bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology of rat spinal motoneurons with normal and hormonally altered specificity
Authors: Kurz Elizabeth M. , Bowers Christine A. , Sengelaub Dale R. 
Published: January 2005

AbstractPotential determinants of motoneuronal morphology were examined by using a sexually dimorphic, steroid‐sensitive neuromuscular system in the rat spinal cord. In males, the spinal nucleus of the bulbocavernosus (SNB) innervates the perineal muscles bulbocavernosus (BC) and levator ani (LA), and the dorsolateral nucleus (DLN) innervates the ischiocavernosus muscle (IC). Adult females normally lack these motoneurons and the peripheral targets. Prenatal exposure of females to the androgen dihydrotestosterone propionate (DHTP) partially masculinizes this neuromuscular system and alters motoneuron‐to‐muscle specificity, resulting in retained SNB target muscles anomalously innervated by motoneurons in the DLN. Because the morphology of SNB and DLN motoneurons normally differs significantly, the influence of spinal cord location and peripheral target on motoneuron morphology can be directly compared.Injection of cholera toxin conjugated to horseradish peroxidase (CTHRP) into the LA of DHTP‐treated females labeled motoneurons predominantly in the SNB. These (SNB‐LA) motoneurons in DHTP females were identical in all morphological measures to those of normal males. CTHRP injection into the BC of DHTP females labeled motoneurons in both the SNB and the DLN. SNB‐BC motoneurons in DHTP females resembled those of normal males in process number and orientation, but were significantly smaller in dendritic length per motoneuron and in soma size. The DLN motoneurons anomalously projecting to the BC in DHTP females differed significantly from SNB‐BC motoneurons in soma size and number and orientation of primary processes. However, these motoneurons were identical in all respects to DLN‐IC motoneurons in DHTP females; DLN‐IC motoneurons were similar to those of normal males in the orientation of their dendritic arbor, but were significantly smaller in dendritic length, soma size, and number of primary processes.These comparisons make it clear that DHTP selectively affects motoneuronal specificity and morphology in specific motoneuron classes. Further, motoneuronal morphology in the SNB/DLN system appears to be influenced more by spinal cord location than by peripheral target.
Organization of adrenergic inputs to the paraventricular and supraoptic nuclei of the hypothalamus in the rat
Authors: Cunningham E. T. , Bohn M. C. , Sawchenko P. E. 
Published: January 2005

AbstractAnterograde transport, retrograde transport, and immunohistochemical techniques were used to characterize the organization of neural inputs to the paraventricular (PVH) and supraoptic (SO) nuclei from the C1, C2, and C3 adrenergic cell groups in the rostral medulla. The results are as follows: (1) Phenylethanolamine‐N‐methyltransferase–immunoreactive (PNMT‐IR) fibers and terminals were distributed to all parts of the parvicellular division of the PVH; the dorsal and dorsal medial subdivisions received the most prominent inputs, the lateral and ventral medial parts the least. Sparse terminal fields were found consistently in the magnocellular division of the PVH and in the SO. (2) A combined retrograde transport–immunohistochemical method was used to estimate the number and proportion of cells in the regions of the C1, C2, and C3 cell groups that contribute to the PNMT‐IR innervation of the PVH. On average, 232 ± 37 retrogradely labeled cells in the C1 cell group, 73 ± 32 in the C2 cell group, and 96 ± 26 in the C3 group stained positively for PNMT‐IR. These values comprised 70%, 84%, and 89%, respectively, of all retrogradely labeled neurons in these regions. (3) Fibers and terminals arising from the regions of each of the three adrenergic cell gruops were labeled by local injections of the anterogradely transported plant lectin PHA‐L. Each component projection was found to distribute in a very similar fashion and to mimic the overall distribution of PNMT‐IR; differential projection patterns within the PVH or SO were not seen consistently following deposits in any of the individual adrenergic cell groups or at different rostrocaudal levels of any individual cell group. (4) A dual anterograde tracing (PHA‐L)–immunohistochemical (PNMT) labeling method revealed an appreciable number of varicosities arising from the regions of C1, C2, and C3 cell groups to contain PNMT‐IR. These results suggest that adrenergic inputs to the PVH and So, while arising from distinct medullary cell groups and presumably relaying different types of sensory information, are in a position to influence similar groups of parvicellular neurosecretory and/or autonomic‐related projection neurons.
Dorsomedial telencephalon of lungfishes: A pallial or subpallial structure? criteria based on histology, connectivity, and histochemistry
Authors: von Bartheld Christopher S. , Collin Shaun P. , Meyer Dietrich L. 
Published: January 2005

AbstractThe dorsomedial telencephalon of lepidosirenid lungfishes has been interpreted in two divergent ways: earlier investigators regarded it as a subpallial (septal) structure; more recently, it has been reinterpreted as the medial pallium (hippocampus). To resolve this question, we identified parameters that are conclusive in their association with either the medial pallium or the septum in anamniotes. The present study examines the position of ependymal thickenings and the distribution of acetylcholinesterase (AchE) in the cerebral hemispheres of the African lungfish Protopterus, the Australian lungfish Neoceratodus, and the amphibian species Xenopusand Ambystoma. In addition, projections from the hypothalamus (paraventricular organ) to the telencephalon are investigated in Protopterus.Ependymal specializations are located dorsally and ventrally in the lateral ventricles of amphibians, but laterally and medially in lungfishes. In Protopterus, the paraventricular organ projects to the medial telencephalic hemisphere, but not to the dorsal roof. High levels of AchE are present in restricted neuropil regions of the medial hemisphere and in the ventral and ventrolateral telencephalon, but they are lacking in the dorsal roof. Intensely AchE‐stained neuronal cell bodies are located in the ventral telencephalon (rostrally) and the dorsomedial telencephalon (at mid‐level). In Neoceratodus, AchE staining is pronounced in the septal area, but absent in the pallium. The terminal nerve proper lacks AchE stain in Protopterus; nerve fibers of the preoptic nerve are AchE‐positive in both lungfish species. In Xenopus, AchE staining of fibers and terminals is restricted to the subpallium (medial septum, tuberculum olfactorium, striatum, nucleus accumbens, and medial amygdala); cell bodies are AchE positive in parts of the subpallium and rostral pallium.Comparison of cytological, histochemical, and “connectional” parameters substantiates the interpretation that the dorsomedial telencephalon of lungfishes represents a subpallial, but not a “medial pallial” structure. The dorsomedial part of the lepidosirenid telencephalon corresponds to the septum in the most plesiomorphic living lungfish, Neoceratodus forsteri, but it differs considerably from the dorsomedial telencephalon (medial pallium) in amphibians.
Coexistence of corticotropin‐releasing factor and enkephalin in the paraventricular nucleus of the rat
Authors: Pretel S. , Piekut D. 
Published: January 2005

AbstractCorticotropin‐releasing factor and enkephalin‐containing neurons are found in the paraventricular nucleus of the rat hypothalamus. Their immunocytochemical distribution suggests that a subpopulation of neurons of the paraventricular nucleus might contain both peptides. The present study describes the coexistence of corticotropin‐releasing factor and enkephalin in parvicellular neurons of the paraventricular nucleus. Immunocytochemical labeling of peptides was combined with in situ hybridization of mRNA to visualize peptide and mRNA labeling in the same tissue section. This resulted in several observations: (1) neurons labeling for the peptide corticotropin‐releasing factor also contain the mRNA to synthesize corticotropin‐releasing factor, (2) neurons labeling for the peptide enkephalin also contain the mRNA to synthesize the peptide enkephalin, (3) a subpopulation of corticotropin‐releasing factor neurons contains the mRNA to synthesize enkephalin, and (4) a subpopulation of enkephalin neurons contains the mRNA to synthesize corticotropin‐releasing factor. A large percentage of enkephalin immunoreactive neurons contains corticotropin‐releasing factor mRNA, where as a smaller percentage of corticotropin‐releasing factor immunoreactive neurons contains enkephalin mRNA. These double‐labeled neurons are present throughout the rostral‐caudal extent of the paraventricular nucleus; the majority of these neurons is present in the medial parvicellular paraventricular nucleus.
Subnuclear organization of the lateral tegmental field of the rat. II: Catecholamine neurons and ventral respiratory group
Authors: Ellenberger H. H. , Feldman J. L. , Zhan W.‐Z. 
Published: January 2005

AbstractBulbospinal and propriobulbar respiratory neurons of the ventral respiratory group and catecholamine neurons of the A1 and C1 cell groups were simultaneously labelled in the rat medulla by a combination of retrograde tracing and immunohistochemical identification. The ventral respiratory group and catecholamine cell groups form adjacent, parallel cell columns in the lateral tegmental field of the ventrolateral medulla. The ventral respiratory group is located immediately dorsal to the A1 and C1 groups, although some A1 neurons are intermingled with neurons of the rostral ventral respiratory group, and some C1 neurons are intermingled with those of the Bötzinger complex. The proximate populations of respiratory, catecholamine, and (presumptive) cardiovascular neurons identified in this study provide further support to the hypothesis that this regin of the lateral tegmental field of the ventrolateral medulla is a site of cardiorespiratory coordination.
Thyrotropin‐releasing hormone‐immunoreactive nerve terminals synapse on the dendrites of gastric vagal motoneurons in the rat
Authors: Rinaman Linda , Miselis Richard R. 
Published: January 2005

AbstractThyrotropin‐releasing hormone stimulates vagally mediated gastric acid secretion and motility by an undefined central mechanism in the rat. The present study sought to determine the anatomical basis for this stimulatory effect by examining the ultrastructural relationship of nerve terminals immunoreactive for thyrotropin‐releasing hormone with the dendrites of gastric vagal motoneurons. A light and electron microscopic double immunostaining technique was employed using the beta subunit of unconjugated cholera toxin as a neural tracer. Cholera toxin (50 μl, 0.25%) was injected into the ventral stomach musculature in five rats. After 72 hours' survival, animals were sacrificed by transcardiac perfusion fixation. Retrogradely transported choleratoxin was immunocytochemically localized in vagal gastric motoneurons and their dendrites in the dorsal motor nucleus of the vagus and nucleus of the solitary tract, alone or in combination with the immunocytochemical localization of thyrotropin‐releasing hormone.Ultrastructural analysis of double‐labeled material revealed thyrotropin releasing hormone‐immunoreactive nerve terminals making asymmetric synaptic contacts on the retrogradely labeled dendrites of vagal gastric motoneurons. Nerve terminals immunoreactive for thyrotropin‐releasing hormone also made asymmetric and symmetric synaptic contacts with unlabeled dendrites of undetermined perikaryal origin. In addition, nonsynaptic varicosities immunoreactive for thyrotropin‐releasing hormone were frequently observed in the vagal nuclei. The synaptic contacts between thyrotropin‐releasing hormone‐immunoreactive nerve terminals and vagal gastric motoneuronal dendrites provide one possible basis for the profound stimulatory effect of central thyrotropin‐releasing hormone on gastric vagal motor activity.
Organization of the six motor nuclei innervating the ocular muscles in lamprey
Authors: Fritzsch B. , Sonntag R. , Dubuc R. , Ohta Y. , Grillner S. 
Published: January 2005

AbstractThe topography of motoneurons supplying each of the six ocular muscles of the lamprey, Lampetra fluviatilis, was studied by selective application of HRP to the cut nerves of identified muscles. In addition, the distributions of motoneuron populations to both eyes were studied simultaneously with fluoresceine and rhodamine coupled dextran‐amines (FDA and RDA) applied to cut ocular muscle nerves of either side. The motoneuron pool of the caudal oblique muscle is represented bilaterally in the trochlear (N IV) motor nucleus. The dorsal rectus muscle is innervated from a contralateral group of oculomotor (N III) motoneurons and the remaining four muscles exclusively from the ipsilateral side (N III and N VI). The inferior and posterior rectus muscles are both innervated by the abducens nerve. In contrast to all jawed vertebrates, only three eye muscles (the dorsal rectus, rostral rectus, and rostral oblique) are innervated by the oculomotor nerve in lampreys (N III). Lampreys have a motor nucleus similar to the accessory abducens nucleus previously described only in tetrapods. They lack the muscle homologous to the nasal rectus muscle of elasmobranchs and the medial rectus muscle of osteognathostomes. The distribution of the dendrites of different groups of motoneurons was studied and is considered in relation to inputs from tectum and the different cranial nerves.
Substance P antibody reveals homologous neurons with axon terminals among somata in the crayfish and crab brain
Authors: Sandeman R. E. , Sandeman D. C. , Watson A. H. D. 
Published: January 2005

AbstractIn the search for particular neurons that stain selectively and can be identified, the cerebral ganglia (brains) of the crayfish Cherax destructor and the crab Leptograpsus variegatus were immunocytochemically treated with a monoclonal antibody raised against substance P. Four large neurons in the cerebral ganglion of the crayfish and crab label selectively with a monoclonal antibody raised against substance P. Two of the large neurons have their cell bodies in the protocerebrum and two in the deutocerebrum in both animals. Each protocerebral cell in both animals projects through the ipsilateral and contralateral olfactory lobes to end among the lateral cell somata of the olfactory lobe and not in the neuropile. Electron micrographs show the presence of synapses within the cell somata area and on the cell somata themselves. Each deutocerebral cell in both animals projects only ipsilaterally and ends within the neuropile of the olfactory lobes. The immunoreactivity to substance P antibody and the shapes and the unique projections of the four cells suggest that they are homologous in the two species. Synaptic connections between axons and cell somata are rare in the arthropods but have been found on the Kenyon cells of the mushroom bodies of Limulus. This raises questions about homologies between the crustacean olfactory lobe and the mushroom bodies of Limulus and insects.
Afferent and efferent synaptic conncetions sof somatostatin‐immunoreactive neurons in the rat fascia dentata
Authors: Leranth Csaba , Malcolm Andrew J. , Frotscher Michael 
Published: January 2005

AbstractThe aim of this study was to determine whether somatostatin (SS)‐immunoreactive neurons of the rat fascia dentata are involved in specific excitatory circuitries that may result in their selective damage in modeis of epilepsy. Synaptic connections of SS‐immunoreactive neurons were determined at the electron microscopic level by using normal and colchicine pretreated rats. Vibratome sections prepared from both fascia dentata of control animals and from rats that had received an ipsilateral lesion of the entorhinal cortex cortex 30‐36 hours before sacrifice were immunostained for SS by using a monoclonal anatibody (SS8). Correlated light and electron microscopic analysis demonstrated that many SS‐immunoreactive neurons in the hilus send dendritic processes into the outer molecular layer of the fascia dentata, and dendrites of the same neurons occupy broad areas in the dentate hilar area. The majority of SS‐immunoreactive axon terminals form symmetric synapses with the granule cell dendrites in the outer molecular laayer and also innervate deep hilar neuronns. Via their dendrites in the outer molelcular layer, the SS‐immunoreactive neurons receive synaptic inputs from perforant pathway axons which were identified by their anaterograde degeneration following entorhinal lesions. The axons from the entorhinal cortex are the first segment of the main hippocampal excitatory loop. The hilar dendrites of the same SS‐immunoreactive cells establish synapses with the mossy axon collaterals which represent the second member in this excitatory neuronal chain. These observations suggest that SS‐immunoreactive neurons in the dentate hilar area amay be driven directly by their perforant path synapses and via the granule cells which are known to receive a dense innervation from the entorhinal cortex. These observations demonstrate that SS‐immunoreactive neurons in the hilar region of integerated in the main excitatory impulse flow of the hippocampal formation.
Cellular events associated with peripherally induced rejection of mature neural xenografts placed into neonatal rat brains
Authors: Backes M. G. , Lund Raymond D. , Lagenaur C. F. , Kunz H. W. , Gill T. J. 
Published: January 2005

AbstractVarious circumstances have brought about a dispute concerning the immunologically privileged status of the central nervous system (CNS). Using a transplantation paradigm, we have examined the cellular events associated with an experimentally induced focal assault on the CNS by the immune system. Chunks of embryonic mouse cortex were transplanted into neonatal rat brains and allowed to survive for 4 weeks. The adult rats then received a skin graft of donor origin to induce rejection of the transplanted tissue. Animals were sacrificed at various time points and examined histologically and immunocytochemically. Under these circumstances, the transplant is rejected via a first‐set rejection response, and astrocytes of donor origin appear to be the primary target of the host immune system. Expression of class I and class II major histocompatibility antigens is noted to correlate with lymphocytic invasion of the transplant.
Organization of cortical, basal forebrain, and hypothalamic afferents to the parabrachial nucleus in the rat
Authors: Moga Margaret M. , Herbert Horst , Hurley Karen M. , Yasui Yukihiko , Gray Thackery S. , Saper Clifford B. 
Published: January 2005

AbstractIn a previous study (Herbert et al., J. Comp. Neurol. [1990];293:540‐580), we demonstrated that the ascending afferent projections from the medulla to the parabrachial nucleus (PB) mark out functionally specific terminal domains within the PB. In this study, we examine the organization of the forebrain afferents to the PB. The PB was found to recive afferents from the infralimbic, the lateral prefrontal, and the insular cortical areas; the dorsomedial, the ventromedial, the median preoptic, and the paraventricualr hypothalamic nuclei; the dorsal, the retrochiasmatic, and the lateral hypothalamic areas; the central nucleus of the amygdala; the substantia innominata; and the bed nucleus of the stria terminalis. In general, forebrain areas tend to innervate the same PB subnuclei from which they receive their input. Three major patterns of afferent termination were noted in the PB; these corresponded to the three primary sources of forebrain input to the PB: the cerebral cortex, the hypothalamus, and the basal forebrain. Hypothalamic afferents innervate predominantly rostral portions of the PB, particularly the central lateral and dorsal lateral subnuclei. The basal forebrain projection to the PB ends densely in the external lateral and waist subnuclei. Cortical afferents terminate most heavily in the caudal half of the PB, particularly in the ventral lateral and medial subnuclei. In addition, considerable topography organization was found within the individual projections. For example, tuberal lateral hypothalamic neurons project heavily to the central lateral subnucleus and lightly to the waist area; in contrast, caudal lateral hypothalamic neurons send a moderately heavy projection to both the central lateral and waist subnuclei. Our results show that the forebrain afferents of the PB are topographically organized. These topographical differences may provide a substrate for the diversity of visceral functions associated with the PB.
Neuropeptide organization of the hypothalamic projection to the parabrachial nucleus in the rat
Authors: Moga Margaret M. , Saper Clifford B. , Gray Thackery S. 
Published: January 2005

AbstractThe hypothalamus is a major source of afferents to the parabrachial nucleus (PB), but the neurotransmitters in this pathway are largely unknown. In this study, we examine the neuropeptide immunoreactivities of neurons in the hypothalamus that project to the PB by using the combined retrograde fluorescence‐immunofluorescence method. After injections of the fluorescent tracer fast blue into the PB, retrogradely labeled neurons were observed in the paraventricular, dorsomedial, ventromedial, median preoptic, and anteroventral periventricular hypothalamic nuclei; in the dorsal, retrochiasmatic, and lateral hypothalamic areas; and in the medial and lateral preoptic areas. Our results show that at least five distinct neuropeptideimmunoreactive cell populations in the hypothalamus project to the PB. In the perifornical lateral hypothalamus, many neurotensin (NT)‐, corticotropin‐releasing factor‐, dynorphin (DYN)‐, angiotensin II (AII)‐, and galanin‐like immunoreactive (‐ir) neurons were retrogradely labeled. A cluster of retrogradely labeled neurons in the juxtacapsular lateral hypothalamus stained with an antiserum against α‐melanocyte stimulating hormone (αMSH). Over 50% of the retrogradely labeled cells in the arcuate nucleus were adrenocorticotropin (ACTH)‐or αMSH‐ir. Many αMSH‐ and ACTH‐ir, and a few DYN‐, NT‐ and AII‐ir neurons in the retrochiasmatic area were retrogradely labeled. Only small numbers of double‐labeled neurons were found in the paraventricular nucleus, and, of these, enkephalin‐ir and dynorphin‐ir neurons were the most common. Somatostatin‐ir cells in the hypothalamus were rarely double‐labeled. The chemical coding of these hypothalamic projections to the PB may provide important clues to the functional organization of these descending pathways.