bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and partial purification of different factors with contraction‐potentiating activities from neurohaemal organs of the locust
Authors: Schiebe Michael , Orchard Ian , Watts Robert , Lange Angela B. , Atwood Harold L. 
Published: May 2005

AbstractPhe‐Met‐Arg‐Phe (FMRF‐NH2) and structurally related peptides enhance neuromuscular transmission and contraction of the M. extensor tibiae preparations of the locusts Locusta migratoria and Schistocerca gregaria (Walther et al.: Neurosci. Lett. 45:99‐104, '84). Similar effects could also be obtained with extracts of locust ganglia (Walther and Schiebe: Neurosci. Lett. 77:209‐214, '87). By using two HPLC systems, we have partially purified extracts of the unpaired median nerves (including their neurohaemal organs) of different locust ganglia. The biological activity of the extracts served as an estimate for the degree of purification. Six different bioactive fractions were identified migrating at and close to retention times of known ‐RFamide peptides with similar bioactivity. No fraction coeluted with authentic FMRF‐NH2 or FLRF‐NH2. We demonstrate that extensor tibiae muscle contractions were potentiated by HPLC fractions from raw material with ‐RF‐NH2 immunoreactivity, but also by HPLC fractions from raw material without such immunoreactivity.
Functional morphology of the telson‐uropod stretch receptor in the sand crab Emerita analoga
Authors: Wilson L. J. , Paul D. H. 
Published: May 2005

AbstractThe telson‐uropod stretch receptor in Emerita analoga belongs to a segmental array of axial‐coxal receptors having sensory neurons with central somata. It consists of an elastic strand innervated by four giant, nonspiking, mechanoreceptive neurons. We examined the elastic (sensory) strand by light and electron microscopy to discover whether (1) functional differences between the four sensory neurons could be surmised from their peripheral terminations and (2) the process of mechano‐electric transduction in this type of receptor might be revealed by the ultrastructure of the dendritic terminals.The elastic strand is divided into nonoverlapping domains by the mechanoreceptive neurons. We discerned no differences other than their serial order along the strand‐ Each neuron has three morphological zones in the periphery. In the zone of dendrite entry, the dendrite bifurcates into 40–60μ primary branches that enter the strand at acute to right angles and turn rostrally and caudally along the strand's axis. The zone of branching consists of 4–35 μm diameter dendritic branches within the strand. Approximately 21,000 dendritic tips (diameters, 0.1–0.7 μm; lengths, 3–20μ) per sensory neuron arise via short stubs from all levels of the zone of branching and constitute the zone of dendrite termination.The repeated bifurcations of dendrites within the zone of branching take place by radial intrusion of longitudinally oriented, partitions of extracellular matrix each of which extends the length of the pair of dendritic branches it divides. Tips project into these partitions. Since they change shape when the elastic strand is stretched, which compresses the extracellular matrix of the partitions, they are probably the site of mechanosensory transduction.Cross‐sectional profiles of dendritic tips are significantly larger but less numerous in stretched than in relaxed receptors. We propose a model in which stretch compresses distal portions of tips until they are too small to be recognized. The large profiles are the proximal portions of tips that have been expanded by hydrostatic pressure.The very large number of dendritic tips/nonspiking mechanoreceptor may be what endows each neuron with (1) high sensitivity to stretch of the elastic strand and (2) ability to respond to a broader range of tensions than is usual for single sensory cells (the entire range experienced by the stretch receptor).
Changes in astroglial scar formation in rat optic nerve as a function of development
Authors: Trimmer Patricia A. , Wunderlich Roshna E. 
Published: May 2005

AbstractAlthough astroglial scar formation is a common response to almost any type of injury to the adult central nervous system, lesions in fetal and neonatal rats have been reported to induce little or no scar formation. To examine this developmental difference further, rats ranging in age from 1 to 65 days postnatal were unilaterally enucleated, a surgical procedure that causes the axons in the optic nerve to degenerate. The optic nerves were processed for light and electron microscopy at times ranging from 7 to 365 days postenucleation. Pronounced and permanent glial scars were formed in every age group examined, including the neonates. However, the time course for removal of the degenerating axonal debris and formation of a compact, debris‐free glial scar varied as a function of developmental age. In neonatal rats, a compact glial scar formed in 1–2 weeks whereas 3–5 months were required for compact glial scar formation in juveniles and adults. Changes in cross‐sectional area were also associated with optic nerve degeneration and glial scar formation. Whereas lesioned neonatal optic nerves underwent little change in area, there was a substantial decrease in area in the juvenile and adult. Morphometric analysis showed that irrespective of the age of the animal at the time of enucleation, the final area of the compact glial scar was 10–20% of the unlesioned adult control. These results suggest that conflict in the literature over the ability of neonatal astrocytes to form a glial scar may be due to the nature of the lesion or the method of detection since astrocytes in the neonatal rat optic nerve clearly have the capacity to become reactive and form a glial scar.
Mandibular motor neurons of the caterpillar of the hawk moth Manduca sexta
Authors: Griss Christian 
Published: May 2005

AbstractAs part of a planned study of the central neural basis of feeding behaviour in larval Manduca sexta, the morphology and physiology of the mandibular motor system is here described.The gross neuroanatomy of the postoral head segments has been investigated, especially the course and structure of the mandibular nerves.The electrophysiology of the mandibular opener and closer muscles has been investigated by extra‐ and intracellular recording during feeding behaviour and during electrical stimulation of the motor nerve. All the muscle fibres examined are of the “fast,” twitch type. Contraction is associated exclusively with locally or completely propagated overshooting action potentials, never with local functional potentials. Control of the muscles is by recruitment of more motor units and/or an increase of frequency of action potentials. No inhibitory synaptic potentials could be found.The motor neurons of the mandibular muscles have been identified by cobalt backfills of the mandibular nerve, and characterized by intracellular recording and dye injection. There are 12 closer and 8 opener motor neurons. All motor neurons recorded so far evoke 1:1 twitches in the muscle, and none appear to be inhibitory. No GABA‐immunoreactive axons could be found in the mandibular nerve.
Postnatal development of striatal neurotensin immunoreactivity in relation to clusters of substance P immunoreactive neurons and the “dopamine islands” in the rat
Authors: Zahm D. S. , Eggerman K. W. , Sprung R. F. , Wesche D. E. , Payne E. 
Published: May 2005

AbstractConventional immunoperoxidase preparations of the coronally sectioned brains of rats killed at various times during the early postnatal period revealed the distributions of tyrosine hydroxylase, substance P, and neurotensin immunoreactivities. At birth, patches of dense tyrosine hydroxylase immunoreactivity were present across the breadth of the rostral striatum, whereas patches displaying substance P immunoreactivity were present only in its lateral half, appearing in its medial half by about postnatal day 3. Neuronal neurotensin immunoreactivity was absent in the rostral striatum at birth, although some neurotensin immunoreactive cells were present in the tail of the caudate‐putamen. Rostrally, neurotensin immunoreactive cells appeared first along the lateral margin of the caudate‐putamen on postnatal day 3, became numerous there about day 5, spread medially into the striatum by day 7, and achieved their medialmost distribution by about day 10. Their numbers and those of substance P immunoreactive neurons diminished thereafter.Substance P immunoreactive patches, which contained numerous labeled neurons and “puncta,” shared coextensive distributions with patches of dense tyrosine hydroxylase immunoreactivity, but interdigitated with neurotensin immunoreactive cell clusters. The neurotensin immunoreactive cell clusters lacked puncta, the light microscopic representation of axon terminals, or swellings.It is concluded that the patchy infrastructure of the striatum, which is established prior to birth, is substrate for the progression of separate “waves” of elevated neuronal peptide content, one reflecting substance P and a later one reflecting neurotensin. These proceed along rostromedialward trajectories to involve interdigitating neuronal domains.
Pathways for motion analysis: Cortical connections of the medial superior temporal and fundus of the superior temporal visual areas in the macaque
Authors: Boussaoud Driss , Ungerleider Leslie G. , Desimone Robert 
Published: May 2005

AbstractTo identify the cortical connections of the medial superior temporal (MST) and fundus of the superior temporal (FST) visual areas in the extrastriate cortex of the macaque, we injected multiple tracers, both anterograde and retrograde, in each of seven macaques under physiological control. We found that, in addition to connections with each other, both MST and FST have widespread connections with visual and polysensory areas in posterior prestriate, parietal, temporal, and frontal cortex. In prestriate cortex, both areas have connections with area V3A. MST alone has connections with the far peripheral field representations of V1 and V2, the parieto‐occipital (PO) visual area, and the dorsal prelunate area (DP), whereas FST alone has connections with area V4 and the dorsal portion of area V3. Within the caudal superior temporal sulcus, both areas have extensive connections with the middle temporal area (MT), MST alone has connections with area PP, and FST alone has connections with area V4t. In the rostral superior temporal sulcus, both areas have extensive connections with the superior temporal polysensory area (STP) in the upper bank of the sulcus and with area IPa in the sulcal floor. FST also has connections with the cortex in the lower bank of the sulcus, involving area TEa. In the parietal cortex, both the central field representation of MST and FST have connections with the ventral intraparietal (VIP) and lateral intraparietal (LIP) areas, whereas MST alone has connections with the inferior parietal gyrus. In the temporal cortex, the central field representation of MST as well as FST has connections with visual area TEO and cytoarchitectonic area TF. In the frontal cortex, both MST and FST have connections with the frontal eye field.On the basis of the laminar pattern of anterograde and retrograde label, it was possible to classify connections as forward, backward, or intermediate and thereby place visual areas into a cortical hierarchy. In general, MST and FST receive forward inputs from prestriate visual areas, have intermediate connections with parietal areas, and project forward to the frontal eye field and areas in the rostral superior temporal sulcus. Because of the strong inputs to MST and FST from area MT, an area known to play a role in the analysis of visual motion, and because MST and FST themselves have high proportions of directionally selective cells, they appear to be important stations in a cortical motion processing system.
Quantitative, three‐dimensional analysis of granule cell dendrites in the rat dentate gyrus
Authors: Claiborne Brenda J. , Amaral David G. , Cowan W. Maxwell 
Published: May 2005

AbstractThe three‐dimensional organization of dentate granule cell dendritic trees has been quantitatively analyzed with the aid of a computerized microscope system. The dendrites were visualized by iontophoretic injection of horseradish peroxidase into individual granule cells in the in vitro hippocampal slice preparation. Selection criteria insured that the analyzed cells were completely stained and that only neurons with two or fewer cut dendrites in the distal portion of the molecular layer were analyzed. Twenty‐nine of the 48 sampled granule cells had no cut dendrites.The granule cells had between one and four primary dendrites. Granule cell dendritic branches were covered with spines and most extended to the hippocampal fissure or pial surface. The mean total dendritic length was 3,221 μm with a range from 2,324 μm to 4,582 μm. The dendrites formed an elliptical plexus with the transverse spread averaging 325 μm and the spread in the septotemporal axis averaging 176 μm. On individual neurons, the maximum branch order ranged from four to eight and the number of dendritic segments ranged from 22 to 40. Approximately 63% of the dendritic branch points occurred in a zone that included the granule cell layer and the inner one‐third of the molecular layer. The dendritic tree was organized so that, on average, 30% of the length was in the granule cell layer and proximal third of the molecular layer, 30% was in the middle third, and 40% was in the distal third. Comparisons were made between the dendrites of granule cells in the suprapyramidal and infrapyramidal blades of the dentate gyrus. Suprapyramidal cells had a significantly greater total dendritic length than infrapyramidal cells, their transverse spread was higher, and they had a greater number of dendritic segments. When neurons in the suprapyramidal blade were further subdivided on the basis of somal position within the depth of the cell body layer, superficial neurons were found to have a greater number of primary dendrites, more elliptical trees, and larger transverse spreads of their dendrites. There were no significant differences in dendritic segment number or total dendritic length between superficial and deep cells.
Specificity of filiform hair afferent synapses onto giant interneurons in Periplaneta americana: Anatomy is not a sufficient determinant
Authors: Blagburn Jonathan M. , Thompson Kevin S. J. 
Published: May 2005

AbstractThe synapses between the filiform hair sensory afferents and giant interneurons (GIs) 1–6 of embryonic and first instar cockroaches, Periplaneta americana, were used to investigate the role of neuronal anatomy in determining synaptic specificity. The pattern of afferent‐to‐GI synapses was first determined by intracellular recording of excitatory postsynaptic potentials (EPSPs). The lateral (L) axon synapses only with GIs 3, 4, and 6, while the medial (M) axon synapses with the contralateral dendrites of all six GIs but with the ipsilateral dendrites only of GIs 1, 2, and 4. The three‐dimensional anatomy of the filiform afferents and GIs was determined by injection of cobalt. There is little anatomical segregation of the filiform afferents; consequently, there is no correlation between the anatomy of the GIs and their synaptic inputs. The M axon and ipsilateral GI3 were studied in more detail by light and electron microscopy. Despite the presence of an anterior M axon branch which loops around the ipsilateral GI3 neurite at a distance of 2 μm, no synapses are formed between them. This lack of synapses is not due to the presence of physical barriers. Investigation of filiform afferents and GIs in embryonic ganglia shows that at no stage are the afferents sufficiently separated for their anatomy to be an important factor in determining the specificity of the synaptic inputs of the GIs. It was postulated that two pairs of complementary cell surface labels would be sufficient to code for this specificity, and that, in GIs 3, 5, and 6, spatial differences in the expression of these labels allow the M axon to distinguish ipsilateral dendrites from contralateral.
Contribution of brainstem GABAergic circuitry to descending antinociceptive controls: II. Electron microscopic immunocytochemical evidence of gabaergic control over the projection from the periaqueductal gray to the nucleus raphe magnus in the rat
Authors: Reichling David B. , Basbaum Allan I. 
Published: May 2005

AbstractPharmacological, physiological, and behavioral studies suggest that inhibitory GABAergic neurons influence the projection from the midbrain periaqueductal gray matter to the medullary nucleus raphe magnus. The present study used electron microscopic immunocytochemical techniques to examine the morphology and synaptic relationships of GABA‐immunoreactive terminals in the ventrolateral periaqueductal gray. These putative GABAergic terminals comprise almost 40% of all axon terminals in the periaqueductal gray. GABA‐immunoreactive terminals contain small, clear, pleomorphic or round, vesicles, and 46% also contain some dense‐cored vesicles. In some experiments we also used a colloidal gold‐conjugated retrograde tracer to label periaqueductal gray neurons that project to the nucleus raphe magnus. About half of the synaptic inputs onto the cell bodies and proximal dendrites of retrogradely labeled neurons are GABA‐immunoreactive; these putative GABAergic synapses, which directly control activity in neurons projecting from the periaqueductal gray to the nucleus raphe magnus, might mediate the antinociception‐related effects of exogenous GABAA receptor ligands.
Architecture of superior and mesial area 6 and the adjacent cingulate cortex in the macaque monkey
Authors: Matelli M. , Luppino G. , Rizzolatti G. 
Published: May 2005

AbstractThe agranular frontal cortex is formed by several distinct functional areas. There is no agreement, however, on its cytoarchitectonic organization. The aim of this study was to redefine the cytoarchitectonic organization of superior and mesial area 6 and the adjacent cingulate cortex in the macaque monkey. A particular goal was to find out whether the so‐called supplementary motor area (SMA) is cytoarchitectonically different from the rest of area 6 and whether it can be considered as a single, independent cytoarchitectonic area.The results showed that, rostral to F1 (area 4), four architectonic areas can be recognized in the superior (dorsal) and mesial area 6. Two of them are located on mesial cortical surface (F3 caudally and F6 rostrally) and two on superior cortical convexity (F2 caudally and F7 rostrally).The main cytoarchitectonic features of the five identified areas can be summarized as follows. F1: (1) giant pyramidal cells organized in multiple rows. (2) columnar pattern extending from the white matter to the superficial layers, (3) low cellular density in the lower part of layer III. F3: (1) high cellular density in the lower part of layer III, which fuses with a dense Va, (2) columnar pattern present only in the deepest layer, (3) occasional presence of giant pyramidal cells in layer Vb. F6: (1) prominent layer V, (2) absence of sublayer Vb, (3) homogeneous cell density in superficial layers. F2: (1) thin row of medium‐size pyramids in the lowest part of layer III, (2) columnar pattern extending to the superficial layers, (3) dense layer Va, (4) few, scattered giant pyramids in layer Vb. F7: (1) prominent layer V, (2) bipartite layer VI. Areas F1, F2, and F3, as defined cytoarchitectonically, coincided with the homonymous histochemical areas.The present data showed also that area 24 is formed by four subareas: 24a, b, c and d. Areas 24a ana b occupy the ventral part of area 24, whereas its dorsal part is formed by area 24c, located rostrally, and area 24d, located caudally. The following features distinguish area 24d from area 24c: (1) larger pyramidal cells in layer V, (2) presence of medium‐size pyramidal cells in the lower part of layer III, (3) more prominent columnar pattern, (4) higher myelinization with the presence of an evident horizontal plexus.Mesial area 6 is usually considered as a single functional entity (SMA). Our findings show that this cortical region is formed by two distinct cytoarchitectonic areas. In the following article (Luppino et al. 1991: J. Comp. Neurol 311:463–482) physiological evidence is presented that the SMA, as classically defined, corresponds to F3, whereas F6 is an independent functional area.
Glutamate, GABA, and glycine in the human retina: An immunocytochemical investigation
Authors: Davanger Svend , Ottersen Ole P. , Storm‐Mathisen Jon 
Published: May 2005

AbstractThe distribution of the neuroactive amino acids glutamate, GABA, and glycine in the human retina was examined in consecutive semithin sections treated with antisera specific for fixed glutamate, GABA, and glycine, respectively.Glutamate immunoreactivity was conspicuous in all photoreceptor cells (rods more strongly labelled than cones), and in a majority (85–89%) of the cells in the inner nuclear layer (INL). Rod spherules and cone pedicles showed a greater enrichment of glutamate immunoreactivity than the parent cell bodies and inner segments. Also, structures of the inner plexiform layer (IPL) were labelled. A large majority (83–91%) of cells in the ganglion cell layer (GCL) was strongly stained, as were most axons in the nerve fibre layer. Muller cell processes appeared unstained.GABA immunoreactivity was present in presumed amacrine but not in bipolar‐like cells. The stained cells were restricted to the inner ⅓ of the INL and were more frequent in central than in peripheral retina (40% and 26% of all cells in the inner ⅓of INL, respectively). GABA positive cell processes, probably originating from interplexiform cells, appeared to traverse the INL and end in the outer plexiform layer. Dense immunolabeling was found in the IPL. GABA immunoreactive cells (some also stained for glutamate) comprised 23% of all GCL cells in the peripheral retina, but only 5% in the central retina. Most of them were localized adjacent to the IPL. A few GABA positive (possibly ganglion) cells extended a single fibre toward the nerve fibre layer. Solitary GABA positive fibres were seen in this layer and in the optic nerve.Glycine immunoreactivity was observed in cells with the location typical of amacrine and bipolar (peripheral retina) cells, as well as in punctate structures of the IPL. In contrast to the GABA positive cells, the glycine positive cells were more frequent in the peripheral than in the central retina (42% and 23% of all cells in inner ⅓ of INL, respectively). A few cells in the GCL (0.5–1.5%) were glycine positive.Glutamate colocalized with GABA or glycine in a majority of the cells stained for either of these inhibitory transmitters (90–95% of the GABA positive cells, and 80–86% of the glycine positive cells, in the INL). Some bipolar cells were stained for both glutamate and glycine. Colocalization of GABA and glycine occurred in a subpopulation (3–4%) of presumed amacrine cells, about half of which was also glutamate positive.