bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nerve cables formed in silicone chambers reconstitute a perineurial but not a vascular endoneurial permeability barrier
Authors: Azzam Nabil A. , Zalewski Andrew A. , Williams Lawrence R. , Azzam Rita N. 
Published: January 2005

AbstractThe passage of molecules into the endoneurial environment of the axons of normal peripheral nerve is regulated by two permeability barriers, the perineurial‐nerve barrier and the endoneurial blood‐nerve barrier. These barriers exist because of the presence of tight junctions between adjacent perineurial cells and adjacent endothelial cells. In the present study we investigated whether permeability barriers form in nerve cables, which develop inside silicone chambers. The sciatic nerves of adult rats were cut, and the proximal and distal ends sutured into opposite ends of silicone chambers that were filled with dialyzed plasma. The presence of barriers was determined with the tracer horseradish peroxidase (HRP), which was injected intravenously and detected histochemically in tissues by light and electron microscopy. At four weeks, a regenerated nerve cable extended across the 10 mm length of each chamber. However, no permeability barriers were present since the reaction product for HRP was visible throughout the cable. At twenty‐six weeks, all the axons in cables were gathered into minifascicles. Each minifascicle of axons was surrounded by perineurial cells. Blood vessels were excluded from the minifascicles by the perineurial cells and the vessels were permeable to HRP, thus indicating that their endothelial cells had not formed tight junctions. Despite the leakage of HRP from the excluded vessels, the tracer did not reach the axons because the perineurial cells encircling the minifascicles developed tight junctions. In some animals, the chambers were removed at four weeks to determine whether the chamber influenced barrier development. This manipulation had no effect since cables, with or without chambers, exhibited similar findings at twenty‐six weeks. Our results indicate that nerve cables regenerate a perineurial but not an endoneurial permeability barrier. We conclude that axons in long‐term cables are protected by only a perineurial permeability barrier.
Efferent connections of the centromedian and parafascicular thalamic nuclei in the squirrel monkey: A PHA‐L study of subcortical projections
Authors: Sadikot A. F. , Parent A. , François C. 
Published: January 2005

AbstractThe subcortical projections of the centromedian (CM) and the parafascicular (Pf) thalamic nuclei were examined in the squirrel monkey (Saimiri sciureus) by using the lectinPhaseolus vulgaris‐leucoagglutinin (PHA‐L) as an anterograde tracer. Both CM and Pf project massively to the striatum where they arborize in a complementary fashion. On the one hand, CM innervates most of the putamen caudal to the anterior commissure, a dorsolateral rim of the putamen rostral to the anterior commissure, discrete areas of the head of the caudate nucleus close to the internal capsule, and a lateral sector of the body of the caudate nucleus. On the other hand, Pf provides a heavy input to the head, body, and tail of the caudate nucleus, and to the rostral putamen, excluding the areas innervated by CM. In addition, Pf projects more discretely to the nucleus accumbens and the olfactory tubercle. Therefore, the projections from both CM and Pf cover the entire striatum, with those from CM arborizing into the “sensorimotor” striatal territory and the ones from Pf innervating the “associative‐limbic” striatal territory. Furthermore, CM and Pf project to extrastriatal subcortical structures, such as the globus pallidus, the subthalamic nucleus, and the substantia nigra, where they also terminate in a complementary fashion. Topographically and cytologically, Pf is closely related to the subparafascicular nucleus (sPf). The Pf‐sPf complex projects to the hypothalamus, the substantia innominata, the peripeduncular nucleus, and the amygdala. It also gives rise to descending efferents arborizing in various brainstem structures, including the inferior olivary complex. Additional studies with retrograde double‐labeling methods show that distinct cell groups within CM project to the motor cortex and the striatum. Likewise, separate neuronal populations within the CM‐Pf‐sPf complex give rise to striatal and brainstem projections, the former arising from CM and Pf and the latter mainly from sPf. The complementary nature of CM and Pf projections to the striatum and other basal ganglia components suggests that this thalamic complex participates in a highly ordered manner in the parallel processing of the information that flows through the basal ganglia.
Connections of the retrosplenial dysgranular cortex in the rat
Authors: van Groen Thomas , Wyss J. Michael 
Published: January 2005

AbstractAlthough the retrosplenial dysgranular cortex (Rdg) is situated both physically and connectionally between the hippocampal formation and the neocortex, few studies have focused on the connections of Rdg. The present study employs retrograde and anterograde anatomical tracing methods to delineate the connections of Rdg. Each projection to Rdg terminates in distinct layers of the cortex. The thalamic projections to Rdg originate in the anterior (primarily the anteromedial), lateral (primarily the laterodorsal), and reunions nuclei. Those from the anteromedial nucleus terminate predominately in layers I and IV‐VI, whereas the axons arising from the laterodorsal nucleus have a dense terminal plexus in layers I and III‐IV. The cortical projections to Rdg originate primarily in the infraradiata, retrosplenial, postsubicular, and areas 17 and 18b cortices. The projections arising from visual areas 18b and 17 predominantly terminate in layer I of Rdg, axons from contralateral Rdg form a dense terminal plexus in layers I‐IV, with a smaller number of terminals in layers V and VI, afferents from postsubiculum terminate in layers I and III‐V, and the projection from infraradiata cortex terminates in layers I and V‐VI. The efferent projections from Rdg are widespread. The major cortical projections from Rdg are to infraradiata, retrosplenial granular, area 18b, and postsubicular cortices, Subcortical projections from Rdg terminate primarily in the ipsilateral caudate and lateral thalamic nuclei and bilaterally in the anterior thalamic nuclei. The efferent projections from Rdg are topographically organized. Rostral Rdg projects to the dorsal infraradiata cortex and the rostral postsubiculum, while caudal Rdg axons terminate predominately in the ventral infraradiata and the caudal postsubicular cortices. Caudal but not rostral Rdg projects to areas 17 and 18b of the cortex. The Rdg projections to the lateral and anterior nuclei also are organized along the rostral‐caudal axis. Together, these data suggest that Rdg integrates thalamic, hippocampal, and neocortical information.
Immunocytochemical localization of the N‐acetyl‐aspartyl‐glutamate (NAAG) hydrolyzing enzyme N‐acetylated α‐linked acidic dipeptidase (NAALADase)
Authors: Stauch Slusher Barbara , Tsai Guochuan , Yoo Grace , Coyle Joseph T. 
Published: January 2005

AbstractN‐acetylated α‐linked acidic dipeptidase (NAALADase) is a membrane bound enzyme that cleaves glutamate from the endogenous neuropeptide N‐acetyl‐aspartyl‐glutamate (NAAG). We report the immunocytochemical localization of NAALADase in rat brain and kidney by using specific anti‐NAALADase antiserum. NAALADase‐immunoreactivity (NAALADase‐IR) was widely distributed, abundant in neuropil, absent from neuronal cytoplasm, and displayed regional heterogeneity. Staining was selectively enriched in several structures previously reported to contain NAAG‐immunoreactivity (NAAG‐IR) including the amygdala, caudate‐putamen, central gray, dorsal raphe, globus pallidus, hippocampus, hypothalamus, locus coerulus, medial and lateral geniculate, olfactory bulb, periaqueductal gray, solitary nucleus, spinal trigeminal nucleus, substantia nigra, superior colliculus, and thalamus. Staining within these structures was enriched in neuropil; no intracellular staining was detected, even after colchicine treatment. In addition, NAALADase‐IR was observed in some NAAG‐containing fiber tracts including the corpus callosum, fornix, habenular commissure, solitary tract, stria medularis, and stria terminals. The co‐localization of NAALADase‐IR and NAAG‐IR support the hypothesis that NAALADase is responsible for the catabolism of NAAG in vivo. NAALADase‐IR was also detected in brain regions that, to date, have not revealed NAAG‐IR, including the bed nucleus of the stria terminalis and the median eminence. In addition, NAALADase‐IR was detected in the rat kidney cortex, specifically in the brush border of the proximal convoluted tubules. The observation that NAALADase‐IR was more widespread than NAAG‐IR suggests that NAALADase may also be involved in the catabolism of other structurally related neural and renal peptides.
Morphine or U‐50,488 suppresses fos protein‐like immunoreactivity in the spinal cord and nucleus tractus solitarii evoked by a noxious visceral stimulus in the rat
Authors: Hammond Donna L. , Presley Robert , Gogas K. R. , Basbaum Allan I. 
Published: January 2005

AbstractImmunohistochemical visualization of Fos protein, the nuclear phosphoprotein product of the early‐immediate gene c‐fos, permits identification of populations of neurons that are activated in response to a variety of stimuli. This study examined the distribution of Fos‐like immunoreactive (FLI) neurons in the spinal cord and the nucleus tractus solitarii (NTS) of the caudal medulla evoked by a noxious visceral stimulus in the unanesthetized rat. It also compared the inhibition of pain behavior and Fos expression by a m̈‐selective opioid agonist, morphine, and a k‐selective opioid agonist, U‐50,488. Intraperitoneal injection of 3.5% acetic acid in the unanesthetized rat evoked the expression of FLI in a discrete population of spinal cord neurons, the distribution of which closely mirrored the spinal terminations of visceral primary afferents. Specifically, FLI neurons were concentrated in laminae I, IIo, V, VII, and X. Large numbers of Fos‐immunoreactive neurons were also present in the NTS of the caudal medulla, most likely as a result of spinosolitary tract and vagal afferent input. The number of labeled neurons in both the spinal cord and the NTS was significantly correlated with the number of abdominal stretches, a pain behavior measure. Both morphine (1–10 mg/kg s.c.) and U‐50,488 (3–30 mg/kg s.c.) produced a dose‐dependent inhibition of the pain behavior in these animals and a dose‐dependent suppression of the number of FLI neurons in both the spinal cord and in the NTS; complete suppression of FLI neurons was, however, not necessary for the production of antinociception. Furthermore, although equianalgesic doses of morphine and U‐50,488 reduced the number of labelled neurons in the spinal cord to a comparable extent, morphine reduced the number of immunoreactive neurons in the NTS to a greater extent than did U‐50,488. These results suggest that morphine and U‐50,488 have comparable effects on the transmission of visceral nociceptive messages by spinal neurons, but differentially affect the autonomic response to noxious visceral stimuli.
Localization of GABA, glycine, glutamate and tyrosine hydroxylase in the human retina
Authors: Crooks Jill , Kolb Helga 
Published: January 2005

AbstractA light microscope study using postembedding immunocytochemistry techniques to demonstrate the common neurotransmitter candidates gamma‐aminobutyric acid (GABA), glycine, glutamate, and tyrosine hydroxylase for dopamine has been done on human retina. By using an antiserum to GABA, we found GABA‐immunoreactivity (GABA‐IR) to be primarily in amacrine cells lying in the inner nuclear layer (INL) or displaced to the ganglion cell layer (GCL). A few stained cells in the INL, which are probably interplexiform cells, were observed to project thin processes towards the outer plexiform layer (OPL). There were heavily stained bands of immunoreactivity in strata 1, 3 and 5 of the inner plexiform layer (IPL). An occasional ganglion cell was also GABA‐IR.By using an antiserum to glycine, stained cells were observed at all levels of the INL. Most of these were amacrines, but a few bipolar cells were also glycine‐IR. Displaced amacrine cells and large‐bodied cells, which are probably ganglion cells, stained in the GCL. The bipolar cells that stained appeared to include both diffuse and midget varieties. The AII amacrine cell of the rod pathway was clearly stained in our material but at a lower intensity than two other amacrine cell types tentatively identified as A8 and A3 or A4. Again, there was stratified staining in the IPL, with strata 2 and 4 being most immunoreactive.An antiserum to glutamate revealed that most of the neurons of the vertical pathways in the human retina were glutamate‐IR. Rod and cone photoreceptor synaptic endings labeled as did the majority of bipolar and ganglion cells. The rod photoreceptor stained more heavily than the cone photoreceptor in our material. While both midget and diffuse cone bipolar cell types were clearly glutamate‐IR, rod bipolars were not noticeably stained. The most strongly staining glutamate‐IR processes of the IPL lay in the outer half, in sublamina a.The antiserum to tyrosine hydroxylase (TOH) revealed two different amacrine cell types. Strongly immunoreactive cells (TOH1) had their cell bodies in the INL and their dendrites ramified in a dense plexus in stratum 1 of the IPL. Fine processes arising from their cell bodies or from the stratum 1 plexus passed through the INL to reach the OPL but did not produce long‐ranging ramifications therein. The less immunoreactive amacrines (TOH2) lay in the INL, the center of the IPL or the GCL and emitted thick dendrites that were monostratified in stratum 3 of the IPL.
Postnatal development of type I retinal ganglion cells in hamsters: A lucifer yellow study
Authors: Lau Kam Cheung , So Kwok‐fai , Tay David 
Published: January 2005

AbstractThe postnatal development of a population of superior colliculus projecting retinal ganglion cells with large somata in hamsters aged from postnatal day (P) 4 to adult was studied by the intracellular injection of Lucifer Yellow. This population of cells was interpreted as Type I cells based on their large soma sizes and dendritic morphology resembling that of mature Type I cells.In addition to the growth of the soma and the dendritic field, transient morphological features such as intraretinal axon collaterals and exuberant dendritic spines, but not somatic spines, were frequently observed on this population of cells in hamsters during development. None of them exhibited any intraretinal axon collaterals after P7. The number of transient spine‐like processes on dendrites increased from P4 onwards to reach a peak at P16, decreased abruptly within a few days after the peak, and stabilised to reach the adult level by P30. These developing cells attained the maximum number of dendritic branches by P16 and there seems to be little, if any, reduction in the number of branch points after this time point. In addition, the length of individual branches of dendrites was not increased excessively during development and then shortened during maturation. Thus, the dendritic remodeling of these cells after P16 seems to be mainly the increase of the length of dendrites and the removal of exuberant dendritic spines.
Central projections of axons from taste hairs on the labellum and tarsi of the blowfly, Phormia regina Meigen
Authors: Edgecomb R. S. , Murdock L. L. 
Published: January 2005

AbstractTaste hairs are located on the labellum and tarsi of blowflies. These multimodal hairs consist of four functionally distinct chemoreceptors and a mechanoreceptor. By staining selected multimodal hairs, we sought to identify the central projection patterns of multiple and single axons from those hairs. On each side of the labellum there are 11 “largest” hairs (LH). The neurons associated with the anteriormost (LH‐1), posteriormost (LH‐11), and one lateral (LH‐6) hair on the labellum were stained selectively with cobaltous sulfide. The overall projection pattern in the central nervous system (CNS) for axons from LH‐1 and LH‐11 is similar and differs markedly from axons from LH‐6. At least three individual axon‐projection patterns were determined for each labellar hair filled, indicating a partial functional organization for axons from multimodal hairs. One identified axon, the dorsalmost axon, has terminal arborizations that do not differ with the location of its associated hair. Another axon, thicker than the others, projects to a region that is distinct from the four thin axons. Within this region the arborizations of the thick axons occupy different areas depending on the location of their associated hair. Neurons from the largest hairs on the distalmost tarsomere (D5) of each leg were also stained and consisted of one thick and four thin axons. All axons except one thin axon from tarsal D5 hairs terminate in their respective leg neuromeres. The remaining thin axon projects to the suboesophageal ganglion ipsilateral to the hair filled and terminates in the same region as a branch of the labellar dorsalmost axon. These data suggest that axonal arbors from multimodal hairs have a limited functional and somatotopic organization in the blowfly CNS.
Target‐specific outgrowth from human mesencephalic tissue grafted to cortex or ventricle of immunosuppressed rats
Authors: Strömberg Ingrid , Bygdeman Marc , Almqvist Per 
Published: January 2005

AbstractHuman fetal mesencephalic tissue was grafted to rats with unilateral lesions of the nigrostriatal pathway. The animals were immunosuppressed with cyclosporine A. Grafts were placed either into the lateral ventricle ipsilateral to the lesion or in the cingulate cortex above corpus callosum. The grafts and newly formed fibers were visualized by immunohistochemistry with antibodies against tyrosine hydroxylase (TH) and the human Thy‐1 glycoprotein. TH‐positive fibers covered the total volume of striatum when the graft was placed either in the ventricle or in the cortex. When the transplant was located in the ventricle, TH‐positive cells migrated from the graft into host striatum. No cell migration was seen into any other areas than striatum. Cortex and septum were sparsely reinnervated by the graft, but not to a density higher than that normally seen. Globus pallidus was totally devoid of TH‐positive fibers. When the graft was placed in cingulate cortex, fiber bundles penetrated through corpus callosum into either striatum, to arborize in its dorsal parts, or followed the medial side of the lateral ventricle to ventral limbic areas, where a fiber network also was formed. Human specific Thy‐1‐immunohistochemistry revealed positivity only on the lesioned side. These data suggest that dopamine neurons in human mesencephalic tissue, grafted to the rat brain, can migrate specifically into host striatum. Furthermore, TH‐positive fiber outgrowth occurred only into dopamine denervated areas of the host, avoiding areas that are normally not innervated by nigral neurons, but also able to reach distant target cells.
Anatomy of dendrites in motoneurons supplying the intrinsic muscles of the foot sole in the aged cat: Evidence for dendritic growth and neo‐synaptogenesis
Authors: Ramírez V. , Ulfhake B. 
Published: January 2005

AbstractMotoneurons (MNs) supplying the intrinsic muscles of the foot sole (IFS) were studied in the aged cat (> 15y). Axon conduction velocity of IFS MNs was 30–40% slower in the aged than in young adult cats. IFS MNs that appeared intact during intracellular recordings and labeling with horseradish peroxidase (HRP) were subjected to anatomical investigation of their dendrites. The results were compared with corresponding data from young adult (< 3y) cats.The average number of dendrites per IFS MN was twelve in both the aged and young adults. However, the branching was significantly more extensive in the aged cat, thus indicating that proliferation of dendritic branches may occur during the later part of life. Topological analysis revealed a significant difference in the frequency distributions of nodal vertices between young adult and aged cats. In the young adult, the dendritic branching pattern was compatible with trees generated by outgrowth from terminal segments, while in the aged there was a clear indication of collateral outgrowth of branches.The dendritic path distance and the length of terminal branches were similar in young adults and aged. The length of preterminal branches was shorter in the aged, while the combined dendritic length of a dendrite was larger compared to young adults. These data are consistent with the topological data, and add further evidence that the proliferation of branches in the aged cat may also take place from preterminal branches.Light microscopic analysis revealed the presence of “growth cone‐like” extensions in the dendrites of the aged cats. Such profiles were not encountered in dendrites from young adults. Electron microscopic observations showed that these “growth cone‐like” formations were not artifacts and that they were apposed by numerous axonal boutons, of which a number made synaptic contact. A distinct feature of the extensions was their rich content of mitochondria and membranous elements. It was suggested that these “growth cone‐like” formations were sites at which novel synaptic connections are established, and that they may represent the initial stage of an outgrowth of new dendritic branches in the aged cat.Local dendritic branch diameter related closely to the amount of dendritic membrane area located distally in both young adults and aged. Curve fitting disclosed that this relationship was quite similar for both age groups, despite concurrent differences in combined dendritic length and branching degree.