bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serotonin‐ and substance P‐containing projections to the nucleus tractus solitarii of the rat
Authors: Thor Karl B. , Helke Cinda J. 
Published: January 2005

AbstractThe objective of the present study was to determine the location of the neurons that give rise to serotonin‐ and substance P‐containing terminals in the nucleus tractus solitarii. This was done by injecting rhodamine‐filled latex microspheres into the nucleus tractus solitarii of rats to retrogradely label neuronal cell bodies and by processing sections from the brains of these animals to determine whether the labelled neurons contained serotonin or substance P immunoreactivity. Serotonin‐immunoreactive neurons that projected to the nucleus tractus solitarii were found in the nucleus raphe magnus, nucleus raphe obscurus, nucleus raphe pallidus, and in the ventral medulla, lateral to the pyramidal tract. Substance P‐immunoreactive neurons that projected to the nucleus tractus solitarii were found in similar areas but were proportionately less numerous in the nucleus raphe magnus and proportionately more numerous in the nucleus raphe pallidus. It is concluded that neurons in the medullary raphe nuclei, some of which presumably utilize serotonin or substance P as a neurotransmitter, could regulate autonomic function via direct projections to the nucleus tractus solitarii.
Purification and characterization of FMRFamidelike immunoreactive substances from the lobster nervous system: Isolation and sequence analysis of two closely related peptides
Authors: Trimmer Barry Andrew , Kobierski Linda A. , Kravitz Edward A. 
Published: January 2005

AbstractIn the preceding paper (Kobierski et al: J. Comp. Neurol. 266:1–15, '87) FMRFamidelike immunoreactivity (FLI) was localized to specific cells and processes in the nervous system of the lobster Homarus americanus. In an effort to establish a role for this material we have purified and characterized a variety of immunoreactive peptides that can be extracted from the secretory pericardial organs. By using gel‐filtration chromatography and three different HPLC systems, it has been established that little or no authentic FMRFamide is present. Of the major immunoreactive components two peptides were purified in sufficient quantity for microsequence analysis and have been tentatively identified as the octapeptides Ser‐Asp‐Arg‐Asn‐Phe‐Leu‐Arg‐Phe‐amide (FLI 3) and Thr‐Asn‐Arg‐Asn‐Phe‐Leu‐Arg‐Phe‐amide (FLI 4). Both of these are novel neuropeptides with some sequence homology to the previously described FMRFamide family.The pericardial organs release FLI when depolarized with 100 mM K+ in the presence of calcium. Between 75 and 80% of this release is accounted for by FLI 3 and FLI 4. One of these peptides (FLI 4) has been synthesized and shown to cochromatograph with the endogenous immunoreactive material. Preliminary studies show that this peptide can act as a modulator of exoskeletal and cardiac neuromuscular junctions.
Segment‐related, mosaic neurogenetic pattern in the forebrain and mesencephalon of early chick embryos: I. Topography of ache‐positive neuroblasts up to stage HH18
Authors: Puelles L. , Amat J. A. , Martinez‐de‐la‐Torre M. 
Published: January 2005

AbstractHistochemical mapping of AChE‐positive neuroblasts in sectioned and whole‐mounted preparations of the chick embryo mesencephalon and prosencephalon allows a correlation of early neural tube morphogenesis (segmentation, longitudinal compartmentation) with the heterochronic pattern of neurogenesis. One significant finding is that the initial appearance of neuroblasts in the forebrain does not follow neuromeric segmentation, but evolves in parallel with it. Early neuroblasts appear as separate, distinct groups within specific matrix territories at the center of the transverse neuromeric segments. Neighbouring segments display different spatiotemporal patterns of neurogenesis. Overall gradients of differentiation in the rostrocaudal and ventrodorsal directions are absent, whereas a clear‐cut segment‐related, mosaic pattern becomes evident. Notwithstanding this, gross regularities of heterochrony in the neurogenetic behavior of the different segments lead to a definition of elemental longitudinal compartments of the forebrain and mesencephalon (floor, paramedian, basal, and alar regions) on the basis of precocious differentiation of the basal region and retarded differentiation of the paramedian and alar regions.
Functional organization of crayfish abdominal ganglia: II. Sensory afferents and extensor motor neurons
Authors: Leise Esther M. , Hall Wendy M. , Mulloney Brian 
Published: January 2005

AbstractAbdominal ganglia of crayfish contain identifiable neuropils, commissures, longitudinal tracts, and vertical tracts. To determine the functional significance of this ganglionic framework, we backfilled the following types of neurons with cobalt chloride: sensory hair afferents, slow and fast extensor motor neurons, the segmental stretch receptor neurons, and their inhibitory accessory cells. After the cobalt ions were precipitated and intensified, we studied the central projections of the filled neurons within the ganglionic structures. All of the axons of these neurons exit or enter each of the first five abdominal ganglia through the second pair of nerves.Our description of the central projections of the hair afferents is the first in the literature. These afferents innervate the large ventral horseshoe neuropil (HN) in the core of each ganglion. This neuropil is homologous to the insect ventral association centers, which also process sensory information. Furthermore, we discovered that some of the crayfish afferents innervate glomeruli within the HN.The slow and fast extensor motor neurons, the stretch receptor neurons, and the accessory cells branch mostly in the dorsal part of the ganglion. We reinterpret previous identifications of the extensor neurons that were based largely on soma position. Together with our previous descriptions of the flexor motor neurons, these results allow us to relate both rapid tail‐flips and slower postural movements to the structure of the segmental ganglia.
Evidence for centripetally shifting terminals on the tectum of postmetamorphic Rana pipiens
Authors: Hitchcock Peter F. , Easter Stephen S. 
Published: January 2005

AbstractIn larval frogs the retina and tectum grow in topologically dissimilar patterns: new cells are added as peripheral annuli in the retina and as caudal crescents in the tectum. Retinotopy is maintained by the continual caudalward shifting of the terminals of the optic axons. After metamorphosis the pattern of growth changes. The retina continues to add new ganglion cells peripherally, but there is no neurogenesis in the tectum. To maintain retinotopy in postmetamorphic frogs, the terminals of the optic axons must continually shift toward the central tectum.We tested the proposal of centripetally shifting axons by making punctate injections of horseradish peroxidase (HRP) in the tectum of adult Rana pipiens and observing the patterns of filled cells in the contralateral retina, as was done in the goldfish (Easter and Stuermer, '84). Punctate applications of HRP in the tectum should be taken up: (1) by fascicles, and label a partial anulus of cells, (2) by terminals, and label a cluster of cells in the corresponding retinotopic site, and (3) by the extrafascicular axonal segments, and label a band of cells connecting the partial annulus to the cluster. If the terminals have shifted centripetally, the band of cells labeled through their extrafascicular segments should have a spoke‐like orientation, with the center of the retina as the hub. As the tectal site moves from rostral to caudal, this band of cells should move, pendulum‐like, from temporal to nasal retina.In general, the patterns of HRP‐filled retinal cells we observed were consistent with our predictions. In addition, HRP taken up by the oldest (rostral) tectal axons produced more complex patterns of filled cells that indicated that these axons had shifted both caudally before metamorphosis and centripetally after.
Trajectories of regenerating retinal axons in the goldfish tectum: I. A comparison of normal and regenerated axons at late regeneration stages
Authors: Stuermer Claudia A. O. 
Published: January 2005

AbstractTo visualize and compare the intratectal path of normal and regenerated retinal axons, HRP was applied to localized sites in the dorsotemporal and dorsonasal retina in normal goldfish and in goldfish at 3–12 months after optic nerve section. The anterogradely labeled axons were traced in tectal whole mounts.In normal animals the axons were confined to the appropriate ventral hemitectum. Therein they ran in very orderly routes (Stuermer and Easter: J. Neurosci. 4:1045–1051, '84) and terminated in regions retinotopic to the labeled ganglion cells in the retina. The terminal arbors of dorsotemporal axons resided in the ventrocaudal tectum and those of dorsonasal axons in the ventrocaudal tectum.In regenerating animals the terminal arbors also resided at retinotopic regions, where they sometimes formed two separate clusters. In contrast to normal axons, the regenerating ones traveled in abnormal routes through the appropriate and inappropriate hemitectum. From various ectopic positions, they underwent course corrections to redirect their routes toward the retinotopic target region. In their approach toward their target sites, dorsotemporal and dorsonasal axons behaved differently in that the vast majority of dorsotemporal axons coursed over the more rostral tectum whereas dorsonasal axons progressed into the caudal tectal half.This differential behavior of regenerating dorsonasal and dorsotemporal axons was substantiated by a quantitative evaluation of axon numbers and orientations.
Neonatal deafening alters nonpyramidal dendrite orientation in auditory cortex: A computer microscope study in the rabbit
Authors: McMullen N. T. , Goldberger B. , Suter C. M. , Glaser E. M. 
Published: January 2005

AbstractIn order to examine the influence of afferent input on nonpyramidal dendrite development in the auditory cortex, unilateral deafening was carried out in neonatal rabbits at birth, approximately 6 days prior to the onset of hearing. Deafening was produced by surgical removal of the incus and stapes ossicles, aspiration of the cochlear perilymph, and kanamycin injection into the oval window. At 60 days of age, acoustic stimulation of the deafened ear was unable to evoke auditory brainstem responses. The brains of experimental and littermate control rabbits were processed according to the Golgi‐Cox Nissl method. The dendritic systems of lamina III/IV spine‐free nonpyramidal cells in the auditory cortex contralateral to the deafened ear were digitized from 340‐μm‐thick coronal sections with the aid of a computer microscope. Three‐dimensional spatial and statistical analyses revealed that nonpyramidal dendrite length in neonatally deafened rabbits increased 27% relative to littermate controls. A fan‐in projection analysis revealed that the increased dendrite length in the deafened animals was maximum in the tangential direction and toward the white matter. Computer rotation of digitized neurons from neonatally deafened rabbits also revealed evidence of abnormal dendritic growth in the form of recurved dendrites. We interpret our results to indicate that unilateral cochlear destruction early in development causes a reorganization of the ascending auditory pathway which extends to the contralateral cerebral cortex. Because the auditory cortex contralateral to the deafened ear still receives acoustic input from the undamaged ipsilateral ear, normal nonpyramidal dendritic growth in the auditory cortex is, in part, dependent upon afferent activity arising from both ears.
Distribution of cells projecting to thalamus vs. Those projecting to cerebellum in subdivisions of the dorsal column nuclei in raccoons
Authors: Ostapoff E.‐Michael , Johnson John Irwin 
Published: January 2005

AbstractTo learn the distribution of cells projecting to the thalamus, as opposed to the cerebellum, in the mechanosensory nuclei of the dorsal medulla of raccoons, we analyzed the retrograde transport of horseradish peroxidase from the ventrobasal complex of the thalamus and from the cerebellum. We found six nuclear regions projecting heavily to the thalamus with very small projections to the cerebellum: Bischoff's, central cuneate, central gracile, rostral cuneate, rostral gracile nuclei, and cell group z. Two regions showed heavy projections to the cerebellum with no projections to the thalamus: the lateral portion of the external cuneate nucleus and the compact portion of cell group x. Four regions showed more equivalent projections to both target regions: basal cuneate, medial portion of the external cuneate nucleus, medial tongue extension of the external cuneate nucleus, and reticular portion of cell group x. Three more ventral regions were labeled: lateral cervical nucleus from thalamic injections but not from cerebellar injections; central cervical nucleus from cerebellar injections, which crossed the mid‐line, but not from thalamic injections; and lateral reticular nucleus from both target regions. In most medullary regions, most cells project to one target and very few project to the other; we suggest that the cells projecting to the minor target convey samples of the information going to the major target.
Medullary sources of projections to the kinesthetic thalamus in raccoons: External and basal cuneate nuclei and cell groups x and z
Authors: Ostapoff E.‐Michael , Johnson John Irwin , Albright Bruce C. 
Published: January 2005

AbstractIn raccoons and other mammals, a pathway for kinesthetic sensation (from muscles, fascia, tendons, and joints) reaches the anterodorsal cap of the ventrobasal thalamus and the anteriormost part of the somatic sensory cerebral cortex. To find the medullary component of this kinesthetic pathway in raccoons, small injections of horseradish peroxidase were made in the thalamus under guidance of simultaneous electrophysiological recording from kinesthetic projections. As determined by retrograde labeling following these injections, kinesthetic thalamic subregions receive projections as follows: caudomedial from cells in the external cuneate nucleus and its medial tongue, rostromedial from cells in basal cuneate nucleus, and rostrolateral from cells in cell group z and the reticular division of cell group x. Electro‐physiological recording showed kinesthetic representations in each of these medullary regions. Labeled cells were also observed in the infratrigeminal subnucleus of the lateral reticular nucleus. Cats have kinesthetic projections to the thalamus from the basal cuneate and cell group z; raccoons (and monkeys) have these plus projections from the external cuneate and cell group x. This suggests that the kinesthetic projection system in raccoons and monkeys is expanded in correlation with their more dextrous use of the hand.
The motor nuclei and sensory neurons of the IIIRD, IVTH, and VITH cranial nerves in the monitor lizard, Varanus exanthematicus
Authors: Barbas‐Henry Heleen A. , Lohman Anthony H. M. 
Published: January 2005

AbstractThe motor nuclei of the oculomotor, trochlear, and abducens nerves of the reptile Varanus exanthematicus and the neurons that subserve the sensory innervation of the extraocular muscles were identified and localized by retrograde and anterograde transport of horseradish peroxidase (HRP). The highly differentiated oculomotor nuclear complex, located dorsomedially in the tegmentum of the midbrain, consists of the accessory oculomotor nucleus and the dorsomedial, dorsolateral, intermediate, and ventral subnuclei. The accessory oculomotor nucleus projects ipsilaterally to the ciliary ganglion. The dorsomedial, dorsolateral, and intermediate subnuclei distribute their axons to the ipsilateral orbit, whereas the ventral subnucleus, which innervates the superior rectus muscle, has a bilateral, though predominantly contralateral projection.The trochlear nucleus, which rostrally overlaps the oculomotor nuclear complex, is for the greater part a comma‐shaped cell group situated lateral, dorsal, and medial to the medial longitudinal fasciculus. Following HRP application to the trochlear nerve, almost all retrogradely labeled cells were found in the contralateral nucleus. The nuclear complex of the abducens nerve consists of the principal and accessory abducens nuclei, both of which project ipsilaterally. The principal abducens nucleus is located just beneath the fourth ventricle laterally adjacent to the medial longitudinal fasciculus and innervates the posterior rectus muscle. The accessory abducens nucleus has a ventrolateral position in the brainstem in close approximation to the ophthalmic fibers of the descending trigeminal tract. It innervates the retractor bulbi and bursalis muscles. The fibers arising in the accessory abducens muscles form a loop in or just beneath the principal abducens nucleus before they join the abducens nerve root.The afferent fibers conveying sensory information from the extraocular muscles course in the oculomotor nerve and have their perikarya in the ipsilateral trigeminal ganglion, almost exclusively in its ophthalmic portion.
Enigmatic bipolar cell of rat visual cortex
Authors: Peters Alan , Harriman Katherine M. 
Published: January 2005

AbstractOur earlier Golgi‐electron microscopic study of bipolar cells in the rat visual cortex showed the axons of these neurons as forming asymmetric synapses (Peters and Kimerer; J. Neurocytol, 10:921–946, '81) in which the most common postsynaptic elements were dendritic spines. This result was unexpected, since Parnavelas (Parnavelas, Sullivan, Lieberman, and Webster: Cell Tissue Res. 183:499–517, '77) had earlier shown a bipolar cell from the same cortex to have an axon forming symmetric synapses with dendritic shafts. Here then was an enigma, strengthened by examination of neuronal components labelled by antibodies to two compounds in particular—namely, vasoactive intestinal polypeptide (VIP) and choline acetyltransferase (ChAT). Antibodies to these compounds preferentially label bipolar cells in the rat cerebral cortex, and the labelled axon terminals form symmetric synapses.Against this background the present study was performed, and it has been shown that the resolution to the enigma is that there are two different populations of bipolar cells in the rat visual cortex. Thus some Golgi‐impregnated bipolar cells examined by electron microscopy after gold toning have been found to possess axons forming asymmetric synapses, and others have been found to have axons forming symmetric synapses, The axons of the bipolar cells forming asymmetric synapses most commonly synapse with dendritic spines (67%), although other terminals synapse with dendritic shafts (33%). In contrast, the bipolar cells with axons forming symmetric synapses preferentially synapse with dendritic shafts (100%). The population of bipolar cells that form symmetric synapses includes the ones that label with antibodies to vasoactive intestinal polypeptide (VIP), for the axons of VIP‐labelled bipolar cells have been traced to labelled terminals forming symmetric synapses. However, examination of the population of VIP‐labelled axon terminals shows that in addition to dendritic shafts, some of the labelled terminals synapse with the cell bodies of pyramidal and nonpyramidal cells, This includes bipolar cells, some of which receive large numbers of VIP‐labelled axon terminals. It is also shown that some VIP‐positive bipolar cells have myelinated axons. Analysis of tissue labelled with VIP antibody reveals that about 50% of the total population of bipolar cells in the rat visual cortex is VIP positive. These results are discussed in the light of information about labelling of bipolar cells with antibodies to γ‐aminobutyric acid (GABA) and to other peptides, and it is suggested that most VIP‐positive bipolar cells also contain GABA.
Light and electron microscopic immunocytochemical localization of parvalbumin in the dorsal lateral geniculate nucleus of the cat: Evidence for coexistence with GABA
Authors: Stichel C. C. , Singer W. , Heizmann C. W. 
Published: January 2005

AbstractThe coexistence in individual neurons of parvalbumin and γ‐aminobutyric acid (GABA) was studied in the dorsal lateral geniculate nucleus (dLGN) of the cat using pre‐ and postembedding immunocytochemical methods.PV(+) cell bodies and processes were found in the perigeniculate nucleus (PGN) and throughout all laminae of the dLGN. PV(+) neurons were relatively small and had circular to fusiform shapes. Electron microscopy revealed PV(+) reaction product within the perikarya, axons, and dendrites of labeled cells. It was associated preferentially with microtubules, postsynaptic densities, and intracellular membranes. PV(+) presynaptic boutons were identified on the basis of their synaptic relations and ultrastructure as retinal terminals (RLP) and as profiles originating from inhibitory interneurons (F1 and F2). Immunopositive somata and dendrites received asymmetric synaptic contacts from labeled RLP and non‐identified, non‐immunoreactive synaptic boutons. Moreover, PV(+) dendrites were postsynaptic to labeled F profiles.In the PGN all neurons were both PV(+) and GABA‐immunoreactive and in the dLGN the vast majority of PV(+) neurons showed GABA‐immunoreactivity.It is suggested that the high incidence of PV in GABAergic neurons is related to the particular activation patterns of these neurons and the resulting demand for calcium buffer systems.
Sympathetic innervation of the rat cornea as demonstrated by the retrograde and anterograde transport of horseradish peroxidase–wheat germ agglutinin
Authors: Marfurt Carl F. 
Published: January 2005

AbstractThe sympathetic innervation of the rat cornea was studied by using the method of intraaxonal transport of horseradish peroxidase–wheat germ agglutinin conjugate (HRP‐WGA). In the first set of experiments, the relative number of superior cervical ganglion neurons that innervate the rat central cornea was estimated by the method of retrograde HRP‐WGA transport. Following tracer application to the scarified central corneal surface, 49–198 labeled neurons were observed in the ophthalmic region of the ipsilateral trigeminal ganglion and zero to four cells in the rostral pole of the ipsilateral superior cervical ganglion. In the second set of experiments, the three‐dimensional distribution and termination sites of the corneal sympathetic nerve fibers were investigated by the technique of HRP‐WGA anterograde transport from the superior cervical ganglion. HRP‐WGA‐labeled axons in corneal whole mounts were identified by the presence within their axoplasm of linear arrays of HRP‐TMB reaction product, and their distribution was plotted faithfully onto line drawings made with a drawing tube attachment. Large numbers of HRP‐labeled fibers were found in all animals within the corneoscleral limbus where the majority were associated with blood vessels. Fewer fibers (zero to 14 per animal) entered the cornea proper. The latter fibers entered the peripheral cornea in the deep to middle layers of the stroma and ascended into progressively more superficial layers as they coursed centrally. The majority of fibers branched infrequently in the peripheral cornea and increased in branching complexity near the central cornea. HRP‐labeled axonal varicosities suggestive of terminal and preterminal expansions were located preferentially in the subepithelial layer of the corneal stroma and in the basal epithelium. Approximately 75% of the axonal varicosities were located in the central half of the cornea.The results of the current investigation reveal that the rat cornea is innervated sparsely by sympathetic nerve fibers derived from the superior cervical ganglion. These data provide additional support to current theories that corneal sympathetic nerve fibers may influence select aspects of corneal physiology, including ion transport and hydration, mitogenesis and wound healing, and sensitivity.