bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurosecretory neurons and their projections to the serotonin neurohemal system of the cockroach Periplaneta americana (L.), and identification of mandibular and maxillary motor neurons associated with this system
Authors: Davis Norman T. 
Published: January 2005

AbstractThe neuroanatomy of a serotonin neurohemal system in the head of Periplaneta americana was studied by means of immunohistochemistry, cobalt backfilling, transmission electron microscopy, and nerve transection.This neurohemal system is supplied by bilateral groups of two or three neurons whose somata are located ventrally in the subesophageal ganglion, near the root of each mandibular nerve. Axons of these serotoninergic neurons extend into all of the nerves of the mouth parts but reach most of these nerves by a very circuitous route. Initially the axons extend from the subesophageal ganglion, through the ipsilateral mandibular nerve trunk, and into the third branch of the mandibular nerve. From here the axons extend into the second branch of the maxillary nerve by way of a link nerve, and then they project retrogradely to reenter the subesophageal ganglion. In the ganglion, branches of these axons extend into the labial nerves, and the axons run dorsally through the subesophageal ganglion, circumesophageal connectives, and tritocerebrum to reach the labral nerves. In the nerves of the mouth parts the serotoninergic axons give rise to numerous secondary branches that form an extensive neurohemal system at the surface of these nerves. The relatively large surface and cephalic location of this system probably indicate that the timely release of relatively large amounts of serotonin plays an important role in the physiology of feeding in this insect.The somata, neurites, and dendritic fields of the serotonin neurohemal neurons and those of the motor neurons of the mandibular abductor muscle occur together, and some of the mandibular abductor motor neurons also stain for serotonin. In order to distinguish clearly between these neurohemal and motor neurons, the anatomy of the mandibular abductor motor neurons has also been determined. Similarly, in the course of this study it has been necessary to work out the anatomy of the motor neurons of the maxillary retractor and cardo rotator muscles in order to distinguish them from the serotoninergic neurons.A nonserotoninergic peripheral neuron is associated with the serotonin neurohemal system, and its soma is located on the mandibular‐maxillary link nerve. This link nerve neuron appears to be neurosecretory.
Morphology of labeled afferent fibers in the guinea pig cochlea
Authors: Brown M. Christian 
Published: January 2005

AbstractCochlear afferent and efferent fibers in the guinea pig were labeled by focal extracellular injections of horseradish peroxidase into the spiral ganglion of the basal turn. The morphology and pattern of termination of these fibers were studied by light microscopy. Fibers labeled by injections into the peripheral side of the ganglion could be grouped on the basis of their courses and terminations in the cochlea into two classes of afferent fibers, two classes of efferent (olivocochlear) fibers, and other presumably autonomic fibers. This paper describes the characteristics of labeled afferent fibers and their parent ganglion cells.Peripheral afferent fibers were grouped into two major classes: (1) thick (mean diameter 1.7 μm)radial fibersprojecting in a primarily radial fashion from the spiral ganglion and terminating on single inner hair cells and (2) thin (mean diameter 0.5 μm)outer spiral fibersthat spiral basalward in the organ of Corti to terminate on outer hair cells, usually in one row. For outer spiral fibers, the number of outer hair cells contacted and the length of the terminal region depend on the row of outer hair cells contacted, with third‐row fibers forming, on the average, the most extensive region of termination. Within the spiral ganglion, two types of ganglion cells could be distinguished:(1)type‐Iganglion cells of large size (mean soma area = 216 μm2) with a ratio of central process diameter to peripheral process diameter greater than one and (2)type‐IIganglion cells of smaller size (mean soma area = 100 μm2) and a central to peripheral process ratio near one. In three cochleae in which injections were made central to the ganglion, 11 type‐I ganglion cells have been traced to radial fibers contacting inner hair cells and eight type‐II ganglion cells have been traced to outer spiral fibers contacting outer hair cells. Thus the afferent innervation of the guinea pig cochlea is similar to the pattern described in other mammals, in which there is separate innervation of the inner and outer hair cells by the two types of ganglion cells.The central axons of both types of ganglion cells were traced individually through serial sections of a block of tissue containing the cochlea, the auditory nerve, and the cochlear nucleus. They followed similar courses in the auditory nerve, and the axons followed into the cochlear nucleus bifurcated in similar regions of the interstitial portion. Type‐I central axons were thick (mean diameter = 2.1 μm) whereas the central axons of type‐II neurons were thin (mean diameter = 0.5 μm). Type‐I axons had periodic constrictions interpreted as nodes of Ranvier; these were lacking on the thin axons of the type‐II ganglion cells. The morphological differences between the two types of afferent fibers suggest that they may play very different functional roles.
Mammalian motoneuron cell death: Development of the lateral motor column of a wallaby (Macropus eugenii )
Authors: Comans P. E. , McLennan I. S. , Mark R. F. 
Published: January 2005

AbstractWe have investigated the development of the lumbar lateral motor column of the tammar as a model of mammalian motoneuron cell death that is accessible to experimental manipulation. The tammar is an Australian marsupial, belonging to the subfamily of wallabies and kangaroos. After a gestational period of 26–28 days, the pup crawls to its mother's pouch using its forelimbs. The major morphometric events that shape the formation of the hindlimb occurred between 21 days gestation and birth. At birth the premuscle masses had divided and motor nerves had begun to penetrate the muscles of the thigh and shank. The period of motoneuron cell death was biphasic and occurred entirely postnatally. During phase I, between birth and 40 days, 59% of motoneurons were lost. Cell numbers then stabilised before falling a further 24%, to give an overall loss of 70%. Most of phase II cell loss occurred between 90 and 150 days. The possibility that a second period of motoneuron cell death maybe a common feature of mammals is discussed.
Cholinergic innervation of hippocampal GAD‐ and somatostatin‐immunoreactive commissural neurons
Authors: Léránth Csaba , Frotscher Michael 
Published: January 2005

AbstractThis study describes the cholinergic innervation of chemically defined nonpyramidal neurons in the hilar region of the rat hippocampus. Cholinergic terminals were identified by immunocytochemistry employing a monoclonal antibody against choline acetyltransferase (ChAT), the acetylcholine‐synthesizing enzyme, and the avidin‐biotin‐peroxidase (ABC) technique. Nonpyramidal neurons in the hilar region were characterized by immunostaining with antibodies against glutamate decarboxylase (GAD), the gamma aminobutyric acid (GABA)‐synthesizing enzyme, and somatostatin (SS). The immunoreactivity to these antibodies was detected by using biotinylated secondary antibodies and avidinated ferritin as an electron‐dense marker. This electron microscopic double immunostaining procedure enabled us to demonstrate that immunoperoxidase‐labeled ChAT‐immunoreactive terminals established symmetric synaptic contacts on the ferritin‐labeled GAD‐and SS‐immunoreactive hilar cells.In additional experiments at least some of the GAD‐ and SS‐immunoreactive hilar neurons were further characterized as commissural neurons by retrograde filling with horseradish peroxidase (HRP) following an injection of the tracer into the contralateral hilus. From these triple labeling experiments, we concluded that at least some GABAergic and somatostatin‐containing neurons in the hilar region, which are postsynaptic to cholinergic terminals, project to the contralateral hippocampus. Together with previous studies on the cholinergic innervation of the hippocampus and fascia dentata, our present results thus demonstrate that different types of hippocampal cells, including GABAergic and peptidergic commissural neurons in the hilar region, receive a cholinergic input.
Alteration of mouse cerebellar circuits following methylazoxymethanol treatment during development: Immunohistochemistry of GABAergic elements and electron microscopic study
Authors: de Barry J. , Gombos G. , Klupp T. , Hamori J. 
Published: January 2005

AbstractMethylazoxymethanol (MAM) injected postnatally affects cerebellar development in mice. A single injection at the fifth postnatal day produces hypogranular cerebella whereas a single injection at birth produces, in addition, a disorderly cytoarchitecture of the folium and alteration of Purkinje cell positioning (Bejar et al.: Exp. Brain Res. 57:279–285, ′85). In the present study we have used immunohistochemistry with anti‐GABA immune serum and electron microscopy to further characterize these alterations. In addition to the already‐described nonoccupied dendritic spines of Purkinje cells both in mice injected the day of birth and or at the fifth postnatal day, we have observed, in animals injected at birth, the absence of pericellular baskets around Purkinje cells and the presence of heterologous synapses between mossy fibres and Purkinje cell dendrites. These heterologous synapses apparently disappear after postnatal day 20.By using an appropriate timing of MAM injection, different types of hypogranular cerebella, phenocopies of different mutants, can be obtained in large enough number to carry out extensive biochemical studies at each developmental age.
Caudal topographic nucleus isthmi and the rostral nontopographic nucleus isthmi in the turtle, pseudemys scripta
Authors: Sereno Martin I. , Ulinski Philip S. 
Published: January 2005

AbstractIsthmotectal projections in turtles were examined by making serial section reconstructions of axonal and dendritic arborizations that were anterogradely or retrogradely filled with HRP. Two prominent tectal‐recipient isthmic nuclei–the caudal magnocellular nucleus isthmi (Imc) and the rostral magnocellular nucleus isthmi (Imr)–exhibited strikingly different patterns of organization. Imc cells have flattened, bipolar dendritic fields that cover a few percent of the area of the cell plate constituting the nucleus and they project topographically to the ipsilateral tectum without local axon branches. The topography was examined explicitly at the single‐cell level by using cases with two injections at widely separated tectal loci. Each Imc axon terminates as a compact swarm of several thousand boutons placed mainly in the upper central gray and superficial gray layers. One Imc terminal spans less that 1% of the tectal surface. Imr cells, by contrast, have large, sparsely branched dendritic fields overlapped by local axon collaterals while distally, their axons nontopographically innervate not only the deeper layers of the ipsilateral tectum but also ipsilateral Imc. Imr receives a nontopographic tectal input that contrasts with the topographic tectal input to Imc.Previous work on nucleus isthmi emphasized the role of the contralateral isthmotectal projection (which originates from a third isthmic nucleus in turtles) in mediating binocular interactions in the tectum. The present results on the two different but overlapping ipsilateral tecto‐isthmo‐tectal circuits set up by Imc and Imr are discussed in the light of physiological evidence for selective attention effects and local‐global interactions in the tectum.
Histological characterization of neurones innervating functionally different muscles of Locusta
Authors: Kutsch Wolfram , Schneider Henning 
Published: January 2005

AbstractThe innervation of four functionally different muscles (subalar, remoter 1, remoter 2, pleuroalar), all served by the same nerve branch, was studied in both winged segments of the locust, Locusta migratoria. Several anatomical techniques were applied: With the cobalt backfill and silver intensification technique four cell types (motoneurone, dorsal unpaired median neurone, common inhibitory neurone, and small median neurone) were demonstrated. Serial sections enabled the morphology of the motoneurones to be described in more detail and in respect to a possible functional organization of the arborizations. A differential staining technique allowed us to stain various neurones in different colours in the same preparation. With this technique the anatomy of both the “rostral” and the “caudal” subalar motoneurones could be described in parallel, thus avoiding errors in comparison due to possible individual variations from preparation to preparation. Axon counts in the peripheral nerve branch enabled us to compile a list of the total innervation for each muscle. Results from other orthopterans are integrated and whether differences in the dendritic fields might be of functional significance is discussed.
Trajectory of group Ia and Ib fibers from the hind‐limb muscles at the L3 and L4 segments of the spinal cord of the cat
Authors: Hongo Toshinori , Kudo Norio , Sasaki Shigeto , Yamashita Masayuki , Yoshida Kaoru , Ishizuka Norio , Mannen Hajime 
Published: January 2005

AbstractNineteen physiologically identified group Ia and five group Ib fibers at the L3 and L4 levels of the spinal cord originating from various hind‐limb muscles were intraaxonally injected with horseradish peroxidase (HRP). The trajectories of the stained axons were reconstructed. They extended for distances of 8.6 mm–18.0 mm rostrocaudally.Ascending axons ran in various regions of the dorsal funiculus: The ascending axon from a toe muscle (3 μm in diameter) ran in the ventralmost part of the paramedian region; those from shank muscles (3.0–5.0 μm) in both dorsal and ventral paramedian regions; those from thigh muscles (5.0–7.0 μm) in both the paramedian and the more lateral regions; and those from hip muscles (6.0–7.0 μm) in the lateral region. Main collaterals arising from the parent fiber were given off at intervals of 0.5–6.2 mm (mean 2.4 mm). Collaterals of a fiber from a toe muscle (1.0 μm in diameter) entered Clarke's column from the dorsomedial side and ramified mostly in the dorsomedial one‐third of the column. Collaterals of fibers from shank muscles (1.0–2.0 μm) entered Clarke's column from the dorsal side and terminated in its middle parts as well as in laminae V–VII. Collaterals of fibers from thigh muscles (1.0–2.5 μm) passed lateral to or through the lateral part of Clarke's column and terminated in its ventrolateral part and in laminae V–VIII. Collaterals of fibers from hip muscles (1.5–2.5 μm) passed lateral to Clarke's column and ramified mostly in laminae VII–IX. As the muscle of origin became more proximal, the proportion of termination outside of Clarke's column progressively increased. Thus, the trajectory of group I fibers was somatotopically organized both in the dorsal funiculus and in the gray matter.The long axis of boutons ranged from 0.5 to 17 μm in Ia fibers and from 0.5 to 8 μm in Ib fibers. “Giant” Ia boutons (above 7 μm) were found both in and outside Clarke's column.
Patterns of glutamate decarboxylase immunostaining in the feline cochlear nuclear complex studied with silver enhancement and electron microscopy
Authors: Adams Joe C. , Mugnaini Enrico 
Published: January 2005

AbstractThe cochlear nuclear complex of the cat was immunostained with an antiserum to glutamate decarboxylase (GAD), the biosynthetic enzyme for the inhibitory neurotransmitter GABA, and studied with different procedures, including silver intensification, topical colchicine injections, semithin sections, und immunoelectron microscopy. Immunostaining was found in all portions of the nucleus. Relatively few immunostained cell bodies were observed: most of those were in the dorsal cochlear nucleus and included stellate cells, cartwheel cells, Golgi cells, and unidentified cells in the deep layers. An accumulation of immunoreactive cells was also found within the small cell cap and along the medial border of the ventral cochlear nucleus. Immunostained cells were sparse in magnocellular portions of the ventral nucleus. Most staining within the nucleus was of nerve terminals. These included small boutons that were prominent in the neuropil of the dorsal cochlear nucleus, the granule cell domain, in a region beneath the superfi‐cial granule cell layer within the small cell cap region, and along the medial border of the ventral nucleus. Octopus cells showed small, GAD‐positive terminals distributed at moderate density on both cell bodies and dendrites. Larger, more distinctive terminals were identified on the large cells in the ventral nucleus, in particular on spherical cells and globular cells. There was a striking positive correlation of the size, location, and complexity of GAD‐positive terminals with the size, location, and complexity of primary fiber endings on the same cells. This correlation did not hold in the dorsal nucleus, where pyramidal cells receive many large GAD‐positive somatic terminals despite the paucity of primary endings on their cell bodies. The GAD‐positive terminals contained pleomorphic synaptic vesicles and formed symmetric synaptic junctions that occupied a substantial portion of the appositional surface to cell bodies, dendrites, axon hillocks, and the begin‐ning portion of the initial axon segments. Thus, the cells provided with large terminals can be subjected to considerable inhibition that may be activated indirectly through primary fibers and interneurons or by descending inputs from the auditory brainstem.
Glycine: An alternative transmitter candidate of the pallidosubthalamic projection neurons in the rat
Authors: Takada M. , Hattori T. 
Published: January 2005

AbstractAutoradiographic retrograde tracing techniques with radioactive transmitters were used to analyse the identity of a putative transmitter in the rat pallidosubthalamic (GP‐STN) pathway. One to 2 hours after the stereotaxic injection of 3H‐glycine restricted to the STN, a large number of neuronal somata were radiolabeled in the GP. No comparable labeling was observed following the injection of 3H‐γ‐aminobutyric acid (3H‐GABA) into the same nucleus even with survival times as long as 6 hours. Specifically, no significant somatic labeling was detected either in the GP or in the caudoputamen (CPU). Only when 3H‐GABA was injected into the substantia nigra did CPU and GP neurons become labeled. On the contrary, STN neuronal somata were invariably labeled 6 hours after the intrapallidal injection of 3H‐GABA, whereas no perikaryal labeling was observed in the STN after 3H‐glycine injection into the GP. The perikaryal labeling was prevented in all cases by intraventricular administration of colchicine 1 day before the isotope injections. The observations suggest that 3H‐glycine was preferentially transported retrogradely through the GP‐STN pathway, and 3H‐GABA through the STN‐GP projection. In view of the recent controversy on the role of GABA as a putative transmitter of the GP‐STN projection, we now propose glycine as an alternative transmitter candidate of these critically situated neurons in the basal ganglia.
Abrupt loss of dependence of retinopetal neurons on their target cells, as shown by intraocular injections of kainate in chick embryos
Authors: Catsicas Stefano , Clarke Peter G. H. 
Published: January 2005

AbstractWe have examined the capacity of neurons in the chick isthmo‐optic nucleus (ION) to survive when their target neurons in the contralateral retinal are destroyed by intraocular injections of kainate (KA) at different stages in development.The retinal vulnerability to KA builds up progressively from embryonic day 10 (E10) until a plateau is reached at E15 (see accompanying paper); and the effects on the ION increase in parallel, almost all the ION neurons being rapidly lost after the E15 injections. KA injection before E15 lesioned only part of the retina and caused degeneration only in the topographically corresponding region of the ION.Near the end of the natural cell death period in the ION (E17), this initial dependence on the target cells is rapidly lost. Already at E16 the injections kill less ION neurons, and by E19 they kill none of them. The ION neurons have become completely insensitive to the KA injections and appear normal more than 4 months later, although axotomy (by eye removal) at a similar age would by then have killed them. The ectopic ION neurons, scattered outside the ION but projecting to the retina, are never affected by KA injections at any age.
Organization of vasotocin‐immunoreactive cells and fibers in the canary brain
Authors: Kiss J. Z. , Voorhuis T. A. M. , van Eekelen J. A. M. , de Kloet E. R. , de Wied D. 
Published: January 2005

AbstractThe distribution of vasotocin (VT)‐immunoreactive neuronal perikarya and fibers in the canary (Serinus canaria) was investigated with immunohistological techniques. The results suggest that most VT‐stained cell bodies are located in three diencephalic regions. First, a large number of densely packed neurons are found in the paraventricular nucleus (PVN) and the anterior preoptic nucleus. Neurons here vary widely in size and shape. Small‐size rounded neurons and large‐size multipolar neurons appear to concentrate in separate subdivisions. Second, a series of loosely organized cell groups of medium‐ to large‐size cells occurs in the lateral parts of the hypothalamus. Those aggregates of neurons apparently correspond to subdivisions of the supraoptic nucleus (SON). Third, diffusely distributed, lightly stained cells are found dorsal to the paraventricular nucleus in the dorsal diencephalons. A number of cells of this group seem to be located in the basal septal area and bed nucleus of the stria terminalis. Immunoreactive fibers and varicosities concentrate in brain regions that are associated with neuroendocrine, autonomic, and limbic functions. Axons from the PVN and SON form compact bundles of the hypothalamohypophysial tract in the lateral hypothalamus and then funnel into the internal zone of the medium eminence (ME). Furthermore, a heavy innervation seems to be present in the pulisadal, external zone of the ME. A substantial number of fibers appear to leave the PVN toward extrahypothalamic areas. Most extrahypothalamic VT fibers innervate telencephalic and brainstem regions that are thought to be involved in mediation of limbic and autonomic functions. These areas include the lateral and medial septum, the lateral habenula, the subtantia grisea centralis, the area ventralis (Tsai), the locus coeruleus, raphe nuclei, the nucleus tractus solitarii, and lateral medulla. In addition, fibers with immunoreactivity for VT innervate structures such as the optic tectum and the nucleus ovoidalis that have been implicated in sensory processing of visual and auditory information. Finally, VT fibers and varicosities occur in centers including the nucleus robustus archistriatalis and nucleus intercollicularis that have been implicated in vocal control.