bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunohistochemical studies of cholecystokininlike peptides and their relation to 5‐HT, CGRP, and bombesin immunoreactivities in the brainstem and spinal cord of lampreys
Authors: Brodin Lennart , Buchanan James T. , Hökfelt Tomas , Grillner Sten , Rehfeld Jens F. , Frey Peter , Verhofstad Albert A. J. , Dockray Graham J. , Walsh John H. 
Published: January 2005

AbstractThe distribution of cholecystokinin (CCK)‐like immunoreactivity in the brainstem and spinal cord of lampreys was studied by using CCK antisera with different properties. In the spinal cord, three separate systems reacted with CCK antisera: (1) A ventral and lateral fiber system descending from a group of neurons in the posterior reticular nucleus of the rhombencephalon was labeled by both a C‐terminal‐directed CCK antiserum and a monoclonal CCK antibody. (2) A dorsal root–dorsal column system of fibers originating from cell bodies in the dorsal root ganglia was labeled only by the C‐terminal CCK antiserum. This CCK immunoreactivity could be abolished by preabsorption with calcitonin‐gene‐related peptide (CGRP), suggesting that it was due to cross‐reactivity with a CGRP‐like peptide. This system also contained 5‐hydroxytryptamine (5‐HT)‐, bombesin‐, and CGRP‐like immunoreactivities. (3) An intraspinal system of 5‐HT neurons was labeled with an antiserum to the midportion of CCK‐33 but not by the other CCK antisera. The CCK labeling of this system was difficult to reduce by preabsorption with CCK peptide and thus appeared to be nonspecific.Groups of cell bodies in the middle reticular nucleus of the rhombencephalon, the reticular nucleus of the mesencephalon, and the hypothalamus were labeled by both the C‐terminal and the monoclonal CCK antisera. The gut contained two types of CCK‐like immunoreactivity, one of which appeared to be due to cross‐reactivity with CGRP.A biochemical analysis showed that the content of CCK was low in the spinal cord compared to the brain, and these results agreed with the immunohistochemical findings.
Neuronal microtubule‐associated proteins in the embryonic avian spinal cord
Authors: Tucker Richard P. , Binder Lester I. , Matus Andrew I. 
Published: January 2005

AbstractWe have used monoclonal antibodies to study the distribution of three developmentally regulated microtubule‐associated proteins–MAP2, MAP5, and tau–during the morphogenesis of the thoracic spinal cord and peripheral nervous system in the quail. MAP5 is the only one of the three that is present in growing motor neuron processes in the day 3 embryo. The lowmolecular weight form of MAP2, MAP2c, is found in motor neuron cell bodies at embryonic day 3. At later stages MAP2c appears in axons and in glia; it decreases in abundance between embryonic days 5 and 7. High‐molecular weight MAP2 appears in motor neuron cell bodies and spinal cord gray matter at embryonic day 4, and is never encountered in axons. Tau is found in axons, but only at embryonic day 3.5, after they have commenced active extension. The molecular form and patterns of intracellular compartmentalization of each of the microtubule‐associated proteins studied is conserved in mammalian and avian neurons. We conclude that MAP5 may be involved in the active growth of neuronal processes, whereas MAP2 and tau are not, and that high‐molecular weight MAP2 and tau may stabilize dendritic and axonal processes, respectively.
Central projections of intracellularly labeled auditory nerve fibers in cats: Morphometric correlations with physiological properties
Authors: Ryugo D. K. , Rouiller E. M. 
Published: January 2005

AbstractThe central arborizations and endings of type I spiral ganglion neurons were labeled with intracellular injections of horseradish peroxidase (HRP) after their characteristic frequency (CF) and spontaneous discharge rate (SR) were physiologically determined. A fiber‐by‐fiber analysis was conducted and the morphological data compared with the fiber's response properties. The total number of branch points was correlated with total fiber length, a relationship that remained relatively constant when analyzing the ascending and descending branches together or separately. On the other hand, the ascending branches of four out of five fibers having CFs below 0.5 kHz bifurcated and gave rise to a pair of terminal endbulbs of Held.Low‐ and medium‐SR fibers gave rise to more endings than did high‐SR fibers, especially on the ascending branch. This difference was accounted for by small endings, a category composed of terminal boutons, string endings, and small complex endings. The categories of modified endbulbs, and endbulbs of Held did not vary in number with respect to fiber SR. The mean area of each ending type within the small ending category was statistically smaller for low‐ and medium‐SR fibers than for high‐SR fibers, whereas the mean area of modified endbulbs and endbulbs of Held was not correlated with fiber SR. Total ending area per fiber appeared independent of either CF or SR. These results are discussed in relation to issues of conservation of axon arborizations and terminals, and convergence of input from the different SR groups.
Morphological and physiological development of olfactory receptor cells in rainbow trout (Salmo gairdneri) embryos
Authors: Zielinski Barbara , Hara Toshiaki J. 
Published: January 2005

AbstractThe morphological and functional differentiation of the olfactory receptor cells were investigated in developing rainbow trout (Salmo gairdneri) embryos by means of light and electron (transmission and scanning) microscopy and electrophysiology. Ciliated receptor cells first appeared when the olfactory placode was folded to form a groovelike structure rostrad to the eye at stage 24 (day 18; 18 days postfertilization). Ciliated receptor cells predominated until immature microvillar receptor cells developed in stage 28 (day 26) embryos. At stage 29, the day of hatching, the anterior edge of the olfactory epithelium contained only ciliated receptor cells, and the midregion contained both ciliated and microvillar receptor cells. Spontaneous neural firing activity was recorded from the olfactory mucosa as early as stage 25. The neural responses to amino acids were initially recorded from stage 26 embryos, containing sparse ciliated receptor cells with a few short cilia. The D‐enantiomers of amino acids were less effective. From these results we concluded that in rainbow trout the olfactory receptor cell has two separate morphological forms, ciliated and microvillar. These are ontogenetically distinct; the ciliated receptor cells preceded the microvillar. The ciliated receptor cells respond to amino acid stimulation.
Distribution of serotonin immunoreactivity in the forebrain and midbrain of the lizard Gekko gecko
Authors: Smeets Wilhelmus J. A. J. , Steinbusch Harry W. M. 
Published: January 2005

AbstractThe distribution of serotonin (5‐hydroxytryptamine, 5‐HT) in the forebrain and midbrain of the lizard Gekko gecko was studied by means of antibodies against serotonin. In the diencephalon, serotonin‐immunoreactive (5‐HTi) cell bodies were found in the hypothalamic periventricular organ and the ependymal wall of the infundibular recess. In the midbrain, 5‐HTi cells were observed in the nucleus raphes superior and the lateral portion of the nucleus reticularis superior. In addition, 5‐HTi cell bodies were found lateral to the ventral interpeduncular nucleus and around the ventral aspect of the medial longitudinal fasciculus. Serotonin‐immunoreactive fibers and varicosities are present throughout the forebrain and the midbrain, but particularly in the nucleus accumbens, the septal area, the dorsal cortex, the dorsal thalamus, the lateral geniculate body, the ventromedial hypothalamic nucleus, the pretectal nucleus, and the basal optic nucleus. The medial habenular nucleus contains a dense 5‐HTi plexus that shows a patchlike pattern. A laminar organization of 5‐HTi fibers and varicosities is present in the midbrain tectum. When compared with data obtained in other vertebrates, the present study has confirmed that in the phylogenetic series fishes‐amphibians‐reptiles‐birds‐mammals there appears to be (1) a gradual decrease in the number of cerebrospinal‐fluid‐contacting serotoninergic cells in the hypothalamic periventricular layer and (2) a remarkable increase in number of serotoninergic cells in the midbrain tegmentum. As in mammals, a strong serotoninergic innervation of structures related to sensory, in particular visual, pathways could be recognized.
Vestibular Projections to the thalamus of the pigeon: An anatomical study
Authors: Wild J. Martin 
Published: January 2005

AbstractIn a series of retrograde tracing studies involving the injection of WGA‐HRP into the thalamus of the pigeon, labeled neurons were consistently observed in anterior regions of the vestibular nuclei. Following small dorsal thalamic injections, labeled neurons were located predominantly in rostroventrolateral regions of te superior vestibular nucleus, less numerously within the ventral part of the lateral vestibular nucleus, and least numberously within the medial vestibular nucleus. Following large dorsal thalamic injections, many more vestibular neurons were labeled, and these were distributed more extensively throughout anterior parts of the superior, lateral, and medial nuclei. No labeled neurons were found in the descending nucleus. Injections of tritiated amino acids into vetibular nuclei revealed a terminal field within the dorsal thalamic nucleus: dorsolateralis posterior, pars rostralis. The location of this field between auditory, somatosensory, and paleostriatally and neostriatally projecting nuclei suggests a general similarity to the organization of vestibulothalamic projections in mammals.
Ultrastructural localization and characterization of sensory nerves in the rat kidney
Authors: Ferguson Meredith , Bell C. 
Published: January 2005

AbstractThe ultrastructural localization of sensory nerves in the rat kidney was examined by using the chromaffin reaction to distinguish sympathetic catecholaminergic fibres from sensory fibres. The sensory fibres were further characterized by use of an immunoperoxidase staining method to identify nerves immunoreactive for substance P and for calcitonin‐gene‐related peptide. Sympathetic fibres were observed in the renal cortex, medulla, and pelvis, but sensory fibres were seen only in the renal pelvis. Immunostaining for substance P labelled 40% of the sensory fibres. Following incubation in calcitonin‐gene‐related peptide antiserum, 53% of the sensory nerves were positively stained. Simultaneous immunostaining for substance P and calcitonin‐gene‐related peptide resulted in immunoreactivity in 82% of the sensory fibres, a percentage of axons significantly lower than that expected if the axons containing each peptide had been entirely separate populations. The results indicate that sensory nerves in the rat kidney are located entirely in the renal pelvis. On the basis of their neuropeptide content, there appear to be at least four separate populations of sensory axons present: two large groups containing substance P or calcitonin‐gene‐related peptide alone and two small groups containing both peptides and containing neither.
Synaptic organization of serotonin‐immunoreactive fibers in primary visual cortex of the macaque monkey
Authors: de Lima Ana D. , Bloom Floyd E. , Morrison John H. 
Published: January 2005

AbstractThe macaque neocortex is very densely innervated by serotonin‐containing fibers. The highest density of these fibers is in primary sensory regions such as the primary visual cortex. By using an antibody against serotonin, we analyzed the distribution and morphology of serotonin‐immunoreactive fibers and synapses in the primary visual cortex of the adult cynomolgus monkey. In addition, we quantified the laminar distribution of labeled varicosities and the distances between varicosities in single fibers. While serotonin‐immunoreactive fibers are found in all cortical layers, at least three bands of heightened density of innervation were readily recognized that were coincident with (1) layer IIIB to IVCα, (2) layer VA, and (3) layer VIB. Layer IVCα of area 17 contained more varicosities per unit area than any other sublayer. There was a high degree of variability in the intervaricosity distances along single fibers; more than half were longer than 10 μm.At the electron microscopic level, synaptic contacts were also observed throughout the entire thickness of area 17, with the highest frequency in layer IV. The labeled varicosities were packed with electron‐lucent synaptic vesicles and formed synaptic complexes with small, but conspicuous, postsynaptic densities. Dendritic shafts were the most common postsynaptic target of the labeled synapses. Among these characteristically slender postsynaptic shafts, profiles with structural features of both spiny and smooth dendrites were observed. The small diameter of most of the postsynaptic dendrites indicated that distal dendrites were preferentially contacted by serotonin‐immunoreactive varicosities. Although direct identification of the postsynaptic neurons will be required for complete characterization of this circuitry, the distribution of serotonin‐immunoreactive varicosities suggests that serotoninergic interactions in the primary visual cortex of the cynomolgus monkey are directed predominantly at the distal dendrites of granular and infragranular neurons rather than at targets in the supragranular layers.
Ultrastructural localization of immunoreactivity in the developing piriform cortex
Authors: Westenbroek R. E. , Westrum L. E. , Hendrickson A. E. , Wu J.‐Y. 
Published: January 2005

AbstractThe purpose of this study was to determine the ultrastructural basis for the immunoreactivity patterns in synaptic structures during development in layers I and II of the piriform cortex (PC) of rats. Antisera to cholecystokinin (CCK) and glutamic acid decarboxylase (GAD) were used at several different postnatal days (PN) and in adults to describe the distribution, characteristics, and relative frequency of labeled profiles–especially axons and terminals–with emphasis on details of the synaptic contacts. GAD‐positive terminals occur from PN 2 to adulthood but only form contacts in deeper sublayers (Ib and II) initially. Contacts increase in layer I after PN 6 and are reduced in layer II after PN 21 when the GAD‐labeled terminals and synapses take on adult features with flattened vesicles and symmetric contacts. CCK‐labeled terminals are present in deeper sublayers at PN 2 but are few and rarely form contacts. Both terminals and contacts increase between PN 2 and 9, taking on distinctive shapes and vesicle morphology by PN 13. At PN 21 and older, CCK terminals have mainly flattened vesicles and mostly form symmetric contacts onto dendrites and somata in deeper layers (Ib and II). Superficial sublayer Ia has very few CCK‐labeled synapses and axons. Thus immunoreactivity occurs in terminals prior to synapse formation; labeling of the presynaptic specializations precedes subsequent maturation; synaptic vesicle morphology and membrane specializations are similar for the vast majority of both CCK and GAD terminals; inhibitory (GABA) synapses are established sooner than the possibly excitatory CCK synapses; a deep to superficial gradient of synaptogenesis is associated with GAD‐positive terminals in the PC; and the labeling patterns may be related to critical developmental or synaptogenic periods.
Normal and regenerating optic fibers in goldfish tectum: HRP‐EM Evidence for rapid synaptogenesis and optic fiber‐fiber affinity
Authors: Hayes William Pär , Meyer Ronald L. 
Published: January 2005

AbstractThe distribution of normal and regenerating retinal fibers and synapses was studied on tectum in goldfish by light (LM) and electron microscopy (EM). Since labeling of the early regenerating fibers was previously reported to be difficult, a new “cold‐fill” HRP labeling protocol was developed, which labeled regenerating optic fibers and terminals on tectum as early as 14 days after nerve crush when they first arrive on tectum. In order to characterize the laminar distribution of optic afferents in normal fish and in fish regenerating for 14–240 days, EM photomontages of areas 14 μm wide by 160 μm deep through the HRP‐labeled primary optic innervation layer (S‐SO‐SFGS) were constructed. The time points in regeneration that were examined spanned the period in which others have shown that an initially diffuse retinotopic map becomes spatially restricted.At the LM level regenerating optic fibers were restricted to the optic lamina. They reinnervated tectum in an anterior to posterior sequence as previously seen with autoradiography. In addition, at 14 days, some “pioneer” optic fascicles were found to have already grown to posterior tectum where they gave rise to branches with boutonlike terminations and growth‐cone‐like processes.From the ultrastructural analysis it was clear that optic fibers and terminals observed strict laminar boundaries as they partitioned themselves in the optic laminae (S, SO and SFGS) in both normal and regenerating fish. The behavior of optic fibers was lamina specific with respect to synapse formation and the orientation of fiber outgrowth. As early as 14 days regeneration, optic fibers made synapses onto the four types of postsynaptic profiles observed in normal fish. Numerous optic terminals were labeled at 14 days, and there appeared to be no waiting period between fiber ingrowth to the SO and synapse formation in the S and SFGS. At 14–60 days, atypical synaptic contacts which appear to be nascent synapses were made by labeled optic fibers in fascicles and by growth‐cone‐like processes. By 21–30 days, the density of optic terminals was high and there were many more fasciculated optic fibers in the SFGS than normal as late as 240 days.These findings suggest that optic fiber lamination is highly constrained by tectal cues, that fibers rapidly regenerate many synaptic terminals before retinotopic map refinement is complete, and that fibers have a strong affinity for each other.
Metabolic activity in striate and extrastriate cortex in the hooded rat: Contralateral and ipsilateral eye input
Authors: Thurlow G. A. , Cooper R. M. 
Published: January 2005

AbstractThe extent of changes in glucose metabolism resulting from ipsilateral and contralateral eye activity in the posterior cortex of the hooded rat was demonstrated by means of the C‐14 2‐deoxyglucose autoradiographic technique. By stimulating one eye with square wave gratings and eliminating efferent activation from the other by means of enucleation or intraocular TTX injection, differences between ipsilaterally and contralaterally based visual activity in the two hemispheres were maximized. Carbon‐14 levels in layer IV of autoradiographs of coronal sections were measured and combined across sections to form right and left matrices of posterior cortex metabolic activity. A difference matrix, formed by subtracting the metabolic activity matrix of cortex contralateral to the stimulated eye from the ipsilateral “depressed” matrix, emphasized those parts of the visual cortex that received monocular visual input. The demarcation of striate cortex by means of cholinesterase stain and the examination of autoradiographs from sections cut tangential to the cortical surface aided in the interpretation of the difference matrices. In striate cortex, differences were maximal in the medial monocular portion, and the lateral or binocular portion was shown to be divided metabolically into a far lateral contralaterally dominant strip along the cortical representation of the vertical meridian, and a more medial region of patches of more or less contralaterally dominant binocular input. Lateral peristriate differences were less than those of striate cortex, and regions of greater and lesser monocular input could be distinguished. We did not detect differences between the two hemispheres in either anterior or medial peristriate areas, thus indicating either completely binocular input (which seems unlikely given the retinotopic organization of these regions), or a greater dependence than in the lateral peristriate on inputs that were not affected by the visual manipulations.
The lateral giant fibers of the tubificid worm, Branchiura sowerbyi: Structural and functional asymmetry in a paired interneuronal system
Authors: Zoran Mark J. , Drewes Charles D. , Fourtner Charles R. , Siegel Alan J. 
Published: January 2005

AbstractNeuroanatomical and ultrastructural studies of the paired lateral giant nerve fibers (LGFs) in posterior segments of the tubificid worm, Branchiura sowerbyi, demonstrate that the fibers are (1) segmental in origin (two cell bodies per segment), (2) joined longitudinally and transversely to form an intersegmental syncytial network, and (3) surrounded by a myelinlike sheath. The LGFs are unique among paired giant fiber systems because of their extreme asymmetry, the diameter of the left fiber being several times greater than that of the right. Electrophysiological studies demonstrate that the small, right fiber has a high input resistance and, during mechanosensory stimulation, functions as the locus for LGF spike initiation. The larger, left fiber contributes by enhancing the speed of LGF spike conduction along the animal. One physiological benefit of this asymmetric arrangement may be optimization of escape reflex sensitivity to mechanosensory inputs.