bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology of intracellularly labeled interneurons in the dentate gyrus of the immature rat
Authors: Seay‐Lowe Starie L. , Claiborne Brenda J. 
Published: January 2005

AbstractAlthough many aspects of the morphological development of interneurons in the dentate gyrus have been described, the full extent of their dendrites and local axon projections in immature rodents has not been examined. Here intracellular labeling was used to assess the branching patterns of interneurons in the dentate gyrus of rat pups between 7 and 9 days of age. Labeled neurons were located within or just below the granule cell layer, and most were classified as GABAergic basket neurons on the basis of their dendritic morphologies.All labeled interneurons exhibited immature characteristics. Spines were present on cell bodies and dendrites, and growth cones were visible on some dendrites and axons. In spite of these immature features, the dendrites and axon arbors of the labeled neurons were extensive. Many apical dendrites reached the top of the molecular layer, and a number of basal dendrites extended to the CA3 pyramidal cell layer of the hippocampus. Elaborate axon plexuses were present within the dentate gyrus itself, and axon collaterals of several neurons extended beyond the dentate gyrus to branch within regions CA3 and CA1 of the hippocampus.These results indicate that the dendrites and axon collaterals of dentate interneurons are extensive at a time when the principal neurons, the granule cells, are still proliferating. These data are consistent with the idea that GABAergic interneurons may influence granule cell development in the dentate gyrus, as well as pyramidal cell maturation in the hippocampus proper.
Musculotopic organization of the hypoglossal nucleus in the cynomolgus monkey, Macaca fascicularis
Authors: Sokoloff Alan J. , Deacon Terrence W. 
Published: January 2005

AbstractThe movements of the tongue in feeding and vocalization are enabled by a complex system of interdigitated muscle fibers in the tongue body. Because of this complexity, the detailed anatomical connections between individual intrinsic tongue muscles and corresponding motoneurons in the hypoglossal nucleus have not been described for any mammal. In this study we describe the distribution of retrogradely labeled neurons in the hypoglossal nucleus, following injections of wheat‐germ agglutinin‐horseradish peroxidase into different regions of the tongue of 21 cynomolgus monkeys. These experiments demonstrate a spatial organization of hypoglossal motoneurons that reflects the anatomical and functional organization of tongue body muscles: motoneurons innervating the transversus and verticalis muscles are located in medial hypoglossal nucleus regions, motoneurons innervating the genioglossus are located in intermediate hypoglossal nucleus regions, motoneurons innervating the hyoglossus and inferior longitudinalis are located in ventrolateral hypoglossal nucleus regions, and motoneurons innervating the styloglossus and superior longitudinalis are located in dorsolateral hypoglossal nucleus regions. Motoneurons innervating the suprahyoid muscle, the geniohyoid, are situated in a cell column separated ventrally from the main body of the hypoglossal nucleus. Motoneurons innervating the palatoglossus are located in the nucleus ambiguus and, possibly, in dorsolateral hypoglossal nucleus regions. Motoneurons of the medial divisions of the hypoglossal nucleus innervate tongue muscles that are oriented in planes transverse to the long axis of the tongue whereas motoneurons of the lateral divisions innervate tongue muscles that are oriented parallel to this axis. These results suggest that the segregation of motoneurons corresponds to the functional distinction between tongue protrusion and retrusion.
Embryonic development of synapses on spiking local interneurones in locust
Authors: Leitch Beulah , Laurent Gilles , Shepherd David 
Published: January 2005

AbstractThe development of synapses on an identified population of spiking local interneurones in the thoracic ganglia of embryonic locusts was examined by means of intracellular horseradish peroxidase injection and electron microscopy. In adult locusts, spiking local interneurones of the midline group receive direct inputs onto a ventral field of branches from leg mechanosensory afferents and in turn make output synapses, mainly from a dorsal field of branches, directly upon leg motor neurones, nonspiking local interneurones, and intersegmental interneurones. The aim of this study is to examine the development of these connections. These interneurones are born relatively late in embryogenesis and are not identifiable until approximately 55% of development. At this time (55–60%) only simple filopodial contacts or punctate contacts are evident between the stained interneurones and other neurones. By 65–70% embryogenesis, vesicles are found adjacent to regions where apposed membranes are symmetrically thickened with amorphous electron‐dense material. These symmetrical contacts lack distinct presynaptic bar‐shaped densities and therefore, are not considered to be synapses. At this stage, the interneurones do not produce action potentials upon intracellular injection of depolarising current. Morphologically identifiable synapses, with vesicles, a presynaptic bar, and relatively little postsynaptic density, are first evident at 70–75%, coincident with the time of arrival of the majority of leg mechanosensory afferents into the central nervous system. At this stage, action potentials and synaptic potentials are also recorded for the first time. The midline spiking interneurones thus become electrically excitable when synapses are first recognisable, at approximately 70% embryogenesis. Most of the synapses found on the interneurones are outputs. The ratio of outputs to inputs on ventral branches is 7.5:1 which contrasts markedly to the adult ratio of 1:2. By 85–90%, output synapses still predominate on the ventral branches, but the ratio of outputs to inputs is reduced to almost 2:1. Dorsal branches have predominantly output synapses throughout embryogenesis. The ratio of dorsal outputs to inputs at 85–90% is 8.5:1 which compares with the adult ratio of 6.5:1 At this stage, action potentials and synaptic activity are always recorded.© 1992 Wiley‐Liss, Inc.
Butyrylcholinesterase‐rich neurons in rat brain demonstrated by a sensitive histochemical method
Authors: Tago Hisao , Maeda Toshihiro , McGeer Patrick L. , Kimura Hiroshi 
Published: January 2005

AbstractButyrylcholinesterase (BChE) is a highly active enzyme in brain, but little is known about its physiological functions. One obstacle has been the lack of a sensitive and specific method for determining its cellular localization. We report here on a histochemical technique that has permitted BChE to be detected in neuronal, glial, and vascular structures. The method, which utilizes butyrylthiocholine iodide as the substrate, is a modification of our previously described method for acetylcholinesterase (AChE) histochemistry. BChE‐rich neuronal somata stained much more intensely than capillaries or glia. Prominent neuronal groups were located in the anterodorsal, laterodorsal, anteroventral, reuniens, centrolateral, paratenial, and periventricular thalamic nuclei, the laterodorsal tegmental nucleus, the pedunculopontine tegmental nucleus, and the dorsal motor nucleus of vagus. Several other areas of the forebrain and brainstem showed modest numbers of positive cells. No positive cells were detected in the striatum, hippocampus, and most parts of the hypothalamus, which are regions containing numerous AChE‐rich neurons. Although the distribution pattern of BChE‐rich neurons differed from that of AChE‐rich neurons, some neuronal groups contained both esterases. The results suggest that BChE may play a unique role in neuronal function, particularly since many BChE‐rich neurons have not been identified as to neurotransmitter type. © 1992 Wiley‐Liss, Inc.
Cholecystokinin concentrations and peptide immunoreactivity in the intact and deafferented medullary dorsal horn of the rat
Authors: Jacquin Mark F. , Beinfeld Margery C. , Chiaia Nicolas L. , Zahm Daniel S. 
Published: January 2005

AbstractTo further address the hypothesis that cholecystokinin (CCK) in the medullary dorsal horn (MDH) arises from intrinsic or higher‐order neurons. CCK‐8‐specific radioimmunoassay (RIA) and immunohistochemichal (IHC) experiments were carried out in adult rats after trigeminal tractotomy. RIA of punches from deafferented superficial layers of the MDH revealed no significant change in CCK levels vs. the control right side. In this same area, IHC revealed modest reductions in CCK, gastrin, and substance P staining. Calcitonin gene‐related peptide (CGRP) staining was reduced substantially. Gastrin immunoreactive cell bodies, present normally in inner lamina II, were reduced in number.RIA and IHC methods were also used to assess MDH CCK concentrations in adult rats subjected to left infraorbital nerve section at birth. The left medulla contained significantly higher levels of CCK than the control right medulla (1.27 ± 0.19 vs. 0.97 ± 0.11 ng/mg protein). IHC revealed a dense band of CCK‐like staining in laminae I and II ipsi‐ and contralateral to the lesion. Thus, neonatal deafferentation elevates medullary CCK.To determine if the neonatal lesion‐induced increase in medullary CCK is due to primary afferent or higher‐order reorganization, RIA and IHC experiments were run after infraorbital nerve section at birth and trigeminal tractotomy in adulthood. RIA revealed no significant change in CCK levels caudal to the tractotomy, although they were higher than control levels in 9 of 12 cases. IHC revealed modest reductions in CCK, substance P, and gastrin staining that resembled the reductions observed in tractotomy‐alone cases.These data suggest that (1) most MDH CCK is of non‐primary afferent origin, (2) gastrin immunoreactivity in layer II probably originates in CCK‐containing cells intrinsic to layer II, the expression of which is dependent upon trigeminal primary afferent input, (3) neonatal V deafferentation induces increased CCK in the superficial MDH, oflecting reorganized intrinsic or higher‐order inputs, and (4) higher‐order substance P in the MDH is robust. © 1992 Wiley‐Liss, Inc.
Galanin receptors in the brain of a teleost: Autoradiographic distribution of binding sites in the Atlantic Salmon
Authors: Holmqvist Bo I. , Carlberg Mats 
Published: January 2005

AbstractThe distribution of galanin (GAL) binding sites in the brain of the Atlantic salmon (Salmosalar) was investigated by means of radioligand binding in conjunction with autoradiography by using high‐performance liquid chromatography (HPLC) characterized radio‐iodinated porcine galanin ([125I]GAL). On slide‐mounted sections of frozen salmon brain homogenate, [125I]GAL(4 nM) bound rapidly and reversibly to a single population of sites with a Kd of 1.0 ± 0.08 nM (n = 3) and Bmax of 2.380 ± 0.19 fmol/mg wet tissue. Specific [125I]GAL binding was found in cellular regions, in fiber tracts, and in neuropil areas throughout the brain, except for in the olfactory bulb, pineal organ, and cerebellum.Autoradiographic microdensitometric measurements revealed high total [125I]GAL binding in the ventral hypothalamus (inferior lobes; around 7–12 fmol/mg tissue), the dorsal spinal cord (between 6 and 12 fmol/mg tissue), sublayers of the optic tectum (around 8 fmol/mg), torus semicircularis (around 7 fmol/mg), and glomerular complex (around 6 fmol/mg). Intermediate densities of [125I]GAL binding (3–5 fmol/mg tissue) were found in the pituitary, telencephalon, dorsolateral thalamic nucleus, and raphe nuclei and in association with the forebrain bundles. Except for in the optic tectum, there is a good concordance of [125I]GAL binding sites and GAL‐immunoreactive fiber projections in most brain areas of the salmon. The wide distribution of GAL binding sites provides further evidence that a GAL‐like substance might be involved in a diversity of brain functions of teleosts. The topographic distribution of target sites in the hypothalamo‐hypophyseal axis indicates that GAL‐like substances may have both direct and indirect effect on pituitary functions while in extrahypothalamic areas, functional implications by GAL may include involvement in somatosensory, central gustatory, olfactory, and visual functions.This study provides evidence for the presence of a specific GAL receptor in the brain of the Atlantic salmon. Together the distribution of GAL binding and GAL‐like molecules provide a covering delineation of the GAL neuronal system in the brain of the Atlantic salmon. Comparisons with mammals suggest that the GAL receptor molecule has been well preserved during evolution and that GAL‐like substances may be present, and even possess similar functional properties, throughout the vertebrate phylogeny. © 1992 Wiley‐Liss, Inc.
Comparative molecular neuroanatomy of cloned GABAAreceptor subunits in the rat CNS
Authors: Persohn E. , Malherbe P. , Richards J. G. 
Published: January 2005

Abstractγ‐Aminobutyric acidA(GABAA) receptors in the mammalian central nervous system (CNS) are members of a family of ligand‐gated ion channels consisting of heterooligomeric glycoprotein complexes in synaptic and extrasynaptic membranes. Although molecular cloning studies have identified 5 subunits (with ∼40% amino acid homology) and isoforms thereof (∼70% homology), namely α1–6, β1–4, γ1–3, δ, and ρ, the subunit composition and stoichiometry of native receptors are not known.The regional distribution and cellular expression of GABAAreceptor messenger RNAs (mRNAs) in the rat CNS have now been investigated by in situ hybridization histochemistry with subunit‐specific35S‐labelled oligonucleotide probes on adjacent cryostat sections. Whereas α1, β2, and γ2 transcripts were the most abundant and ubiquitous in the rat brain—correlating with the radioautographic distribution of GABAAreceptors revealed by an ionophore ligand—others had a more restricted expression while often being abundant. For example, α2 transcripts were found only in the olfactory bulb, cerebral cortex, caudate putamen, hippocampal formation, and certain lower brain stem nuclei; α3 only in the olfactory bulb and cerebral cortex; α5 in the hippocampal formation; and α6 only in cerebellar granule cells. In addition, β1, β3, γ1, and δ mRNAs were also uniquely expressed in restricted brain regions. Moreover, in the spinal cord, α1–3, β2,3, and γ2 mRNAs were differently expressed in Rexed layers 2–9, with α2, β3, and γ2 transcripts most prominent in motoneurons of layer 9.Although differential protein trafficking could lead to the incorporation of some subunits into somatic membranes and others into dendritic membranes, some tentative conclusions as to the probable composition of native proteins in various regions of the CNS may be drawn. For example, according to the strength of the hybridization signal the following subunits might be expected to play a prominent role in GABAergic neurotransmission in the corresponding regions: α1, β2 (1,3), γ2 in olfactory bulb mitral cells; α2, β3, γ2, δ in caudate putamen; α1,3 (2,5), β2,3, γ2 in cerebral cortex; α1, β2, γ1,2 in pallidum; α1,2,5, β1–3, γ2 in hippocampus; α1,5, β3, γ2, δ in dentate gyrus; α1, β2, γ1,2 in substantia nigra zona reticularis; α1, β2, γ2 in cerebellar Purkinje cells; α1,6, β2,3, γ2, δ in granule cells; α1,2, β2,3, γ2 in vestibular and facial nuclei; and finally α2, β3, γ2 in motoneurons of Rexed layer 9 in the spinal cord. © 1992 Wiley‐Liss, Inc.
Nerve growth factor‐induced sprouting of mature, uninjured sympathetic axons
Authors: Isaacson L. G. , Saffran B. N. , Crutcher K. A. 
Published: January 2005

AbstractThe infusion of nerve growth factor (NGF) into the lateral ventricle ofthe mature rat brain elicits a sprouting response from axons associated with the intradural segment of the internal carotid artery. Using electron microscopic techniques, we observed a three–fold increase in the total number of perivascular axons. This NGF‐elicited response is characterized by a dramatic reduction in glial cell ensheathment similar to that observed during development and by the presence of profiles devoid of organelles that may represent newly formed sprouts. In spite of the increase in axon number, no significant changes in the percentage of small, medium, or large axons wereobserved.The three‐fold increase in the total number of axons was accompanied byan increase in the number of axons/fascicle but no change in the number of fascicles. This, along with the observation that a majority of sprouted axons were associated with other axons, supports the idea that the sprouted axons tend to associate preferentially with other axons. Bilateral superior cervical ganglionectomies following cytochrome C infusion indicate that approximately 60% of the axons associated with the internal carotid artery arise from the superior cervical ganglion and that the majority of axons contacting the smooth muscle layer arise from this ganglion. Sympathectomy following NGF infusion resulted in a 79% reduction in the total number of perivascular axons, demonstrating overwhelmingly that the majority of sprouted axons are sympathetic fibers. These results demonstrate that infusion of NGF into the mature rat brain results in the preferential sprouting of sympathetic axons associated with the internal carotid artery. These findings are consistent with the hypothesis that NGF normally plays a role in the regulation of autonomic cerebrovascular innervation in the adult animal and that mature, uninjured sympathetic neurons remain responsive to NGF. © 1992 Wiley‐Liss, Inc.
A quantitative dendritic analysis of wernicke's area in humans. I. Lifespan changes
Authors: Jacobs Bob , Scheibel Arnold B. 
Published: January 2005

AbstractAge‐related increases and decreases have been described in cortical dendritic neuropil. Here, we examine age‐related changes in the basilar dendrites of supragranular pyramidal cells in human superior temporal gyrus (i.e., Wernicke's area) of left and right hemispheres. Tissue was obtained from 20 neurologically normal right‐handers from 18–79 years: 10 males (Mage = 52.2 years; SD age = 17.4) and 10 females (Mage = 47.8; SDage = 20.5). In tissue prepared by a modified rapid Golgi technique, ten pyramidal cells were sampled from each hemisphere and evaluated according to the following parameters: total dendritic length, mean dendritic length, and dendritic segment count.Despite considerable interindividual variation, the data exhibited significant dendritic degeneration with aging. There was an age‐related decrease in total dendritic length (r[20] = −0.44; P < 0.05) and especially in mean dendritic length (r[20] = –0.69; P < 0.001) with increasing age. Age‐mean dendritic length correlations were negative for all segment orders and revealed a progressive decrease in segment length in more distal branches. The number of dendritic segments remained relatively stable across the age span sampled. The data also indicated that interhemispheric dendritic asymmetries decreased with age. Individuals under 50 years of age had significantly greater total dendritic length values in the left hemisphere. Interhemispheric dendritic differences were not significant in individuals over 50. © 1993 Wiley‐Liss, Inc.
Specificity in the efferent projections of the nucleus accumbens in the rat: Comparison of the rostral pole projection patterns with those of the core and shell
Authors: Zahm D. S. , Heimer Lennart 
Published: January 2005

AbstractThe efferent connections of the rostral pole of the rat accumbens, where distinct core and shell subterritories can not be identified, were examined with the aid of the anterogradely transported plant lectin, Phaseolus vulgaris‐leucoagglutinin (PHA‐L), for comparison with the previously reported projection patterns of the accumbal core and shell. Injection sites and transported PHA‐L were evaluated with the aid of reference to adjacent sections processed to display substance P or calbindin 28 kD immunoreactivities, i.e., markers that demonstrate the core and shell. Lateral parts of the rostral pole gave rise to a “core‐like” projection system that involved the rostroventral globus pallidus, subcommissural ventral pallidum, entopeduncular nucleus and an adjacent part of the lateral hypothalamus, lateral ventral tegmental area, dorsal pars compacta, and structures in the lateral mesencephalic tegmentum and central grey. The medial part of the rostral pole gave rise to a “shell‐like” innervation of the subcommissural ventral pallidum, lateral preoptic region, lateral hypothalamus, ventral tegmental area, dorsalmost pars compacta, retrorubral field, lateral midbrain tegmentum, and central grey. In contrast to the large numbers of axon varicosities observed through the entire length of lateral hypothalamus following shell injections, dense accumulations of axon collaterals and varicosities in hypothalamus were limited to the levels of origin of the stria medullaris bundle and entopeduncular nucleus and to the posterlateral region following medial injections. The medial part of the rostral pole contributed some projections to preoptic and sublenticular regions, but not to the bed nucleus of the stria terminalis. Noteworthy concentrations of calbindin immunoreactive cells observed in the lateral rostral pole correlate with the origin of the “basal ganglia‐like” projection system, provoking the speculation that ventral striatal calbindin immunoreactive cells contribute principally to basal ganglia‐like projections while cells lacking calbindin immunoreactivity contribute to the innervation of hypothalamus and midbrain tegmentum. © 1993 Wiley‐Liss, Inc.
Detection of the 5‐HT1Areceptor and 5‐HT1Areceptor mRNA in the rat bowel and pancreas: Comparison with 5‐HT1Preceptors
Authors: Kirchgessner A. L. , Liu M.‐T. , Howard M. J. , Gershon M. D. 
Published: January 2005

AbstractWe tested the hypothesis that the rat bowel and pancreas contain 5‐HT1Areceptors.3H‐8‐hydroxy‐2‐(di‐n‐propylamino) tetralin (3H‐8‐OH‐DPAT) was used as a radioligand. Binding of3H‐8‐OH‐DPAT to membranes derived from the myenteric plexus and the pancreas was investigated by rapid filtration. Alternatively, radioautography was employed to locate3H‐8‐OH‐DPAT binding sites in frozen sections of unfixed bowel or pancreas. An excess of 5‐HT (10 μM) was used to define nonspecific binding. Saturable, high affinity binding of3H‐8‐OH‐DPAT to enteric (Kd= 2.8 ± 1.1 nM; Bmax=83.8 ± 4.3 fmol/mgproteim) and pancreatic (Kd= 6.6 ± 1.3 nM; Bmax= 44 ± 2.2 fmol/mg protein) membranes was found. The binding of3H‐8‐OH‐DPAT to enteric and pancreatic membranes was inhibited by 8‐OH‐DPAT, NAN‐190, and spiperone. In contrast, the binding of3H‐8‐OH‐DPAT to enteric and pancreatic membranes was not inhibited by 5‐carboxyamidotryptamine, or by avariety of compounds known to bind to other subtypes of 5‐HT receptor. Digoxigenin‐labeled oligonucleotides were found to detect mRNA encoding the 5‐HT1Areceptor in a subset of neurons in myenteric and submucosal ganglia. In contrast, 5‐HT1AmRNA was not found in the pancreas. Radioautography revealed that the highest density of3H‐8‐OH‐DPAT binding sites was found in the stomach. These sites were especially numerous in the lamina propria adjacent to gastric glands, and in myenteric ganglia. Pancreatic 5‐HT1Areceptors were located on nerves, lymphoid tissue (especially the capsule of nodes), and on cells scattered in the pancreatic parenchyma. The concentration of3H‐8‐OH‐DPAT binding sites in the rat bowel and pancreas was less than that of3H‐5‐HT binding sites; however, the distribution of3H‐8‐OH‐DPAT binding sites was similar to that of sites that bind3H‐5‐HT. It is concluded that the rat gut and its extension in the pancreas contains 5‐HT1Areceptors. Many, if not all, of the nerve cells and processes that express 5‐HT1Areceptors express 5‐HT1preceptors as well. The function of these receptors in the physiology of the entero‐pancreatic innervation remains to be determined. © 1993 Wiley‐Liss, Inc.