bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abnormal thalamocortical pathfinding and terminal arbors lead to enlarged barrels in neonatal GAP‐43 heterozygous mice
Authors: McIlvain Vera A. , Robertson Douglas R. , Maimone Margaret M. , McCasland James S. 
Published: June 2003

AbstractGAP‐43 has been implicated in axonal pathfinding and sprouting, synaptic plasticity, and neurotransmitter release. However, its effect on cortical development in vivo is poorly understood. We have previously shown that GAP‐43 knockout (−/−) mice fail to develop whisker‐related barrels or an ordered whisker map in the cortex. Here we used cytochrome oxidase (CO) histochemistry to demonstrate that GAP‐43 heterozygous (+/−) mice develop larger than normal barrels at postnatal day 7 (P7), despite normal body and brain weight. Using serotonin transporter (5HT‐T) histochemistry to label thalamocortical afferents (TCAs), we found no obvious abnormalities in other somatosensory areas or primary visual cortex of GAP‐43 (+/−) mice. However, TCA projections to (+/−) primary auditory cortex were not as clearly defined. To clarify the mechanism underlying the large‐barrel phenotype, we used lipophilic (DiI) axon labeling. We found evidence for multiple pathfinding abnormalities among GAP‐43 (+/−) TCAs. These axons show increased fasciculation within the internal capsule, as well as abnormal turning and branching in the subcortical white matter. These pathfinding errors most likely reflect failures of signal recognition and/or transduction by ingrowing TCAs. In addition, many DiI‐labeled (+/−) TCAs exhibit widespread, sparsely branched terminal arbors in layer IV, reflecting the large‐barrel phenotype. They also resemble those found in rat barrel cortex deprived of whisker inputs from birth, suggesting a failure of activity‐dependent synaptogenesis and/or synaptic stabilization in (+/−) cortex. Our findings suggest that reduced GAP‐43 expression can alter the fine‐tuning of a cortical map through a combination of pathfinding and synaptic plasticity mechanisms. J. Comp. Neurol. 462:252–264, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of aromatase mRNA and protein in the brain and pituitary of female rainbow trout: Comparison with estrogen receptor α
Authors: Menuet Arnaud , Anglade Isabelle , Le Guevel Remy , Pellegrini Elisabeth , Pakdel Farzad , Kah Olivier 
Published: June 2003

AbstractRecent data indicate that estrogens locally produced in the brain by aromatization of androgens could be important for neurogenesis and brain repair. In this respect, fish are interesting because of the extremely high aromatase activity of their brain. In this study, the rainbow trout brain aromatase was cloned and riboprobes were used to map the distribution of cells expressing the corresponding mRNAs. A very strong hybridization signal was detected in the pituitary and in cells bordering the ventricles in the telencephalon and ventral diencephalon, with the highest expression in the preoptic area and hypothalamus. A weaker signal was detected in the ependymal layer bordering the torus semicircularis and optic tectum. This localization was fully confirmed by immunohistochemistry using antibodies against a teleost aromatase. In addition, this antibody showed that aromatase expression in fact corresponds to radial glial cells because immunoreactive cells had long cytoplasmic processes extending toward the pial surface. Because brain aromatase was shown to be upregulated by estradiol in fish, the distribution of aromatase mRNAs was compared with that of rainbow trout estrogen receptor α (rtERα) on adjacent sections. Although the highest aromatase expression was found in regions expressing rtERα, no obvious coexpression was found, as rtERα was never observed in radial cells. However, reverse transcriptase‐polymerase chain reaction experiments performed on brain cell cultures enriched in glial cells suggest that a weak expression of rtERα in glial cells cannot be excluded. The possible role of the high brain aromatase content in fish could be related to the continuous growth of their central nervous system during adulthood. J. Comp. Neurol. 462:180–193, 2003. © 2003 Wiley‐Liss, Inc.
Expression patterns of epidermal growth factor receptor and fibroblast growth factor receptor 1 mRNA in fetal human brain
Authors: Fu Lijuan , Abu‐Khalil Amir , Morrison Richard S. , Geschwind Daniel H. , Kornblum Harley I. 
Published: June 2003

AbstractFactors that interact with the epidermal growth factor and fibroblast growth factor receptors have numerous effects in the central nervous system (CNS), inducing the proliferation of CNS stem cells and astrocytes and the survival and differentiation of neurons. Both receptors are expressed in the embryonic rodent brain in proliferative and nonproliferative regions, suggesting roles in numerous developmental processes. However, the roles of these factors in human brain development are not known. In the current study, we examined the expression of human epidermal growth factor receptor (HEGFR) and human fibroblast growth factor receptor 1 (HFGFR1) mRNAs in the human fetal brain. The expression of both receptors is strikingly conserved relative to previously reported patterns in the rodent. In the germinal zones, the sites of cellular proliferation, HFGFR1 was expressed primarily in the ventricular zone, whereas HEGFR was expressed in the subventricular zone, suggesting different roles in CNS progenitor proliferation. Differential expression was also observed in other brain areas examined, including the hippocampus and the cerebellum. The current study suggests that HEGFR and HFGFR1 are likely to play different roles during human brain development, but that these roles will be similar to those observed in the rodent brain. J. Comp. Neurol. 462:265–273, 2003. © 2003 Wiley‐Liss, Inc.
Examination of the relationship between astrocyte morphology and laminar boundaries in the molecular layer of adult dentate gyrus
Authors: Bushong Eric A. , Martone Maryann E. , Ellisman Mark H. 
Published: June 2003

AbstractAstrocytes are known to play an integral role in the development of compartmental boundaries in the brain and in the creation of trauma‐induced boundaries. However, the physical relationship between astrocytes and such boundaries in the adult brain is less clear. If astrocytes do respect or play an ongoing role in maintaining such boundaries, a correlation between the position of such a boundary and the morphology of neighboring astrocytes might be observable. In this study, we examined the distribution of astrocytes with respect to the laminar boundaries compartmentalizing afferents to the dentate gyrus molecular layer. In addition, we attempted to determine whether astrocyte morphology is influenced by these laminar boundaries. To this end, protoplasmic astrocytes in the adult rat dentate gyrus were revealed with fluorescent tracer dyes and subsequently analyzed with respect to laminar boundaries demarcated by means of immunolabeling for the lamina‐specific molecules EphA4 and neural cell adhesion molecule (N‐CAM). We find that astrocyte distribution is influenced by the boundary separating the associational/commissural and perforant path afferents. In addition, we show that astrocytes in this region are polarized in their morphology, unlike typically stellate astrocytes, but that the laminar boundaries themselves do not appear to confer this morphology. This polarized morphology, however acquired, may have import for the functioning of astrocytes within the highly organized composition of the dentate gyrus molecular layer and for the overall microphysiology of this and other brain regions. J. Comp. Neurol. 462:241–251, 2003. © 2003 Wiley‐Liss, Inc.
Brain nitric oxide synthase expression in the developing ferret lateral geniculate nucleus: Analysis of time course, localization, and synaptic contacts
Authors: Mccauley Anita K. , Carden W. Breckinridge , Godwin Dwayne W. 
Published: June 2003

AbstractNitric oxide (NO) is a diffusible neurotransmitter that has been implicated in key developmental events, including the refinement of retinogeniculate axons into ON/OFF sublayers in the ferret lateral geniculate nucleus (LGN), and in the formation of eye‐specific laminae in other species. To understand the role of NO in the LGN, it is critical to fully characterize the pattern of brain nitric oxide synthase (bNOS) expression within the nucleus, including the phenotype of the neural elements that express it. We have examined the temporal and spatial pattern of bNOS expression in the ferret LGN during the first 6 weeks of postnatal development, and in the adult, by detecting bNOS with a monoclonal antibody as well as β‐nicotinamide adenine dinucleotide phosphate–diaphorase histochemistry. We have found that bNOS is expressed in neurons in the A laminae of the LGN as early as postnatal day 7 (P7), a time coincident with eye‐specific segregation of retinal axons. This expression continues through P35, with peak somatodendritic expression at P21. Fluorescent double labeling using antibodies to bNOS and glutamic acid decarboxylase indicate that bNOS is expressed in γ‐aminobutyric acid–ergic interneurons within the A laminae. Electron microscopic examination of bNOS‐labeled cells showed synaptic contacts from terminals with two distinct morphologic profiles. Expression of bNOS within interneurons that receive contacts from multiple sources indicates that the synaptic circuitry associated with bNOS activation and the potential targets of NO may be more complex than originally thought and supports a potential new role for interneurons as cellular intermediaries in the refinement of pathways in the LGN. Our findings broaden the window of time that bNOS may be active within the developing LGN, suggesting an expanded role for NO during early postnatal development. J. Comp. Neurol. 462:342–354, 2003. © 2003 Wiley‐Liss, Inc.
Primary cortical motor neurons undergo apoptosis after axotomizing spinal cord injury
Authors: Hains Bryan C. , Black Joel A. , Waxman Stephen G. 
Published: June 2003

AbstractSpinal cord injury (SCI) results in loss of voluntary motor control followed by incomplete recovery, which is partly mediated by the descending corticospinal tract (CST). This system is an important target for therapeutic repair strategies after SCI; however, the question of whether apoptotic cell death occurs in these axotomized neurons remains unanswered. In this study, adult (150–175 g) male Sprague‐Dawley rats underwent T9 transection of the dorsal funiculus, which axotomizes the dorsal CST, and introduction of the retrograde tracer Fluoro‐Gold into the lesion site. Primary motor cortex (M1) was then examined for evidence of apoptosis weekly for 4 weeks after injury. Axotomized pyramidal cells, identified by retrograde transport of Fluoro‐Gold, were found in M1 (57.5 ± 9.6/median section, 6,127 ± 292 total), and a significant proportion were terminal deoxynucleotidyl transferase (TdT) ‐mediated deoxyuridine triphosphate (dUTP)‐rhodamine nick end labeling (TUNEL) ‐positive at 1 week after injury (39.3 ± 5.6%), compared with animals undergoing sham surgery (1.2 ± 1.4%). At 2–4 weeks, fewer cells were Fluoro‐Gold–positive (24.6 ± 65.06 to 25.3 ± 6.4/median section, 2,338 ± 233 to 2,393 ± 124 total), of which very few were TUNEL‐positive. In TUNEL‐positive cells, Hoechst 33342 staining revealed nuclear morphology consistent with apoptosis, chromatin condensation, and formation of apoptotic bodies. Fluoro‐Gold–positive cells showed increased caspase‐3 and Bax immunoreactivity. Hematoxylin and eosin staining revealed similar nuclear changes and dystrophic cells. Internucleosomal DNA fragmentation was detected by gel electrophoresis at the 1‐week time point. Lesioned animals not receiving Fluoro‐Gold exhibited the same markers of apoptosis. These results document, for the first time, features of apoptotic cell death in a proportion of axotomized cortical motor neurons after SCI, suggesting that protection from apoptosis may be a prerequisite for regenerative approaches to SCI. J. Comp. Neurol. 462:328–341, 2003. © 2003 Wiley‐Liss, Inc.
Trafficking of the muscarinic m2 autoreceptor in cholinergic basalocortical neurons in vivo: Differential regulation of plasma membrane receptor availability and intraneuronal localization in acetylcholinesterase‐deficient and ‐inhibited mice
Authors: Decossas Marion , Bloch Bertrand , Bernard Veronique 
Published: June 2003

AbstractIn vivo, the abundance of receptors at the neuronal plasma membrane may be critical in the mediation of pre‐ and postsynaptic responses. Thus, we have studied the membrane availability and intraneuronal distribution of the m2 muscarinic autoreceptor (m2R) in cholinergic neurons of the nucleus basalis magnocellularis (NBM) projecting to the frontal cortex (FC). We have studied the subcellular compartmentalization of m2R at somatodendritic postsynaptic and axonal presynaptic sites in control animals (AChE +/+) and in two animal models: mice displaying acute acetylcholinesterase (AChE) inhibition by treatment with metrifonate, and AChE‐deficient mice (AChE ‐/‐). In control animals, m2R was mainly located at the plasma membrane in the somatodendritic field of NBM and in cortical varicosities. Acute AChE inhibition and chronic AChE deficiency induced a dramatic decrease of cell surface m2R in the somatodendritic compartment. This finding was associated with two different intracytoplasmic events: (1) internalization of m2R in endosomes after acute AChE inhibition, (2) exaggerated storage of m2R in the endoplasmic reticulum and Golgi complex in AChE ‐/‐ mice. In contrast, the m2R density was higher at the membrane of cortical varicosities in AChE ‐/‐ mice but unchanged in acutely AChE‐inhibited mice. Our data demonstrate that acute and chronic stimulation provoke, in vivo, depletion of the membrane store of somatodendritic m2R through different intracellular mechanisms: endocytosis of receptors from the plasma membrane to the cytoplasm (acute) or regulation of their delivery from intracytoplasmic stores to the plasma membrane (chronic). The increase of m2R at the membrane of axonal varicosities after chronic stimulation suggest modulation of presynaptic cholinergic activity, including neurotransmitter release. J. Comp. Neurol. 462:302–314, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of glutamate‐gated chloride channel subunits in the parasitic nematode Haemonchus contortus
Authors: Portillo Virginia , Jagannathan Suchitra , Wolstenholme Adrian J. 
Published: June 2003

AbstractGlutamate‐gated chloride channels (GluCl) are related to γ‐aminobutyric acid‐A (GABAA) receptors and are the target sites for the avermectin/milbemycin (A/M) anthelmintics, drugs that cause paralysis of the somatic and pharyngeal muscles in nematodes. We have previously identified four GluCl subunits, HcGluClα, HcGluClβ, HcGluClα3A, and HcGluClα3B from the sheep parasite Haemonchus contortus. We raised specific antisera against all of these subunits and used them in immunofluorescence experiments on adult parasites. All of the subunits were expressed in the motor nervous system, especially motor neuron commissures. Double‐immunostaining experiments suggested that HcGluClα and HcGluClβ were expressed on the same commissures; these were also stained with an anti‐GABA antibody, suggesting that they may be inhibitory motor neurons. The HcGluClβ subunit was also detected in lateral and sublateral nerve cords. The HcGluClα3A and ‐B subunits, products of an alternatively spliced gene, were expressed in different neurons. We found HcGluClαA in a pair of sensory, possibly amphid, neurons in the head, in addition to the motor neuron commissures. HcGluClα3B was detected in three cell bodies, probably of pharyngeal neurons, and to ventral and lateral cords. These results indicate that the GluCl are widely distributed in the H. contortus nervous system and suggest that they have critical roles controlling locomotion, pharyngeal function, and possibly sensory processing in parasitic nematodes. They also provide an explanation for the observed effects of the A/M anthelmintics. J. Comp. Neurol. 462:213–222, 2003. © 2003 Wiley‐Liss, Inc.
Rats and mice exhibit distinct inflammatory reactions after spinal cord injury
Authors: Sroga Julie M. , Jones T. Bucky , Kigerl Kristina A. , McGaughy Violeta M. , Popovich Phillip G. 
Published: June 2003

AbstractSpinal contusion pathology in rats and mice is distinct. Cystic cavities form at the impact site in rats while a dense connective tissue matrix occupies the injury site in mice. Because inflammatory cells coordinate mechanisms of tissue injury and repair, we evaluated whether the unique anatomical presentation in spinally injured rats and mice is associated with a species‐specific inflammatory response. Immunohistochemistry was used to compare the leukocytic infiltrate between rats and mice. Microglia/macrophage reactions were similar between species; however, the onset and magnitude of lymphocyte and dendritic cell (DC) infiltration were markedly different. In rats, T‐cell numbers were highest between 3 and 7 days postinjury and declined by 50% over the next 3 weeks. In mice, significant T‐cell entry was not evident until 14 days postinjury, with T‐cell numbers doubling between 2 and 6 weeks. Dendritic cell influx paralleled T‐cell infiltration in rats but was absent in mouse spinal cord. De novo expression of major histocompatability class II molecules was increased in both species but to a greater extent in mice. Unique to mice were cells that resembled lymphocytes but did not express lymphocyte‐specific markers. These cells extended from blood vessels within the fibrotic tissue matrix and expressed fibronectin, collagen I, CD11b, CD34, CD13, and CD45. This phenotype is characteristic of fibrocytes, specialized blood‐borne cells involved in wound healing and immunity. Thus, species‐specific neuroinflammation may contribute to the formation of distinct tissue environments at the site of spinal cord injury in mice and rats. J. Comp. Neurol. 462:223–240, 2003. © 2003 Wiley‐Liss, Inc.
Using a continuous index of laterality to determine how laterality is related to interhemispheric transfer and bimanual coordination in children
Authors: Fagard Jacqueline , Corroyer Denis 
Published: June 2003

AbstractWe sought to determine whether laterality is related to interhemispheric transfer and bimanual coordination during development. Children between 3 and 8 years of age were observed. In the first part of the experiment, we devised a continuous index to order the subjects according to their laterality. The laterality index included evaluation of hand and eye preference, and the right–left performance difference. In the second part of the experiment, we used this single index to determine whether laterality is related to interhemispheric transfer and bimanual coordination. Interhemispheric transfer was assessed by means of two tactile transfer tasks and one visuo–manual transfer task. We assessed bimanual coordination using the tapping task and the bimanual crank‐rotation task. Results showed that right‐ and left‐hand writers overlap on certain measures of laterality. They confirmed the improvement of interhemispheric transfer at around age 5 years, earlier progress in bimanual coordination with mirror than with parallel movements, and the existence of a relationship between visuo–manual interhemispheric transfer and bimanual coordination. The laterality index was not related to interhemispheric transfer, but it was related to the younger subjects' performance on the bimanual crank‐rotation task: the less right handed, the better the bimanual coordination. In addition, on the same bimanual task, crossed hand–eye laterality was associated with better performance. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 44–56, 2003.
Placentophagia in rabbits: Incidence across the reproductive cycle
Authors: Melo Angel I. , González‐Mariscal Gabriela 
Published: June 2003

AbstractRabbits show placentophagia at parturition, but the regulation of this behavior and its incidence across the reproductive cycle are unknown. By testing estrous, midpregnant, prepartum (day 1), and postpartum (days 1 and 5) food‐deprived rabbits with liver and placenta, we found an absence or infrequency (<%) of placentophagia in the former three groups, an invariable occurrence at parturition, and a persistence into postpartum days 1 and 5 (50 and 48%, respectively). Most placentophagic females also ate liver on postpartum day 1, but not on postpartum day 5. In different food‐deprived rabbits, tested every 2 hr with placenta and food pellets, placentophagia incidence was 20% at 8 hr prepartum, 100% at parturition, and 67 and 21% at 8 and 24 hr postpartum, respectively. Most placentophagic rabbits also ate food pellets in postpartum (but not in prepartum) tests. Results suggest that somatosensory, hormonal, or both factors of the peripartum period regulate placentophagia expression. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 37–43, 2003.
Effects of perinatal visual stimulation on preference, growth, and mortality in African clawed frogs (Xenopus Laevis)
Authors: Mann Katherine M. , Sleigh Merry J. 
Published: June 2003

AbstractTwo exploratory experiments examined the effects of flashing light stimulation on growth, mortality, and behavioral preferences of Xenopus laevis tadpoles. Experiment 1 showed that tadpoles exposed to continuous visual stimulation, from egg‐laying through postnatal day 40, had significantly higher mortality rates and weighed significantly less than controls. In contrast to controls, experimental tadpoles showed a preference for visual stimulation throughout early development. Results support the notion that augmented visual stimulation during early development affects species‐typical development and the creation of postnatal preferences. Experiment 2 exposed subjects to propranolol in their water to investigate a potential sympathetic nervous system (SNS) mechanism responsible for the previous results. Tadpoles exposed to propranolol and visual stimulation simultaneously did not show a preference for the visual stimulation. Although this preliminary finding suggests SNS involvement, this notion deserves further investigation. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 28–36, 2003.
The effects of isolation rearing on open‐field behavior in male rats depends on developmental stages
Authors: Arakawa Hiroyuki 
Published: June 2003

AbstractThe effects of the duration of isolation and age during isolation on open‐field behavior in rats were examined. An inner wall divided the floor of the field into two areas, a peripheral alley and the center square, and the subjects' behavior in each area was measured. An increase in the tendency to avoid the center square was found in rats isolated during their juvenile stage, which disappeared if they were reared in pairs for a long period after isolation. On the other hand, subjects isolated during their postmaturity stage displayed an increased tendency to approach the center square whereas isolation during sexual maturity had no effect. The duration of isolation showed no consistent effect; rather, the effect depended on the age of the subjects during isolation. These findings suggest that isolation affects the open‐field behavior of rats in various ways, depending on their age during isolation. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 11–19, 2003.