bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fetal development of primate chemosensory corpuscles. II. Synaptic relationships in early gestation
Authors: Zahm Daniel S. , Munger Bryce L. 
Published: January 2005

AbstractFungiform papillae contained well‐developed chemosensory corpuscles in macaque monkey fetuses with crown‐rump lengths of 5.0‐9.0 cm. These fetuses corresponded to stages from the last part of the first and beginning of the second trimester of gestation. Chemosensory cells extended from the epithelial basal lamina to the taste pore anlage at the apex of the corpuscle and had typical afferent synaptic contacts with presumptive gustatory axons. Apical secretory granules, the distinctive cytologic feature of sustentacular cells, were absent. Cells with cytologic characteristics intermediate between chemosensory cells and basal extragemmal cells were considered to be differentiating chemosensory (DC) cells and appeared to arise from existing basal cells as well as undifferentiated postmitotic cells. Although extragemmal cells were extensively coupled by gap junctions which are apparent in electron micrographs of thin sections, similar junctions were absent from chemosensory and DC cells. While having minimal structural requirements for transduction and transmission of sapid stimuli (i.e., an intraoral surface and afferent synaptic contacts) chemosensory cells lacked efferent synapses and subsurface cisternae, which can be observed at later stages of gestation. Axoaxonic synapses, present between gustatory axons in the intragemmal and extragemmal epithelium and in the subgemmal connective tissue, were observed with greater frequency than at later stages of gestation. We conclude that the differentiation of chemosensory cells precedes the differentiation of sustentacular cells by several weeks. This fact lends support to the concept that chemosensory cells are a unique identifiable cell type in all chemosensory corpuscles.
Morphology of cat phrenic motoneurons as revealed by intracellular injection of horseradish peroxidase
Authors: Cameron W. E. , Averill D. B. , Berger A. J. 
Published: January 2005

AbstractThe morphology of phrenic motoneurons (PMs) of adult cat was examined by utilizing the technique of intracellular injection of horseradish peroxidase. Twenty‐one cells were reconstructed from serial sections in transverse, sagittal, and horizontal planes. The cell bodies were ellipsoid, with the major diameter oriented parallel to the longitudinal axis of the spinal cord.The dendrites of PMs are not distributed in a radially symmetric fashion, but rather project to four separate fields. The field containing the greatest number of dendrites extends rostrocaudally within the phrenic motor column. This collection of dendrites forms a rostrocaudal bundle in which the dendrites from neighboring PMs lie in close association with one another. The remaining dendrites project dorsolaterally, dorsomedially, and to a lesser extent, ventrally. The dorsolaterally directed dendrites form bundles upon entering the lateral funiculus with the dendrites from other PMs. Several of the dorsomedially directed dendrites cross to the contralateral spinal cord via the anterior commissure or central gray. A wide variety of dendritic spines and appendages was observed.There were no instances in which axon collaterals were observed for the 11 well‐stained axons examined. The length of the initial segment of the axon was a function of the distance of the cell body from the ventral funiculus.
Posterior lateral line afferent and efferent pathways within the central nervous system of the goldfish with special reference to the Mauthner cell
Authors: Zottoli Steven J. , Van Horne Craig 
Published: January 2005

AbstractThe goldfish posterior lateral line nerve consists of a dorsal and a ventral branch, each of which is associated with a ramus of the sensory branch of the VII th nerve (ramus recurrens facialis). The afferent and efferent pathways of these nerves within the central nervous system were studied by using horseradish peroxidase (HRP) histochemistry.The afferent fibers of the ramus recurrens facialis travel in the ventral portion of the VIIth nerve as it enters the brain and project predominantly to the ipsilateral half of the facial lobe.The afferent fibers of either the dorsal or ventral branch of the posterior lateral line nerve split into two bundles as they enter the brain. The caudally projectingfascicle terminates predominantly in thenucleusmedialis. The fibers of the rostrally projecting bundle terminate predominantly in nucleus medialis and nucleus magnocellularis and in the eminentia granularis.The posterior lateral line efferent somata were located in the diencephalon as well as in the medulla oblongata. The medullary efferent neurons formed two distinct groups, a rostral and a caudal nucleus. The cell bodies of the latter were more numerous and larger than those of the former. The axons of the efferent neurons exit from the brain by one of two routes. The first is at the level of the rostral efferent nucleus and the second at the level of the Mauthner cell.Previous reports have described input of posterior lateral line afferent fibers to the Mauthner cell soma and proximal lateral dendrite of the goldfish. This electrophysiological input was bilateral and was interpreted as monosynaptic. The afferent input described in this study was ipsilateral and ended in the vicinity of the distal lateral dendrite. These differences are discussed in the context of the neuronal circuitry that may be present.
The dual origins of the olivocochlear bundle in the albino rat
Authors: White James S. , Warr Bruce W. 
Published: January 2005

AbstractRecent studies of the origins and terminations of the olivocochlear bundle (OCB) in the cat provide evidence that separate efferent systems differentially innervate the two types of hair cells in the organ of Corti. To begin to test the generality of these separate olivocochlear systems, the cells of origin of the OCB were determined in the albino rat by using axonal transport of horseradish peroxidase. Our findings are that, as in the cat, two classes of olivocochlear (OC) neurons project to the cochlea. These neurons could be dichotomized according to their location in the superior olivary complex (lateral or medial), their size (small or large), and their preferred side of projection (ipsilateral or contralateral). All labeled OC neurons also exhibited a positive reaction for acetylcholinesterase. In the rat, however, lateral and medial OC neurons are each restricted to a single nucleus, and, furthermore, the lateral OC neurons project only ipsilaterally. The rat also has significantly fewer mean totals of both lateral (240vs. 710)and medial (240 vs. 520) OC neurons than the cat. The present methods also demonstrated the course of axons of the OCB and axon collaterals entering the cochlear nuclear complex. Vestibular efferent neurons were also labeled bilaterally medial and lateral to the facial genu. Our results suggest that the general organizational plan of OC neurons in the rat may offer advantages over the situation in the cat for studies of connectional neuroanatomy, neurophysiology, and behavioral functions of the two olivocochlear systems.
The distribution of serotonin in the CNS of an elasmobranch fish: Immunocytochemical and biochemical studies in the atlantic stingray, Dasyatis sabina
Authors: Ritchie T. C. , Livingston C. A. , Hughes M. G. , McAdoo D. J. , Leonard R. B. 
Published: January 2005

AbstractThe distribution of serotonin (5HT) in the brain of the Atlantic stingray was studied with peroxidase‐antiperoxidase immunocytochemistry and high‐pressure liquid chromatography. The regional concentrations of 5HT determined for this stingray fell within the range of values previously reported for fishes. A consistent trend in vertebrates for the hypothalamus and midbrain to have the highest concentrations and the cerebellum the lowest was confirmed in stingrays. Neuronal cell bodies and processes exhibiting 5HT‐like immunoreactivity were distributed in variable densities throughout the neuraxis. Ten groups of 5HT cells were described: (I) spinal cord, (II‐IV) rhombencephalon, (V, VI) mesencephalon, (VII, VIII) prosen‐cephalon, (IX) pituitary, and (X) retina. There were three noteworthy features of the 5HT system in the Atlantic stingray: (1) 5HT cells were demonstrated in virtually every location in which 5HT‐containing cells have been described or alluded to in the previous literature. The demonstration of immunopositive cells in the spinal cord, the retina, and the pars distalis of the pituitary suggests that 5HT may be an intrinsic neurotransmitter (or hormone) in these regions. (2) The distribution of 5HT cells in the brainstem shared many similarities with that in other vertebrates. However, there were many 5HT cells outside of the raphe nuclei, in the lateral tegmentum. It appears that the hypothesis that “lateralization” of the 5HT system is an advanced evolutionary trend cannot be supported. (3) 5HT fibers and terminals were more widely distributed in the Atlantic stingray brain than has been reported for other nonmammalian vertebrates on the basis of histofluorescence. It appears that this feature of the 5HT system arose early in phylogeny, and that the use of immunohistochemistry might reveal a more general occurrence of widespread 5HT fibers and terminals.
Fine structure of dividing astroglia and oligodendroglia during myelin formation in the developing mouse spinal cord
Authors: Meinecke Douglas L. , de F. Webster Henry 
Published: January 2005

AbstractTo study the morphology and cellular relationships of dividing glial cells during myelin formation, we perfused newborn and 5‐day mouse pups and embedded slices of cervical, thoracic, and lumbar cord for light and electron microscopic study. In semithin epon sections stained with toluidine blue, all levels of spinal cord at both ages contained mitotic glia in gray columns and funiculi. In electron micrographs of funiculi, dividing astroglia contained bundles of glial filaments, many glycogen granules, and had large processes extending into the surrounding neuropil. Cytoplasmic organelles of many immature interphase oligodendroglia and mitotic oligodendroblasts were similar and included microtubules, clusters of free ribosomes, and scattered profiles of granular endoplasmic reticulum. Unlike astroglia, dividing oligodendroblasts lacked large processes and in metaphase they were ellipsoids and had smooth plasma membranes. When these cells were studied in alternating serial thin and semithin sections over 10–15‐μm distances, we did not identify connections between myelin sheaths and mitotic oligodendroblasts. Our findings indicate that oligodendroglia in developing white matter multiply before developing large processes. Our data also suggest that oligodendroglia do not divide while forming myelin.
Light and electron microscopic studies of the basilar papilla in the duck, Anas platyrhynchos. I. The hatchling
Authors: Chandler John P. 
Published: January 2005

AbstractThe intent of this study was to describe in detail the normal structure of the basilar papilla in the duck, Anas platyrhynchos, with light and electron microscopy. The cochlear duct is supported by a ring of dense periotic connective tissue, the limbus. Distribution of hair cells in the basilar papilla follows the general avian pattern. Tall hair cells occupy the neural margin of the papilla. Short hair cells cover the abneural margin from the proximal tip to the middistal area. Intermediate hair cells form a transition zone from genu to distal tip. Patterns of innervation are correlated with hair cell morphology, which supports the classification of hair cells in birds into three groups. Tall hair cells synapse with two to four large afferents and one efferent; intermediate hair cells synapse with one or two afferents and one or two efferents; short hair cells synapse with one small afferent and one or two large efferents. In this relatively primitive species of bird, cuticles in all classes of hair cells reach the plasmalemma on the neural side of the cell, a condition that supports the contention that tall hair cells are more primitive than short hair cells.
Acetylcholinesterase activity in the sexually dimorphic area of the gerbil brain: Sex differences and influences of adult gonadal steroids
Authors: Commins Deborah , Yahr Pauline 
Published: January 2005

AbstractThe morphology of the medial preoptic area‐anterior hypothalamus (MPOA‐AH) of gerbils is sexually dimorphic and influenced by adult gonadal hormones. This research shows that the distribution of (MPOA‐AH) cells that synthesize acetylcholinesterase (AChE) and the activity of AChE within the MPOA‐AH are also sexually dimorphic and hormone sensitive. Adult male and female gerbils were gonadectomized, gonadectomized and implanted subcutaneously with testosterone (T), or sham operated 4–8 weeks before sacrifice. Coronal sections through the sexually dimorphic area (SDA) of the MPOA‐AH were stained for AChE. Planimeter measurements of camera lucida drawings showed that the total volume of the SDA is similar in the two sexes, but the proportion of the SDA that stains darkly and/or stands out clearly from the surround (dark volume) is larger in males. Optical density readings also indicated that AChE staining is darker in the male SDA. Gonadectomy decreases staining intensity in both sexes and reduces total SDA volume. Dark volume decreases more than 50%. Testosterone treatment reverses all effects of gonadectomy, although hormonal influences are smaller in females than in males. There were no sex differences or hormonal influences on AChE staining lateral to the SDA. The pars compacta of the male SDA was essentially devoid of AChE, indicating that this cell group is distinct from the rest of the SDA. It also shrinks after castration unless the males receive T. Histochemical changes in the SDA may be related to hormonal control of scent marking, a form of communication in this species.
Motoneuron death after sciatic nerve section in newborn rats
Authors: Schmalbruch Henning 
Published: January 2005

AbstractWhen the sciatic nerve was cut in newborn rats almost all of the motoneurons were subsequently lost. The adult sciatic nerve contained 7,640 myelinated fibers of which 1,650 were motor axons. The ventral roots of the sciatic nerve (L4‐L6) contained in all 4,080 myelinated fibres; only 2,380 were present 5–30 weeks after the sciatic nerve had been cut at birth. The deficit of 1,700 fibres corresponded to the number of motor axons in the sciatic nerve. The motoneuron pools were depleted and practically no labelled or unlabelled perikarya were after found after HRP had been applied to the nerve proximal to the former lesion. The deficit of ventral root fibres was 1,030 when the nerve had been cut at age 1 week; nerve section 4 weeks after birth was not followed by retrograde loss of motor axons. Nerve crush at birth caused a deficit of 1,230 ventral root fibres. The incomplete loss of motor axons after crushing was due to the fact that not all axons had been severed.The continuity of the nerves cut at birth was always restored and myelinated axons which probably were dorsal root ganglion afferents grew into the atrophic muscles. Roughly two‐thirds of the myelinated sensory fibres degenerated after axotomy at birth. The denervated muscle fibres were not reinnervated but vanished eventually and were replaced by fat cells.
Embryonic development of monoaminergic neurons in the chick retina
Authors: Kato S. , Negishi K. , Teranishi T. 
Published: January 2005

AbstractBy means of a histofluorescence technique, embryonic and postnatal development of monoaminergic neurons was followed in the chicken retina with or without intravitreal injection of monoamines 30–60 minutes before eye removal. Fluorescent cells were tentatively classified into five subsets with respect to the soma shape, localization, migration of somata during retinal development, uptake capacity (color and intensity in fluorescence), and sensitivity to neurotoxins. The five subsets of cells were endogenous dopaminergic (DA), catecholamine‐accumulating (CA), indoleamine‐accumulating (IA), CA‐bipolarlike, and IA‐bipolarlike cells. Greenish endogenous DA‐cells first appeared at the 14–15th embryonic day. The cell body of DA‐cells was initially fusiform and located slightly distal to the innermost level of the inner nuclear layer (INL). They became round or oval and migrated to the innermost level of the INL by day 20. Both large and small bottle‐shaped CA‐cells were visualized at an intermediate portion of INL by intravitreal injection of exogenously applied dopamine or noradrenaline (1–2 m̈g/eye) at day 10. Large bottle‐shaped cells, like the DA cells, changed to round or oval and migrated to the innermost level of the INL by day 20. On the other hand, small bottle‐shaped CA‐cells retained their cell shape and location in the INL as retinal development progressed. Therefore, the large bottle‐shaped CA‐cells seen in an early developmental stage correspond to the DA‐cells. IA‐cells were visualized one or two cell rows outward in the INL first at day 13–14 by intravitreal injection of 5,6‐dihydroxytryptamine or 5‐hydroxytryptamine (1–5 m̈g). These cells did not change their relative location during development. The emergence of the catecholaminergic uptake property (DA‐ and CA‐cells) may slightly precede that of the indoleaminergic property (IA‐cells) in the embryonic stage. When excess doses (10–20 m̈g) of monoamines were intravitreally injected, a large number of CA‐ and IA‐bipolarlike cells became visible, peaking in number probably during a certain embryonic period (after day 14–15). DA‐ and CA‐cells could be destroyed by intravitreal injection of 6‐hydroxydopamine (15 m̈g, twice) and IA‐cells could be selectively eliminated by intravitreal 5,7‐dihydroxytryptamine, whereas CA‐ and IA‐bipolarlike cells were not influenced by the dose of neurotoxins used.
Diencephalic connections of the raphé nuclei of the rat brainstem: An anatomical study with reference to the somatosensory system
Authors: Peschanski Marc , Besson Jean‐Marie 
Published: January 2005

AbstractThe present study was undertaken to analyse in detail the connections of the various raphé nuclei with thalamic structures. Micropipettes filled with an aqueous solution of wheat‐germ agglutinin conjugated to horseradish peroxidase were used to produce small iontophoretic deposits restricted to the various raphé nuclei in male Sprague Dawley albino rats. Tetramethyl benzidine was used as a chromogen to reveal both fiber terminals anterogradely labeled and retrogradely filled neurons. A detailed discussion of the possible cases of artefactual labeling using this technique is given.The present study confirms the results obtained previously in the cat that indicate that the various raphé nuclei project to different areas of the diencephalons. Related to the somatosensory system, the B3area (nucleus raphé magnus) projects to the nucleus submedius and anterior intralaminar nuclei know to receive spinothalamic inputs, but not to the ventrobasal complex. The distribution of afferents from this nucleus suggests an innervation primarily of thalamic structures involved in the somatosensory system. The nucleus raphé medianus projects to the rentrobasal complex and the nucleus submedius, but the fact that its projections are widespread, including all thalamic sensory „relay”︁ nuclei and the entire nucleus reticularis thalami, suggests that it could participate in a „nonspecific”︁ system of control of different sensory modalities. The nucleus raphé dorsalis generally does not project to the thalamic nuclei believed to the involved in the somatosensory system.
Co‐localization of retrogradely transported wheat germ agglutinin and the putative neurotransmitter substance P within trigeminal ganglion cells projecting to cat middle cerebral artery
Authors: Liu‐Chen Lee‐Yuan , Gillespie Steven A. , Norregaard Thorkild V. , Moskowitz Michael A. 
Published: January 2005

AbstractNeurons containing both wheat germ agglutinin (WGA) and substance P (SP) immunoreactivities were found in the ophthalamic division of the ipsilateral trigeminal ganglia following application of the axonally transported lectin WGA to cat middle cerebral artery. Immunohistochemistry was accomplished by staining for WGA and SP on adjacent sections by using the chromogen diaminobenzidine, or by staining on a single section with sequential application of WGA and SP antisera using the chromogens diaminobenzidine and 4‐chloro‐1‐naphthol, respectively. These observations confirm the results of trigeminal lesion studies indicating that trigemino‐vascular projections to the middle cerebral artery in the cat contain the neurotransmitter SP. In addition, other neurotransmitters may be present in this pathway since less than 50% of WGA‐labeled cells contained SP.
A Golgi study of the development of the inferior olivary nuclear complex in the chicken
Authors: Furber Susan E. 
Published: January 2005

AbstractThe present study is an examination of the qualitative and quantitative changes in the morphology of neurons in the inferior olivary nuclear complex (IOC) of the chicken. The development of the chicken IOC was studied with the Golgi technique between embryonic day 11 (E11) and posthatch day 35 (P35). The olivary cells change most between E11 and E19 and are essentially mature (i.e., similar to P35) at E19. These changes chiefly involve a gradual loss of features that typify immature growing cells (e.g., growth cones, growth buds, filopodia, beaded dendrites); from E11 to P35 there is an increase in the soma size by 42%, an increase in the dendritic field size by 49%, and a decrease in the number of dendritic branches by 47%. A minor but significant fall in the number of dendrites per neuron between E11 and E19 was observed, but as there is no significant difference between E11 and P35, the relevance of this observed change, if any, is unclear.On the basis of dendritic branching, it appears that one type of olivary neuron is present in the chicken, which is similar to the type of neuron found in the caudal medial olive (MO) and the caudal dorsal olive (DO) of mammals (Schiebel and Schiebel, ′55; Rutherford and Gwyn, ′80). This finding correlates with the proposal that the avian IOC corresponds mostly to the mammalian MO and DO and that only a small portion corresponds to the mammalian principal olive (Furber, ′83).