bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of the extrinsic innervation of the guinea pig pylorus with the horseradish peroxidase tracing technique
Authors: Elfvin L.‐G. , Lindh B. 
Published: January 2005

AbstractThe extrinsic innervation of the guinea pig pylorus was studied by the use of the horseradish peroxidase (HRP) tracing technique. Forty‐eight hours after injection of HRP into the pyloric sphincter labeled neurons of varying sizes were found throughout the rostrocaudal extent of the dorsal motor nuclei of the vagus. No HRP positive cells were seen in the medial solitary nuclei or the ambiguus nuclei. Many HRP‐positive cells were observed in the celiac‐superior mesenteric ganglion complex. Occasional cells in the superior cervical and stellate ganglia were also labeled. When the vagal ganglia were analyzed many enzyme‐containing cells were found in the nodose ganglia and some cells in the jugular ganglia. Furthermore, about 15–20% of the labeled afferent neurons were located in dorsal root ganglia on both sides, with the majority of cells at the T5–T10 levels. The results are discussed in relation to recent transmitter histochemical findings as well as to possible functional roles of the neurons.
Morphology of the substantia nigra pars reticulata projection neurons intracellularly labeled with HRP
Authors: Grofova I. , Deniau J. M. , Kitai S. T. 
Published: January 2005

AbstractThe technique of intracellular recording and staining of the same neuron with horseradish peroxidase (HRP) was used to study the soma‐dendritic and axonal morphology of nigrothalamic and nigrotectal cells in the rats.The nigrothalamic and nigrotectal cells were spread throughout the dorsoventral extent of the pars reticulata (SNR) and exhibited the same soma‐dendritic and axonal features. Both populations consisted of medium‐sized and large cells with extensive dendritic fields overlapping in all three directions. Their axons collateralized within the substantia nigra (SN) and in the mesencephalic tegmentum. The intrinsic collaterals were thin and branched partly within the dendritic field of a parent cell partly in remote regions of the SNR, and even in the pars compacta (SNC). The extrinsic branches involved thin arborizations in the rostroventral mesencephalic reticular substance and thicker descending and ascending collaterals.This material was supplemented by physiologically nonidentified HRP stained medium‐sized and large neurons located in the SNR. The two kinds displayed the same extent and orientation of their dendrites but the branching patterns differed slightly. Proximal dendrites of all cells were coarse and smooth; thinner distal dendrites had varicosities and spinelike appendages. Some dendrites, especially those near the crus cerebri, terminated in dendritic thickets bearing many pleomorphic appendages.The orientation of dendritic fields varied with dorsoventral position of cells within the SNR. The most ventral region of the SNR contained neurons with dendrites oriented parallel to the crus cerebri and thus remained confined to the deepest stratum. The dendrites of cells in the central region of SNR were oriented mainly anteroposteriorly and ventrally, the ventral dendrites terminating in the ventralmost layer. Cells in the dorsolateral part of the SNR were characterized by the large dorsoventral extent of their dendrites which penetrated the entire thickness of SN. This variation in the arrangement of dendritic fields indicates that the SN is organized in three dorsoventral layers.
Myelination of S1 dorsal root axons in the cat
Authors: Berthold C.‐H. , Carlstedt T. 
Published: January 2005

AbstractSamples of S1 dorsal root nerve fibers from cats of different pre‐ and postnatal ages were examined electron microscopically with regard to axon caliber and number of myelin lamellae. Each root was examined at four different cross‐sectional levels. Two levels were situated close to the spinal cord entrance on each side of the peripheral (PNS) and central nervous system (CNS) border. The third and fourth levels were located more distally. The first compact myelin lamella was observed in the CNS part of the root in a 47‐day‐old fetus. In the 53‐day‐old fetus the degree of myelination was the same in the CNS as distal in the PNS part of the root. Surprisingly, all axons appeared unmyelinated close to the PNS‐CNS border and remained so for a further 10‐day period. After this time lag, this part of the root became myelinated and showed a rapid increase in myelin sheath thickness. Calculations of axonal growth, mesaxonal length, and myelin volume indicated a maturation process that progressed discontinuously. Myelination did not proceed in a strict somatofugal direction, but was a regionally differentiated process. The maximal myelin production, expressed as the increase in myelin volume per Schwann cell, was found during the second to fourth postnatal months, i. e., very late in development.
LHRH immunopositive cells and their projections to the median eminence and organum vasculosum of the lamina terminalis
Authors: King J. C. , Tobet S. A. , Snavely F. L. , Arimura A. A. 
Published: January 2005

AbstractThe purpose of this study was to determine the distribution of luteinizing hormone‐releasing hormone (LHRH) cells and pathways projecting to the median eminence and organum vasculosum of the lamina terminalis in the hypothalamus of the rat. Immunopositive LHRH was detected by the PAP method of immunocytochemistry on vibratome sections without embedding. Female rats were ovariectomized and treated with estradiol benzoate or implanted with estradiol capsules prior to sacrifice in order to minimize variations in LH and ultimately to maximize hypothalamic LHRH content. Immunoreactive LHRH perikarya are diffusely aggregated across several nuclear groups: nucleus of the vertical limb of the diagonal band of Broca, medial septal nucleus, medians preoptic nucleus, rostral and medial preoptic areas, anterior hypothalamic area, and lateral and basal hypothalamic areas. The aggregate of LHRH cells when projected upon a horizontal plane resembles the form of a V bisected by the third ventricle. The apex of the V is directed rostrally toward the midline nuclear groups whereas the ends of the V incline ventrally toward the base of the brain and the median eminence. The majority of LHRH cells are in the rostral portion of the V in preoptic and anterior hypothalamic areas. Few cells are present in the basal hypothalamus. The processes of LHRH cells form two diffuse fiber systems which are separated by the midline hypothalamic nuclei over most of their course and converge in the basal hypothalamus close to the median eminence. The more lateral fiber system forms part of the medial forebrain bundle, while the periventricular system is associated with the wall of the third ventricle. The dispersion of LHRH cells over many nuclear groups may allow for the integration of afferents from divergent regions of the neuraxis to mediate both tonic and phasic gonadotropin secretion in the rat.
A quantitative study of regenerative sprouting by optic axons in goldfish
Authors: Murray Marion 
Published: January 2005

AbstractRegenerative sprouting by optic axons of goldfish was examined distal to the site of a crush lesion. Normally, optic nerves of large goldfish contain approximately 2 × 105 myelinated axons. The number of axonal processes in the nerve distal to the lesion increases fourfold during the first 3 months postoperatively and then returns toward preoperative numbers after 3 months. The excess number of axonal processes therefore persists several months beyond the return of visual function. The magnitude and time course of regenerative sprouting by goldfish optic axons is similar to that reported for mammalian and nonmammalian peripheral axons.
The pattern of distribution of the local axonal collaterals of Purkinje cells in the intermediate cortex of the anterior lobe and paramedian lobule of the cat cerebellum
Authors: Bishop Georgia A. 
Published: January 2005

AbstractPurkinje cells in the intermediate cortex of the anterior lobe and paramedian lobule of the cat cerebellum were intracellularly injected with horseradish peroxidase. Light microcopic analysis of the distribution paterns of the local collaterals arising from the axons of Purkinje cells in these two cortical areas was carried out. These data suggest that the distribution of the axon collaterals is different in these two areas of the cerebellar cortex. Collaterals arising from the axons of Purkinje cells in the anterior lobe form a highly branched, densely beaded plexus which is restricted to the immediate area of the cell of origin. The axonal ramification is located primarily along the Purkinje cell layer, although a few branches extend into the deep to middle molecular layer. In contrast, collaterals derived from Purkinje cells in the paramedian lobule branch infrequently, and give rise to only a few beaded chains. They extend for great distances, up to 1 mm from the cell of origin. In some cases, collateral branches of paramedian lobule Purkinje cells course into the subcortical white matter to the opposite side of their folium of origin or extend to adjacent folia. These data suggest that the distribution pattern of recurrent collaterals within the cerebellar cortex may not be uniform. In addition, differences in distribution may be correlated with differences in the afferent and efferent organization of the two areas in the cerebellar cortex.
Neural correlates of flight loss in a mexican grasshopper, Barytettix psolus. I. Motor and sensory cells
Authors: Arbas Edmund A. 
Published: January 2005

AbstractThe nervous systems of locusts (Schistocerca gregaria) and flightless grasshoppers (Barytettix psolus) are compared to evaluate modifications to neurons which are associated with flight loss.Locusts are well known for their powerful flight capability. Barytettix never fly. They lack hindwings, have immobile vestiges of forewings, and are devoid of skeletal specializations for wing movement. Their pterothoracic musculature is similar to that of locusts, except for the absence of those muscles that, in locusts, have the primary function of moving the wings.Individually identified leg motorneurons, the extensors of the tibia, were compared between locusts and Barytettix and were found to have very similar morphologies.Nerve roots which correspond to those suppyling wing muscles of locusts were stained by cobalt backfilling in Barytettix to test for presence of counterparts to wing muscle motorneurons.Cobalt backfills of metathoracic nerve 1 reveal the presence in Barytettix of neurons corresponding to locust dorsal longitudinal motorneurons‐neurons which persist in adult Barytettix in the complete absence of pe‐ripheral targets. These cells occupy characteristic positions within the CNS but their soma sizes are greatly reduced by comparison to their locust counterparts.Locust metathoracic ganglia bear large flight motorneurons on their ventral anterolateral margin. Viewed in toluidine blue‐stained wholemounts, Barytettix ganglia show considerably smaller neuron somata in the corresponding region. In locusts, comparisons of the fast extensor tibiae (FETi) motorneuron soma profile areas with those of the largest anterior cell showed no significant difference between the two, while in Barytettix, the largest anterior cell is 51% smaller than the FETi.A counterpart to the locust wing hinge stretch receptor (SR) was revealed by backfilling metathoracic nerve 1 in Barytettix. Despite its lack of function as a wing movement detector, the central projection of Barytettix SR differs from its locust counterpart only in reduced spread of specific central branches.
Distribution of substance P‐like immunoreactivity in the brain of the newt (Triturus cristatus)
Authors: Taban C. H. , Cathieni M. 
Published: January 2005

AbstractThe distribution of immunoreactive substance P (sP)‐containing structures in the newt brain and spinal cord was explored with an indirect im‐munofluorescence method. Five sP‐positive elements were detected: perikarya, dots, fibers, pericellular appositions, and pipe‐shaped structures. Perikarya were seen at the levels of the spinal ganglia, spinal cord, raphe nucleus, interpeduncular nucleus, mesencephalon, preoptic area, infundibulum, dorsocaudal part of the ventral hypothalamus, habenula, and corpus striatum. Pericellular terminals were observed in periventricular areas, known to be rich in catecholaminergic cells; pipe‐shaped structures were ob‐served from the corpus striatum to diencephalon, and in mesencephalon. The olfactory nerve and nuclei were devoid of sP‐positive elements. Six sP‐immunofluorescent pathways were detected. One of them is composed of axons with huge varicosities and extends from the lateral spinal cord area to the mesencephalon. This pathway has not been described as yet in other animals and could be peculiar to the newt.
The differentiation of the olfactory placode in Xenopus laevis: A light and electron microscope study
Authors: Klein S.L. , Graziadei P.P.C. 
Published: January 2005

AbstractThe origin and development of the olfactory neuroepithelium of Xeno‐pus laevis has been investigated with light microscopy and scanning and transmission electron microscopy.The cranial ectoderm of the Xenopus laevis embryo consists of two layers: The inner layer is called the sensory or nervous layer (NL) and the outer layer is called the nonnervous layer of the ectoderm (NNE). Between stages 23 and 26, the presumptive olfactory region consists of two discretely arranged cellular populations: the cells of the olfactory placode proper derived from the NL and the cells of the overlying NNE. After stage 26 the placodal cells begin to move toward the body surface by migrating between the NNE cells. As the placodai cells migrate they sprout an apical process which reaches the body surface at approximately stage 28. The apical process contains free and membrane‐bound ribosomes, elongated mitochondria, and microtubules oriented parallel to the process. Centrioles and basal bodies are present in the apical cytoplasm and microvilli and cilia project from the process's surface. The structure and ultrastructure of the apical process identify it as the dendrite of an olfactory neuron. As the apical process reaches the epithelial free surface, a second process sprouts from the base of the cell. This process pierces the basal lamina at stage 29/30 to reach the underlying telencephalon. The basal process is considerably thinner than the apical one and contains only free ribosomes and mitochondria. Between the stages 29/30 and 32+ it elongates and displays at its distal end the characteristics of a growth cone. The structural and ultrastructural morphology of the basal process identifies it as the axon of the olfactory neuron. Thus the placodai cells which migrate superficially differentiate into the olfactory neurons. Many placodai cells do not migrate, however, butremain at the epi‐thelial base as basal cells.As the placodal cells migrate to the body surface the NNE cells, originally confined to the surface layer (NNE), elongate and project processes toward the basal lamina. Beginning at stage 27 the apical surface of these cells becomes domed; the dome is filled with dense‐core vesicles and is covered with microvilli and globular material. The supranuclear cytoplasm of these cells contains free and membrane‐bound ribosomes, microtubules, and bundles of filaments. These cells can be characterized as the supporting cells of the olfactory neuroepithelium.The results indicate that (1) the olfactory neurons and basal cells are derived from the cells of the nervous layer, (2) the supporting cells are derived from the cells of the nonnervous ectoderm, (3) the olfactory nerve emerges from the olfactory neuroepithelium at stage 29/30, and (4) the placodai cells begin to display the morphological features of the mature olfactory neurons before their axons reach their target, the olfactory bulb.
Different granule cell populations innervate superficial and deep regions of the external plexiform layer in rat olfactory bulb
Authors: Orona Edward , Scott John W. , Rainer Elizabeth C. 
Published: January 2005

AbstractStudies on the morphological organization of the main olfactory bulb have indicated that there are subpopulations of granule cells with different dendritic patterns in the external plexiform layer (EPL). Small, extracellular injections of horseradish peroxidase (HRP) were made iontophoretically into superficial and deep parts of the EPL and the granule cell layer (GCL) in adult rats. Superficial EPL injections principally labeled superficial granule cell somata, whereas deep EPL injections labeled both superficial and deep granule cell somata. Injections in the superficial GCL labeled granule cell dendritic processes extending across the entire EPL. However, deep GCL injections labeled few granule cell dendrites in the superficial EPL, but labeled many such processes in the deep EPL. These results were the same in material processed with the Hanker‐Yates procedure, where the morphology of individual neurons could be studied, and in the more sensitive tetramethyl benzidineprocedure.Serial reconstructions of individual granule cells were made from both HRP and Golgi‐Kopsch material. The distal dendrites of deep granule cells reached only as far as the deep EPL, where they branched extensively and had many dendritic spines. The dendrites of superficial granule cells, however, reached the most superficial part of the EPL where they ramified most extensively. The superficial granule cells typically had a higher spine density in the superficial part of the EPL than in the deep part. On the basis of these results, we conclude that the superficial granule cells predominantly innervate the superficial EPL and that the deep granule cells exclusively innervate the deep EPL. Granule cells are believed to exert inhibitory influences on the bulbar output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses. Since the secondary dendrites of the tufted cells ramify in the superficial EPL and the dendrites of most mitral cells ramify in deep EPL, the superficial and deep granule cells may preferentially modulate the responses of tufted and mitral cells, respectively.
Afferent connections of the lateral agranular field of the rat motor cortex
Authors: Donoghue Johnp P. , Parham Carol 
Published: January 2005

AbstractRetrograde axonal transport techniques were used to identify the afferent connections of the lateral agranular field (AG) of the rat frontal cortex. This cytoarchitectonically distinct cortical field forms the bulk of the primary motor cortex (MI) as defined by intracqrtical microstimulation studies (Donoghue and Wise, 1982). Following injections of horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP into AG1, retrogradely labeled cells are found in the forebrain, thalamus, and brainstem. Within the cerebral cortex labeled neurons are mainly present in the first somatic sensory area (SI), the second somatic sensory area (SII), and the medial agranular field, which lies medial and rostral to AG1. In SI, labeled cells are found primarily in a cytoarchitecturally distinct region called the dysgranular field of SI. Labeled neurons are present in layers II and III, Va, and the deepest part of layer VI in this field and in SII. Labeled cells are also present in layers Va and VI of the densely granular field of SI, which is the part of SI that is strongly activated by cutaneous inputs. Commissural inputs to AG/ arise from layers II‐VI of the contralateral AG1 and thalamic inputs arise from the ventrolateral, ventromedial, posterior medial, and central lateral nuclei. Additional afferent fibers originate from neurons in the basal forebrain, the ventral thalamus, the midbrain raphe nuclei, and the locus coeruleus. This combination of inputs to AG1 from somatic sensory and frontal cortical fields, thalamic motor centers, and several other subcortical areas implies that AG1 forms a subdivision of sensorimotor cortex that is important in centrally directed movements as well as those that are guided by somatic sensory feedback.
Olivocerebellar connections in sheep studied with the retrograde transport of horseradish peroxidase
Authors: Saigal R.P. , Karamanlidis A.N. , Voogd J. , Michaloudi H. , Mangana O. 
Published: January 2005

AbstractWe describe here the morphology of the inferior olive and the localization of labeled cells after HRP injections into various lobules of vermis and hemisphere of the cerebellum of the sheep. The medial part of the caudal half of the medial accessory olive projects to a medial zone in the anterior lobe, the simple lobule, and the lobules VII and VIII. The lateral part of the medial accessory olive projects to more lateral parts of these lobules with the exception of lobule VII. The group β projects in a differential manner to the lateral parts of the lobules VII and VIII and the medial parts of the lobules IX and X. The dorsomedial cell column projects to lobules VIII, IX, and X; the connections of the dorsal cap are restricted to lobule X.Fibers from the caudal limb of the dorsal accessory olive terminate in the B zone, the simple lobule, and in lobule VIII. The rostral half of the medial accessory olive projects to lobule IX and to the hemisphere. The other projections of the accessory olives and the principal olive to the hemisphere are similar to those reported for the cat. An accessory cell group in the sheep, located between the principal and the dorsal accessory olive, has connections with the caudal vermis and the hemisphere.