bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of the olfactory bulb of the hedgeho (erinaceus europaeus): Description of cell types in the granular layer
Authors: López‐Mascaraque L. , De Carlos J. A. , Valverde F. 
Published: January 2005

AbstractThe cytoarchitecture of the olfactory bulb and the cell types in the granular layer of adult hedgehogs have been studied with the Golgi method. The mitral cell layer does not stand out as a monolayer as in most mammals; it is arranged as a diffuse stratum with mitral cells displaced into the external plexiform layer. The external plexiform layer is exceedingly thick and contains the branches of peripheral processes of granule cells and displaced mitral and tufted cells. The granular layer contains granule cells and varieties of short‐axon cells. Among granule cells a type of cell with an elaborate system of protrusions close to the cell body has been found. Four main varieties of short‐axon cells are described. These include cells with local or extended axons, according to the branching pattern of their axons inside the granular layer or extending into the external plexiform layer as well. Short‐axon cells were also classified as cells with smooth and spinous dendrites. A variety of cell with smooth dendrites and elaborate axonal system reaching the periglomerular zone is described. This type of cell has been found frequently in the olfactory bulb of the hedgehog. In comparison to several other mammals, short‐axon cells in the olfactory bulb of the hedgehog have been found to be particularly abundant and to have more complex axonal systems. It is suggested that some of them may represent inhibitory interneurons acting upon granule and periglomerular cells, playing an important role in the centrifugal pathway controlling the olfactory input.
Variability of axonal arborizations hides simple rules of construction: A topological study from HRP intracellular injections
Authors: Triller Antoine , Korn Henri 
Published: January 2005

AbstractIntracellular staining with horseradish peroxidase (HRP) allows the analysis of the extent and diversity of axonal field, as the Golgi techniques did for dendritic fields. In this study, we have used such HRP injections to investigate possible rules of construction that underlie the variability in the observed morphological patterns of axons. The Mauthner cell of the teleost provides a suitable material for such a work since it receives inhibitory inputs from two distinct classes of cells that can be identified physiologically prior to their intracellular staining: those that contribute to a recurrent collateral network and those that are part of the commissural vestibuloves‐tibular pathway. The distribution of their terminal boutons over the M‐cell surface was quantified and their axonal arborizations were analyzed topologically with the help of a centripetal method of terminal ordering.The results indicated (1) that both types of interneurons have qualitatively a similar distribution of boutons over this target, encompassing the soma, initial portions of the main dendrites, and the cap‐dendrites, and (2) that furthermore, the terminals have a tendency to form clusters, the proportion of which is relatively constant regardless of the total number of boutons established by a given afferent cell. In respect to their projection on the M‐cell, the two populations differ mainly in the number of established contacts, which averaged 44.1 ± 28.2 (n = 10) and 14.4 ± 11.3 (n = 43) for collateral and commissural interneurons, respectively. These differences reflect the variations in axonal arborizations. A topological analysis has revealed that (1) branching occurs mainly as bifurcations, whereas in contrast three or four segments issuing from a branch point are only occasionally observed at the level of the last segment; (2) for each cell, the distribution of boutons within orders is not random and rather follows an unimodal distribution, centered on the mean order (θ); (3) the terminals of each subset, or class, of neurons have their own pattern of distribution within orders; and finally (4) the mean order (θ) is linked to the number of terminal segments (nT) by the relation θ = 1.28 log2 nT. This parameter is of importance: it characterizes the axonal arborization and it allows one to predict the number of terminal segments of individual neurons. Similar analysis of camera lucida reconstruction of axonal arborizations of various cell types studied by other investigators suggests that this relation can be generalized.Thus, although the axons of each class of neurons can be distinguished on the basis of their ramifications (or number of boutons), their arborizations might nevertheless result from common principles of construction, for which simple mathematical expressions have been found.
Neurotoxic action of kainic acid in the isolated toad and goldfish retina: I. Description of effects
Authors: Kleinschmidt Jochen , Zucker Charles L. , Yazulla Stephen 
Published: January 2005

AbstractThe neurotoxic action of kainic acid (KA) was investigated by histological methods in the isolated retina of toads and goldfish. Particular attention was paid to the earliest and most sensitive response to KA in the outer plexiform layer (OPL). KA caused vacuolization of proximal and distal segments of horizontal cell dendrites in the OPL as well as perikaryal vacuolization and/or chromatin clumping in selected classes of neurons in the inner nuclear layer. Further, KA caused vacuolization and swelling in the inner plexiform layer. These effects were very similar in the retinae of goldfish and toad.The extent of vacuolization in the OPL was graded with KA concentration and with length of incubation. For 15‐minute incubations, half‐maximal vacuolization was found at 10–20 μM KA. At 25 μM KA, OPL vacuolization was evident within 1–2 minutes of application of KA. In goldfish, but not in toad, rod‐connecting dendrites were less sensitive to KA than cone‐connecting dendrites.
Neurotoxic action of kainic acid in the isolated toad and goldfish retina: II. Mechanism of action
Authors: Kleinschmidt Jochen , Zucker Charles L. , Yazulla Stephen 
Published: January 2005

AbstractThe specificity and mechanism of the neurotoxic action of kainic acid (KA) was investigated by histological methods in the isolated retina of toads and goldfish. Particular attention was paid to the earliest and most sensitive response to KA in the outer plexiform layer (OPL). Of 21 compounds tested as potential mimics of KA neurotoxicity in the OPL, only the enantiomers of glutamate and aspartate mimicked KA, inducing a low‐level neurotoxic effect at concentrations 5,000–10,000‐fold higher than concentrations of KA giving comparable effects. Further, of 22 compounds tested as potential blockers of KA neurotoxicity in the OPL, only D‐γ‐glutamylglycine, D,L‐α‐amino pimelic acid, sodium pentobarbital, D,L‐α‐amino adipic acid, L‐glutamate, and L‐aspartate blocked KA neurotoxicity (IC50 values of 0.1, 0.3, 0.3, 2, 5, and 15 mM, respectively). In ionic substitution experiments, KA‐induced vacuolization was found to require sodium and chloride ions but not calcium ions in the extracellular medium.These findings support the hypothesis that KA combines with specific receptors in the membrane of susceptible neurons in the retinal OPL, leading to prolonged opening of membrane channels permeable to sodium and potassium ions. An accompanying equilibrating chloride influx may result in intracellular ion excess, leading to osmotic swelling and vacuolization. The membrane receptors involved in mediating the action of KA in the OPL are likely to be a class of postsynaptic or extrasynaptic glutamate receptor.
Olivocochlear neurons in the squirrel monkey brainstem
Authors: Thompson Glenn C. , Thompson Ann M. 
Published: January 2005

AbstractCentrifugal projections from the brain to the cochlea have been well described in rodents and cats. In order to gain a better understanding of the general mammalian features of this efferent projection system—the olivocochlear (OC) system—we have begun to extend its description to other mammalian orders, particularly primates. This report describes the origin, cellular morphology, and cholinergic nature of OC neurons in squirrel monkey.Olivocochlear neurons were identified after cochlear injection and subsequent retrograde transport of one of the tracers, horseradish peroxidase, True Blue, or Diamidino Yellow. One series of sections was processed to demonstrate the tracer and an adjacent series was processed to demonstrate acetylcholinesterase (AChE). In some cases, a series of sections was immunohistochemically processed to identify the presence of choline acetyltransferase (CAT), the synthesizing enzyme for acetylcholine.Approximately 1,700–1,800 OC neurons were contained in five distinct regions surrounding the major nuclei of the superior olivary complex (SOC), namely: (1) dorsal to medial superior olive (MSO); (2) between MSO and lateral superior olive (LSO); (3) lateral to LSO; (4) medial to SOC; and (5) in the ventral nucleus of the trapezoid body (VTB). These neurons were larger in the regions dorsal to MSO, lateral to LSO, and within VTB; they tended to be smaller in the regions between MSO and LSO and medial to SOC. Neuronal shapes varied among regions and included oval, elongate, round, and multipolar cells. In further support of their cholinergic nature as implied by AChE reactivity, OC neurons also stained positively for the cholinergic marker, CAT.
Peptidergic innervation of insect reproductive tissue: The association of proctolin with oviduct visceral musculature
Authors: Lange Angela B. , Orchard Ian , Adams Michael E. 
Published: January 2005

AbstractThe visceral muscles of the oviducts of Locusta migratoria are sensitive to the pentapeptide proctolin (H‐Arg‐Tyr‐Leu‐Pro‐Thr‐OH). Amounts of proctolin as low as 2 fmol induce a tonic contraction that is dose‐dependent up to 200 fmol. By use of this bioassay we have quantified the amount of material showing proctolinlike bioactivity associated with the oviducts.Reversed‐phase high performance liquid chromatography of tissue extracts indicates that material with proctolinlike bioactivity and co‐eluting with proctolin is present in the oviducts, the oviducal nerve, and the VIIth abdominal (penultimate) ganglion. The proctolin is present in areas of oviduct that receive extensive innervation. There is tenfold less proctolin in areas of oviduct that receive little or no innervation.Proctolinlike immunoreactivity is present in axons of the oviducal nerve as well as in a number of cell bodies in the VIIth abdominal ganglion. Three of these neurons lie in a position similar to that of the previously described oviduct motoneurons. Neuropilar axons and processes, as well as axons in the median nerve, also show proctolinlike immunoreactivity.The results indicate that proctolin, which has previously been identified as a neurotransmitter of insect hindgut visceral muscle, is also associated with visceral muscle of the reproductive system.
Distribution of noradrenaline in the brain of the teleost gasterosteus aculeatus L.: An immunohistochemical analysis
Authors: Ekström Peter , Reschke Maria , Steinbusch Harry , Van Veen Theo 
Published: January 2005

AbstractThe distribution of noradrenergic neurons in the brain of the threespined stickleback was demonstrated with the indirect peroxidase‐antiperoxidase (PAP) immunohistochemical method with antibodies against a noradrenaline‐bovine serum albumin conjugate. Noradrenergic neuronal somata were exclusively located in the isthmal area of the brain stem and in the lower medulla. Noradrenergic varicose axons innervate the reticular formation, motor nuclei, and interpeduncular nucleus of the brain stem, the hypothalamus and habenular nuclei, various parts of the area dorsalis telencephali (forebrain pallium), and the olfactory bulbs. Scattered noradrenergic axons were observed in the optic tectum and in various parts of the cerebellum. It is concluded that the isthmal cell group of the stickleback is, on topological and cytoarchitectonic grounds, equivalent to the ventral portion of the locus coeruleus/subcoeruleus area of amniotes, but that its efferent connections display features characteristic both of those originating in the locus coeruleus, and in the lateral tegmental cell groups of mammals.
Distribution of acetylcholinesterase in the hippocampal region of the rabbit: I. Entorhinal area, parasubiculum, and presubiculum
Authors: Geneser Finn A. 
Published: January 2005

AbstractThe distribution of acetylcholinesterase (AChE) was examined in three areas of the hippocampal region of adult rabbit, viz., the entorhinal area, the parasubiculum, and the presubiculum. AChE was demonstrated histochemically according to a modification of the Koelle copper thiocholine method. In each of the examined areas the pattern of AChE was distinctly stratified and corresponded extensively to fields and layers defined on the basis of cyto‐ and fibro‐architectonics. The enzyme activity was mainly present in the neuropil, but in addition, moderately to weakly stained nerve cell bodies were seen scattered in the entorhinal area and the presubiculum. Only a very small minority of the total number of neuronal somata showed an intense staining reaction for AChE.Two subfields were discernible in the entorhinal area, these being termed pars medialis and pars lateralis. Pars medialis showed a distinctly stratified enzyme distribution, whereas stratification was less conspicuous in pars lateralis, especially at basal levels. The deep cortical layers (IV–VI) showed a similar distribution of AChE in all three areas—a medium‐stained layer IV, a weakly stained layer V, and a weakly to moderately stained layer VI. However, at more dorsal horizontal levels of pars medialis, heavily stained patches occurred in layer IV. In the entorhinal area, the superficial cortical layers (I–III) contained most enzyme activity in the superficial two‐thirds of layer I, the interstices between the stellate cell bodies in layer II, and the superficial part of layer III. In the parasubiculum, layers I–III formed a wedge‐shaped field with a very high content of AChE. The presubiculum was well stained in layers I and III, whereas the densely packed cell bodies of layer II were unstained.The distribution of AChE in the rabbit was compared with that in the rat and guinea pig, previously described. The staining pattern is fundamentally similar in all three species, but certain clear differences exist.Possible structural correlates to the AChE observed in the three areas are considered in detail, especially the relation to the distribution of afferent systems known from experimental studies in other animal species. Although a substantial amount of the enzyme is probably associated with the septohippocampal projection, at present it cannot be excluded that other fiber systems may account for some of the observed AChE.
Responses of rat dorsal horn neurons to natural stimulation and to iontophoretically applied norepinephrine
Authors: Howe James R. , Zieglgäunsberger Walter 
Published: January 2005

AbstractExtracellular recordings were obtained of 177 neurons throughout the lumbar spinal dorsal horn of urethane‐ or halothane‐anesthetized rats. These neurons all responded to Iontophoretically applied L‐glutamate and their responses to natural stimulation of the ipsilateral hindlimb were characterized. Iontophoretically applied norepinephrine was tested on 94 of these neurons. Fifty‐one neurons were inhibited and 22 were excited. Norepinephrine produced a biphasic inhibitory/excitatory effect on nine neurons. Norepinephrine was exclusively inhibitory on superficial dorsal horn neurons that responded only to innocuous brush and touch and on neurons in the nucleus proprius that responded to brush, touch, and noxious skin pinch. Norepinephrine excited some superficial brush/touch/pinch neurons and produced short inhibitions that were followed by prolonged excitations of some nucleus proprius neurons that responded only to noxious skin pinch. Neurons in the base of the dorsal horn that responded to low‐threshold proprioceptive stimulation were excited by norepinephrine. Both the inhibitory and excitatory effects of norepinephrine were stereoselective, but they were not blocked by receptor subtype‐selective antagonists. Desensitization to norepinephrine occurred for 30% of the neurons.This study demonstrates that the inhibitory effects of norepinephrine on rat dorsal horn neurons are not restricted to neurons that are responsive to noxious stimuli and that some of these neurons are primarily excited by norepinephrine. The excitatory effects of norepinephrine on low‐threshold proprioceptive neurons may contribute to norepinephrine's known enhancement of spinal flexor reflex activity.
Relationship between astrocytes, ganglion cells and vasculature of the retina
Authors: Stone Jonathan , Dreher Zofia 
Published: January 2005

AbstractWe have studied the distribution of astrocytes in the ganglion cell and nerve fibre layers of the retina in cat, rat, rabbit, and possum using antiserum and a monoclonal antibody against glial fibrillary acidic protein (GFAP) and our own monoclonal antibody against glial filaments. The distribution of retinal astrocytes appears to be strongly determined by the vasculature of the retina; astrocytes are absent from almost all the retina of the possum and from the avascular regions of the rabbit retina. In the cat and rabbit, retinal astrocytes also show a strong affinity for the bundles of ganglion cell axons found at the inner surface of the retina.Retinal astrocytes do not invest the somas of ganglion cells, and even in areas of retina in which they are numerous, they are sharply confined to the layer of ganglion cell axons. It is suggested that retinal astrocytes are “immigrant” fibrous astrocytes that enter the retina with its vasculature.
A comparison of GABA‐ and GAD‐like immunoreactivity within the area postrema of the rat and cat
Authors: Newton Bruce W. , Maley Bruce E. 
Published: January 2005

AbstractThe immunohistochemical localization of gamma‐aminobutyric acid (GABA) was compared to that of glutamate decarboxylase (GAD) in the rat and cat area postrema with the aid of a polyclonal antibody produced in rabbits directed against GABA. In both the rat and cat, dense and very dense accumulations of GABA‐like immunoreactive (GABA‐LI) varicosities were present throughout the area postrema. GABA‐LI cell bodies were present in both species and were evenly distributed throughout the area postrema's extent. However, the rat area postrema contained more GABA‐LI cell bodies and varicosities than the cat area postrema. In the cat area postrema, a range of cell sizes were immunostained with the GABA antibody. The GAD antibody, however, failed to reveal cell bodies in the area postrema of the cat, thus indicating that the GABA polyclonal antibody may be a better indicator of GABA‐containing somata. Although the mechanism of action of GABA in the area postrema is not understood, it is possible that GABA may play a role in the different functions of the area postrema in emetic and nonemetic species.
Time course of reactive synaptogenesis in the subcortical somatosensory system
Authors: Wells Joseph , Tripp Leslie N. 
Published: January 2005

AbstractThese experiments were designed to determine when synaptogenesis begins in the adult rat ventral posterolateral nucleus of the thalamus following lesions of the dorsal column nuclei. Given the relatively uncomplicated structure of the neuropil in the ventral posterolateral nucleus of the rat, the specificity of reactive synaptogenesis of the lemniscal input and the effect of the loss of lemniscal terminals on terminals from other sources could be determined. By use of morphometric analysis of electron micrographs, the numerical density of the 3 terminal types in the neuropil was determined at a series of postlesion survival times ranging from 12 hours to 50 days. Synaptogenesis began about 30 days after the lesions of the dorsal column nuclei and was complete by 50 days. The slow onset of synaptogenesis was in response to a loss of the lemniscal terminals, which account for only 3% of the total number of synapses in the ventral posterolateral nucleus. The low level of synaptogenesis early in the recovery process differs from the recovery seen in other central nervous system sites, which show an early rapid increase in synapses in response to much greater denervation. The loss of lemniscal terminals has relatively little effect on the numerical density or distribution of the terminals of other types. The new terminals that are formed come both from axons that originate from the undamaged portion of the dorsal column nuclei and from axons originating in the spinal cord.
The ventral striatopallidothalamic projection: II. The ventral pallidothalamic link
Authors: Zahm D. S. , Zaborszky L. , Alheid G. F. , Heimer L. 
Published: January 2005

AbstractThe projection of ventral pallidal neurons to the mediodorsal nucleus of the thalamus (MD) was examined in rats by combined retrograde transport of horseradish peroxidase (HRP) after injections in the MD and glutamate decarboxylase (GAD) immunocytochemistry at light and electron microscopic levels, with and without prior exposure of the brains to colchicine. HRP was transported Lo the soma of medium‐sized and large ventral pallidum neurons, which along with their long, large dendrites were contacted by many glutamate decarboxylase immunoreactive synaptic boutons. The retrograde tracer positive neurons bore a remarkable resemblance to the projecting cells of the globus pallidus and entopeduncular nucleus. When colchine exposure was included in the tissue preparation, some but not all tracer positive cells also exhibited cytoplasmic GAD immunoreactivity.
Selective retrograde labeling of lateral olivocochlear neurons in the brainstem based on preferential uptake of 3H‐D‐aspartic acid in the cochlea
Authors: Ryan Allen F. , Schwartz Ilsa R. , Helfert Robert H. , Keithley Elizabeth , Wang Zhi‐Xian 
Published: January 2005

AbstractWe have previously shown that perfusion of the gerbil cochlea with probe concentrations of 3H‐D‐aspartic acid (D‐ASP) results in immediate, selective labeling of 50–60% of the efferent terminals under the inner hair cells, presumably by high‐affinity uptake. The present study was undertaken to determine the origin of these endings. Twenty‐four hours after cochlear perfusion with D‐ASP, labeled neurons were observed in the ipsilateral, and to a much lesser extent in the centralateral, lateral superior olivary nucleus (LSO). The cells were small, primarily fusiform, and showed fewer synaptic contacts than other LSO cells. Combined transport of D‐ASP and horseradish peroxidase indicated that all olivocochlear neurons within the LSO that projected to the injected cochlea were labeled by D‐ASP.Labeled fibers coursed dorsally from the LSO, joined contralateral fibers that had passed under the floor of the fourth ventricle, and entered the VIIIth nerve root at its ventromedial edge. Adjacent to the ventral cochlear nucleus (VCN), densely labeled collateral fibers crossed the nerve root to enter the VCN. Labeled fibers and terminals were prominent in the central VCN.Neither retrograde transport of D‐ASP by medial olivocochlear and vestibular efferents nor anterograde transport by VIIIth nerve afferents was observed.The D‐ASP‐labeled cells and fibers are clearly lateral olivocochlear efferents. Retrograde transport of D‐ASP thus allows the cells, axons, and collaterals of the lateral olivocochlear system to be studied, morphologically, in isolation from other cells that project to the cochlea. Since the olivocochlear neurons are almost certainly cholinergic, retrograde amino acid transport does not necessarily identify the primary neurotransmitter of a neuron. Rather, it indicates the presence of selective uptake by the processes of that neuron at the site of amino acid injection. Retrograde labeling appears to be markedly enhanced by the use of metabolically inert compounds such as d‐isomer amino acids.