bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aromatic L‐amino acid decarboxylase‐immunohistochemistry in the cat lower brainstem and midbrain
Authors: Kitahama Kunio , Denoyer Michel , Raynaud Brigitte , Borri‐Voltattorni Carla , Weber Michel , Jouvet Michel 
Published: January 2005

AbstractBy indirect immunohistochemistry, the present study examined the distribution of neuronal structures in the cat medulla oblongata, pons, and midbrain, showing immunoreactivity to aromatic L‐amino acid decarboxylase (AADC), which catalyzes the conversion of L‐3, 4‐dihyroxyphenylalanine (L‐DOPA) to dopamine, and 5‐hydroxytryptophan to serotonin (5HT). With simultaneous and serial double immunostaining techniques, immunoreactivity to this enzyme was demonstrated in most of the catecholaminergic and serotonergic neurons. We could also demonstrate AADC‐IR cell bodies that do not contain tyrosine hydroxylase (TH‐) or 5HT‐immunoreactivity (called “D‐type cells”) outside such monoaminergic cell systems. At the medullo‐spinal junction, very small D‐type cells were found within and beneath the ependymal layer of the 10th area of Rexed surrounding the central canal. D‐type cells were localized in the caudal reticular formation, nucleus of the solitary tract, a dorsal aspect of the lateral parabrachial nucleus, and pretectal areas as have been reported in the rat. Furthermore, the present study describes, in the cat brainstem, new additional D‐type cell groups that have not been reported in the rat. Dense or loose clusters of D‐type cells were localized in the external edge of the laminar trigeminal nucleus, dorsal motor nucleus of the vagus, external cuneate nucleus, nucleus praepositus hypoglossi, central, pontine, and periaqueductal gray, superficial layer of the superior colliculus, and area medial to the retroflexus. D‐type cells were loosely clustered in the lateral part of the central tegmental field dorsal to the substantia nigra, extending dorsally in the medial division of the posterior complex of the thalamus and medial side of the brachium of the inferior colliculus. They extended farther rostrodorsally along the medial side of the nucleus limitans and joined with the pretectal cell group. Almost all these cells were very small and ovoid to round with 1–2 short processes with the exception of dorsal motor vagal cells, AADC‐IR axons were clearly identified in the vagal efferent nerves, longitudinal medullary pathway, dorsal tegmental bundle rostral to the locus coeruleus. Serotonergic axons were identified not only in the central tegmentum field and lateral side of the central superior nucleus, but also in the ventral surface of the medulla oblongata. We describe principal densely stained fiber plexuses in the cat brainstem. The findings of the present study provide a morphological basis for neurons that decarboxylate endogenous and exogenous L‐DOPA, 5HTP, and other aromatic L‐amino acids.
Descending neurons supplying the neck and flight motor of diptera: Organization and neuroanatomical relationships with visual pathways
Authors: Strausfeld Nicholas J. , Gronenberg Wulfila 
Published: January 2005

AbstractIn dipterous insects, a volume of behavioral and electrophysiological studies promote the contention that three wide‐field motion‐sensitive tangential neurons provide a necessary and sufficient input to specific channels that drive the torque motor during flight. The present studies describe the results of neuroanatomical investigations of the relationships between motion‐sensitive neuropil in the fly optic lobes and descending neurons that arise from a restricted area of the brain and supply segmental neck and flight motor neuropil. The present observations resolve at least 50 pairs of descending neurons supplying flight motor centers in the thoracic ganglia. The majority of descending neurons receive a distributed output from horizontal motion‐sensitive neurons. However, the same descending neurons are also visited by numerous small‐field retinotopic neurons from the lobula plate as well as hitherto undescribed small tangential neurons. Neuroanatomical studies, using cobalt, Golgi, and Texas red histology, demonstrate that these smaller inputs onto descending neurons have dendrites that are organized at specific strata in retinotopic neuropil and that these correspond to horizontal and vertical motion sensitivity layers. Conclusions that only a restricted number of wide‐field neurons are necessary and sufficient for visually stabilized flight may be premature. Rather, neuroanatomical evidence suggests that descending neurons to the flight motor may each be selectively tuned to specific combinations of wide‐ and small‐field visual cues, so providing a cooperative descending network controlling the rich repertoire of visually evoked flight behavior.
Thalamo‐cortical processing of vibrissal information in the rat. II. Spatiotemporal convergence in the thalamic ventroposterior medial nucleus (VPm) and its relevance to generation of receptive fields of S1 cortical “Barrel” neurones
Authors: Armstrong‐James Michael , Callahan Christopher A. 
Published: January 2005

AbstractOne hundred and twenty‐six cells, sampled in the vicinity of the D1 barreloid in the ventroposterior medial nucleus of the thalamus, were tested for magnitude and latency of response to brief deflections (3 ms; 1.14°) of vibrissae in adult rats under controlled conditions of light urethane anaesthesia. Similar results were achieved for D1 and non‐D‐dominant cells. D1‐dominant cells (N = 76) responded to the centre‐receptive field (D1) vibrissa with a mean of 1.08 spikes per stimulus at modal latencies of 3–12 ms (inter‐quartile range 4–5 ms) and to surrounding vibrissae with a mean of 0.26 spikes per stimulus at latencies of 3–41 ms (inter‐quartile range 5–8 ms). Surround‐receptive fields showed extensive overlap but were reduced and finally eliminated by deepening anaesthesia. A cell‐by‐cell analysis showed no correlation between latency and response magnitude for responses to surround vibrissae. Response magnitudes to the surround‐ and centre‐receptive field inputs for D1‐dominant barrel cells were some 2.5‐ and 1.7‐fold greater, respectively, than for thalamic cells under identical experimental conditions. The latencies to centre‐ and surround‐receptive field inputs for D1‐dominant barrel cells were 2.5 and 10–20 ms later than for thalamus, respectively. These data on a mismatch of latencies for surround‐ and centre‐receptive fields in thalamus and cortex support the notion that surround‐receptive fields of cortical barrel cells are almost entirely constructed intracortically during light an anaesthesia (Armstrong‐James et al., '91), although it is argued that surround‐receptive fields of thalamic cells conceivably could be relayed in other cortical states or serve a role in plasticity.
Chicken optic tract cells showing GABA‐like immunoreactivity: Morphological and immunocytochemical studies
Authors: Granda R. H. , Eyck G. R. Ten , Crossland W. J. 
Published: January 2005

AbstractA population of cells has been found in the chick optic tract and chiasm exhibiting GABA‐like immunoreactivity (GABA+; Granda and Crossland, J. Comp. Neurol. 287:455–469, '89). It is not known, however, whether the cells are neurons. We have studied the GABA+ cells by using morphological and immunocytochemical methods. We found that there are more than 500 cells in each tract. At the light microscopic level, the cells possess processes resembling dendrites and axons. At the electron microscopic level, the organelle content of the cells is similar to that of neurons. The cells are immunoreactive with antibodies to MAP2 and neuron specific enolase, two proteins characteristic of neurons. Taken together the findings indicate that the GABA+ cells of the chick optic tract are neurons, perhaps similar to the interstitial neurons found in the white matter of other vertebrates.
Subpopulations of mesencephalic dopaminergic neurons express different levels of tyrosine hydroxylase messenger RNA
Authors: Weiss‐Wunder Linda T. , Chesselet Marie‐Françloise 
Published: January 2005

AbstractSubpopulations of mesencephalic dopamine containing neurons possess different electro‐physiological, pharmacological, biochemical, and anatomical properties. In order to determine whether such differences are related to the regulation of tyrosine hydroxylase, the rate limiting enzyme in the synthesis of catecholamines, the regional distribution of tyrosine hydroxylase messenger RNA in these neurons was examined using in situ hybridization histochemistry. In the mouse, labelling for tyrosine hydroxylase messenger RNA associated with individual neurons was significantly less in the lateral substantia nigra pars compacta than in the medial substantia nigra pars compacta and the ventral tegmental area. A similar pattern of labelling was observed in the rat. Labelling for tyrosine hydroxylase messenger RNA was significantly less in the lateral substantia nigra pars compacta than in medial pars compacta (a densely cellular region), the area dorsal to the medial substantia nigra pars compacta (a less cell dense region), and the ventral tegmental area. Differences in levels of labelling for messenger RNA in mesencephalic dopamine neurons were not related to differences in cell size as measured in sections processed for tyrosine hydroxylase immunohistochemistry. The results suggest that tyrosine hydroxylase messenger RNA is differentially regulated in Subpopulations of mesencephalic dopamine neurons, supporting the view that these neurons are physiologically distinct.
Distribution of catecholamine uptake sites in human brain as determined by quantitative [3H] mazindol autoradiography
Authors: Donnan Geoffrey A. , Kaczmarczyk Stan J. , Paxinos George , Chilco Peter J. , Kalnins Renate M. , Woodhouse Dianne G. , Mendelsohn Frederick A. O. 
Published: January 2005

AbstractBecause of the importance of the catecholamine system in Parkinson's disease and its relevance to a variety of clinical movement disorders, catecholamine uptake sites were mapped in the human brain using [3H] mazindol autoradiography. Displacement studies with known dopamine (DA) and noradrenaline (NA) uptake blockers showed that binding in the striatum was to dopamine uptake sites; binding in the locus coeruleus was to noradrenergic uptake sites. By using the selective noradrenergic uptake blocker desmethylimipramine (DMI), a comprehensive map of both DA and NA uptake sites was generated. In general, catecholamine uptake sites were better seen in terminals than in cells of origin or axonal projections. In some areas, such as the locus coeruleus, punctate binding could be seen over individual pigmented cells. A variegated pattern of binding was seen in caudate nucleus and putamen and some correspondence of patches of low binding with striosomes was observed in the caudate. The highest levels of binding to DA uptake sites was observed in the striatum, where regional differences in binding occurred. The most dense binding was seen in the ventral striatum, and a rostral‐to‐caudal decrement in binding levels in caudate nucleus and putamen was evident. Binding was more intense in the putamen compared to the caudate and within the caudate lower values were seen laterally. The highest levels of binding to noradrenergic uptake sites were in the locus coeruleus and dorsal raphé, although these sites may be on terminals from other projections. Whereas uptake sites were more often evident in known catecholamine pathways, [3H mazindol binding was seen in some areas where catecholamine neurons or terminals had not been identified previously. These maps of the catecholamine uptake system add further information concerning the nature of the distribution of catecholamines in human brain and provide an important baseline for the study of disease and ageing processes.
Incorporation of 3H‐thymidine in the embryonic vomeronasal and olfactory epithelia of garter snakes
Authors: Holtzman David A. , Halpern Mimi 
Published: January 2005

AbstractPrevious studies have shown that the vomeronasal and olfactory epithelia of adult vertebrates provide good models for studying normal neuronal turnover and regeneration in response to axotomy. However, little is known about the cell dynamics in the embryonic vomeronasal and olfactory epithelia or the origins of different cell types in these structures. By using 3H‐thymidine autoradiography, both in vivo and in vitro, the origins of receptor and supporting cells and the survival of labelled cells in the embryonic vomeronasal and olfactory epithelia of garter snakes were examined. The results of this study suggest that the receptor and supporting cells of both epithelia arise from separate stem cells and that two subpopulations of stem cells exist for receptor cells in the embryonic vomeronasal epithelium. One subpopulation generates cells that migrate through the receptor cell columns, while another subpopulation remains at the base of the epithelium for approximately 50 days. Although it is unclear how long receptor cells in the embryonic olfactory epithelium survive, the results of this study suggest that they survive at least 37 days and may survive over 56 days. In addition, the development of these sensory epithelia appears different in early versus late embryos, and regeneration in the vomeronasal and olfactory epithelia of adult garter snakes appears similar to development during late gestation. Cells in the developing receptor cell layer of the olfactory epithelium lose their ability to incorporate 3H‐thymidine before those in the vomeronasal epithelium, suggesting that the onset of neuronal maturation occurs earlier in the olfactory epithelium than in the vomeronasal epithelium.
Localized denervation demonstrates the innervation pattern of olfactory bulb glomeruli and second order cells
Authors: Wellis David P. , Scott John W. 
Published: January 2005

AbstractSensory systems rely upon spatially organized projections for the faithful transfer of receptor activity into the central nervous system. While the mammalian olfactory nerve shows a regional topographical organization, data on the sources of variation within this projection are scarce. We evaluated the degree of precision of olfactory bulb glomerular innervation from the olfactory nerve layer (ONL) by making small cuts across the trajectory of the olfactory nerve fibers and assessing the resulting denervation by wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) labeling of primary nerve fibers. In control animals (no ONL cut), the ONL and glomerular layer showed intense labeling around the entire circumference of the bulb. Transneuronal labeling of the mitral cell layer and the external plexiform layer was also observed in animals surviving at least 2 days, which allowed us to study the nerve fiber innervation of second order cells as well. ONL cuts on the lateral face of the bulb produced a stripe of denervation, as evidenced by the absence of primary and transneuronal label in a well‐defined region. Fascicles of fibers within the ONL were never observed to enter the denervated region from more than one or two glomerular widths away, indicating a relatively tight limit of variation in the spatial termination of olfactory nerve fibers on the lateral bulb surface. This limit of variation does not hold around the circumference of the bulb since similar ONL cuts on the dorsal surface failed to produce a distinct stripe of denervation. Field potential measurements from the ONL after similar cuts supported the anatomic findings. These results show that primary olfactory axons and their terminals lie in parallel along the lateral face of the olfactory bulb. These spatial relationships of olfactory input to the bulb are maintained in the second order connections. This organization allows one to study the spatial aspects of interneuronally mediated synaptic mechanisms involved in olfactory coding.
Distribution of mRNAs coding for liver and heart gap junction proteins in the rat central nervous system
Authors: Micevych Paul E , Abelson Lauren 
Published: January 2005

AbstractThe present study examined the distributions of connexin43 mRNA and connexin32 mRNA in the central nervous system (CNS) of the rat by using in situ hybridization histochemistry. These connexins are the best studied gap junction proteins; connexin32 forms direct cell‐cell channels in the liver, as does connexin43 in the heart. There was a differential distribution of cells containing connexin32 mRNA compared with the population of cells which contained connexin43 mRNA, thus implying a regional specificity in the expression of connexins in the CNS. Cells containing connexin43 mRNA were uniformly distributed throughout the gray matter of the neuraxis. Several areas had a higher concentration of cells that express connexin43, such as layer IA of the piriform cortex, supraoptic and paraventricular nuclei of the hypothalamus, anterior cortical amygdaloid nucleus, the reticular part of the substantia nigra, lateral habenula, mesencephalic trigeminal nucleus, Purkinje cell layer of the cerebellum, facial nucleus, prepositus hypoglossal nucleus, and dorsal cochlear nucleus. The pattern of connexin43 hybridization and the morphology of connexin43 mRNA containing cells suggest that this gap junction forming protein is found predominantly in astrocytes, Con‐nexin32 mRNA was detected in discrete cell groups of the gray matter that appeared to be neurons, including cells in layer 2 of the neocortex, layer II of the piriform cortex, pyramidal cell layer of the hippocampus, granule and polymorphic cell layers of the dentate gyrus, islands of Calleja, olfactory tubercle, lateral thalamic nuclei, lateral habenula, and Purkinje cell layer of the cerebellar cortex. A large population of cells in white matter tracts that were labelled with the connexin32 riboprobe appeared to be oligodendrocytes. These studies suggest that neurons and glial cells express connexin32 mRNA, but only astrocytes express connexin43 mRNA. Many of the areas in which connexin mRNAs were demonstrated have electrically coupled cells, morphologically distinct gap junction plaques, and/or have immunocytochemically identifiable connexin proteins. These results indicate that cells with mRNAs coding for intercellular channels have a widespread distribution in the mammalian CNS.
Spatial relationships of axons arising from the substantia nigra, spinal trigeminal nucleus, and pedunculopontine tegmental nucleus within the intermediate gray of the cat superior colliculus
Authors: Harting John K. , Van Lieshout David P. 
Published: January 2005

AbstractWe have utilized two different anterograde transport methods (Phaseolus vulgaris leucoagglutinin [PHA‐L] immunocytochemistry and autoradiography) in the same experiment to compare the sublaminar location and arrangement of tectopetal axons arising from the substantia nigra pars reticulata, the spinal trigeminal nucleus, and the pedunculopontine tegmental nucleus.Our findings reveal that the nigrotectal projection terminates in a patchy fashion within three horizontally oriented sublaminae of the stratum griseum superficial (SGI), the dorsal, middle and ventral. The middle tier of nigrotectal axons exhibits an exquisite, puzzle‐like, complementary spatial relationship with trigeminotectal axons. In contrast, axons arising from the pedunculopontine tegmental nucleus overlap with patches of nigrotectal axons within the middle tier. Thus the middle tier of the SGI consists of domains of overlapping nigral and pedunculopontine tegmental inputs which interdigitate with domains rich in somatosensory inputs.
The parabigeminogeniculate projection: Connectional studies in eight mammals
Authors: Harting John K. , Van Lieshout D. P. , Hashikawa T. , Weber J. T. 
Published: January 2005

AbstractAnterograde and retrograde tracing methods have been used to analyze the origin and distribution of parabigeminogeniculate axons in the gray squirrel, the gopher, the rat, the opossum, the cat, the greater bushbaby, the squirrel monkey and the macaque monkey. Our findings reveal that parabigeminogeniculate axons most heavily innervate regions of the lateral geniculate that are also targeted by axons arising from the superior colliculus (tectogeniculate). These geniculate layers and zones of parabigeminal and tectal overlap contain small cells, and in several species are associated with the small W cell retino‐geniculocortical pathway.In addition to the dense input to small‐celled layers and zones, parabigeminal axons in several species also innervate regions of the lateral geniculate nucleus that are relatively free of tectogeniculate axons and that are associated with the medium (X) and large (Y) cell streams.Finally, our data reveal that the laterality of parabigeminogeniculate pathways varies across mammals, being primarily crossed in the gray squirrel, the gopher, the rat, and the opossum, bilateral in the cat, and primarily ipsilateral in the three primates.
Subregional topography of capillaries in the dorsal vagal complex of rats: II. Physiological properties
Authors: Gross Paul M. , Wall Katharine M. , Wainman Dan S. , Shaver Steven W. 
Published: January 2005

AbstractThe differentiated cytoarchitecture, neurochemistry, and capillary organization of the rat dorsal vagal complex prompted this comprehensive investigation of micro vascular physiology in 11 subdivisions of area postrema, 5 subnuclei of nucleus tractus solitarii (NTS), the dorsal motor nucleus of the vagus nerve, and 4 other gray matter structures in the dorsal medulla oblongata. Microvascular exchangeable volume (residual plasma volume), capillary blood and plasma flow, and unidirectional transfer constants for a tracer amino acid, [14C]α‐aminoisobutyric acid (AIB), varied considerably among the structures analyzed. Exchangeable volume, largest in area postrema medial zones (about 29 μl μl · g−1) and smallest in medullary gray matter (7–11 μl · g−1), correlated directly with subregional densities of capillaries and rates of tissue glucose metabolism. Capillary blood flow (range of 1,430–2,147 μl · g−1 · min−1), plasma flow, and tissue glucose metabolism (range of 0.48–0.71 μmol · g−1 · min−1) were linearly related in the dorsal vagal complex. The most striking quantitative difference among structures in this brain region were the rates of transcapillary influx and derived permeability X surface area (PS) products of [14C]AIB, which has physicochemical properties resembling those of hormones. PS products for AIB were negligible in most medullary gray matter regions (< 1 μl · g−1 · min−1, indicative of blood‐brain barrier properties), but were 20–59 × and 99–402 × higher in NTS subnuclei and area postrema, respectively. An extraordinary feature of the microcirculation in area postrema was the long‐duration transit of tracer sucrose and blood, a characteristic that would amplify the sensing ability of area postrema as it monitors the composition of the circulation.