bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural morphology, synaptic relationships, and CGRP immunoreactivity of physiologically identified c‐fiber terminals in the monkey spinal cord
Authors: Alvarez Francisco J. , Kavookjian Anahid M. , Light Alan R. 
Published: January 2005

AbstractThe spinal cord terminations of two electrophysiologically identified single C‐fibers (one identified as a C‐nociceptor) were intraaxonally labeled with horseradish peroxidase and analyzed with both light and electron microscopy. Serial section ultrastructural analysis and postembedding immunocytochemical techniques for calcitonin gene‐related peptide (CGRP), substance P (SP), and GABA were used to study the synaptology, and neuropeptide content.All C‐terminal synapses were in laminae I and II. The terminals sampled (n = 73) from these two C‐fibers rarely established glomerular synaptic complexes, but rather, simple terminals, usually measuring 1–4 μm in length and 1–3 μm in diameter. They most often established 1 or 2 (range 1 to 5) quite large asymmetric axodendritic synaptic contacts. Postsynaptic structures included dendritic spines and shafts with and without vesicles. C‐terminals were filled with small round synaptic vesicles (45–60 nm) and also contained variable numbers of large dense‐core vesicles (LDCVs, 80–110 nm). LDCVs inside identified C‐terminals frequently displayed CGRP immunoreactivity. We were unable to detect SP immunoreactivity inside our sample of C‐fiber LDCVs. C‐terminals were never found postsynaptic to other profiles.Thus, the C‐fiber terminals sampled in this study have simple synaptology, do not receive presynaptic control and contain CGRP immunoreactivity. They differ greatly from the terminals of Aδ nociceptors studied previously by our group that had glomerular endings, often received presynaptic input and did not contain CGRP immunoreactivity. This suggests the existence of different processing mechanisms, at the level of the first synapse, for nociceptive inputs arriving to lamina I and II through different types of primary afferents. © 1993 Wiley‐Liss, Inc.
Deafferentation‐induced terminal field expansion of myelinated saphenous afferents in the adult rat dorsal horn and the nucleus gracilis following pronase injection of the sciatic nerve
Authors: Lamotte Carole C. , Kapadia Shanta E. 
Published: January 2005

AbstractWe have previously demonstrated sprouting of small diameter saphenous afferents, labelled with wheat germ agglutinin conjugated with horseradish peroxidase (WGA‐HRP) and (HRP), into the sciatic territory of the adult rat superficial dorsal horn follwing destruction of sciatic afferents by injection of the sciatic nerve with pronase (a combination of proteolytic enzymes). In the present experiments, we examined the response of myelinated saphenous axons, which terminate in lamina I and the deep dorsal horn (laminae III–V) under the same conditions, with the tracer B subunit of cholera toxin conjugated to HRP (B‐HRP) which specifically labels myelinated primary afferents when injected into a peripheral somatic nerve. We also examined changes in the nucleus gracilis, another site of sciatic degeneration and a target of saphenous afferents. Four months after injection of the pronase, the area of label determined by measurement of the width of the saphenous territory in lamina III was expanded by 24% on the pronase side. Since there was also expansion throughout the deep dorsal horn, the area measured by tracing the labelled region in transverse sections was actually twice that of the control side, and the intensity of labelling within the traced area increased by 18%. There was no change in grey matter area due to the lesion. The traced area of labelling in the nuleus gracilis increased by 40%, and increased in intensity by 17%. The substantia gelatinosa is not normally supplied by B‐HRP‐labelled afferents, and there was no expansion of these sprouted saphenous afferents into the gelationosa. These results indicate that myelinated afferents can sprout as vigorously in lamina I and the deep dorsal horn as the small diameter afferents do in the substantia gelatinosa; that there is no invasion of the substantia gelatinosa by the myelinated afferents at least as long as the small diameter afferents also have the opportunity to sprout; and that primary afferents have the potential to sprout at more than one site of termination, i.e., both the dorsal horn and the dorsal column nuclei.
Dorsal motor nucleus of the vagus nerve: A cyto‐ and chemoarchitectonic study in the human
Authors: Huang Xu‐Feng , Törk Istvan , Paxinos George 
Published: January 2005

AbstractIn order to investigate the topography and subdivisions of the human dorsal motor nucleus of the vagus nerve (10), studies were conducted using cyto‐ and chemoarchitectonic (acetylcholinesterase and substance P‐like immunoreactivity) and computer reconstruction techniques.The six brainstems examined were obtained within 17 hours postmortem from adults with no known neurological disorders. Serial sections cut in transverse, sagittal, and coronal planes were stained with cresyl violet, or tested for acetylcholinesterase or substance P. The neurons of the 10 (16,826 ± 967) displayed cyto‐ and chemoarchitectonic heterogeneity and could be classified into six types. Types I–V consist of presumed vagal motor neurons (13,802 ± 844), while the remaining type (Type VI) consisted of presumed interneurons (3,024 ± 769). The 10 was subdivided into nine subnuclei grouped regionally into rostral, intermediate, and caudal divisions on the basis of neuronal morphology, cell density, and differential AChE and substance P reactivities. The rostral division contains the dorsorostral (DoR) and the ventrorostral (VeR) subnuclei; the intermediate division contains the rostrointermediate (RoI), dorsointermediate (DoI), centrointermediate (CeI), ventrointermediate (VeI), and caudointermediate (CaI) subnuclei; the caudal division (Ca) is not subdivided. Morphologically, small round or oval cells populate the VeR and VeI. Medium‐sized oval cells occur in the DoR, CeI, and Ca, while medium‐sized fusiform and multipolar cells are the main features of CaI. Large triangular cells appear mainly in DoI. Glial cells show the highest predilection for CeI, lowest densities in DoI and medial fringe subnucleus (MeF), and intermediate densities in the remaining six subnuclei. VeI showed the strongest AChE reactivity. Although the cell bodies of VeR and DoI are AChE positive, the neuropil (background) is weakly stained. Densely distributed fine granular substance P‐like immunoreactivity occurs throughout the entire nucleus, while the intermediate and caudal divisions contain substance P‐like‐immunoreactive neurons. Three‐dimensional computer reconstructions afforded an appreciation of the distinctiveness of the intermediate division (a division that contains the majority of cells) and the caudal division, which displays the lowest density of presumed vagal motoneurons. It is possible that the subnuclei identified herein form functional units innervating specific organs.
Adrenalectomy‐induced granule cell degeneration in the rat hippocampal dentate gyrus: Characterization of an in vivo model of controlled neuronal death
Authors: Sloviter Robert S. , Sollas Anne L. , Dean Evelyn , Neubort Simon 
Published: January 2005

AbstractThe recent discovery that adrenalectomy results in hippocampal granule cell loss suggested that this phenomenon might be useful as a model of selective, experimentally controlled neuronal death possibly relevant to neurodegenerative disorders. This study was designed to provide a detailed qualitative anatomical description of the phenomenon and to determine whether adrenalectomy‐induced dentate granule cell degeneration constitutes a reliable model of selective neuronal death. Silver impregnation staining revealed that granule cell degeneration begins immediately after adrenalectomy and continues for months in both sexes, in young and older adults, and in all strains tested. In one group of 77 adrenalectomized rats, 82% exhibited silver‐impregnated granule cells. This phenomenon is extraordinarily selective in that no neurons other than dentate granule cells degenerated after adrenalectomy. There was considerable variability among animals in the number of cells degenerating at a given time‐point or in the degree of ultimate cell loss. In the most extreme cases, virtually complete granule cell loss was present throughout approximately 80% of the dentate gyrus. Nissl staining revealed that degenerating granule cells exhibited coalescing of nuclear chromatin into multiple nuclear bodies and pyknosis without accompanying glial swelling. This morphology is distinct from the necrosis caused by other neurotoxic insults and is the subject of the ultrastructural companion paper identifying this type of cell death as apoptosis. Taken together, these results indicate that adrenalectomy reliably initiates an immediate, highly selective, and longcontinuing process of hippocampal granule cell degeneration that exhibits morphological features characteristic of apoptosis, rather than necrosis. The possibility that this apoptotic cell death involves a biochemical cascade relevant to programmed cell death and/or neurodegenerative diseases suggests that this model may be valuable for studies of neuronal death and its prevention. Some practical guidelines for use of this model are described.
Electron microscopic analysis of adrenalectomy‐induced hippocampal granule cell degeneration in the rat: Apoptosis in the adult central nervous system
Authors: Sloviter Robert S. , Dean Evelyn , Neubort Simon 
Published: January 2005

AbstractAs described in the preceding paper, adrenalectomy triggers hippocampal granule cell degeneration that begins within days after adrenalectomy, continues for months, and is the only apparent cell death anywhere within the brain. At the light microscopic level, granule cell degeneration is characterized by coalescing of nuclear chromatin into numerous spherical bodies. Since the morphology at the light microscopic level resembled the nuclear morphology characteristic of “apoptosis” rather than “necrosis”, we undertook this ultrastructural study to determine if adrenalectomy induces the morphological features characteristic of apoptosis. Electron microscopy revealed coalescing of nuclear chromatin, compaction of cytoplasm, and the budding‐off of cytoplasmic bodies that were engulfed by glia. Mitochondria, the Golgi apparatus, and rough endoplasmic reticulum appeared relatively normal early in the process of granule cell degeneration when nuclear changes were prominent. Presynaptic terminals innervating degenerating granule cells appeared normal. Electron‐dense degeneration of granule cell axon terminals in association with normal postsynaptic elements of CA3 pyramidal cells highlighted the extraordinary selectivity of adrenalectomy‐induced granule cell death. Ten weeks after adrenalectomy, astrocytes were filled with abnormally abundant glial fibrils and neuronal debris. This “apoptotic” morphology produced by adrenalectomy was clearly distinct from the “necrotic” granule cell morphology produced by intrahippocampal injection of the neurotoxin volkensin. These results indicate that, in a manner possibly analogous to castrationinduced prostate cell death, loss of adrenal hormone triggers a process in dentate granule cells that causes the morphological changes characteristic of “apoptosis.”. Thus, adrenal steroids may be obligatory growth factors for dentate granule cells and their loss may initiate a selective process in the mature brain that is unique or that may normally occur only in the developing brain.
Organum vasculosum laminae terminalis (OVLT) in rabbit and rat: Topographic studies
Authors: Yamaguchi Kazuhito , Morimoto Akio , Murakami Naotoshi 
Published: January 2005

AbstractThe microcirculation and fine structure of the rabbit and rat organum vasculosum laminae terminalis (OVLT) were examined by light microscopy and scanning and transmission electron microscopy. In both animals, the microcirculation is composed of a superficial and a deep vascular bed but the system is more complex and extensive in the rabbit. This was particularly true of the deep vascular bed. In the rabbit, the deep bed is composed of fenestrated capillaries, which are arranged in glomerular tufts surrounded by very wide perivascular spaces (PVS). In contrast, the deep vascular bed of the rat OVLT usually consists of only one or two small vessels. These are either fenestrated and surrounded by a PVS or lined by continuous endothelium with only a few fenestrae and without a dilated PVS. A corresponding difference was seen in the contours of the ventricular surface. It is much more irregular in the rabbit than in the rat and numerous bulges reflect the underlying vascular tufts and pockets of PVS in the rabbit. Supraependymal cells are present in both species and two sizes of them occur in the rabbit.The results demonstrate that the microcirculation of the OVLT is more elaborate and more highly developed in the rabbit than in the rat. We suggest that this might result in a different neurohemal microenvironment and, ultimately, in functional differences.
Neurons in rat hippocampus that synthesize nitric oxide
Authors: Valtschanoff Juli G. , Weinberg Richard J. , Kharazia Viktor N. , Nakane Masaki , Schmidt Harald H. H. W. 
Published: January 2005

AbstractWe studied the distribution and light‐ and electron‐microscopic morphology of neurons in the hippocampal formation containing nitric oxide synthase (NOS), and thus likely to release nitric oxide, a freely diffusible neuromediator implicated in long‐term potentiation. Only a small fraction of hippocampal neurons contained NOS or its marker, NADPH diaphorase. Most of the positive neurons were in the pyramidal layer of the subiculum, stratum radiatum of Ammon's horn, and subgranular zone of the dentate gyrus. Positive neurons were also conspicuous in the molecular layer of the dentate gyrus and in the pyramidal layer of CA3, sparse in the pyramidal layer of CA2 and CA1, and almost absent from presubiculum and parasubiculum. Numerous positive fibers were seen, especially in stratum radiatum and stratum lacunosum‐moleculare of Ammon's horn. Double staining experiments demonstrated that nearly all NADPH diaphorase‐positive neurons in the hippocampus also contained γ‐aminobutyric acid.On the basis of their morphology, distribution, and inhibitory neurotransmitter content, most NOS‐positive cells in the hippocampus are probably local circuit neurons. These data suggest that nitric oxide in CA1 may function as a paracrine agent, rather than a spatially precise messenger, in long‐term potentiation. © 1993 Wiley‐Liss, Inc.
Distribution of acetylcholinesterase in the hippocampal region of the mouse. III. The area dentata
Authors: Slomianka L. , Geneser F. A. 
Published: January 2005

AbstractThe distribution of acetylcholinesterase (AChE) was examined in the area dentata of the adult mouse (Mus musculus domesticus). A distinctly stratified distribution of the enzyme was observed and was compared in detail with cytoarchitectural fields and layers. In the stratum moleculare, bands of relatively high AChE activity were seen immediately beneath the pia, at the borders between the outer, middle, and deep portions of the stratum moleculare, and superficial to the granule cell layer. AChE activity was low in the intervening parts of the stratum moleculare. In contrast to the rat, three sublaminae could be discerned in the hilus of the mouse at most septotemporal levels: a limiting subzone, a hilar plexiform layer, and a deep hilar cell mass. Deep to the granule cell layer, AChE activity was high in the limiting subzone and, septally, in the hilar plexiform layer. The deep hilar cell mass stained lightly towards the septal pole of the region but darker at more temporal levels. Numerous AChE‐stained cells were seen in the hilus, with the exception of the most temporal levels. A comparative analysis of the AChE pattern of the area dentata reveals that (1) AChE‐intense supra‐ and infragranular bands are found in all mammals, whereas (2) considerable differences between various strains of mice and between species are seen in the stratum moleculare. The functional significance of the AChE pattern is discussed in relation to species differences and connectivity and also with respect to possible activities of the enzyme other than hydrolysis of ACh, which may be involved in growth‐related functions and in the plastic and degenerative processes observed in Alzheimer's disease. © 1993 Wiley‐Liss, Inc.
Comparative localization of mRNAs encoding two forms of glutamic acid decarboxylase with nonradioactive in situ hybridization methods
Authors: Esclapez Monique , Tillakaratne Niranjala J. K. , Tobin Allan J. , Houser Carolyn R. 
Published: January 2005

AbstractNonradioactive in situ hybridization methods with digoxigenin‐labeled cRNA probes were used to localize two glutamic acid decarboxylase (GAD) mRNAs in rat brain. These mRNAs encode two forms of GAD that both synthesize GABA but differ in a number of characteristics including their molecular size (65 and 67 kDa). For each GAD mRNA, discrete neuronal labeling with high cellular resolution and low background staining was obtained in most populations of known GABA neurons. In addition, the current method revealed differences in the intensity of labeling among neurons for each GAD mRNA, suggesting that the relative concentrations of each GAD mRNA may be higher in some groups of GABA neurons than in others.Most major classes of GABA neurons were labeled for each GAD mRNA. In some groups of GABA neurons, the labeling for the two mRNAs was virtually identical, as in the reticular nucleus of the thalamus. In other groups of neurons, although there was substantial labeling for each GAD mRNA, labeling for one of the mRNAs was noticeably stronger than for the other. In most brain regions, such as the cerebellar cortex, labeling for GAD67 mRNA was stronger than for GAD65 mRNA, but there were a few brain regions in which labeling for GAD65 mRNA was more pronounced, and these included some regions of the hypothalamus. Finally, some groups of GABA neurons were predominantly labeled for one of the GAD mRNAs and showed little or no detectable labeling for the other GAD mRNA, as, for example, in neurons of the tuberomammillary nucleus of the hypothalamus where labeling for GAD67 mRNA was very strong but no labeling for GAD65 mRNA was evident. The findings suggest that most classes of GABA neurons in the central nervous system (CNS) contain mRNAs for at least two forms of GAD, and thus, have dual enzyme systems for the synthesis of GABA. Higher levels of one or the other GAD mRNA in certain groups of GABA neurons may be related to differences in the functional properties of these neurons and their means of regulating GABA synthesis. © 1993 Wiley‐Liss, Inc.
Spinal and facial innervation of the skin in the gadid fish Ciliata mustela (Teleostei)
Authors: Kotrschal Kurt , Whitear Mary , Finger Thomas E. 
Published: January 2005

AbstractThe pattern of innervation of the skin of the rockling Ciliata mustela was investigated to sort out spinal from facial nerve innervation of cutaneous chemosensory and mechanosensory systems. This fish has a variety of appendages with different functional sensory specializations, i.e., the chin barbel, pelvic fin, anterior dorsal fin, and dorsal trunk skin. The carbocyanine dye, diI, was applied to nerve stumps in dissected aldehyde‐fixed tissue. In the case of the chin barbel, the dye was applied to both the trigeminal and facial nerve components. In the other cases, the dye was applied either selectively to the spinal nerves, to the facial nerves, or to both components. In the chin barbel, diI labeled nerve fibers associated with taste buds (TBs) and solitary chemosensory cells (SCCs) as well as relatively blunt free nerve endings, which closely approach the epidermal surface. In the pelvic fin, anterior dorsal fin, and dorsal trunk skin, taste buds, solitary chemosensory cells, and their innervation were labeled only after diI was applied to the facial nerve stumps. Application of diI to spinal nerves labeled delicate, free nerve endings and nerve fibers associated with small cells deep in the epidermis with features characteristic of Merkel cells. Transmission electron microscopy supports these results; after denervation of the facial component of the anterior dorsal fin, synaptic contacts with Merkel cells remained intact, whereas the synapses with the SCCs vanished. © 1993 Wiley‐Liss, Inc.
Tyrosine hydroxylase neurons in the male hamster chemosensory pathway contain androgen receptors and are influenced by gonadal hormones
Authors: Asmus Stephen E. , Newman Sarah Winans 
Published: January 2005

AbstractChemosensory and hormonal signals, both of which are essential for mating in the male Syrian hamster, are relayed through a distinct forebrain circuit. Immunocytochemistry for tyrosine hydroxylase, a catecholamine biosynthetic enzyme, previously revealed immunoreactive neurons in the anterior and posterior medial amygdaloid nucleus, one of the nuclei within this pathway. In addition, dopamine‐immunoreactive neurons were located in the posterior, but not hte anterior, medial amygdala. In the present study, tyrosine hydroxylase‐immunostained neurons were also observed in other areas of the chemosensory pathway, including the posteromedial bed nucleus of the stria terminalis and the posterior, lateral part of the medial preoptic area, while dopamine immunostaining was only seen in the posteromedial bed nucleus of the stria terminalis. The colocalization of tyrosine hydroxylase and androgen receptors was examined in these four tyrosine hydroxylase cell groups by a double immunoperoxidase technique. The percentage of tyrosine hydroxylase‐immunolabeled neurons that were also androgen receptor‐immunoreactive was highest in the posterior medial amygdaloid nucleus (74%) and the bed nucleus of the stria terminalis (79%). Fewer tyrosine hydroxylase‐immunostained neurons in the anterior medial amygdala (33%) and the medial preoptic area (4%) contained androgen receptors. Surprisingly, castration resulted in a significant decrease in the number of tyrosine hydroxylase‐immunoreactive neurons only in the anterior medial amygdaloid nucleus, and this effect was transient. Six weeks after castratio, the anterior medial amygdala contained 61% fewer tyrosine hydroxylase‐immunolabeled neurons, but 12 weeks after gonadectomy, immunostaining returned to intact values. The number of immunostained neurons in testosterone‐replaced, castrated hamsters was not significantly different from that of intact or castrated animals at any time. The results of this study indicate that a substantial number of tyrosine hydroxylase‐immunostained neurons in the chemosensory pathway are influenced by androgens; the majority of these neurons in the posterior medial amygdala and the posteromedial bed nucleus of the stria terminalis produce androgen receptors, and tyrosine hydroxylase immunoreactivity is altered by castration in the anterior medial amygdala. © 1993 Wiley‐Liss, Inc.