bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal age defines specificity of immediate early gene induction by cocaine in developing rat brain
Authors: Kosofsky Barry E. , Genova Lisa M. , Hyman Steven E. 
Published: January 2005

AbstractClinical and animal data suggest that exposure of developing brain to cocaine has adverse consequences. One candidate mechanism for such effects is drug regulation of gene expression. In adult rats, cocaine induces expression of nuclear immediate early genes with specific spatial and temporal patterns. The products of such genes (e.g., c‐Fos, c‐Jun, and Zif/268) subserve the coupling of cell surface receptor stimulation to transcriptional regulation. Thus, activation of immediate early gene expression in developing brain by cocaine could alter programs of neural gene expression and, thereby, neuronal phenotype and function. We report that, during rat brain development, cocaine produced brain region‐specific and developmental age‐specific induction of c‐fos, c‐jun, and zif/268 mRNAs. At each age studied (P8, P15, P28, and adults), we found that acute cocaine administration resulted in a unique cell‐specific pattern of c‐fos mRNA induction and c‐Fos protein expression in striatum. We also observed cocaine‐induced activation of AP‐1 DNA binding activity in striatal extracts prepared at these different ages, suggesting that the observed induction of c‐fos and c‐jun may have biological consequences for the developing brain. These findings suggest a mechanism by which cocaine could alter patterns of gene expression during critical developmental periods with differential regional, temporal, and cellular vulnerabilities and, therefore, consequences for developing brain. © 1995 Willy‐Liss, Inc.
A1 catecholamine cell group: Fine structure and synaptic input from the nucleus of the solitary tract
Authors: Chan R. K. W. , Peto C. A. , Sawchenko P. E. 
Published: January 2005

AbstractPreembedding immunoperoxidase staining methods were used to characterize tyrosine hydroxylase‐immunoreactive (TH‐ir) elements in the caudal ventrolateral medulla, and to determine the extent to which neurons of the A1 cell group are directly innervated by projections of the nucleus of the solitary tract (NTS). TH‐ir neurons in the A1 region were medium‐sized and multipolar. They possessed rounded nuclei with infrequent invaginations, well‐developed Golgi apparati, high cytoplasmic densities of mitochondria, and a low to moderate tendency for rough endoplasmic reticulum (RER) to align in parallel stacks. A1 cell bodies were commonly juxtaposed to TH‐positive and TH‐negative neurons, myelinated profiles, glia and /or vascular elements, but close membrane appositons were only seen with glial elements. Synaptic input to A1 neurons was predominantly asymmetric, provided virtually exclusively by non‐TH‐ir terminals, and directed principally to dendritic shafts; A1 somata are relatively sparsely innervated. In a second experiment, silver‐intensified immunogold localization of TH‐ir was combined with immunoperoxidase labeling for anterogradely transported Phaseolus vulgaris‐leucoagglutinin (PHA‐L), following tracer injections in the caudal aspect of the medial division of the NTS. These experiments revealed a small proportion of PHA‐L‐labeled axon terminals that made asymmetric contacts with dendritic shafts of TH‐ir neurons. These results suggest that the fine structure and synaptic input of A1 neurons are somewhat distinct from that of rostrally situated C1 catecholamine cells. In addition, while they document a direct NTS‐A1 projection that may participate in the interoceptive control of vasopressin secretion, the bulk of ventrolaterally directed projections from the caudomedial NTS contact noncatecholaminergic elements in the A1 region, some of which may correspond to so‐called depressor neurons implicated in the baroreflex control of sympathetic outflow and vasopressin secretion. © 1995 Willy‐Liss, Inc.
Localization of a nicotinic acetylcholine receptor‐like antigen in the thoracic nervous system of embryonic locusts, Schistocerca gregaria
Authors: Watkins B. L. , Leitch B. , Burrows M. , Knowles B. H. 
Published: January 2005

AbstractSodium dodecyl sulfate‐polyacrylamide gel electrophoresis and subsequent immunoblotting of neuronal membrane proteins derived from thoracic ganglia of adult Locusta and Schistocerca reveal that a polyclonal antiserum raised against the Locusta nicotinic acetylcholine receptor (nAChR), binds strongly to an identical polypeptide band corresponding to 65 kDa in both locust species. This polyclonal antiserum was used to analyze the distribution of antigenic sites within the developing thoracic central nervous system of Schistocerca embryos. Axonal outgrowths from the earliest differentiated neurons are first labeled between 30% and 35% development. By 40% to 45% development, labeled granules appear in the cytoplasm of neuronal cell bodies. When the developing neuropil is first enclosed at approximately 45% to 50% development, it appears uniformly labeled, but by 55% development, unlabeled areas appear that represent the sites of future tracts and commissures. By 75%, an adult pattern of neuropil immunogenicity is established in which synaptic regions are stained but tracts and commissures are not. This suggests that during the early development of the thoracic nervous system nAChR‐like antigenic sites are evenly distrubuted, but later become concentrated in the developing synaptic areas. © 1995 Willy‐Liss, Inc.
Light and electron microscopic study of m2 muscarinic acetylcholine receptor in the basal forebrain of the rat
Authors: Levey Allan I. , Edmunds Sharon M. , Hersch Steven M. , Wiley Ronald G. , Heilman Craig J. 
Published: January 2005

AbstractThe m2 muscarinic acetylcholine receptor gene is expressed at high levels in basal forbrain, but the paucity of information about localization of the encoded receptor protein has limited the understanding of cellular and subcellular mechanisms involved in cholinergic actions in this region. The present study sought to determine the cellular localization of m2 protein, its relationship to cholinergic neurons, and its pre‐and postsynaptic distribution in the rat medial septum‐diagonal band complex using immunocytochemistry with polyclonal rabbit antibodies and a newly developed rat monoclonal antibody specific to the m2 receptor. Light microscopic colocalization studies demonstrated that m2 was present in a subset of choline acetyltransferase immunoreactive neurons, in choline acetyltransferase‐negative neurons, and in more neuropil elements than was choline acetyltransferase. Intraventricular injections of 192 IgG‐saporin, an immunotoxin directed to the low‐affinity nerve growth factor receptor, resulted in depletion of choline acetyltransferase‐immunoreactive neurons in the medial septum‐diagonal band complex, whereas m2 immunoreactivity in neurons and in the neuropil was unchanged. By electron microscopy, m2 receptor in medial septum‐diagonal band complex was localized to the plasmalemma of a small population of small to medium‐sized neurons, and it was also found in dendrites, axons, and axon terminals in the neuorpil Neurons expressing m2 immunoreactivity recived synaptic contacts from unlabelled axon terminals. A small distinct subpopulation of large neurons, unlabelled by m2 immunoreactivity, received synaptic contacts from m2‐immunoreactive terminals. Thus, m2 receptor is situated to mediate the local effects of acetylcholine on basal forebrain cholinergic and noncholinergic neurons and, also, at both pre‐and postsynaptic sites. © 1995 Willy‐Liss, Inc.
Fine sensory innervation of the knee joint capsule by group III and group IV nerve fibers in the cat
Authors: Heppelmann B. , Messlinger K. , Neiss W. F. , Schmidt R. F. 
Published: January 2005

AbstractAfferent group III and IV nerve fibers of the knee joint markedly differ in their responsiveness to mechanical stimulation, which may be reflected in the structure and location of their terminals. Therefore, in sympathectomized cats, the fine afferent innervation of the knee joint capsule was studied via ultrastructural three‐dimensional reconstructions over distance of up 300 μm. Small peripheral nerves and “free” (noncorpuscular) sensory nerve ending were found in a superficial layer of the outer fibrous part of the capsule, in the patellar retinaculum, and in the outer and inner surface layers of the medial collateral and patellar ligaments. Group III nerve fibers showed a proximal myelinated portion inside the nerve, an intermediate portion that lacks a myelin sheath and is only surrounded by perineurium, and a distal portion outside of the perineurium that forms the sensory ending proper. Group IV fibers showed only two distinct portions, an intraperineurial (proximal) and an extraperineurial (distal) portion without any further morphological differences. Outside of the perineurium, a network formed by Schwann cells (“Schwann cell reticulum”) provides a pathway for the distal portion of the sensory axons. No distinct subgroups of the sensory terminal fibers could be defined according to the configuration of the Schwann cells and the nerve fiber terminals. Sensory terminals were located adjacent to different structures such as venous and lymphatic veesels, fat cells, and collagenous fibers. Distinct parts of the same terminal nerve fiber were found in close contact to a vessel wall; others were surrounded by dense collagenous tissue. Close to sensory endings, mast cells and mast cell‐like cells were frequently found, indicating a functional relationship. © 1995 Willy‐Liss, Inc.
Embryonic development of the antennal lobes of a hemimetabolous insect, the cockroach periplaneta americana: Light and electron microscopic observations
Authors: Salecker Iris , Boeckh Jürgen 
Published: January 2005

AbstractIn the hemimetabolous insect Periplaneta americana, the adult‐like organization of the primary olfactory centers, the antennal lobes, is established during the ∼31 days of embryogenesis. This report describes the temporal sequence of developmental events as viewed in the light and electron microscope by means of histological stains and by DiI labeling of antennal receptor axons with subsequent photoconversion.Glomeruli, characteristic differentiations of the antennal lobe neuropil, are first observed on day 19; their development, which is not synchronous in the various parts of the antennal lobe, lasts until about day 22. From day 10 on, glial cells begin to form a narrow boundary layer between the soma cortex and the central neuropil. They exhibit a lengthening of their processes in parallel with the formation of glomeruli. Marked proliferation or migration of these glial cells into the neuropil between glomeruli has not been observed. Antennal receptor axons could be labeled from stage 15 on. They terminate in an elongated growth cone with numerous filopodia. From day 18 on, some of these become bent or show an initial bifurcation. From day 22 on, the first afferent axons develop an adult‐like arborization pattern. Synaptic contacts between receptor axons, and unidentified neurons were observed as early as stages 16 and 19, in which the axons still have a growth cone‐like form. In stage 27, in which the fibers have adult‐like arborizations, many output contacts and few input contacts were found. © 1995 Wiley‐Liss, Inc.
Localization of amyloid P component in human brain: Vascular staining patterns and association with alzheimer's disease lesions
Authors: Perlmutter Lynn S. , Barrón Ernesto , Myers Martha , Saperia David , Chui Helena Chang 
Published: January 2005

AbstractAmyloid P component is a normal serum protein that is highly conserved across phylogeny. Although it resembles the classic acute‐phase reactant C‐reactive protein, and is considered to be a normal extracellular matrix component, its physiologic role in humans is unknown. Amyloid P component is also colocalized with accumulations of all recognized forms of amyloid. The present study uses light and electron microscopy to compare the cerebral localization of amyloid P component in cases with (n = 19) and without (n = 15) Alzheimer's disease (AD). In non‐AD cases, amyloid P component was predominantly localized to the cerebrovasculature. Perivascular staining was observed in most cases, more so in the white than in the gray matter. In AD cases, amyloid P component was localized to all three characteristic histopathologic lesions, namely, neurofibrillary tangles, senile plaques, and amyloid angiopathy. Furthermore, in cases with prominent staining of gray matter parenchymal lesions, intravascular staining was decreased. Given the fixation and processing methods used, amyloid P component was never seen to be localized to the cerebrovascular basement membrane. These data argue against amyloid P component's postulated role as the anchor for vascular β‐amyloid deposition. Because there is no evidence for intrinsic amyloid P component production in brain, its perivascular and parenchymal distributions suggest either compromise of the blood‐brain barrier or transport across vascular endothelium. © 1995 Wiley‐Liss, Inc.
Synaptic distribution of afferents from reticular nucleus in ventroposterior nucleus of cat thalamus
Authors: Liu Xiao‐Bo , Warren Richard A. , Jones Edward G. 
Published: January 2005

AbstractThis study was aimed at determining the synaptic circuitry that contributes to the alterations in thalamic function that accompany changes in behavioral states.The somatosensory sector of the thalamic reticular nucleus (RTN) was identified by microelectrode recording in cats and injected with Phaseolus vulgaris‐leucoagglutinin (PHA‐L). The axons of labeled RTN cells gave rise to collaterals within the RTN and continued into the dorsal thalamus where they terminated predominately in the ventral posterior lateral nucleus (VPL). After small injections in the upper limb representation of RTN, most labeled terminations in VPL were confined to its medial part, suggesting the presence of a topographic organization in the projection.Terminations were concentrated in localized, focal aggregations of boutons. Combined electron microscopic immunocytochemistry, using immunogold labeling for γ‐aminobutyric acid (GABA), showed that the PHA‐L labeled boutons were GABA‐positive terminals that ended in symmetrical synapses. Eighty‐two percent of these synapses were on dendrites of relay neurons, 8.5% on dendrites of interneurons, and 9.3% on somata.The terminals of RTN axons form the majority of axon terminals ending in symmetrical synapses in VPL. Their concentration on relay neurons probably underlies the capacity of the RTN projection to reduce background activity of VPL relay neurons in the awake state and to maintain oscillatory behavior of these neurons in drowsiness and early phases of Sleep. © 1995 Wiley‐Liss, Inc.
Host primary olfactory axons make synaptic contacts in a transplanted olfactory bulb
Authors: Goheen B.L. , Kott J.N. , Anderson N.L. , Kim A. , Westrum L.E. 
Published: January 2005

AbstractPrevious light microscopic studies have shown that host olfactory neurons are able to grow into a transplanted fetal olfactory bulb, and behavioral studies have shown that animals with transplanted olfactory bulbs recover functional olfactory abilities. We examined the olfactory bulb transplant at the ultrastructural level to determine whether synaptic contacts are reestablished between host olfactory neurons and donor olfactory bulb. Mature rats that, as neonates, had received embryonic olfactory bulb transplants following olfactory bulb removal were studied. An antibody specific for olfactory marker protein was used to identify the primary olfactory neurons; it was bound by a gold‐conjugated secondary antibody for visualization. To preserve the antigenicity of the olfactory marker protein for immunolabeling, Lowicryl K4M hydrophilic resin was used. Synaptic contacts were unmistakable between labeled axons of host olfactory neurons and unlabeled processes within glomerulus‐like areas of the transplanted olfactory bulb. The surrounding neuropil contained other elements similar to those found in normal tissue, including synaptic contacts between unlabeled profiles. We clearly show that the transplanted olfactory bulb exhibits sufficient plasticity to form an array of normal synaptic contacts, including the contacts from host primary olfactory neurons. © 1995 Wiley‐Liss, Inc.
Origins of serotonin‐like immunoreactivity in the optic tectum of rana pipiens
Authors: Liu Qin , Debski Elizabeth A. 
Published: January 2005

AbstractWe have previously identified a population of serotonin‐like immunoreactive (5‐HT‐ir) retinal ganglion cells in Rana pipiens. In this study, we examined serotonin‐like immunoreactivity (5‐HTLI) in a probable target of those cells, the optic tectum. We observed both 5‐HT‐ir fibers and cell bodies in this structure. 5‐HT‐ir cells were located in the cellular layers of the tectum, layers 2, 4, and 6, and scattered in its superficial layers. 5‐HT‐ir fibers in the tectum displayed a laminated organization and were located in tectal layers 3, 5, 6, 7, and 9. Retrograde labelling experiments showed that 5‐HT‐ir retinal ganglion cells projected to the optic tectum. However, these experiments also demonstrated that serotonergic neurons in the midbrain tegmentum, the nucleus isthmi, and the medulla did so as well. 5‐HT‐ir fibers seen in lamina A of layer 9 were very much reduced in density in animals in which the optic nerve had been lesioned for 3–6 months. Immunoreactive fibers in lamina B of layer 9 were not affected by the lesion.Our results suggest that 5‐HT‐ir fibers in lamina A of layer 9 are mainly of retinal origin, whereas those in lamina B originate from other brain areas. The 5‐HT‐ir tectal cells located in the cellular layers probably contribute the 5‐HT‐ir fibers seen in layers 3, 5, 6, and 7. © 1995 Wiley‐Liss, Inc.
Sensory neuron development revealed by taurine immunocytochemistry in the honeybee
Authors: Eichmütler Stefan , Schäfer Sabine 
Published: January 2005

AbstractThe formation of ommatidia in the compound eyes and sensilla on the antennae of the honeybee was followed and the development of their sensory neurons was traced using an antiserum against taurine as a marker. Taurine‐like immunoreactivity (Tau‐IR) is expressed in sensory neurons of several modalities, namely visual, olfactory, gustatory, and mechanosensory. Staining intensity is very high in the larva and in the first half of the pupal stage and gradually decreases towards the end of metamorphosis. In the photoreceptor cells of the compound eyes, Tau‐IR can be detected from the fifth larval instar onwards, prior to differentiation of other components of the ommatidium. Already in the midstage larvae, when the antennal primordia of the adult still lie within the peripodial cavity, a few presumably mechanosensory neurons are labelled in the pedicellus of the developing antenna. The majority of the antennal sensory neurons which are located on the flagellum start to exhibit Tau‐IR upon pupation, long before any cuticular specializations such as sensory hairs or plates are detectable. All known types of antennal sensilla were identified and it could be shown that all of them are innervated by Tau‐IR sensory neurons. Thus, taurine immunocytochemistry can be applied as a useful label for developing sensory neurons. Functional implications of taurine during development are discussed. © 1995 Wiley‐Liss, Inc.
Neural organization of ocellar pathways in the cockroach brain
Authors: Mizunami Makoto 
Published: January 2005

AbstractA large number of photoreceptors of insect ocelli converge onto a smaller number of second‐order neurons. Second‐order neurons exit the ocellus and project into the ocellar tract neuropil of the brain. Here, the anatomy and physiology of ocellar interneurons of the ocellar tract neuropil of the cockroach are described. The total number and gross morphologies of ocellar tract neurons were examined by extracellular cobalt impregnations into the neuropil. Morphology and physiology of individual neurons were examined using intracellular recording and stainings. Each ocellar tract neuropil contains at least 25 interneurons comprising: (1) four second‐order neurons, (2) 15 third‐order neurons that receive synapses from second‐order neurons at the ocellar tract and project into a number of target neuropil areas of the brain, (3) two possible efferent neurons, (4) three third‐order or efferent neurons, and (5) one neuron still to be characterized. The projection areas of ocellar third‐order neurons include (1) visual, olfactory, and mechanosensory centers; (2) the mushroom body (a higher associative center); (3) the posterior slope, a premotor center from which descending brain neurons originate; and (4) the thoracic motor systems. By comparing the present results to those reported from other insects, I conclude that the cockroach ocellar system has two distinctive features. (1) The ratio of convergence at synapses between photoreceptors and second‐order neurons is higher than those reported for other insects so far studied. (2) Ocellar signals are transmitted to various target neuropils by third‐order neurons, whereas ocellar systems of all other insects possess pathways in which ocellar signals are transmitted to target neuropils by second‐order neurons. The functional significance of these features of the cockroach ocellar system is discussed. © 1995 Wiley‐Liss, Inc.
Hippocampal mossy fiber sprouting and synapse formation after status epilepticus in rats: Visualization after retrograde transport of biocytin
Authors: Okazaki Maxine M. , Evenson Debra A. , Victor Nadler J. 
Published: January 2005

AbstractIn complex partial epilepsy and in animal models of epilepsy, hippocampal mossy fibers appear to develop recurrent collaterals, that invade the dentate molecular layer. Mossy fiber collaterals have been proposed to subserve recurrent excitation by forming granule cell‐granule cell synapses. This hypothesis was tested by visualizing dentate granule cells and their mossy fibers after terminal uptake and retrograde transport of biocytin. Labeling studies were performed with transverse slices of the caudal rat hippocampal formation prepared 2.6–l70.0 weeks after pilocarpine‐induced or kainic acid‐induced status epilepticus. Light microscopy demonstrated the progressive growth of recurrent mossy fibers into the molecular layer; the densest innervation was observed in slices from pilocarpine‐treated rats that had survived 10 weeks or longer after status epilepticus. Thin mossy fiber collaterals originated predominantly from deep within the hilar region, crossed the granule cell body layer, and formed an axonal plexus oriented parallel to the cell body layer within the inner one‐third of the molecular layer. When sprouting was most robust, some recurrent mossy fibers at the apex of the dentate gyrus reached the outer two‐thirds of the molecular layer. The distribution and density of mossy fiber‐like Timm staining correlated with the biocytin labeling. When viewed with the electron microscope, the inner one‐third of the dentate molecular layer contained numerous mossy fiber boutons. In some instances, biocytin‐labeled mossy fiber boutons were engaged in synaptic contact with biocytin‐labeled granule cell dendrites. Granule cell dendrites did not develop large complex spines (“thorny excrescences”) at the site of synapse formation, and they did not appear to have been permanently damaged by seizure activity. These results establish the validity of Timm staining as a marker for mossy fiber sprouting and support the view that status epilepticus provokes the formation of a novel recurrent excitatory circuit in the dentate gyrus. Retrograde labeling with biocytin showed that the recurrent mossy fiber projection often occupies a considerably greater fraction of the dendritic region than previous studies had suggested. © 1995 Wiley‐Liss, Inc.