bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and plasticity of the serotoninergic projection to the Hamster's superior colliculus
Authors: Rhoades Robert W. , Mooney Richard D. , Chiaia Nicolas L. , Bennett‐Clarke Carol A. 
Published: January 2005

AbstractImmunocytochemical techniques were employed to investigate the normal adult organization, development, and effects of both neonatal and adult eye removal upon the organization of the serotoninergic projection to the hamster's superior colliculus. Immunocytochemistry, both alone and in combination with retrograde tracing with true blue and fluorogold, was used to determine the organization of the serotoninergic projection to the superior colliculus in normal adult hamsters. Immunoreactive fibers were present in all laminae of the superior colliculus, but they were most dense in the lower part of the stratum griseum superficiale, the stratum opticum, the stratum griseum profundum, and the stratum album profundum. When retrograde tracing from the colliculus was combined with immunocytochemistry for serotonin, cells containing both labels were found in the lateral portions of the nucleus raphe dorsalis and also in periaqueductal gray, the median and pontine raphe nuclei, and in the region of the medial lemniscus. Such cells were visible both ipsilateral and contralateral to the injection site.Serotonin immunoreactive fibers were visible in the superior colliculus by embryonic day 14 (2 days prior to birth). On the day of birth, a small number of immunoreactive fibers were present just below the pial surface and others were generally oriented either parallel or orthogonal to the collicular laminae. At this age, there were also many immunoreactive fibers that crossed from one side of the brainstem to the other in the commissure of the superior colliculus. Some serotonin‐positive axons appeared to terminate as growth cones in fetal and newborn hamsters. Over the next 2 weeks, the serotoninergic innervation of the SC increased in density and assumed the laminar distribution observed in adult animals. By this age, only a very few immunoreactive fibers were present in the commissure of the superior colliculus.Removal of one eye on either on the day of birth or in adulthood resulted in reorganization of the serotoninergic innervation of the partially deafferented colliculus. There was a marked increase in the density of serotonin‐positive fibers in the upper stratum griseum superficiale on the side ipsilateral to the remaining eye. This change was apparent within 2 weeks after enucleation in either neonatal or adult animals. Quantitative analysis demonstrated that the magnitude of this effect was greater after adult enucleation than after neonatal eye removal. Both neonatal and adult enucleation also resulted in an increase in the density of the serotoninergic projection to the dorsal and ventral lateral geniculate nuclei ipsilateral to the remaining eye.
Immunocytochemical localization of protein kinase C subspecies in the rat spinal cord: Light and electron microscopic study
Authors: Mori Miyako , Kose Akiko , Tsujino Takeshi , Tanaka Chikako 
Published: January 2005

AbstractDistinct expression of protein kinase C (PKC) subspecies in the central nervous system suggested that each subspecies has a distinct neural function in the processing and modulation of a variety of physiological responses to external signals. In this study, the cellular and subcellular distributions of βI‐, βII‐ and γ‐subspecies of PKC were demonstrated by using subspecies‐specific antibodies in the rat spinal cord.By light microscopy both γ‐ and βII‐subspecies immunoreactivities were found only in neurons of the substantial gelatinosa and axons of the dorsal corticospinal tract in the spinal cord. Use of a double staining method, however, revealed that βII‐subspecies immunoreactivity was localized in the outer part of the lamina II, whereas γ‐subspecies immunoreactivity was found in the inner part of lamina II. Immunoreactive neurons containing βI‐subspecies were scattered in the substantia gelatinosa. Beta I‐subspecies immunoreactivity varied in neuronal types. Furthermore, electron microscopic analysis clearly showed the subcellular distribution of these subspecies to be different from one another. Dense γ‐subspecies immunoreactivity was found in the cytoplasm except within cell organelles of the perikarya and dendrites. Some nuclei were stained as strongly as the cytoplasm and others were stained less heavily. The nucleoli had faint or no immunoreactivity. Reaction products of βII‐subspecies were located against the inner plasma membrane but not seen in the nuclei or nucleoli. Beta I‐subspecies immunoreactivity appeared to be associated with the Golgi complex. No immunoreactive products of any PKC subspecies were detected in the presynaptic terminals.The different patterns of expression described above imply that individual PKC subspecies may have a specific function in modulating the neuronal activity in the different neurons of the spinal cord.
Single fiber studies of ascending input to the cuneate nucleus of cats: II. Postsynaptic afferents
Authors: Pierce Joseph P. , Weinberg Richard J. , Rustioni Aldo 
Published: January 2005

AbstractThe morphology of single postsynaptic afferent fibers terminating in the feline cuneate nucleus was investigated by using transport of Phaseolus vulgaris leucoagglutinin from the cervical spinal cord and intraaxonal injections of horseradish peroxidase into identified postsynaptic fibers in the cuneate fasciculus.Injections of Phaseolus in C5 and C6 of both rhizotomized and non‐rhizotomized cats gave similar results and confirmed previous observations with other techniques. In one animal with the smallest injection and the fewest labeled fibers in the cuneate nucleus, ten individual collaterals were reconstructed from serial sections. Most of these collaterals were at middle levels of the cuneate (from obex to about 4 mm caudal to it); they were largely confined to the rim and ventral regions of the nucleus, and their terminal fields were restricted rostrocaudally. Electrophysiologically identified fibers stained with horseradish peroxidase had large receptive fields on the ipsilateral forepaw, and latencies suggesting an oligosynaptic link to the periphery. Most of the collaterals from these fibers were also at middle cuneate levels and terminated mainly at the periphery of the nucleus but gave rise to larger terminal arbors, including sparse terminal branches to the core of the nucleus.Individual postsynaptic fibers differed in several respects from primary afferent fibers. While the spacing of collaterals of postsynaptic fibers was intermediate between that of G hair and Ia fibers, their arbors were larger than either, and could extend through the dorsoventral extent of the cuneate nucleus. The pattern of bifurcation of postsynaptic fibers resulted in stringier arbors which encompassed larger and less dense terminal fields than those of primary afferents. The number of boutons per collateral was intermediate between G hair and Ia fibers, but boutons of postsynaptic fibers were substantially smaller. These morphological differences are consistent with distinct functional roles for the two main ascending afferent systems, as suggested by electrophysiological data.
Proximity as a factor in the innervation of host brain regions by retinal transplants
Authors: Radel J. D. , Hankin M. H. , Lund R. D. 
Published: January 2005

AbstractEmbryonic mouse retinae transplanted to a variety of locations within the rostral midbrain of neonatal rats exhibit selective innervation of host visual nuclei when studied at maturity. Some of these nuclei (superior colliculus, nucleus of the optic tract, dorsal terminal nucleus) usually receive extensive transplant projections, others are innervated partially (dorsal division of the lateral geniculate nucleus, olivary pretectal nucleus, medial terminal nucleus), while a few (ventral division of the lateral geniculate nucleus, suprachiasmatic nucleus, intergeniculate leaflet) are not innervated at all. The selectivity of this innervation is largely independent of the transplant's position within the rostral brainstem, while the density of innervation of individual nuclei depends in part upon the proximity of the transplant to the nucleus and upon whether the host retinal projection to that nucleus is present or absent. These findings provide a foundation for further studies of the behavioral capabilities of retinal transplants, for developmental studies of factors responsible for the establishment of normal neural projections, and for examination of the immunological consequences of transplantation.
Monoclonal antibody cat‐301 identifies Y‐cells in the dorsal lateral geniculate nucleus of the cat
Authors: Hockfield Susan , Sur Mriganka 
Published: January 2005

AbstractIn mammalian visual pathways, information is carried in parallel channels from the retina through the visual thalamus to visual cortex. The cat's visual pathway comprises at least three major channels that begin with the X, Y, and W ganglion cells in the retina. In the dorsal lateral geniculate nucleus (LGN) of the thalamus, neurons in the X, Y, and W channels receive input from their retinal counterparts and can be discriminated from one another on the basis of their anatomical and physiological properties.The search for molecular properties that might correlate with anatomically or physiologically defined classes of neuron has been a major area of research in recent years. Monoclonal antibody Cat‐301 recognizes a neuronal surface‐associated proteoglycan in many areas of the mammalian central nervous system. In the cat LGN Cat‐301 immunoreactivity is restricted to a subset of neurons. We show here that the distribution, size, morphology, and cortical projection pattern of Cat‐301‐positive LGN neurons match those previously described for Y‐cells. Taken together with our previous studies of the development of immunoreactivity and the sensitivity of Cat‐301 staining to visual deprivation, these studies suggest that Cat‐301 specifically recognizes Y‐cells in the cat‐LGN. These results indicate that neurons within a physiologically and anatomically denned cell class share a molecular property. They further suggest that differences in molecular traits may reflect, and possibly subserve, differences in anatomical and physiological characteristics.
Immunohistochemical analysis of the visual wulst of the pigeon (Columba livia)
Authors: Shimizu Toru , Karten Harvey J. 
Published: January 2005

AbstractThe avian wulst, a laminated “bulge” in the dorsal telencephalon, contains several distinct regions. The posterolateral portion (visual wulst) has been proposed to be an avian equivalent of the mammalian striate cortex. The present study examines specific neurotransmitters and neuropeptides within the visual wulst by immunohistochemical techniques. Antisera and monoclonal antibodies against choline acetyltransferase (ChAT), nicotinic acetylcholine receptor (nAChR), tyrosine hydroxylase (TH), serotonin (5‐HT), glutamic acid decarboxylase (GAD), gammaaminobutyric acid A receptor (GABAAR), cholecystokinin (CCK), substance P (SP), leucine‐enkephalin (L‐ENK), neurotensin (NT), neuropeptide Y (NPY), somatostatin (SRIF), corticotropin‐releasing factor (CRF), and vasoactive intestinal polypeptide (VIP) were used. Somata and neuropil displaying specific immunoreactivity were generally distributed in accordance with the laminar cytoarchitectonic organization of the wulst. The superficial layer of the wulst, the hyperstriatum accessorium, contained the highest densities of TH‐, 5‐HT‐, SP‐, NPY‐, SRIF‐, CRF‐, and VIP‐positive neuropil in the wulst, whereas the highest density of CCK‐ and NT‐staining was found in the deepest layer of the wulst, the hyperstriatum dorsale, In addition to the traditionally defined four laminae of the wulst, the immunoreactive staining revealed several subregions within each lamina. The most dorsolateral portion of the wulst contained the highest densities of ChAT‐ and L‐ENK‐stained fibers in the wulst, as well as moderately dense staining of neuropil for 5‐HT‐, TH‐, SP‐, and CCK‐like immunoreactivity. The nACh‐Rimmunoreactivity was faint and distributed rather uniformly throughout the wulst. The results suggest that the wulst consists of multiple regional variations within layers comparable to laminar variations found within different cytoarchitectonic areas of the mammalian neocortex.
Proportion of parvalbumin‐positive basket cells in the GABAergic innervation of pyramidal and granule cells of the rat hippocampal formation
Authors: Ribak Charles E. , Nitsch Robert , Seress László 
Published: January 2005

AbstractRecent studies have indicated that hippocampal GABAergic neurons in both the dentate gyrus and Ammon's horn contain immunoreactivity for the calcium‐binding protein parvalbumin (PARV). Although the distribution of PARV‐positive neurons has been previously described, detailed quantitative electron microscopic studies of the PARV‐positive axon terminals in the hippocampal formation are lacking. In the present study, immunocytochemical methods were used to localize PARV‐positive neurons and axon terminals to determine their similarity to GABAergic neurons. The PARV‐positive cells and axon terminals are associated closely with the pyramidal and granule cell layers. In agreement with previous studies, the morphology of PARV‐positive neurons is similar to that of GABAergic cells, including the basket cells of both the dentate gyrus and Ammon's horn. The PARV‐positive axon terminals form exclusively symmetric synapses with somata, dendrites, dendritic spines, and axon initial segments. However, these terminals represent only a portion of the total number of terminals that form symmetric synapses. Quantitative results indicate that only 32–38% of the total number of terminals forming symmetric axosomatic synapses with principal cells of the dentate gyrus and Ammon's horn are PARV positive. Together with previous findings from light microscopic double‐labeling studies, these data indicate that the PARV‐positive terminals arise from a subpopulation of GABAergic hippocampal neurons. Finally, it is important to note that the terminal plexus of PARV‐positive hippocampal axons overlaps at all postsynaptic sites with a plexus of PARV‐negative axons.
Evaluation of the activity of chemically identified enteric neurons through the histochemical demonstration of cytochrome oxidase
Authors: Kirchgessner A. L. , Gershon M. D. , Mawe G. M. 
Published: January 2005

AbstractThe measurement of the density of the reaction product produced by the histochemical demonstration of cytochrome oxidase activity provides a method for the visual identification of physiologically active enteric neurons. The current study utilized the cytochrome oxidase technique in order to evaluate the metabolic history of neurons in different regions of the bowel and in chemically identified types of neuron. In addition, the effect of drugs or neurotoxins commonly used in the immunocytochemical identification of enteric neuronal phenotypes was also analyzed. Cytochrome oxidase activity was visualized with a blue‐black reaction product resulting from the cobalt‐intensified oxidation of 3,3′‐diaminobenzidine. Peptides or 5—hydroxytryptamine (5‐HT) were localized with biotinylated secondary antibodies and alkaline phosphatase‐labeled avidin. Bound avidin or endogenous alkaline phosphatase was visualized with a red reaction product in the presence or absence, respectively, of levamisole. Use of monochromatic red light permitted the cytochrome oxidase reaction product density to be measured without interference from a simultaneously demonstrated histo‐or immunochemical marker. A multi‐peptidergic class of cholinergic submucosal secretomotor neuron containing neuropeptide Y (NPY) and calcitonin gene related peptide (CGRP)immunoreactivities was found to be less metabolically active than the average of all submucosal neurons. In contrast, a non‐cholinergic submucosal secretomotor neuron containing dynorphin (which is also known to contain vasoactive intestinal peptide) immunoreactivity was more metabolically active than submucosal neurons that do not contain this peptide. On average, submucosal neurons were more metabolically active than those of the myenteric plexus, and levels of metabolic activity in the myenteric plexus were found to be higher in the duodenum and the cecum than in the jejunum‐ileum or colon. Myenteric neurons characterized by CGRP or NPY immunoreactivities or by endogenous alkaline phosphatase activity, were all less metabolically active than the average of all neurons in myenteric ganglia. Colchicine, which stimulates intestinal motility, was observed to increase cytochrome oxidase activity in enteric neurons, suggesting that an effect on the enteric nervous system contributes to its action on the bowel. The neurotoxins, 6‐hydroxydopamine and 5,7‐dihydroxytryptamine (5,7‐DHT) were each found to stimulate neuronal metabolic activity. 5,7‐DHT appeared to activate excitatory subtypes of 5‐HT receptor since its effects were blocked or mimicked by compounds that act as antagonists or agonists, respectively, at these receptors. The cytochrome oxidase technique is thus useful for studying the metabolic activity of chemically identified types of enteric neuron as well as for evaluating the action of experimental procedures on these cells.
Somatodendritic morphology of on‐ and off‐cells in the rostral ventromedial medulla
Authors: Mason P. , Floeter M. K. , Fields H. L. 
Published: January 2005

AbstractThe rostral ventromedial medulla (RVM) contains two classes of physiologically defined neurons, on‐cells and off‐cells, that are implicated in nociceptive modulation. In a continuing effort to detail the neural circuitry that underlies the activity of these two distinct neuronal types, the somatodendritic morphology of on‐ and off‐cells was studied in the cat, rat, and ferret.In lightly anesthetized animals, on‐cells increased and off‐cells decreased their discharge rate during a withdrawal reflex evoked by noxious stimuli. Following their physiological characterization by using intracellular recording, on‐ and off‐cells were injected with either horseradish peroxidase or biocytin and their somatodendritic arborizations were examined.Labeled on‐ and off‐cells included fusiform and stellate cells of all sizes as well as large multipolar neurons. Although the somatic shape of both on‐ and off‐cells in RVM was heterogeneous, off‐cells tended to be fusiform neurons whose long axis was oriented mediolaterally.The dendritic domains of both on‐ and off‐cells extended bilaterally past the lateral edge of the trapezoid body or pyramid and ventrally to, and sometimes including, the trapezoid body or pyramid. In contrast to their extensive mediolateral spread, the dendritic domains of both cell types were limited to the ventral half of the reticular formation and were compressed along the rostrocaudal axis. The dendritic arbor of individual on‐ and off‐cells extended well beyond the cytoarchitechtonic boundaries of any single nuclear region, within the domain delineated as the RVM. The spatial domains of the dendritic arbors of on‐ and off‐cells are further evidence that the on‐ and off‐cells throughout the RVM constitute an integrated unit in the modulation of nociceptive transmission.
Quantitative analysis of a vulnerable subset of pyramidal neurons in Alzheimer's disease: I. Superior frontal and inferior temporal cortex
Authors: Hof Patrick R. , Morrison John H. , Cox Kevin 
Published: January 2005

AbstractVarious cytoskeletal proteins have been implicated in the cellular pathology of Alzheimer's disease. A monoclonal antibody (SMI32) that recognizes nonphosphorylated epitopes on the medium (168 kDa) and heavy (200 kDa) subunits of neurofilament proteins has been used to label and analyze a specific subpopulation of pyramidal neurons in the prefrontal and inferior temporal cortices of normal and Alzheimer's disease brains. In Alzheimer's disease, the distribution of neuropathological markers predominates in layers III and V in these association areas. In these neocortical regions, SMI32 primarily labels the perikarya and dendrites of large pyramidal neurons, predominantly located within layers III and V. In Alzheimer's disease, a dramatic loss of SMI32‐immunoreactive (ir) cells was observed, affecting particularly the largest cells (i.e., cells with a cross‐sectional perikaryal area larger than 350 m̈m2). The staining intensity of the largest SMI32‐ir neurons was significantly reduced in Alzheimer's disease cases, suggesting that an inappropriate phosphorylation of these cytoskeletal proteins may take place in the course of the pathological process. In addition, the SMI32‐ir neuron loss and total neuron loss were highly correlated with neurofibrillary tangle counts, whereas such a correlation was not observed with neuritic plaque counts.These quantitative data suggest that SMI32‐ir neurons represent a small subset of pyramidal cells that share certain anatomical and molecular characteristics and are highly vulnerable in Alzheimer's disease. Other studies have suggested that SMI32‐ir neurons are likely to furnish long corticocortical projections. Thus, their loss would substantially diminish the effectiveness of the distributed processing capacity of the neocortex, resulting in a neocortical isolation syndrome as reflected by the clinical symptomatology observed in these patients. Such correlations between the expression of a selective cellular pathology and specific elements of cortical circuitry will increase our understanding of the molecular and cellular characteristics underlying a given neuronal subclass vulnerability in Alzheimer's disease or other neurodegenerative disorders.