bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primary afferent projections of the major splanchnic nerve to the spinal cord and gracile nucleus of the cat
Authors: Kuo David C. , de Groat William C. 
Published: January 2005

AbstractSplanchnic afferent projections to the spinal cord and gracile nucleus were labeled following the application of HRP to the central cut end of the major splanchnic nerve. Labeled afferent fibers were detected in the ipsilateral dorsal column, in Lissauer's tract (LT), in laminae 1, 5, 7, and 10, and in the dorsal gray commissure at T1–T13 levels of the spinal cord. Afferent projections were not identified in laminae 2–4. Collaterals from LT projected ventrally along the lateral and medial margins of the dorsal horn (called lateral and medial pathways, respectively). Afferents in the lateral pathway formed small bundles, spaced rostrocaudally at intervals of 300–1,000 μm, which passed medially at the base of the dorsal horn into laminae 5, 7, and 10 and to the cortralateral spinal cord. Some afferents in the lateral pathway projected to the intermediolateral nucleus where labeled sympathetic preganglionic neurons were located. Afferents in the medial pathway entered the lateral aspect of the dorsal column and projected as a group near the midline rostrally to the medulla. The dorsal column pathway terminated in the ventral gracile nucleus in four or five clusters, each occupying a region ranging in size from 0.01–0.1 mm3and separated in the rostrocaudal axis by distances of 400–800 μm. These clusters were concentrated in the middle and caudal portions of the nucleus below the obex.A comparison of the present results with those from earlier experiments on the central projections of afferent fibers from the heart, kidney, and pelvic organs demonstrates a consistent pattern of visceral afferent termination in the thoracolumbar and sacral segments of the spinal cord. This is not unexpected, since visceral afferent pathways to different organs perform similar functions, such as the transmission of nociceptive information and the initiation of autonomic reflexes.
Quantitative electron microscopic observations on the non‐neuronal cells and lipid droplets in the posterior funiculus of the cat after dorsal rhizotomy
Authors: Franson Peter 
Published: January 2005

AbstractAdult cats were subjected to unilateral dorsal L6, L7, and S1 rhizotomies. After survival times of 1–1,552 days the different glial cell types, the perivascular cells, and the lipid droplet content of each cell type were studied quantitatively at the ultrastructural level in sections from the posterior funiculus at the L1 level.The number of astrocytes did not appear to change during the degeneration process. From 105 days postoperatively (p.o.), a marked reduction in the oligodendroglial cell population was observed. The number of microglial cells increased from 5 days p.o. onward. A large increase was observed particularly between 20 and 160 days p.o. The occurrence of pericytes was unchanged during the degeneration but the number of non‐pericytic perivascular cells/blood vessel was increased from 10 days p.o. onward.The number of lipid droplets in the microglial cells increased early during the degeneration period. Subsequently an increase in lipid droplet number was observed in the astrocytes and somewhat later also in the non‐pericytic perivascular cells. These findings have been interpreted to reflect a redistribution of lipid droplet material from the degenerating white matter to cells in the perivascular space during the observed time period.
Number and distribution of stapedius motoneurons in cats
Authors: Joseph Michael P. , Guinan John J. , Fullerton Barbara C. , Norris Barbara E. , Kiang Nelson Y. S. 
Published: January 2005

AbstractCell bodies of stapedius motoneurons were identified by retrograde transport of horseradish peroxidase (HRP) following injections into the stapedius muscle. Large injections were made in an attempt to label all stapedius motoneurons. To control for labeling of non‐stapedial neurons resulting from spread of HRP, we determined the locations of brainstem neurons labeled by HRP applied to the facial nerve, the chorda tympani nerve, the auricular branch of the vagus nerve, the tensor tympani muscle, and the cochlea. In three cats analyzed in detail, 1,133–1,178 neurons projecting to the stapedius muscle were identified. Arguments are given which suggest that in these three cats all stapedius motoneurons were labeled. The labeled stapedius neurons may all be motoneurons because they all stain positively for acetylcholinesterase and have medium–coarse Nissl bodies. Most stapedius motoneurons were located around the motor nucleus of the facial nerve. Stapedius motoneurons were also found near the descending limb of the facial‐nerve root, in the peri‐olivary neuropil, and in the reticular formation with the ascending fibers of the facial‐nerve root.
Representation of whisker follicle intrinsic musculature in the facial motor nucleus of the rat
Authors: Klein Bradley G. , Rhoades Robert W. 
Published: January 2005

AbstractRetrograde transport of wheatgerm‐agglutinin horseradish peroxidase (WGA‐HRP) and fluorescent tracers (true blue‐TB, nuclear yellow‐NY, and diamidino yellow‐DY) from isolated whisker follicles was used to define the somatotopic organization of the facial (VII) motoneurons which innervate the intrinsic follicle muscles. Motoneurons supplying these muscles were restricted almost completely to the lateral (Martin and Lodge, 1977) facial subnucleus and the motoneurons which innervated a given follicle were distributed over the entire length of this subnucleus. Cells projecting to dorsal (A‐row) follicles were located in the most lateral part of the lateral subnucleus, while those supplying ventral (E‐row) follicles were restricted to the medial part of the subnucleus. Injections of different tracers into rostral and caudal follicles within a given row revealed no somatotopic representation of the rostrocaudal axis of the whiskerpad. Additional control experiments demonstrated that some of the labelling obtained with WGA‐HRP resulted from spread of this tracer to extrinsic muscles. This was not the case with the fluorescent tracers. The results of the control experiments suggested further that a significant percentage of the motoneurons in the lateral facial subnucleus innervate only intrinsic follicle muscles.
Ontogeny of the visual system in the cuttlefish, sepiella japonica. II. Intramembrane particles, histofluorescence, and electrical responses in the developing retina
Authors: Yamamoto Masamichi , Takasu Nobuo , Uragami Itsuo 
Published: January 2005

AbstractTo study molecular and functional differentiation of photoreceptive membranes, the development of the retina in embryos of the cuttlefish, Sepiella japonica, was examined by the freeze‐fracture technique, by histofluorescence of retinal‐related protein, and by electrical responses to photic stimulation. P‐face particles in the microvillar plasma membrane of the receptor cell increased in density from about 2,000/μm2 to about 6,000/μm2 during the early stages of rhabdomere formation (from stage 31 to stage 36). The size distribution of P‐face particles in the microvillar and the cell body plasma membranes showed a similar monomodal pattern with a peak at 8 nm in diameter from stage 31 to 33. In the cell body plasma membrane, the size distribution pattern hardly changed throughout later stages, but in the microvillar membrane, the peak shifted progressively to 9 nm (stages 35 and 36) and then to 10 nm (stage 37). The histofluorescence of reduced rhodopsin was first visible at stage 36 in the layer of growing apical processes. The fluorescence of reduced retinochrome first appeared faintly at stage 40 on both sides of the basal lamina. Electroretinograms (ERGs) were first obtained at stage 34 when many microvilli appeared from the apical processes, increasing rapidly in amplitude with increase in regularity of the microvillar arrangement from stage 35 to 36. Early receptor potentials (ERPs) elicited by a bright light flash were first recorded at the earliest stage of the apical process formation (stage 30), increasing gradually in amplitude during development. The increase was correlated with an increase in the total number of P‐face particles in the microvillar membrane within the retina. These findings suggest that the P‐face particles in the microvillar membrane are associated with rhodopsin, that the receptor cells have a small amount of rhodopsin before rhabdomere formation, and that differentiation of the apical plasma membrane of the receptor cells into the functional photoreceptive membrane occurs in conjunction with its morphological differentiation into rhabdomeres.
The formation of the axonal pattern in the embryonic avian retina
Authors: Halfter Willi , Deiss Silvia , Schwarz Uli 
Published: January 2005

AbstractBoth the polarity of the axonal growth and the formation of the optic fiber pattern early in retinal morphogenesis were studied in silver stained whole mounts of embryonic chick, quail, and pigeon retinae. The surface area of the retina and of the optic fiber layer increases in size exponentially, the optic fiber layer expanding faster than the retina. The optic fiber layer covers the retinal surface at E5 in quail and at E6 in chick and pigeon. In all species studied, the retinal fiber layer does not expand homogeneously with the optic nerve head as the center. Instead, the retinal fiber layer enlarges with polarities in the dorsal to ventral and nasal to temporal direction. The very first axon bearing ganglion cells appear at stage 16 in the dorsal and central portion of the retina and grow ventrally to merge at the optic disk. From stage 23 on, the optic fiber layer expands faster in the temporal than in the nasal side. Measurements on the initial polarization of young axonal processes show that the axonal growth is directed toward the optic fissure and the optic nerve head. This growth polarization is found at the onset of growth cone formation and in axons far from the nearest ganglion cells or ganglion cell axons. Therefore axon‐axon interaction cannot be involved in the initial axon orientation early in retinal morphogenesis.
Central distribution of efferent and afferent components of the pudendal nerve in macaque monkeys
Authors: Ueyama Teizo , Mizuno Noboru , Takahashi Osamu , Nomura Sakashi , Arakawa Hisao , Matsushima Ryotaro 
Published: January 2005

AbstractCentral distribution of efferent and afferent components of the pudendal nerve was studied by the horseradish peroxidase (HRP) method in 13 macaque monkeys, i.e., in nine Japanese monkeys (Macaca fuscata), two rhesus monkeys (Macaca mulatta), and two crab‐eating monkeys (Macaca fascicularis). The enzyme was applied to the central cut end of the pudendal nerve; then the monkeys were allowed to survive for 36 to 72 hr.Retrogradely labeled neuronal cell bodies of pudendal motoneurons constituted a slender longitudinal cell column in the ventral horn. The cell column extended from high or middle S1 to high or middle S2 in eight monkeys, from middle or low L7 to high S2 in four monkeys, and from high L7 to middle S1 in a monkey. The cell column appeared to correspond to Onuf's X nucleus in man. No sex difference was recognized in the position of the cell column.The average number of HRP‐labeled pudendal motoneurons was larger in male than in female adult Japanese monkeys, whereas no sex difference was found in the average soma diameter of the pudendal motoneurons.Transganglionically labeled axons entered into the spinal cord through the S1 and S2 dorsal roots in 12 monkeys and through the L7 and S1 dorsal roots in one monkey. Labeled axons were distributed ipsilaterally in laminae I–VI and X of the spinal cord at the same and adjacent levels of entry of HRP‐labeled dorsal root fibers (from L7 to S3 in 12 monkeys and from L6 to S3 in one monkey). At the levels of entry, some of the labeled dorsal root fibers crossed the midline of the cord through the dorsal commissural gray to distribute contralaterally in the medial portions of lamine I–VI, especially laminae III–V, of the dorsal horn. Although the craniocaudal extent of HRP‐labeled afferent fibers varied somewhat among 13 monkeys examined, no HRP‐labeled axons were observed in the gray matter of the spinal cord segments cranial to L6 and caudal to S3. In a Japanese monkey with a postoperative survival time of 72 hr, two clusters of labeled axons were observed ipsilaterally in the medial portions of the gracile nucleus.
The morphology and synaptic connections of spiny stellate neurons in monkey visual cortex (area 17): A golgi‐electron microscopic study
Authors: Marie Richard L. Saint , Peters Alan 
Published: January 2005

AbstractBased on a gold‐toning, Golgi‐electron microscope examination of 12 small and medium‐sized spiny stellate neurons in laminae 4A, 4B, and 4C of the monkey visual cortex (area 17), the ultrastructure of the cell somata, dendrites, and axons of these neurons is described. Particular attention is paid to the synapses involving the surface of different parts of these neurons. Only symmetric synapses occur on the somata of spiny stellate neurons, and these occur with a frequency of 11.0–15.9 synapses/100 μm2 perikaryal surface. Symmetric synapses also occur on dendritic shafts and, occasionally, on dendritic spines. Asymmetric synapses are occasionally present along the dendritic shafts of spiny stellate neurons, but the majority of asymmetric synapses (75–95%) occur on their dendritic spines. The initial axon segments of the smallest spiny stellate neurons possess no axo‐axonal synapses, but several symmetric synapses are present along the initial segment of a medium‐sized, spiny stellate neuron in layer 4B. Fifty‐three synapses made by boutons of the axons of these spiny stellate neurons have been identified, and all are asymmetric. Sixty per cent of the synapses are formed by boutons en passant and the remainder by the terminal swellings of spine‐like axonal appendages, boutons terminaux. Of the synapses formed by the axons of spiny stellate cells, axo‐spinous synapses outnumber axo‐dendritic synapses two to one, and axo‐dendritic synapses involve both spinous and aspinous dendrites. Evidence is presented which suggests that many of the axon terminals forming asymmetric synapses with the dendritic shafts and spines of spiny stellate neurons are derived from other spiny stellate neurons.
Aspartate aminotransferase‐like immunoreactivity in the guinea pig and monkey retinas
Authors: Mosinger Judith L. , Altschuler Richard A. 
Published: January 2005

AbstractThe excitatory amino acids, aspartate and glutamate, have been proposed as retinal neurotransmitters. Aspartate aminotransferase (AAT) is an enzyme which is involved in the routine metabolism of these amino acids and may be involved in the specific synthesis of glutamate and/or aspartate for use as a neurotransmitter. On the basis of the hypothesis that increased levels of aspartate aminotransferase may reflect a transmitter role for aspartate and/or glutamate, we have localized aspartate aminotransferase in the guinea pig and cynamolgus monkey retinas with light and electron microscopic immunohistochemical techniques. AAT‐like immunoreactivity is localized to the cones of guinea pig retina and to monkey rods. Both species contain a subpopulation of immunoreactive amacrine cells as well as a subpopulation of immunoreactive cells in the ganglion cell layer. Immunostaining is seen in bipolar cells and terminals in the monkey but not in the guinea pig retina.We have performed quantitative analysis of the immunoreactive staining in the outer plexiform layer and described the synaptic organization of immunoreactive processes in the inner plexiform layer (TPL). Labeled amacrine processes in both species form synaptic contacts predominantly to and from bipolar terminals in the inner third of the IPL and to and from other amacrine and small unidentified processes in the outer portion of the IPL. The majority of labeled bipolar terminals in the monkey retina are seen in the inner third of the IPL where they synapse exclusively onto amacrine processes. Labeled bipolar terminals in the outer third of the IPL occasionally synapse onto ganglion processes.
Rat medulla oblongata. III. Adrenergic (C1 and C2) neurons, nerve fibers and presumptive terminal processes
Authors: Kalia Madhu , Fuxe Kjell , Goldstein Menek 
Published: January 2005

AbstractThe goal of this study was to define the cytoarchitectonic relationships between the catecholaminergic cell groups (the C1 and C2) in the rostral medulla oblongata of the rat. Immunocytochemistry was combined with Nissl staining to determine the nuclear boundaries in this region of the brain stem. In addition, the morphological characteristics of neurons in the C1 and C2 cell groups were determined and the relationship between these populations of neurons and their caudaul counterparts (A1 and A2 cell groups) was established (Kalia et al., '85a).The results indicate that the C1 and C2 cell groups are distributed over a wide region of the rostral medulla. The location of these adrenergic neurons is related to a number of nuclear groups in this region. This finding was remarkably consistent in all the animals studied in this series. In addition, adrenergic nerve fibers were found to be distributed over a large region of the medullary reticular formation. There was homogeneity in the morphology of the C1 and C2 cell groups. These rostrally located adrenergic neurons did not share morphological features in common with the recently described (Kalia et al., '85a) caudally located adrenergic neurons in the dorsal region of the nucleus of the tractus solitarius. These striking anatomical features of the adrenergic C1 and C2 cell groups support the proposal that adrenergic neurons in the rostral medulla oblongata play an important role in the integration of visceral functions (Fuxe et al., '80).
Anatomy of the posterior lateral line system in young larvae of the zebrafish
Authors: Metcalfe Walter K. , Kimmel Charles B. , Schabtach Eric 
Published: January 2005

AbstractWe studied the anatomy of neuromasts, afferent sensory neurons, and efferent neurons of the midbody branch of the posterior lateral line in larvae of the zebrafish (Brachydanio rerio), 5 days after fertilization. This simple sensory system consists often or 11 neuromasts, 15–20 sensory neurons, and about nine efferent neurons. The neuromasts are typical free neuromasts and both afferent and efferent synapses are present on hair cells within them. The sensory neurons project into a single longitudinal column of neuropil in the hindbrain. The sensory terminals appear by light microscopy to contact the dorsolateral dendrite of the ipsilateral Mauthner cell. Three types of efferent neurons are present; two types in the hindbrain and one type in the diencephalon. We provide several lines of evidence that demonstrate that these central neurons are efferent to the lateral line.We conclude from this morphology that the larval system includes all of the components of the adult system and is probably functional at this early stage. We also found that larvae have all of the efferent neurons found in adult zebrafish, while the number of neuromasts and sensory neurons will increase during subsequent development.
Growth and death of cells of the mesencephalic fifth nucleus in Xenopus laevis larvae
Authors: Kollros Jerry J. , Thiesse Mary L. 
Published: January 2005

AbstractPositions, numbers, and cell and nuclear sizes of mesencephalic fifth nucleus (M‐V) cells were determined in Xenopus laevis larvae in stages 47 through the end of metamorphosis at stage 66. M‐V cells may be found at every tectal level, from the rostralmost section almost to the caudal pole, and in the anterior medullary velum. A large majority of the cells lie between 15 and 65% caudad of the rostral tip of the tectum. At anterior and middle tectal levels the cells lie lateral to but mainly above the optic ventricle. At posterior levels, to which the ventricle does not extend, a few cells may be seen at middle and lower tectal levels, as if in transition to the anterior medullary velum. At stage 47 fewer than ten cells are seen in each animal. The numbers rise to 20–40 by stage 50, and are uniformly above 100 after stage 51. Initially many M‐V cells were small, i.e., 6–7 μm in diameter, but grew to a mean diameter of about 19 μm at stage 59, with a maximum value of 29 μm. A single individual at stage 57 had 581 cells. The peak of mean cell numbers 387, occurred at stage 59, which was also the stage with the highest mean values for nuclear and cell sizes. Pyknotic M‐V cells at low frequency were seen at stages 55 and 57, and at all stages thereafter. Cell death frequency peaked at stage 62, but continued through stage 66. By stage 66 mean cell numbers had been reduced to about 240, indicating survival of about 60% of cells present at stage 59.
The neuronal composition of area 17 of rat visual cortex. I. The pyramidal cells
Authors: Peters Alan , Kara Daniel A. 
Published: January 2005

AbstractThe pyramidal cells in area 17 of rat visual cortex have been examined by light microscopy using Golgi preparations and semithin plastic sections, and by electron microscopy. Pyramidal cells have cell bodies in layers II–VIa. The pyramidal cells in the lower portion of layer II/III are typical examples of this neuronal type in that they have pyramidal‐shaped cell bodies, apical dendrites which ascend to layer I, and a skirt of basal dendrites. The pyramidal cells in upper layer II/III are similar in form but have shorter apical dendrites, while the most superficial pyramidal cells lack apical dendrites and instead have two or more primary dendrites that emanate from the upper surface of their somata. In layer V the pyramidal cells are of two sizes, medium and large, and both have a typical morphology, although the larger neurons have thicker apical dendrites and better‐developed axon hillocks than the medium‐sized pyramids. The medium‐sized pyramidal cells of layer V outnumber the large ones to a ratio of 2.5:1. In layer IV a few typical medium‐sized pyramidal cells are present, but the majority are small and can be regarded as star pyramids for they have dendrites radiating in all directions. No clearly identified spiny stellate cells have been encountered in layer IV. The pyramidal cells of layer VIa are also small, and most of them have apical dendrites which only ascend as far as layer IV. In addition to these varieties, both inverted and horizontally inclined pyramidal cells have been encountered.In electron micrographs it is apparent that although all of the pyramidal cells have symmetric axosomatic synapses, the frequency with which these synapses occur varies. The cell bodies of the various forms of pyramidal cells do not show a standard cytology. The medium‐sized pyramidal cells of layer II/III usually have rounded nuclei, while the nuclei of the small pyramidal cells of layers IV and VIa are somewhat more irregular, and the large pyramidal cells of layer V have deeply indented nuclear envelopes. The appearance of the perikaryal cytoplasm also varies. The larger pyramidal cells have numerous mitochondria and well‐developed Nissl bodies in their perikaryal cytoplasm, but the smaller cells have much‐less‐pronounced mitochondria and their rough endoplasmic reticulum is only organized into stacks at the bases of dendrites.Pyramidal cells account for about 87% of profiles of neuronal cell bodies with nuclei in layer II/III, 90% in layer IV, 89% in layer V, and 97% in layer VIa.