bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luteinizing hormone‐releasing hormone (LHRH) in rat olfactory systems
Authors: Witkin Joan W. , Silverman Ann‐Judith 
Published: January 2005

AbstractThe luteinizing hormone‐releasing hormone (LHRH) systems of rat olfactory bulbs and nasal areas were studied in neonatal and adult rats. Animals were perfused with Zamboni's fixative and olfactory bulbs with nasal olfactory areas intact were removed, postfixed, and decalcified. LHRH was immunohistochemically demonstrated in unembedded frozen or vibratome sections.Luteinizinghormone‐releasinghormoneimmunoreactive elements were found along the course of the nervus terminalis (NT) and within both the main and accessory olfactory bulbs (MOB and AOB, respectively). Both LHRH neurons and fibers were present in the AOB, but only fibers were detected in the MOB. The fibers of the AOB were not confined to any particular lamina while fibers in the MOB were found mainly in the external plexi‐form layer. LHRH fibers were found in the mucosa of the olfactory epithelium of the vomeronasal organ in both neonatal and adult rats.The NT probably serves as a source of LHRH fibers for both the AOB and the MOB and for fibers observed in the olfactory epithelium of the vomeronasal organ. Other likely sources of LHRH fibers in the olfactory bulb are discussed.
Bar synapses and gap junctions in the inner plexiform layer: Synaptic relationships of the interstitial amacrine cell of the retina of the cichlid fish, Astronotus ocellatus
Authors: Zimmerman Roger P. 
Published: January 2005

AbstractThe retina of the cichlid fish, Astronotus ocellatus, contains an unusual class of amacrine cell, the interstitial amacrine cell, which has its soma and processes restricted to a sublamina of the proximal inner plexiform layer. The interstitial amacrine cell is unique in making synapses which contain a presynaptic dense bar specialization. The interstitial amacrine cell makes reciprocal synapses with bipolar cell terminals and is presynaptic to other amacrine cells and to ganglion cell dendrites. Processes of interstitial amacrine cells are connected to each other by large gap junctions.
Postnatal development of corticotectal neurons in the kitten striate cortex: A quantitative study with the horseradish peroxidase technique
Authors: Tsumoto Tadaharu , Suda Kouhei , Sato Hiromichi 
Published: January 2005

AbstractPostnatal development of striate cortical neurons projecting to the superior colliculus (SC) was studied in cats, ranging in age from newborn to adult, by injection of horseradish peroxidase (HRP) into the SC. At birth, HRP‐labelled cells were widely distributed throughout the cortex between the splenial and suprasylvian sulci, although a very rough topographic correspondence seemed to exist between the striate cortex and SC. The labelled cells were confined to layer V of the cortex, as in the adult. They were very densely packed and their somas were already pyramidal in shape although very slender.During the third to eighth days, apical dendrites of a substantial number of cells, mostly locatcd in the upper bank of the splenial sulcus, were filled with HRP up to layer I and their somas were larger than those of cells located near the crown of the lateral and postlateral gyri. At the eighth day and thereafter, the distribution of the labelled cells across the visual cortex was not so widespread as that seen in the newborn kittens. The dendritic arborization pattern of labelled cells became nearly adultlike at the fourth week, and its full maturation was seen at the eighth week.A quantitative analysis of the cross‐sectional areas of the cells and their packing density in layer V of the cortex revealed that (1) the size of cells increased very rapidly during the second week and became almost adultlike at the fifth week; (2) the density of cells reduced dramatically during the second week and thereafter at a low rate until the eighth week; and (3) the ratio of the labelled to unlabelled cells in layer V decreased remarkably also during the second week.These results suggest that an elimination of axon collaterals of corticotectal cells or their death may take place mostly during the second week of age, when eye‐opening occurs in kittens. By comparison with previous data on functional development of the SC, it is also suggested that the maturation of visual response properties of SC neurons may depend on postnatal development of corticotectal cells.
The effects of undernutrition during early life on the rat optic nerve fibre number and size‐frequency distribution
Authors: Bedi K. S. , Warren M. A. 
Published: January 2005

AbstractMale rats undernourished from the 18th day of gestation till 100days of age were nutritionally rehabilitated until 200 days of age. Six control and six experimental rats at each of 25, 50, 100, and 200 days of age were killed by perfusion with buffered 2.5% glutaraldehyde. Pieces of optic nerve from just behind the left eye of each rat were postfixed in osmium tetroxide and embedded in resin. Estimates of the total number of fibres and their mean diameter and size‐frequency distributions were made for each nerve.Rats undernourished until 25 days of age had a mean ± of 57,464 ± 6,778 fibres per optic nerve. This represented a 36% deficit (P < 0.01) compared with the 25‐day‐old control value of 89,778 ± 6,625. In addition, these undernourished rats had proportionately more small fibres than the agematched controls. This resulted in a significant deficit in mean fibre diameter at this age. These deficits and distortions disappeared in all the older rats studied, despite the continued undernourishment of some animals up to 100 days of age.It appears that even the lengthy period of undernutrition imposed in the present experiments could not produce a permanent deficit in optic nerve fibre number, size, and size distribution. It is suggested that the deficits seen initially at 25 days of age may have been due to a temporary delay in the growth and development of these nerve fibres.
An immunohistochemical study on the location of GABAergic neurons in rat septum
Authors: Panula P. , Revuelta A. V. , Cheney D. L. , Wu J.‐Y. , Costa E. 
Published: January 2005

AbstractAntisera against L‐glutamate decarboxylase (GAD), the synthesizing enzyme of γ‐aminobutyric acid (GABA) were used to locate GABAergic neurons and nerve terminals in the septal complex of the rat by using the peroxidase‐antiperoxidase method. Varying densities of immunoreactive terminals were observed in saline‐treated rats but nerve cell bodies were only demonstrated after intraventricular or intraseptal injections of colchicine. Small and medium‐sized GAD‐positive neurons were found in lateral septal nuclei, the largest number of these cells being in the pars dorsalis, and in the bed nucleus of the stria terminalis. Several GAD‐immunoreactive neurons were located in the medial septal nucleus and the nucleus of the diagonal band of Broca (DB), where the cells were larger in the ventral than dorsal parts of the region. In the medial septal nucleus and in DB the GAD‐positive cell bodies were distributed similarly to cholinergic neurons. Large GAD‐positive neurons were also found in the septofimbrial nucleus. Intense immunoreactivity in nerve terminals was observed in the lateral septal nucleus, around the island of Calleja magna, between the DB and nucleus accumbens, and in the septofimbrial and triangular septal nuclei. In contrast, the medial septal nucleus, the DB, and the bed nucleus of the stria terminalis only showed weak to moderate immunoreactivity.These results provide direct morphological evidence for the presence of neurons capable of synthesizing GABA in septal nuclei. We suggest that there are two different GABAergic neuronal systems operating in the septum: a population of small cells in the lateral septal nucleus and a group of large cells in the medial septum and DB.
The development of the cervical spinal cord of the mouse embryo. II. A Golgi analysis of sensory, commissural, and association cell differentiation
Authors: Wentworth Lee E. 
Published: January 2005

AbstractThe present report describes for the first time the early differentiation of dorsal root ganglion cells and internuncial cells in the spinal cord of mammals using the rapid Golgi technique; embryos of 9–11 days gestation (E9–E11, where E0 = day vaginal plug observed) were used. On E9 dorsal root ganglion cells are relatively undifferentiated and are just beginning to take on a bipolar appearance. A few commissural neurons are differentiating in the alar and basal plates, but their axons have not yet crossed the ventral commissure. Occasionally an ipsilateral funicular or association cell is seen in the alar plate. By E10 bipolar dorsal root ganglion cells send processes both centrally into the spinal cord and peripherally to join the ventral root as the spinal nerve. The relatively few association neurons are intermingled among commissural cells except that they are not found in the region of the ventral horn. The axon of many commissural neurons crosses the ventral commissure. On E11 a thin lateral funiculus is seen as well as the oval bundle of His (presumptive dorsal funiculus). An occasional dorsal root ganglion cell has attained the unipolar stage of differentiation. The commissural and association neurons are still intermingled along the outer regions of the mantle layer, especially in the alar plate region. Both commissural and association cells start to differentiate within the ventricular layer as radially oriented, bipolar neuroblasts. As the cell somas reach the outer region of the ventricular layer the cells become unipolar. The cells reorient more dorsoventrally and a primary dendrite grows first from the pole opposite the axon. This sequence of cell differentiation is in general agreement with what is seen in the differentiation of ventral root motoneurons.
The subnuclear organization of the rat interpeduncular nucleus: A light and electron microscopic study
Authors: Hamill Geoffrey S. , Lenn Nicholas J. 
Published: January 2005

AbstractThe subnuclear organization of rat interpeduncular nucleus (IPN) has been examined by light microscopy following staining with Nissl and Holmes methods, 3H‐leucine autoradiography, acetylcholinesterase (AChE), and cytochrome oxidase histochemistry, on plastic sections stained with toluidine blue, and by electron microscopy. Three unpaired and four paired subnuclei are recognized.The rostral subnucleus is heavily stained for AChE, which clearly delineates its borders. It is distinguished ultrastructurally by two types of synapses on dendrites, and two on perikarya. Of the former, one type is formed by presynaptic processes which contain spherical and dense‐cored vesicles and make asymmetrical contacts. Dense‐cored vesicles are observed in many of the postsynaptic dendrites. A second type has presynaptic processes containing small, pleomorphic vesicles which make symmetrical contacts. Synapses on perikarya are found in the rostral, central, intermediate, lateral, and interstitial subnuclei. The dorsal subnucleus is continuous with the serotonin‐containing B8 cells. The central subnucleus is distinguished by longitudinally oriented medial habenular axons separating palisades of cell bodies. These axons, which also traverse the intermediate subnuclei, form en passant S synapses with small dendrites of the central subnucleus. The intermediate subnuclei react faintly for AChE and intensely for cytochrome oxidase. They contain crest synapses formed by two habenular afferents, one from each medial habenula, which contact a narrow dendritic process en passant. The lateral subnuclei react intensely for AChE and have ultrastructural features similar to the rostral subnuclei. The interstitial subnuclei lie within each fasciculus retroflexus as it enters IPN. The small dorsal lateral subnuclei are evident by light microscopy.
Relationship between preferred orientation and receptive field position of neurons in extrastriate cortex (area 19) in the cat
Authors: Leventhal Audie G. , Schall Jeffrey D. , Wallace Wendy 
Published: January 2005

AbstractOrientation sensitivity is a characteristic of most retinal ganglion cells (Levick and Thibos, '82), most relay cells in the dorsal lateral geniculate nucleus (Vidyasagar and Urbas, '82), and most neurons in the visual cortex (Hubel and Wiesel, '62) in the cat. In the retina there is a systematic relationship between receptive field position (polar angle) and preferred orientation. Outside of the area centralis most retinal ganglion cells respond best to stimuli oriented radially, i.e., oriented parallel to the line connecting their receptive fields to the area centralis (Levick and Thibos, '82). This relationship is strongest along the horizontal meridian (the visual streak) and appears to reflect the innate, radial orientation of retinal ganglion cell dendritic fields (Leventhal and Schall, '83).A relationship between preferred orientation and polar angle also exists in cat striate cortex; outside of the area centralis representation most cells respond best to lines oriented radially. This relationship is strongest for S type cells, the most orientation‐selective cells, and cells in regions representing the horizontal meridian (Leventhal, '83). To determine if similar relationships exist in cat extrastriate cortex, the preferred orientations and receptive field positions of 226 neurons in area 19 were studied. We find that, as in area 17, most area 19 cells outside of the representation of the area centralis respond best to lines oriented radially; this relationship is strongest for the cells having the narrowest receptive fields and in regions subserving the horizontal meridian. Unlike in striate cortex, in area 19 the relationship between preferred orientation and polar angle is not dependent upon cell type (S or C) or to the degree of orientation sensitivity exhibited. Also, in area 19, but not in area 17, the relationship between preferred orientation and polar angle fails for the cells having the widest receptive fields.The results of this study show that the systematic relationship between preferred orientation and receptive field position which begins in the retina is largely preserved through extrastriate cortex. The functional architecture of orientation sensitive cells throughout the visual pathways may depend ultimately upon the innate, radial orientation of the dendritic fields of retinal ganglion cells.
Three distinct morphological classes of receptors in fish olfactory organs
Authors: Muller Jay F. , Marc Robert E. 
Published: January 2005

AbstractThree morphologically distinct classes of receptor‐neurons are proposed: (1) type I ciliar cells, (2) microvillar cells and (3) type II ciliar cells. Retrograde transport of horseradish peroxidase by axons in the olfactory nerve to the olfactory organs of goldfish (Carassius auratus) and channel catfish (Ictalurus punctatus) provided evidence that these axon‐bearing cells are present in the organs of both species. Goldfish olfactory organs were also studied with scanning electron microscopy, dissociated with papain for isolated cell preparations, and processed for ultrastructural localization of acid phosphatase activity. Type I ciliar cells are similar to ciliar olfactory receptors found in all vertebrate classes. Microvillar cells are present in the olfactory organs of most fishes and in the tetrapod vomeronasal organ. In goldfish and catfish, type I ciliar and microvillar cells are concentrated on the inner third of each lamella, nearest to the median raphe. Type II ciliar cells have often been described as respiratory‐type or ciliated nonsensory cells. They are structurally similar to respiratory epithelial cells in the nasal cavities of tetrapods and have motile cilia that beat synchronously, indicative of their role in mediating fluid flow over the olfactory epithelium. In goldfish they occur singly and in aggregates throughout the organ. In catfish they are segregated from type I ciliar and microvillar cells on the outer two‐thirds of each lamella. In goldfish and catfish they have axons that pass through the olfactory nerve to the olfactory bulb; hence, they are receptor‐neurons as well as analogous to respiratory epithelium.In addition to the three receptor types described above, cells resembling receptors with rodlike distal processes were seen filled with horseradish peroxidase and observed with scanning and transmission electron microscopy. Cells of similar structure have been documented elsewhere, often called “rod cells,” and sometimes considered a separate receptor type in fishes. In this study, a number of rodlike processes were found with their ciliar or microvillar components partially fused. High levels of acid phosphatase activity were localized to these processes, and examples were found that corresponded to each of the three receptor types. Olfactory receptor turnover is believed to persist through life. The evidence presented supports the hypothesis that fusion of their dendritic apical processes marks an early stage of receptor cell senescence.
Central projections of gustatory nerves in the rat
Authors: Hamilton Robert B. , Norgren Ralph 
Published: January 2005

AbstractThe central distributions of gustatory and nongustatory branches of cranial nerves V, VII, IX, and X were examined after application of horseradish peroxidase to the cut nerve. The nerves conveying gustatory information, chorda tympani (CT), greater superficial petrosal (GSP), lingualtonsilar branch of IX (LT‐IX), superior laryngeal branch of X (SL), distributed primarily to the lateral division of the nucleus of the solitary tract (NST) from its rostral pole to the obex. The CT and GSP distributions were coextensive and terminated most densely in the rostral pole of NST. The LT‐IX distribution concentrated between this major CT/GSP distribution and the area postrema with a caudal extension into the interstitial nucleus of NST. This nerve also had a substantial projection, not found in other gustatory nerves, into the dorsolateral aspect of the medial NST. The SL distribution overlapped LT‐IX in the caudal medulla. The lingual and inferior alveolar nerves, two oral trigeminal branches, projected to regions of NST innervated by the gustatory nerves. The cervical vagus nerve distributed primarily to the medial NST in the caudal half of the nucleus and exhibited only minimal overlap with gustatory nerve distributions. The nucleus of the solitary tract appears to have two major functional divisions–an anterior‐lateral oral‐gustatory half, and a posterior‐medial visceral afferent half.
Astrocytic membrane morphology: Differences between mammalian and amphibian astrocytes after axotomy
Authors: Wujek Jerome R. , Reier Paul J. 
Published: January 2005

AbstractPrevious studies have shown that astrocytes in some nonmammalian species provide a favorable environment for axonal elongation, whereas mammalian astrocytes are thought to inhibit fiber outgrowth. The present study was performed to determine whether any plasma membrane differences exist between these glial elements which could account for their contrasting effects upon axonal outgrowth. Astrocytic scars were formed in optic nerves of rats, newts, and frogs by enucleation. Subsequently, the astrocytic membranes were examined with the freeze‐fracture technique. Orthogonal arrays of small intramembranous particles (IMPs) are a prominent component of the plasma membranes of normal mammalian astrocytes; these arrays are most numerous in astrocytic membranes that form an interface between the CNS and nonneural tissue. Astrocytic membranes within the normal CNS parenchyma, however, possess much lower densities of arrays. Following axotomy and Wallerian degeneration, the density of arrays increased threefold within the parenchyma of the optic nerve, while remaining constant at the, glia limitans. In striking contrast, only a few aggregates of IMPs that resembled orthogonal arrays could be found in normal and reactive astrocytes of amphibians, although the cytology of these glial cells and density of the scars are otherwise similar to those of their mammalian counterparts. These findings suggest (1) that a proliferation of orthogonal arrays in astrocytic plasma membranes is a prominent feature of gliosis in the mammalian CNS and (2) that differences in the composition of reactive mammalian and amphibian astrocytic membranes may account for variations in axonal‐glial interactions within the injured CNS.
The dorsal lateral geniculate nucleus of macropodid marsupials: Cytoarchitecture and retinal projections
Authors: Sanderson K. J. , Haight J. R. , Pettigrew J. D. 
Published: January 2005

AbstractThe anatomy of the dorsal lateral geniculate nucleus (LGd) is described in five macropodid marsupial species, including two rat kangaroos (bettong and potoroo), two wallabies (pademelon and tammar), and the large grey kangaroo. The distribution of retinal terminals in the LGd was examined following intraocular injections of tritiated amino acids. There are considerable differences in both LGd cytoarchitecture and the patterns of retinal terminations among the five species. Cytoarchitecture in the bettong LGd is relatively simple, displaying a minimal regional differentiation. In contrast, the potoroo LGd is quite complex and displays several well‐defined cell laminae, each of which is associated with input from a single eye. Both rat kangaroos display the same basic pattern of retinal termination with three bands of terminals from the contralateral eye and four from the ipsilateral eye. The bands are less sharply defined in the bettong, in which terminals from each eye overlap to a greater extent than is seen in the potoroo. The wallabies and kangaroos display a more complex LGd architecture and patterning of retinal terminal bands. Bilateral retinal projections within same LGd lamina are unusual in these large macropodids. The number of the terminal bands reaches ten in the grey kangaroo–four from the contralateral eye and six from the ipsilateral eye. The pademelon LGd is unusual in that it shows intraspecies variation with some animals displaying five ipsilateral terminal bands and others only four. The results are discussed in comparison with the patterns of LGd organization observed in other mammalian lines, placental and marsupial. We conlude that LGd lamination and the segregation of retinal inputs to the LGd in marsupials are likely to be the result of evolutionary factors which differ from those which have produced ocular segregation and complex lamination in several lines of placental mammals.