaneous degeneration of 40% of the neurons between days 10 and 16. Previous studies have shown that although the initial and final number of neurons is different in chick and duck, the magnitude of trochlear cell loss in both species is about 40%. This study shows the average number of neurons in the nucleus of quail, chick, and duck, 2 weeks post‐hatching, to be 658, 743 and 1,459, respectively. Fiber counts in the trochlear nerve from electron micrograph montages at the same period indicated a ratio of about 1:1 between neurons and axons. While a majority of the fibers in these nerves are myelinated, an average of 3–6% of the fibers are unmyelinated. The nucleus in the quail not only contains the smallest number of neurons but it also innervates the smallest muscle in terms of total number of muscle cells and endplates. However, the opposite relationship does not hold true. The nucleus in duck contains the largest number of neurons, yet the largest number of muscle cells and endplates were found in the chick. The ratios between the neurons and muscle cells as well as between neurons and endplates are about the same in quail and duck. These ratios are much higher in the chick, reflecting the relatively small neuron pool destined for a relatively large target. In spite of variations in the number of neurons, muscle fibers, and endplates the average number of endplates per muscle fiber is relatively constant among the three species.
Early estrogen‐induced nuclear changes in rat hypothalamic ventromedial neurons: An ultrastructural and morphometric analysis
Authors: Jones Kathryn J. , Pfaff Donald W. , McEwen Bruce S. 
Published: May 2005

AbstractAlterations in the fine structure of nuclei of ventromedial hypothalamic neurons in ovariectomized (OVX) rats after either a 2‐hour exposure to estradiol (E2) or a discontinuous exposure (2 hours E2/7 hours off/2 hours E2), previously shown sufficient for female rat sexual behavior (Parsons et al., 1982a), were examined with the electron microscope. Morphometric measurements of nucleolar, nuclear, and somal areas, and nuclear shape and perimeter were accomplished at the light microscope level.After 2 hours of E2, the appearance of the nucleoplasm was altered, with a decrease in the small, scattered clumps of heterochromatin. Nuclear shape appeared dramatically altered from nonspherical, invaginated profiles toward spherical, smooth profiles. Nucleolar, nuclear, and somal hypertrophy were evident. In addition, stacked rough endoplasmic reticulum was present more frequently in E2‐treated than control OVX neurons. After the discontinuous (2 hours/7 hours/2 hours) E2 treatment, progressive loss of small clumps of heterochromatin along the nuclear envelope as well as in the nucleoplasm had occurred. Decrease in a large heterochromatin clump along the nuclear envelope was correlated with an increase in nucleolus‐associated chromatin. As determined by a distribution analysis, these estrogen‐induced nuclear changes co‐occurred more frequently than predicted from mutual independence.These findings, the marked co‐occurrence of E2‐induced changes in 30% or more of the cells, and the differences between the 2‐hour E2 and the 2‐hour/7‐hour/2‐hour group are consistent with a cascade of cell nuclear changes in the first few hours after estrogen onset.
Organization of motoneuronal pools in the rostral spinal cord of the sea robin, Prionotus carolinus
Authors: Finger Thomas E. , Kalil Katherine 
Published: May 2005

AbstractThe functional organization of the motoneurons in the spinal cord of the sea robin, Prionotus carolinus, was studied by means of retrograde transport of horseradish peroxidase (HRP). This species has a complex pectoral apparatus which includes not only a webbed fin, but also three independently mobile fin rays.The motoneurons in the rostral spinal cord fall into two longitudinal columns: dorsal and ventral. The motoneurons of the ventral column innervate the appendicular musculature of the pectoral apparatus.Within the ventral motor column of the rostral spinal cord, four distinct motoneuronal pools were found. The largest pool is situated at the rostral‐most end of the spinal cord and contains the motoneurons that innervate the musculature of the webbed pectoral fin. The motoneurons that innervate the fin rays are located in sequentially more posterior pools so that the antero‐ventral fin ray is controlled by motoneurons situated farthest caudally. The somatotopic arrangement exactly corresponds to the sensory somatotopy determined previously. Furthermore, each fin ray has its sensory representation in a unique accessory spinal lobe which is connected in a reflex fashion to the motoneuronal pool that provides motor output to the same fin ray.
Peripheral and central oculomotor organization in the goldfish, Carassius auratus
Authors: Graf Werner , McGurk James F. 
Published: May 2005

AbstractPeripheral and central oculomotor organization was studied in the goldfish. The sizes of the extraocular muscles were quantified by counting the fibers contained in a given muscle and by area measurements of the cross‐sectional surfaces. All the muscles were of approximately similar size. Kinematics were determined by electrical stimulation of a given muscle. The macroscopic appearance and kinematics of the muscles had the characteristics of other lateral‐eyed animals (e.g., rabbit). Locations of extraocular motor neurons wert found by retrograde transport of horseradish peroxidase (HRP) following injections into individual extraocular muscles. The eye muscles were innervated by four ipsilateral (lateral rectus, medial rectus, inferior oblique, inferior rectus) and two contralateral (superior rectus, superior oblique) motor neuron pools. The oculomotor nucleus was found in the midbrain, at the level of the caudal zone of the inferior lobe of the hypothalamus. Inferior rectus motor neurons were located drosally in the oculomotor nucleus, whereas medial rectus, superior rectus, and inferior oblique motor neurons were intermingled in its more caudal portions. All labelled cells were located dorsally and medially to the medial longitudinal fasciculus (MLF) in close proximity to either the floor of the ventricle or the midline region. Occasionally, motor neurons were interspersed within the fiber bundles of the MLF or the exiting fibers of the oculomotor nerve. The trochlear nucleus, containing superior oblique motor neurons, was found in the immediate lateral and caudal neighborhood of the oculomotor nucleus, where its rostral border overlapped with the caudal border of the latter. The abducens nucleus, containing lateral rectus motor neurons, was located in the posterior brainstem in the neighborhood of the vestibular nuclear complex. This nucleus was divided into a rostral and a caudal portion. The axons of ipsilaterally projecting motor neurons headed toward their respective nerve roots via the shortest possible route, as did the axons of superior rectus motor neurons, which crossed the midline without detour to enter the contralateral oculomotor nerve. In contrast, trochlear motor neuron axons arched around the dorsal aspect of the ventricle through the cerebellar commissure to reach the contralateral trochlear nerve. The morphology of individual motor neurons was visualized by intrasomatic injection of HRP. Cell somata had oblong shapes, and their large dendrites were oriented laterally and ventrally. The axons did not collateralize within the midbrain region or the oculomotor nerve as far as they could be traced. The oculomotor system of the goldfish is similar to that found in other teleosts and higher vertebrates, displaying characteristics of an animal whose eye movements cover all regions of its external environment.
Transient tectogeniculate projections in neonatal kittens: An autoradiographic study
Authors: Stein Barry E. , McHaffie John G. , Harting John K. , Huerta Michael F. , Hashikawa Tsutomu 
Published: May 2005

AbstractBy using anterograde transport autoradiography, the present experiments demonstrated that the pattern of tectogeniculate projections in young (birth–14 postnatal days) kittens is strikingly different from that present in adult cats. Rather than being confined to the ventral C laminae, the neonatal projection extended across all layers of the lateral geniculate nucleus. This projection, like that in the adult cat, originates from cells in superficial laminae and is visuotopically organized. Thus, labeling only a portion of the superior colliculus with tritiated leucine produced a topographically appropriate strip of labeling in the ipsilateral lateral geniculate nucleus that encompassed all laminae and was especially dense in all interlaminar zones. Transported label also invaded the medial interlaminar nucleus (MIN).The loss of tectogeniculate projections in the neonate from MIN and the dorsal laminae and interlaminar zones of the lateral geniculate nucleus does not appear to begin until 1–2 weeks postnatal. Once initiated, however, the process is nearly completed by 21 days postnatal. It is not yet known whether the loss of these “anomalous” projections is due to the pruning of axonal collaterals, cell death, or a combination of the two processes. However, by comparing these data with those from other laboratories, it does appear that the loss of tectogeniculate projections depends on the presence of the two eyes and may reflect the differential laminar distribution of W‐, X‐, and Y‐cell types. The protracted postnatal anatomical maturation of tectogeniculate projections differs substantially from the earlier maturing patterns apparent in all other tectofugal pathways.
An HRP‐TMB ultrastructural study of rubral afferents in the rat
Authors: Naus C. G. , Flumerfelt B. A. , Hrycyshyn A. W. 
Published: May 2005

AbstractThe projections from the deep cerebellar nuclei and the sensorimotor cortex to the red nucleus were studied in the rat using anterograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (HRP‐WGA). The anterogradely transported HRP‐WGA was visualized ultrastructurally by using a modification of the tetramethylbenzidine (TMB) histochemical technique of Carson and Mesulam ('82). Following injection of HRP‐WGA into the sensorimotor cortex, ultrastructural examination of anterograde labeling in the ipsilateral red nucleus revealed labeled synaptic terminals located on small‐diameter dendrites of the parvocellular region. These terminals made asymmetrical contacts and contained round vesicles. HRP‐WGA placement in the nucleus lateralis resulted in anterograde labeling of synaptic terminals which made asymmetrical contacts with small‐ to medium‐sized dendrites of the parvocellular red nucleus. Similar placements in the nucleus interpositus gave rise to anterograde labeling of synaptic terminals which made asymmetrical contacts with somata and proximal dendrites of magnocellular neurons. In addition, retrograde labeling of magnocellular neurons was also observed following HRP‐WGA placements in the nucleus interpositus. Anterogradely labeled interpositorubral synaptic terminals were located on retrogradely labeled rubrocerebellar neurons. The rat red nucleus thus receives topographically organized afferents which are characterized by their specificity in location at the cellular level.