bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic morphology and development in the ferret medial superior olivary nucleus
Authors: Henkel Craig K. , Brunso‐bechtold Judy K. 
Published: January 2005

AbstractDendritic morphology and development in the medial superior olivary nucleus of the ferret were studied using the Golgi method. In the adult ferret most medial superior olivary neurons had disk‐shaped dendritic fields. These dendritic fields were oriented such that cells in a coronal plane of section appeared bipolar with major lateral and medial dendritic axes. In the horizontal plane the dendrites radiated about the soma. Dendrites of principal cells branched distally into tufts of numerous, tertiary processes that were beaded and thin. Peripheral cells in the fiber mantle encircling the nucleus were generally spindle‐shaped or tripolar and lacked the tufted dendrites of principal cells. The dendrites of these peripheral cells coursed parallel to the nucleus both dorsoventrally and rostrocaudally. Horizontally oriented dendrites were observed even at birth for some cells in the medial superior olivary nucleus and bipolar dendritic fields were typical of most cells by the end of the second postnatal week. Dendrites of immature cells varied in caliber and radiated in all directions from the soma. Around postnatal days 8‐10 transient appendages appeared on the soma and dendrites, first proximally and then more distally. These appendages persisted until the first postnatal month. Cell size and dendritic radius increased markedly during this same period. Postnatal days 28‐30 were marked by the first appearance of tufts of tertiary dendritic branches. The tendril‐like processes continued to increase in length until about the end of the second postnatal month.
Dendritic morphology of central auditory neurons correlates with their tonotopic position
Authors: Sanes Dan H. , Goldstein Nira A. , Ostad Masoud , Hillman Dean E. 
Published: January 2005

AbstractWe have investigated the morphology of dendritic arbors in a central auditory nucleus, the lateral superior olive, of the Mongolian gerbil. Morphometric observations were obtained directly from Golgi‐impregnated material by using a microcomputer‐based three‐dimensional data acquisition system. In particular, measurements were made to determine the dendritic arborization across each of three axes: the tonotopic axis, the rostrocaudal axis, and the isofrequency axis (i. e., perpendicular to the tonotopic axis). The tonotopic position of each cell was computed on the basis of a topographic map that has been constructed for the gerbil LSO (Sanes et al.: J. Comp. Neurol. 279:436‐444, 1989).It was found that the span of a dendritic arbor along the tonotopic axis was directly correlated with the neuron's tonotopic position: Low frequency neurons had much broader arborizations than high frequency neurons. Moreover, the distribution of frequency bandwidths to which single LSO neurons responded showed a striking similarity to dendritic arborizations across the tonotopic axis. Lower frequency neurons responded to a larger number of octaves than higher frequency neurons.There was no correlation between tonotopic position and dendritic arborization in the isofrequency or rostrocaudal axis. Nor was there any correlation between frequency and total dendritic length, number of primary dendrites, or soma area. However, there was a small but significant difference between the primary dendrite diameter of low and high frequency neurons. Low frequency neurons had significantly greater diameters. These results suggest that the frequency selectivity of central auditory neurons may employ, as one morphological substrate, the distance over which their dendrites arborize along the tonotopic axis.
Tyrosine hydroxylase containing neurons lacking aromatic amino acid decarboxylase in the hamster brain
Authors: Vincent Steven R. , Hope Bruce T. 
Published: January 2005

AbstractWe have recently described populations of tyrosine hydroxylase‐immunoreactive neurons in the hamster brain in regions not known to contain catecholamine cell bodies. In the present study, the nature of the tyrosine hydroxylase immunoreactivity in the hamster brain was determined. In addition, these tyrosine hydroxylase‐immunoreactive cell groups were examined for their ability to express aromatic amino acid decarboxylase. Immunohistochemistry with two different antibodies to tyrosine hydroxylase identified immunoreactive cell bodies in regions known to contain catecholamine neurons, including the substantia nigra and locus ceruleus. In addition, tyrosine hydroxylase‐immunoreactive neurons were observed in other regions, including the basal forebrain, inferior colliculus, lateral parabrachial nucleus, and dorsal motor nucleus of the vagus. Western blotting indicated that hamster brain contained only one immunoreactive molecule, very similar in size to rat tyrosine hydroxylase. Thus it is likely that the immunohistochemical studies stained authentic hamster tyrosine hydroxylase. Indeed, in situ hybridization studies using a synthetic oligonucleotide probe against tyrosine hydroxylase mRNA resulted in specfic and heavy labelling of these novel tyrosine hydroxylase‐immunoreactive neurons.When adjacent sections were stained with antibodies to aromatic amino acid decarboxylase, known catecholamine cell groups were stained. However, the novel tyrosine hydroxylase cell groups did not display any aromatic amino acid decarboxylase immunoreactivity. These results suggest that neurons are present in the hamster brain that are able to hydroxylate tyrosine to L‐DOPA, but that lack the ability to decarboxylate aromatic amino acids to produce dopamine or other catecholamines.
Choline acetyltransferase‐immunoreactive profiles are presynaptic to primary sensory fibers in the rat superficial dorsal horn
Authors: Ribeiro‐Da‐Silva A. , Claudio Cuello A. 
Published: January 2005

AbstractThe specific aim of this study was to search for morphological counterparts to the known antinociceptive effects of cholinomimetic drugs at the spinal cord level. For this, the light microscopic and ultrastructural distribution of choline acetyltransferase immunoreactivity was studied in laminae I‐III of the rat cervical spinal cord. Immunoreactivity was present in cell bodies in lamina III, and in dendrites and axons of all three laminae. Immunoreactive axonal varicosities were often presynaptic to the central varicosities of type II synaptic glomeruli in lamina II and lamina III, less often presynaptic to the central elements of type I glomeruli in lamina II, and often presynaptic to dendrites in both type I and type II glomeruli. In addition, immunoreactive dendrites were often postsynaptic to the central varicosities of glomeruli of all morphological types. These results indicate that (1) primary sensory fibers excite cholinergic interneurons; (2) the acetylcholine released by the axon terminals of these interneurons modulates both nociceptive and non‐nociceptive sensory information at the spinal cord level through both pre‐ and postsynaptic mechanisms. Furthermore, our results reinforce current ideas on reciprocal sensory interaction between thick and fine afferent fibers.
Interaural time sensitivity in the inferior colliculus of the albino cat
Authors: Yin T. C. T. , Carney L. H. , Joris P. X. 
Published: January 2005

AbstractAnatomical studies of the Creel albino cat have demonstrated a pronounced atrophy of cells in the medial superior olive, a structure thought to be important for the detection of interaural time differences (ITDs). We looked for physiological abnormalities in the binaural interaction of cells in three albino cats by recording from single cells in the central nucleus of the inferior colliculus to ITDs of tones and noise. We found that the sensitivity to ITDs of tones and noise was somewhat diminished in the albino cats as compared to normally pigmented cats, though this deficit was only evident when a population of cells was examined. The range of sensitivity of individual cells for both tones and noise was the same in albinos and pigmented animals. Our anatomical measurements showed a smaller reduction in cross‐sectional area of cells in the medial superior olive than that reported earlier, and the cell bodies in the medial superior olive of the albinos were less elongated than in normal cats.
Cutaneous dermatomes for initiation of three forms of the scratch reflex in the spinal turtle
Authors: Mortin Lawrence I. , Stein Paul S. G. 
Published: January 2005

AbstractThe turtle spinal cord produces three forms of the hindlimb scratch reflex. Each scratch form is intiated in response to gentle mechanical stimulation of a distinct set of sites in the periphery, termed the receptive field for that scratch form. The turtle spinal cord consists of 8 cervical segments (C1‐C8), 10 dorsal segments (D1‐D10), 2 sacral segments (S1, S2), and about 16 caudal segments (Ca1‐Ca16). First, we recorded cutaneous afferents in peripheral nerves to reveal the tactile dermatomes of segments D3‐D8. These segments innervate regions of the body between the forelimb and hindlimb, directly lateral to their spinal cord segments. Adjacent segments innervate adjacent and partially overlapping regions of the periphery. Second, we used successive spinal cord transections combined with either (a) behavioral analysis in turtles with limb movements or (b) electroneurographic recordings in immobilized turtles, and mapped the zone of remaining sensibility after each transection to measure the borders of dermatomes D2‐Ca2. This technique revealed that adjacent dermatomes are innervated by non‐adjacent spinal segments in regions near the hip. Segments D8 and Ca1 innervate adjacent and partially overlapping regions ventral to the hip. There is a similar discontinuity in the innervation of the shell and skin dorsal to the hip. These discontinuities correlate with the innervation of the hindlimb skin by segments D8‐Ca1.The rostral scratch receptive field is innervated by sensory afferents entering spinal segments D3‐D6; the pocket scratch receptive field is innervated by D6‐D8; the caudal scratch receptive field is innervated by S2, Ca1, and more caudal segments. The rostral‐pocket transition zone is innervated mainly by one segment, D6; the ventral part of the caudal‐pocket transition zone is innervated by two non‐adjacent segments, D8 and Ca1. Thus the motor pattern blends elicited by stimulation of sites within the rostral‐pocket transition zone must be produced in response to a very different distribution of sensory inputs than the blends elicited by stimulation of sites within the caudalpocket transition zone.
Glial fibrillary acidic protein and vimentin immunohistochemistry in the developing and adult midbrain of the lizard Gallotia galloti
Authors: Monzon‐Mayor M. , Yanes C. , Ghandour M. S. , De Barry J. , Gombos G. 
Published: January 2005

AbstractThe distribution of glial fibrillary acidic protein (GFAP)‐and vimentin‐containing cells was studied by immunohistochemistry in the midbrain of the lizard Gallotia galloti. At embryonic stage 32 (E32), vimentin immunoreactivity appeared first in cell bodies located in the ventricular walls, in radial fibers, and subpial end‐feet and increased in these structures until E34/E35. Faint GFAP immunoreactivity gradually appeared in the same structures between E34 and E37, and this increased until adulthood, whereas vimentin immunoreactivity decreased after E35, becoming limited to a few end‐feet and fibers in the adult, mainly in the tegmentum. Thus, in developing Gallotia midbrain a shift from vimentin‐containing to GFAP‐containing intermediate filaments begins around E36 or E37. At E40, in addition to the cell bodies in the ependymal area, dispersed GFAP‐positive cells, possibly immature astrocytes appeared. These cells showed the same shift. In the adult lizard, GFAP‐positive radial glia are still present and coexist with GFAP‐positive astrocytes, which are prefentially located in the marginal optic tract and the oculomotor nuclei, but are absent in the fasciculus longitudinalis medialis. Optic tectum, pretectum, tegmentum, and isthmic nuclei are the areas richest in GFAP‐positive radial fibers: these were much less abundant in the deep mesencephalic nuclei. Thus, in this lizard, GFAP‐positive astrocytes display a clear cut regional distribution: they are present in mesencephalon, whereas they are absent in telencephalon Yanes et al.: J. Comp. Neurol.,′90:295:559–568.
Immunolocalization of cellular retinoic acid binding protein to müller cells and/or a subpopulation of GABA‐positive amacrine cells in retinas of different species
Authors: Milam Ann H. , De Leeuw A. Margreet , Gaur Vinod P. , Saari John C. 
Published: January 2005

AbstractRetinoic acid (RA) and its specific binding protein, cellular RA binding protein (CRABP), are found in relative abundance in bovine and rat retinas. Since RA does not participate in the visual cycle, the presence of RA and its binding protein in retina suggests that they may be involved in other aspects of retinoid action. As an initial step in identifying the role of RA and its binding protein in retina, monoclonal antibodies were prepared against CRABP purified from bovine retina and used to localize this antigen by immunocytochemistry in retinas of different species. Human and monkey retinas showed specific cytoplasmic labeling of Müller cells. Cat, bovine, rabbit, rat, turtle, and chick retinas showed specific cytoplasmic labeling of some somata in the inner nuclear and ganglion cell layers and characteristic strata in the inner plexiform layer. Cat and bovine retinas also showed cytoplasmic labeling of Müller cells. Immunoreactivity in these species was absent with nonimmune serum or abolished when the antibodies were preabsorbed with purified antigen. Chameleon, goldfish, and frog retinas were nonreactive.We used double‐labeling immunofluorescence experiments to determine if the CRABP‐positive cells were also positive for known neurotransmitters or associated enzymes. CRABP‐positive amacrine cells of cat, cow, rabbit, rat, and chick represented a subset of the more numerous γ‐aminobutyric acid (GABA)‐positive amacrine cells. However, turtle CRABP‐positive amacrine cells were negative for GABA despite the fact that turtle retina contains many GABA positive cells. CRABP‐positive amacrine cells in rat retinas were not immunoreactive for glycine, choline acetyltransferase, somatostatin, or tyrosine hydroxylase.To test whether CRABP‐positive somata in the ganglion cell layer were ganglion cells, we retrogradely labeled the ganglion cells of rat retinas with rhodamine dextran. No rhodamine labeled ganglion cells were positive with anti‐CRABP, indicating that the CRABP‐positive cells in the ganglion cell layer are probably amacrine cells.Other retinoid binding proteins thought to be involved in the visual cycle have been localized to Müller and retinal pigment epithelium cells. This study reveals that CRABP immunoreactivity is present in Müller and/or amacrine cells, depending on the species. CRABP immunoreactivity in amacrine cells of certain species was an unanticipated and provocative result. Its significance remains to be determined.
Hippocampal and midline thalamic fibers and terminals in relation to the choline acetyltransferase‐immunoreactive neurons in nucleus accumbens of the rat: A light and electron microscopic study
Authors: Meredith Gloria E. , Wouterlood Floris G. 
Published: January 2005

AbstractThe synaptic interactions between terminals of allocorticostriatal and thalamostriatal fibers and the cholinergic neurons in the nucleus accumbens were investigated using degeneration and dual labelling immunocytochemistry in Wistar rats. The presumptive cholinergic neurons were labelled with antibodies directed against choline acetyltransferase and the afferent fibers were labelled anterogradely with Phaseolus vulgaris‐leucoagglutinin.Fibers from the subiculum of the hippocampal formation and from the midline and intralaminar thalamus project densely into the medial nucleus accumbens where they overlap a relatively dense population of choline acetyltransferase‐immunoreactive neurons. Varicosities containing Phaseolus vulgaris‐leucoagglutinin juxtapose the immunoreactive neurons.To study the possibility that the cholinergic neurons could be the synaptic targets of these incoming fibers, the subiculum, the fornix, and the midline/intralaminar thalamus were lesioned in separate animals and brain sections were immunoprocessed for choline acetyltransferase and studied with the electron microscope. In addition, dual‐labelling electron microscopic immunocytochemistry was employed. In total, 164 synaptic terminals from the subiculum/hippocampus and 130 from the midline/intralaminar thalamus were examined; all formed asymmetrical synaptic specializations. No hippocampal endings were seen to contact the somata or primary dendrites of the choline acetyltransferase‐immunoreactive neurons; however, three were found in synaptic contact with distal, immunolabelled dendritic shafts. Most hippocampal terminals established contacts with unlabelled spines. Fifteen percent of the thalamic endings were found to synapse on the somata and the primary and distal dendrites of the choline acetyltransferase‐immunoreactive neurons. The remaining thalamic terminals established synaptic junctions with small unlabelled dendrites or spines. These findings have important implications not only for our understanding of the synaptic organization of the hippocampal and thalamic projections to the nucleus accumbens, but also for the contribution of the cholinergic neurons to the circuitry of this nucleus.
Functional recovery after spinal cord hemisection in guinea pigs: The effects of applied electric fields
Authors: Borgens Richard B. , Blight Andrew R. , McGinnis Michael E. 
Published: January 2005

AbstractRight lateral hemisection of the lower thoracic spinal cord was performed in 216 adult guinea pigs. Animals that proved suitable for the study were divided into one control and two experimental groups. Experimental animals were implanted with intraperitoneal stimulators delivering regulated current of 35 or 50 μA through electrodes placed 1 cm rostral and caudal of the hemisection. The cathode was cranial to the lesion in one group (n= 67) and caudal in the other (n= 33). Control animals (n= 62) were implanted with sham stimulators and electrodes delivering no current. The functional status of the animals was measured by tactile stimulation of the back skin to elicit the cutaneus trunci muscle reflex, and by the vestibulospinal free‐fall response. The cutaneous response ipsilateral and caudal to the lesion was lost following hemisection and did not recover in any of the control animals or in animals with cathode caudal to the lesion. Recovery of the response was found in 9 of 67 animals in the cathode rostral group, between 56 and 139 days after injury. Toe spreading recovered spontaneously in 80–90% of animals in all groups. Of the possible mechanisms of skin reflex recovery, most current evidence points to regrowth of ascending nerve fibers in the lateral funiculus of the spinal cord local to the lesion.
GABA‐like immunoreactivity in the macaque monkey retina: A light and electron microscopic study
Authors: Grünert Ulrike , Wässle Heinz 
Published: January 2005

AbstractThe distribution of GABA‐like immunoreactivity in the macaque monkey retina was studied by using postembedding techniques on semithin and ultrathin sections. At the light microscopic level, both inner and outer plexiform layers showed strong GABA‐like immunoreactivity in the central retina. All the horizontal cells, some bipolar cells, 30–40% of amacrine cells, occasional interplexiform cells, and practically all displaced amacrine cells were labeled. In the peripheral retina (beyond 5 mm eccentricity), the outer plexiform layer and the horizontal cells were not labeled, but all other cell types showed the same labeling pattern as in the central retina.Synapses of the inner plexiform layer involving a pre‐ or postsynaptic GABA‐labeled process were studied electron microscopically. Synapses involving a GABA‐labeled presynaptic amacrine cell process made up 80% of the synapses observed. These GABA‐labeled amacrine processes synapsed onto amacrine, bipolar, and ganglion cell processes as well as onto amacrine and ganglion cell bodies.Synapses involving a postsynaptic GABA‐labeled process made up 20% of the synapses studied. The GABA‐like immunoreactive processes were postsynaptic to bipolar cells at the dyads and to amacrine cells at conventional synapses.
Histaminelike immunoreactive neurons innervating putative neurohaemal areas and central neuropil in the thoraco‐abdominal ganglia of the flies Drosophila and Calliphora
Authors: Nässel Dick R. , Pirvola Ulla , Panula Pertti 
Published: January 2005

AbstractThe fused thoraco‐abdominal ganglia of the flies Calliphora vomitoria and Drosophila melanogaster were investigated immunocytochemically with antisera against histamine. In both insect species, 18 histaminelike immunoreactive (HA‐IR) neurons were resolved in these ganglia. Six of these neurons have cell bodies in the thoracic neuromeres and 12 in the fused abdominal neuromeres. All cell bodies are situated ventrally. In Calliphora all cell bodies are arranged in a segmental pattern. In Drosophila only the thoracic cell bodies have a segmental arrangement, whereas the abdominal ones are clustered anteriorly close to the last thoracic neuromere.In both species the six thoracic neurons supply processes to the synaptic neuropil in the thoracic neuromeres and to the dorsal neural sheath. The processes in the neural sheath run anteriorly in the lateral portions of the ganglion into the cervical connective. In a few regions laterally arborizing terminals are found in putative neurohaemal areas. These areas were investigated by electron microscopic immunocytochemistry in Calliphora. The HA‐IR terminals (containing small granular vesicles were found outside the “blood‐brain barrier” below the acellular basal lamina of the neural sheath. Release of histamine into the circulation is therefore theoretically possible. The central processes of the six thoracic HA‐IR neurons may interact synaptically with large numbers of other neurons in the neuropil, and the peripheral varicose fibers from the same HA‐IR neurons possibly are neurohaemal release sites. The abdominal HA‐IR neurons, in contrast, form extensive arborizations within the synaptic neuropil only. Both thoracic and abdominal neurons have ipsilateral and contralateral branches as well as processes that invade more than one neuromere. A single HA‐IR neuron thus invades large volumes of synaptic neuropil. Histamine may be used by neurons of the ventral ganglia both as neurotransmitter (or neuromodulator) and as a circulating neurohormone released from the neural sheath.