bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunocytochemical expression of the blood—brain barrier glucose transporter (GLUT‐1) in neural transplants and brain wounds
Authors: Rosenstein Jeffrey M. , More Newton S.
Published: January 2005

The present study examined the immunocytochemical expression of the blood—brain barrier glucose transporter (GLUT‐1) in a series of fetal neocortical transplants, autonomic tissue transplants, and stab wounds to the rat brain. GLUT‐1 is one of a family of different glucose transporters and is found exclusively on barrier‐type endothelial cells. In the brain it is responsible for the regulated facilitative diffusion of glucose acress the blood—brain barrier. This investigation is the first to determine if this important molecule is altered during the process of angiogenesis that occurs following neural transplanatation procedures of direct brain injury.

Beginning in late fetal brain, e.g., E18 and continuing into maturity, GLUT‐1 was strongly and exclusively expresed on normal cerebral vessels. In solid fetal central nervous system (CNS) transplants up to around 3 weeks postoperative, CLUT‐1 was only weakly expressed, particularly as exemplified by colloidal gold immunostaining when compared with the host. At later times examined, up to 15 months postoperative, GLUT‐1 immunoexpression was comparable with the normal adjacent brain. In autonomic tissue transplants, where the vessels do not have a blood—brain barrier, as expected, GLUT‐1 was not expressed. In stab wounds, at 1 week there was extensive gliosis, and the injured vessels appeared fragmented and collapsed but still expressed GLUT‐1, although to a somewhat lesser extent than normal brain. Between 3 and 6 weeks, GLUT‐1 was expressed on tortuous vessels and in apparently fibrillar processes in the wound vicinity with a similar pattern to astrocyte (GFAP) reactivity. These results suggest the occurrence of a down‐regulation of GLUT‐1 in early transplats, perhaps related to reduced glycolytic activity or transient ischemia, or possibly due to the utilization of alternative energy sources. That GLUT‐1 expression was not entirely lost in stab wounds to the mature brain suggests that the protein may be more labile in fetal or perinatal brain than in the adult and may not be affected by direct injury. Coupled with previous transplantation studies that have shown reduced neuronal glycolysis and potential barrier alteraations, the reduction of GLUT‐1 activity within nearly the identical time frame could indicate a relatively early critical period in cellular metabolism following transplantation of CNS tissue. © Wiley‐Liss, Inc.
Morphology, physiology, and homology of the N‐cell and muscle receptor organs in the thorax of the crayfish Cherax destructor
Authors: Macmillan David L. , Field Laurence H.
Published: January 2005

The serial homology of arthropods, together with our ability to identify individual neurons from segment to segment, and from animal to animal, provides opportunities for studying the changes wrought by natural selection on specific neural elements when functional requirements change in different parts of the trunk. Using this concept as a guide, we studied the morphology and physiology of the thoracic N‐cells and muscle receptor organs (MROs) of the crayfish Cherax destructor for evidence of serial homology and functional plasticity. Methylene blue staining, together with anterograde and retrograde filling with cobalt through cut axons, revealed the morphology of the receptors, disposition of their endings, and the pathways of their axons from receptor to ganglion. The seventh thoracic segment has tonic and phasic MROs with receptor muscles in parallel with different heads of the deep thoraco‐abdominal extensor muscle. The sixth segment has a tonic MRO with a receptor muscle in parallel with one head of the abdominal abductor. These three receptors are typical MROs complete with accessory nerves. Thoracic segments 1–5 each give rise to one mechanosensory N‐cell with a small cell body and long processes ramifying in a target muscle. N‐cell 5 is associated with the abdominal‐thoracic abductor muscle, and the other four are associated with parts of the epimeral attractor. The responses of N‐cells 1–4 range from tonic to phasico‐tonic and show a range of thresholds to passive muscle stretch and active contraction. Cobalt introduced into bundles of nerve fibers known to include N‐cell axons reveals projections with branching patterns and morphology similar to abdominal MROs. The present findings, together with information on thoracic MROs and N‐cells from other species, were tabulated according to neurotome. The clear pattern revealed leads us to propose that N‐cells are derivatives of segmentally repeating MROs modified to monitor postural and locomotory movements in the less mobile thorax.
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

Clinical 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

Preembedding 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

Sodium 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

The 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

Afferent 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

In 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

Amyloid 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

This 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

Previous 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

We 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

The 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

A 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

In 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.
Expression of chondroitin sulfate and keratan sulfate proteoglycans in the path of growing retinal axons in the developing chick
Authors: McAdams Brian D. , McLoon Steven C.
Published: January 2005

Previous investigations have identified proteoglycans in the central nervous system during development and have implicated some proteoglycans as axon guidance molecules that act by inhibiting axon extension. The present study investigated the pattern of immunoreactivity for several glycosaminoglycans common to certain proteoglycans relative to growing retinal axons in the developing chick visual system and in retinal explant cultures. Immunostaining for chondroitin‐6‐sulfate, chondroitin‐4‐sulfate, and keratan sulfate was observed to colocalize with retinal axons throughout the retinofugal pathway during the entire period of retinal axon growth. The proteoglycan form of collagen IX, however, was only observed in the retina, primarily peripheral to the areas with actively growing axons, The pattern of immunostaining for chondroitin sulfate in tissue sections suggested that the retinal axons might be a source for some of the chondroitin sulfate immunostaining in the developing visual pathway. This was confirmed in that chondroitin sulfate immunostaining was also observed on neurites emanating from cultured retinal explants. These findings indicate that retinal axons grow in the presence of chondroitin sulfate and keratan sulfate proteoglycans and that these proteoglycans in the developing chick visual pathway have functions other than to inhibit axon growth. © 1995 Wiley‐Liss, Inc.
Localization of the heptapeptide GFSKLYFamide in the sea cucumber holothuria glaberrima (echinodermata): A light and electron microscopic study
Authors: Díaz‐Miranda Lucy , Blanco Rosa E. , García‐Arrarás José E.
Published: January 2005

Two peptides, Gly‐Phe‐Ser‐Lys‐Leu‐Tyr‐Phe‐ NH2 (GFSKLYFamide) and Ser‐Gly‐Tyr‐Ser‐Val‐Leu‐Tyr‐Phe‐ NH2 (SGYSVLYFamide), recently isolated from the sea cucumber Holothuria glaberrima [Díaz‐Miranda et al. (1992) Biol. Bull. 182:241–247] represent the first neuropeptides isolated from holothurians. Using an antibody against GFSKLYFa, we describe here the localization and distribution pattern of GFSKLYFa‐like immunoreactivity in H. glaberrima, where immunoreactive fibers form a prominent and extensive peptidergic nervous system component. Neuron‐like cells and nerve fibers expressing GFSKLYFa‐like immunoreactivity are found in the ectoneural and hyponeural divisions of the radial nerve cords as well as in the digestive, haemal, respiratory, and reproductive systems; in the tentacles; and in tube feet. Neuroendocrine‐like cells are found in the mucosal layer of the intestine. Ultrastructure immunocytochemical analysis revealed that, in nerve cells and fibers in the serosal layer of the intestine, the immunoreactivity is concentrated in vesicles. The immunoreactive nerve fibers are found mainly within a dense nerve plexus overlying and in close contact with smooth muscle cells of the intestine.

The exclusive expression of GFSKLYFa‐like immunoreactivity in neuronal or neuroendocrine tissue together with the close apposition of some fibers to muscle cells suggests that GFSKLYFa acts as a neuromuscular transmitter or neuromodulator in H. glaberrima. The wide occurrence of GFSKLYFa‐like immunoreactivity throughout the nervous system of the sea cucumber suggests that GFSKLYFa plays an important role in the control of multiple action systems, including digestion, respiration, circulation, reproduction, and locomotion. © 1995 Wiley‐Liss, Inc.
Early cytoskeletal changes following injury of giant spinal axons in the lamprey
Authors: mcHale Mary K. , Hall Garth F. , Cohen Melvin J.
Published: January 2005

The spinal cord of the larval sea lamprey contains identified giant axons that readily regenerate following spinal transection. In this study, we used serial light and electron microscopy to analyze the early ultrastructural consequences of axotomy in the proximal stumps of these axons near the lesion site. Axotomy results in two types of striking ultrastructural changes: (1) changes associated with the degeneration of axoplasm and subsequent retraction of the cut axon from the lesion and (2) changes associated with the early stages of axonal regeneration. Degenerative changes include the disruption of mitochondria to form large vacuoles, the collapse of neurofilaments into closely packed masses (condensed filamentous cores; CFCs), and the appearance of amorphous electron‐dense bodies (dense granular masses; DGMs). Events associated with regeneration include the disappearance of vacuoles, DGMs, and CFCs and the appearance of small, sprout‐like projections from the axon stump. Thus, we show that degenerative and regenerative events can be clearly separated from one another in identified axons, unlike the situation in the central nervous systems of amniote vertebrates such as mammals. © 1995 Wiley‐Liss, Inc.
Ultrastructural and immunocytochemical characterization of terminals of postsynaptic ascending dorsal column fibers in the rat cuneate nucleus
Authors: De Biasi S. , Vitellaro‐Zuccarello L. , Bernardi P. , Valtschanoff J. G. , Weinberg R. J.
Published: January 2005

The morphology, synaptic contacts, and neurotransmitter enrichment of postsynaptic dorsal column terminals in the cuneate nucleus of rats were investigated and compared with those of identified primary afferents. For this purpose, anterograde transport of horseradish peroxidase–based tracers injected in the spinal cord was combined with postembedding immunogold labeling for glutamate and gamma‐aminobutyric acid (GABA).

Anterogradely labeled postsynaptic dorsal column terminals were morphologically homogeneous: they were small (mean area = 1. 37 μM2) and dome‐shaped, contacted single dendritic shafts or cell bodies, and were not involved in axoaxonic synapses. The majority of them were not enriched in glutamate or GABA immunoreactivity compared with other tissue components. Their morphology, size, and neurotransmitter content thus differed from that of primary afferents. These differences are consistent with distinct functional roles for the two main afferent systems ascending to the cuneate nucleus. © 1995 Wiley‐Liss, Inc.
Neurochemical coding of enteric neurons in the guinea pig stomach
Authors: Schemann Michael , Schaaf Cornelia , Mäder Michael
Published: January 2005

The aim of this study was to investigate the neurochemical coding of myenteric neurons in the guinea pig gastric corpus by using immunohistochemical methods. Antibodies and antisera against calbindin (CALB), calretinin (CALRET), choline acetyltransferase (ChAT), calcitonin gene‐related peptide (CGRP), dopamine β‐hydroxylase (DBH), β‐endorphin (ENK), neuropeptide Y (NPY), neuron‐specific enolase (NSE), nitric oxide synthase (NOS), protein gene product 9.5 (PGP), parvalbumin (PARV), serotonin (5‐HT), somatostatin (SOM), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. Double‐ and triple‐labeling studies revealed colocalization of certain transmitters and enabled the identification of distinct subpopulations of gastric enteric neurons. NPY/VIP/NOS/ENK were present in 28% of all neurons, whereas 11% had NPY/VIP / DBH / ChAT; NOS‐only neurons made up 2% of the population. The combination SP/ChAT/ENK occurred in 21% of the population, whereas SP/ChAT/ENK/CALRET and SP/CHAT/SOM/ ± CALRET was identified in 5% and 6% of all cells, respectively. 5‐HT‐containing neurons comprised 2% of all cells and could be further classified by the presence of additional antigens as 5‐HT/SP/(ChAT) or 5‐HT/VIP/(ChAT). Approximately 21% of all neurons contained only ChAT with no additional antigen present and are referred to as ChAT/–. Gastric myenteric ganglion cells were not immunoreactive for CALB, PARV, CGRP, or TH. The results of this study indicate that gastric myenteric neurons can be characterized on the basis of different chemical coding. Neurochemical coding of corpus myenteric neurons revealed some similarities and significant differences in comparison with other regions of the gut. These differences might reflect adaptation of enteric nerves according to regional specialization and the distinct functions of the proximal stomach as a gastric reservoir. © 1995 Wiley‐Liss, Inc.
Preservation of topography in the connections between the subiculum, field CA1, and the entorhinal cortex in rats
Authors: Tamamaki Nobuaki , Nojyo Yoshiaki
Published: January 2005

In order to examine whether the entorhinal‐hippocampal‐entorhinal circuit is reciprocal and topographic, the connections between the subiculum, the CA1 field, and the entorhinal cortex were studied with the carbocyanine dye (Dil), which moves in both retrograde and anterograde directions. We investigated the organization of reciprocal connections revealed by injections of Dil in the entorhinal cortex along the rhinal sulcus. Anterograde fluorescent labeling showed the same pattern reported in previous studies of the dorsal hippocampus. When the injection site of DiI extended into the deep layers (IV–VI) of the same cortical column, the anterograde labeling of the perforant path was accompanied by retrograde labeling of the subicular neurons and the CA1 neurons. The distribution of labeled cells overlapped the distribution of labeled fibers, and the distribution of labeled cells paralleled that of the labeled fibers in the CA1 field. DiI injection into the medial entorhinal cortex revealed fewer retrogradely labeled subicular neurons than injection into the lateral entorhinal cortex, whereas the number of labeled CA1 neurons was not dependent on the injection site. The number of labeled CA1 neurons was always several times greater than the number of subicular neurons. Thus, the amount of information conveyed by the CA1 projection might be higher than that conveyed by the subicular projection. These results indicate that the entorhinal cortex, CA1, and the subiculum are connected reciprocally and topographically. We believe that the framework of the major hippocampal circuit proposed in previous studies should be reconsidered. We propose that the CA1 projection, rather than the subicular projection, is the main projection that feeds back information from the hippocampus to the entorhinal cortex. © 1995 Wiley‐Liss, Inc.
Distribution of myomodulin‐like immunoreactivity in the brain and retrocerebral complex of the locust, schistocerca gregaria
Authors: Swales Lesley S. , Evans Peter D.
Published: January 2005

The distribution of myomodulin‐like immunoreactivity is described for the brain and retrocerebral complex of an insect, the locust, Schistocerca gregaria. The locust brain contains 70–100 neuronal cell bodies and numerous neuropilar processes exhibiting myomodulin‐like immunoreactivity. The most marked feature of the staining is a group of lateral tritocerebral neurones that form a highly immunoreactive tract that gives rise to a complex neuropile of stained processes in the dorsal tritocerebrum. This tract continues dorsally and bifurcates into a major branch that exits the brain via nervi corpora cardiaca 1 (NCC1) to innervate the corpora cardiaca and the corpora allata. A minor branch, consisting of several individual axons, combines with immunoreactive processes from the ventral nerve cord and generates a complex immunoreactive neuropile in the anterior and posterior regions of the protocerebrum. Immunoreactive processes are also found in the structured neuropile of the central body complex. Immunoreactive cell bodies are also found in the antennal lobes, in the lateral margins of the protocerebrum, in the optic lobes, and in a few cells in the pars intercerebralis.

The results suggest that myomodulin‐like neuropeptides may play roles as central neurotransmitters or neuromodulators in insects as well as being released into the circulation as neurohormones or acting as releasing agents for neurohormones in neurohaemal areas. They also further strengthen the idea that myomodulins, which were first identified in molluscs, may represent another interphyletic family of neuropeptides. © 1995 Wiley‐Liss, Inc.
Distribution and developmental expression of octopamine‐immunoreactive neurons in the central nervous system of the leech
Authors: Gilchrist Laura S. , Klukas Kathleen A. , Jellies John , Rapus Jürgen , Eckert Manfred , Mesce Karen A.
Published: January 2005

Octopamine, a biogenic amine analogous to norepinephrine, plays an important role in the orchestration and modulation of invertebrate behavior. In the leech, the behavioral actions of octopamine have been demonstrated; however, identification of octopaminergic neurons had not been determined by using immunohistochemical techniques. Thus, we used an antibody highly specific to octopamine to examine the distribution of octopamine‐immunoreactive neurons in the segmental ganglia of American and European medicinal leeches (Macrobdella decora and Hirudo medicinalis). One pair of octopamine‐immunoreactive neurons was located in the dorsolateral ganglionic region of anterior ganglia 1–6 and posterior ganglia 15–21. No corresponding octopamine‐immunoreactive neurons were found in midbody ganglia 7–14. Using Neutral Red staining in combination with intracellular Neurobiotin injections and octopamine immunostaining, we determined the identity of the dorsolateral octopamineimmunoreactive cells. The dorsolateral octopamine‐immunoreactive neuron (the DLO) was not cell 21, the only previously reported Neutral Red staining neuron in the dorsolateral position. We also determined that the Leydig neuron was not octopamine immunoreactive in either of the two medicinal leech species. Octopamine immunostaining in the sex ganglia revealed hundreds of immunoreactive neurons in sexually mature leeches. Such neurons were not observed in juvenile leeches. The developmental time course of octopamine immunoreactivity in the dorsolateral octopamine‐immunoreactive neurons was also investigated by staining embryonic Hirudo medicinalis, Octopamine expression occurred relatively late as compared with the detectable onset of serotonin expression. Octopamine expression in the dorsolateral octopamine‐immunoreactive cells was not detectable at early to mid‐embryonic stages, and must commence during late embryonic to early juvenile stages. The identification of octopamineimmunoreactive cells now sets the stage for further investigations into the functional role of octopamine in leech behavior and the development of behavior. © 1995 Wiley‐Liss, Inc.
Organization of the efferent projections from the spinal cervical enlargement to the parabrachial area and periaqueductal graye. A PHA‐L study in the rat
Authors: Bernard Jean‐Franiçois , Dallel Radhouane , Raboisson Patrick , Villanueva Luis , Bars Daniel Le
Published: January 2005

The organization of efferent projections from the spinal cervical enlargement to the parabrachial (PB) area and the periaqueductal gray (PAG) was studied in the rat by using microinjections of Phaseolus vulgaris–leucoagglutinin (PHA‐L) into different laminae around the C7 level. The results demonstrated two areas of cervical enlargement which project in different ways to the PB area and PAG.

First, the superficial laminae (I, II) showed a very dense projection, with a clear contralateral dominance at the coronal level where the inferior colliculus merges with the pons, to a restricted “superficial” portion of the PB area, namely the lateral crescent area, the dorsal lateral, the superior lateral (PBsl), and the outer portion of the external lateral PB subnuclei. Less dense projections were observed in the Kölliker‐Fuse nucleus (KF) and in the ventrolateral/ lateral quadrant of the caudal and mid PAG. By contrast, the labeling was weak or absent in the other PB subnuclei and the outer adjacent regions; in particular, no, or very little, labeling was found in the cuneiform nucleus. The PB area appeared to be the supraspinal target that received the densest projection from laminae I and II. Projections were less dense in the PAG and the thalamus and markedly less in other sites such as the ventrolateral medulla, the subnucleus reticularis dorsalis, and the nucleus of the solitary tract.

Second, the reticular portion of lamina V, the medial portion of laminae IV–VI up to X and lamina VIII, showed bilateral projections with a weak ipsilateral dominance and a high to medium density on a very restricted portion of the PB area, namely the internal lateral PB subnucleus. A lesser projection was also observed in the adjacent portion of the PBsl, the KF, and the lateral quadrant of the PAG.

These results suggest that signals carried by neurons from lamina I–II converge on a restricted superficial portion of the PB area and the ventral part of the lateral quadrant of the PAG. These results are discussed in the context of the role of the spino‐PB and spino‐PAG pathways in nociception. © 1995 Wiley‐Liss, Inc.
Two channels in the cerebellothalamocortical system
Authors: Steriade M.
Published: January 2005

Two channels of the cerebellothalamocortical system were investigated in cats by using cerebellar‐evoked synaptic responses and cortical‐evoked antidromic invasion of single thalamic cells. One channel arises in interpositus and dentate cerebellar nuclei and mainly projects through ventroanterior‐ventrolateral (VA‐VL) thalamic nuclei to cortical motor areas 4 and 6; the other channel arises in cerebellar fastigial nuclei and projects through ventromedial (VM) thalamic nuclei to more widespread cortical areas. The antidromic response latencies of VM neurons to stimuli applied to cortical areas 4 and 6 were longer (medians 2.8 and 3.0 msec, respectively) than the antidromic response latencies of VA‐VL neurons to stimulation of the same cortical areas (1.8 and 2.3 msec). This was a statistically significant difference, and it matched the longer latencies of fastigial‐evoked synaptic responses of VM cells (2.9 msec) compared to the response latencies of VA‐VL cells elicited by stimulation of interpositus or dentate nuclei (1.7 and 2.4 msec).

These differences among thalamic nuclei relaying cerebellocortical impulses were corroborated by dissimilar effects exerted on the electroencephalogram (EEG) during high‐frequency (300 Hz) pulse trains applied to different deep cerebellar nuclei. The distribution of activated EEG patterns over the cortex depended on the stimulated site. Fastigial stimulation elicited the blockage of slow EEG rhythms and the appearance of fast oscillations (20–40 Hz) over widespread cortical areas in the proreus, pericruciate, and suprasylvian gyri. At variance, the activating influence of interpositus or dentate nuclei was restricted to the motor cortex. It is proposed that, besides their role in controlling the postural axial and proximal musculature, fastigial nuclei are part of diffusely activating systems. © 1995 Wiley‐Liss, Inc.