bluuebunny/crossref_metadata_2025_split huggingface dataset:
Co‐localization of tyrosine hydroxylase, GABA and neuropeptide Y within axon terminals innervating the intermediate lobe of the frog Rana ridibunda
Authors: Tonon Marie‐Christine , Bosler Olivier , Stoeckel Marie‐Elisabeth , Pelletier Georges , Tappaz Marcel , Vaudry Hubert 
Published: January 2005

AbstractPossible co‐existence of gamma‐aminobutyric acid (GABA), catecholamines, and neuropeptide Y (NPY) in the same nerve terminals of the frog intermediate lobe was investigated by immunocytochemistry at the electron microscopic level. Co‐localization of GABA and tyrosine hydroxylase (TH) was studied by using a double immunogold labeling procedure. Co‐localization of glutamate decarboxylase (GAD) and NPY was studied by combining, respectively, the peroxidase‐antiperoxidase method and a radioimmunocytochemical labeling procedure. Catecholamines and GABA were systematically co‐localized in nerve endings of the pars intermedia. Most of the NPY‐immunoreactive fibers also contained GAD‐like immunoreactivity. However, a few NPY‐positive nerve terminals were not immunoreactive for GAD. These data provide evidence for co‐existence of a regulatory peptide (NPY) and several neuro transmitters (i.e., GABA and catecholamines) within the same axon terminals in the intermediate lobe. Since GABA, dopamine, and NPY have all been shown to inhibit the activity of frog melanotrope cells, the present findings suggest that these neuroendocrine factors may interact either at the pre‐synaptic or post‐synaptic level. © 1992 Wiley‐Liss, Inc.
Substance P immunoreactive boutons form synapses with feline sympathetic preganglionic neurons
Authors: Pilowsky Paul , Llewellyn‐Smith Ida J. , Lipski Janusz , Chalmers John 
Published: January 2005

AbstractIn this study, the relationship between substance P‐immunoreactive boutons and antidromically activated sympathetic preganglionic neurons was examined by light and electron microscopy. Sympathetic preganglionic neurons in the T2–T4 spinal segments of the cat were identified by intracellular recording and antidromic activation from the corresponding white ramus. Neurons were filled with lucifer yellow and then stained to reveal, simultaneously, substance P and lucifer yellow immunoreactivity. All of the neurons examined with the light microscope (n = 13) received appositions from substance P‐immunoreactive boutons. Appositions were found on all parts of the neuron, including the somata, dendrites, and axon initial segment. In most cases (11/13) few close appositions were seen; however, two neurons received large numbers of appositions from substance P‐immunoreactive boutons. On one neuron, 16 substance P‐immunoreactive varicosities that were identified as being closely apposed at the light microscope level were serially sectioned and examined with the electron microscope. Of these 16 varicosities, eight either directly contacted the neuron or formed morphologically identifiable synapses. The remaining eight varicosities were separated from the neuron by thin glial processes. Two other sympathetic preganglionic neurons that were examined ultrastructurally also received substance P‐immunoreactive synapses and close contacts. These findings suggest that substance P‐containing nerve fibres could affect all sympathetic preganglionic neurons but are likely to be important in regulating the activity of only a small proportion of these neurons.
Correlation of filiform hair position with sensory afferent morphology and synaptic connections in the second instar cockroach
Authors: Thompson Kevin S. J. , Blagburn Jonathan M. , Gibbon Charles R. , Bacon Jonathan P. 
Published: January 2005

AbstractAn attempt is made to relate the distribution of filiform hairs on the cercus of the second instar cockroach, Periplaneta americana, to the morphology and patterns of synaptic connectivity of their afferents. We studied the most distal 25 of the 39 filiform hairs which are commonly present. Filiform afferent arborizations were stained by cobalt filling from the cell body in the cercus. Three fundamental arbor types were found, two similar to those of the first instar medial (M) and lateral (L) afferents, and a third, novel type. L‐type arbors could be divided into four subtypes. The most obvious correlate of arbor type is the circumferential position of the hair on the cercus. The proximodistal position of the sensillum within each cereal segment is also a determinant of its arbor. By comparison of hair positions and afferent morphologies, we were able to ascribe homologies between the second instar hairs and members of adult longitudinal hair columns. The patterns of monosynaptic connections between afferents and giant interneurons (GIs) 1, 2, 3, 5, and 6 were determined by recording synaptic potentials in GIs evoked by direct mechanical displacement of individual filiform hairs. Latency from stimulus onset to the rise phase of the first excitatory postsynaptic potential (EPSP) was used as the criterion of monosynapticity. The EPSP amplitudes of the two original L and M afferents are halved in the second instar, in the absence of a significant decrease in GI input resistance. The other afferents can be divided into two basic classes: those which input to GI5 (M‐type), and those which input to GI3 and GI6 (L‐type). The former is correlated with a central or medial position, while the latter is associated with a group of afferents situated laterally on the cercus. In segments 3 and 4, input to GIs 1 and 2 also correlates with a medial cereal position, however, in the more proximal segments 5 and 6, afferents at all positions input to these interneurons. The occurrence of afferents of identical morphology and similar connectivity in equivalent positions in different segments suggests that each sensory neuron is determined by its two‐dimensional position within a segment. The presence of afferents with the same morphology which display proximodistal differences in synaptic connectivity, and of other afferents which have M‐type connectivity despite L‐type morphology, means that anatomy is generally a poor predictor of synaptic connectivity.
Effect of bilateral tectum lesions on retinal ganglion cell morphology in rats
Authors: Bähr Mathias , Wizenmann Andrea , Thanos Solon 
Published: January 2005

AbstractWe have examined morphological changes of retinal ganglion cells (RGCs) during postnatal development in albino rats. Somatic diameter, dendritic field diameter, and branching frequencies of RGCs of normal rats were compared with those of animals that had received bilateral lesions of the tectum immediately after birth. Bilateral lesions of the tectum at P1 (first postnatal day) induced a dramatic increase in RGC death during the time of naturally occurring cell death in the first postnatal week. RGC densities in adult experimental animals were found to be reduced to about 55% of normal. RGCs of normal and operated animals were retrogradely stained with crystals of the fluorescent dye DiI, which was applied to the optic disc of flat mounted and fixed retinae. In normal rats, the somatic and the dendritic field diameters of the RGCs increased and the branching frequency of type I and III RGCs decreased from P1 to P14. By P14, neither the somatic diameter nor the dendritic field size had yet reached adult values and the branching frequencies were still higher than those of adult rat RGCs.In animals with bilateral lesions of the tectum, all cell types showed an increase in somatic sizes, and in type I and II RGCs an expansion of dendritic territories could be observed. The branching frequencies, however, were significantly lower than those of normal rats of the same age. The dendritic morphology in type III RGCs in operated animals was not significantly different from controls.These findings demonstrate a potential plasticity of type I and II RGCs, which respond to a loss of neighbouring cells by expansion of their dendritic field during postnatal development.
Immunoreactivity to GABAA receptor in the outer plexiform layer of the cat retina
Authors: Vardi Noga , Masarachia Patricia , Sterling Peter 
Published: January 2005

AbstractThe distribution of GABAA receptor in the outer plexiform layer of cat retina was studied by immunocytochemistry with monoclonal antibodies. Staining was observed at the base of the cone pedicle, extracellularly, in association with the “triad” synaptic complex. Some bipolar dendrites and the basal processes that interconnect the cone pedicles were also stained. Rod spherules and horizontal cells were negative. The findings support the idea that the cone horizontal cells are GABAergic.
Heterogeneity of layer II neurons in human entorhinal cortex
Authors: Beall Melissa J. , Lewis David A. 
Published: January 2005

AbstractAbnormalities in the layer II neurons of human entorhinal cortex have been implicated in the pathophysiology of Alzheimer's disease and schizophrenia. The reported abnormalities are not homogeneously distributed throughout the entorhinal cortex, suggesting that layer II of entorhinal cortex may contain different subpopulations of neurons, each with a different susceptibility to pathological mechanisms. In order to investigate the possible heterogeneity of neurons in layer II of human entorhinal cortex, we first identified distinct subdivisions of human entorhinal cortex by adapting the cytoarchitectonic criteria for subdivisions of monkey entorhinal cortex described by Amaral et al. (J Comp Neurol 264:326, 1987). The morphology and regional distribution of distinct subpopulations of human layer II neurons were determined through the use of immunohistochemical techniques. Multipolar, stellate, and modified pyramidal neurons in the characteristic cell clusters or islands of layer II were immunoreactive for nonphosphorylated neurofilament proteins. The intensity of immunoreactivity for the nonphosphorylated neurofilament proteins gradually increased along the rostrocaudal axis of entorhinal cortex and was primarily due to a similar gradient in the density of labeled neurons per island. The calcium‐binding protein calbindin D‐28K was found in both pyramidal and nonpyramidal neurons in layers II and superficial III. The distribution of calbindin‐immunoreactive neurons also depended upon the region of entorhinal cortex. In rostral entorhinal cortex, labeled neurons were scattered throughout the superficial layers, whereas in caudal entorhinal cortex, distinctive patches of small calbindin‐immunoreactive neurons were found among the layer II islands. Another calcium‐binding protein, parvalbumin, was present in nonpyramidal neurons in layers II and III that were distinct from those containing calbindin. The regional distribution of parvalbumin‐positive neurons was very similar to that of the neurofilament immunoreactive neurons; in rostral entorhinal cortex very few parvalbumin‐labeled neurons were present but their frequency gradually increased in the caudal direction. In addition, punctate parvalbumin immunoreactivity was frequently encountered in the location of the nonphosphorylated neurofilament protein‐positive layer II islands. These findings demonstrate that layer II of human entorhinal cortex contains distinct subpopulations of neurons, that the relative density of each subpopulation differs across cytoarchitectonic regions, and that the patterns of distribution of these subpopulations are in some cases similar and in other cases complementary. This heterogeneity in the organization of layer II of human entorhinal cortex has important implications for the study of some neuropsychiatric disorders. © 1992 Wiley‐Liss, Inc.
Two classes of vesicles are present and change in relative proportion during post‐embryonic development of rectifying electrical synapses in the crayfish
Authors: Leitch B. , Heitler W. J. , Pitman R. M. , Cobb J. L. S. 
Published: January 2005

AbstractThe size and shape of vesicles at junctional appositions of the rectifying electrical synapses between the medial giant fibre and motor giant neurone of the crayfish were measured during the first 2 months after hatching. Summed data over this period reveal a bimodal distribution in vesicle diameter.From the day of hatching until about 7 days of age, small vesicles (circa 25 nm diameter) predominate. From day 7 onwards, larger vesicles (circa 55 nm diameter) occur in increasing numbers, until at day 56 they constitute about 85% of the population at any one junctional apposition. At intermediate ages (day 7–28) individual junctional appositions may show the same bimodal distribution in size as does the age group as a whole, indicating that large and small vesicles occur together at the same junction. The larger vesicles are mainly circular, while the small vesicles are pleomorphic, with shapes ranging from almost circular down to a shape factor of about 0.6. © 1992 Wiley‐Liss, Inc.
Connections from the lateral vestibular nucleus to the upper cervical spinal cord of the cat: A study with the anterograde tracer PHA‐L
Authors: Rose P. K. , Wainwright K. , Neuber‐Hess M. 
Published: January 2005

AbstractThe projections of neurons in the lateral vestibular nucleus (LVN) to the upper cervical spinal cord of the cat were investigated by means of the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA‐L). At the junction of C1 and C2, axons were distributed bilaterally in the ventromedial funiculi, and ipsilaterally in the ventrolateral and lateral funiculi. The majority of boutons were found ipsilateral to the injection sites and most of these boutons were found at the base of the ventral horn and throughout the medial two‐thirds of lamina VIII. A more modest termination zone was found along the ventral border of lamina VII and a small number of boutons were scattered in the dorsal horn. Contralateral termination zones were similar to the ipsilateral projections.There were significant changes in the distribution of vestibulospinal axons and density of boutons at the junction of C3 and C4. At this level, most vestibulospinal axons travelled ipsilaterally and were found along the medial border of the ventromedial funiculus and the ventral margin of the ventrolateral funiculus. The overall distribution of boutons near the border of C3 and C4 was similar to the pattern seen at the junction of C1 and C2. However, bouton density fell by a factor of three. Large zones of the grey matter were devoid of boutons in individual experiments.These results demonstrate that the projections of neurons in the LVN to the upper cervical spinal cord are densest in the regions containing motoneurons supplying suboccipital muscles. This result suggests that monosynaptic connections to those motoneurons may be an important part of the neural circuitry responsible for vestibulocollic reflexes. However, the large number of boutons found in regions dorsal to motoneuron nuclei in all upper cervical segments indicates that the primary path from vestibulospinal axons to neck motoneurons may be indirect and involve relays via spinal interneurons. © 1992 Wiley‐Liss, Inc.
Sex differences in densities of dopaminergic fibers and GABAergic neurons in the prenatal rat striatum
Authors: Ovtscharoff W. , Eusterschulte B. , Zienecker R. , Reisert I. , Pilgrim C. 
Published: January 2005

AbstractOn the basis of observations on dopaminergic neurons developing in gender‐specific cultures of embryonic rat mesencephalon, we have hypothesized that as yet unknown sexual dimorphisms might be found in projection areas of dopaminergic neurons. Therefore we searched for possible sex differences in the striatum during the period when massive ingrowth of mesencephalic afferents occurs and the striatal gamma‐aminobutyric acid (GABA)ergic neurons differentiate.Male and female rats of embryonic days (E) 16, 18, 20, and 21 were fixed by perfusion through the heart. Vibratome sections were cut from the striatal anlage and sequentially immuno stained for GABA by the immunogold‐silver technique and tyrosine hydroxylase (TH) by the avidin‐biotin‐peroxidase method. Ultrathin sections were scanned for numbers of GABA‐ and TH‐immunoreactive (IR) elements.Densities of TH‐IR axons as well as of GABA‐IR cell body profiles progressed with time. Contacts between TH‐IR axons and GABA‐IR and immunonegative cells were observed as early as E‐16, increasing in numbers toward later stages. Throughout prenatal development, female striata displayed higher densities of both TH‐TR axon and GABA‐TR cell body profiles than male ones.This is the first report of a distinct anatomical sex difference regarding two major components of a key center of motor control. Prenatal sexual differentiation of the striatum may lead to a sexually dimorphic extrapyramidal circuitry, the existence of which, in the adult, is suggested by experimental and clinical data. © 1992 Wiley‐Liss, Inc.
Expression of cholecystokinin and somatostatin genes in the human thalamus
Authors: Burgunder J.‐M. , Young W. S. 
Published: January 2005

AbstractThe cholecystokinin (CCK) gene is expressed in thalamocortical and thalamostriatal neurons of the rat. In the cat, this peptide is found in some intralaminar and midline nuclei, whereas somatostatin (SRIF) is expressed in the reticular nucleus of the cat but not in rat. Since the putative neurotransmitters used by thalamic neurons are still incompletely known, especially in humans, we investigated the expression of the CCK and SRIF genes in the human thalamus by using hybridization histochemistry.CCK mRNA was found in many neurons, located in several nuclei of the dorsal thalamus. They were especially numerous and widespread in the nuclei associated with the internal thalamic lamina. They formed a continuum in the basal medial thalamus, from the central‐medial nucleus, through the centre median/parafascicular complex to the limitans and suprageniculate nuclei. In addition, neurons with CCK mRNA were found medially and laterally to the mediodorsal nucleus, in the midline and intralaminar nuclei. Only rare neurons with CCK mRNA were found in other nuclei (e.g., in the ventral group of nuclei). SRIF mRNA was found in many neurons of the reticular nucleus, but not in the dorsal thalamus.Neurochemical features of the human thalamus, for the genes studied here, resemble those found in the cat. SRIF may play a role in modulating dorsal thalamic impulses, which may be conveyed through CCK innervation to the striatum and, partly, to the cortex.
Immunohistochemical localization of ryanodine binding proteins in the central nervous system of gymnotiform fish
Authors: Zupanc Günther K. H. , Airey Judith A. , Maler Leonard , Sutko John L. , Ellisman Mark H. 
Published: January 2005

AbstractThe ryanodine receptor, an integral membrane protein of the sarcoplasmic reticulum in muscle, embodies a high conductance channel permeable to calcium ions. Recent studies have identified ryanodine‐binding proteins in avian and mammalian central nervous systems. These neuronal ryanodine receptors appear to function as Ca2− channels which may gate the release of Ca2+ from caffeine‐sensitive intracellular pools in neurons.In the present investigation, we employed monoclonal antibodies against ryanodine‐binding proteins of avian muscle cells to the brain of weakly electric gymnotiform fish. Immunoprecipitation and Western blot analysis revealed two isoforms in the fish brain, with molecular weights comparable to those of avian and fish muscle ryanodine‐binding proteins. By employing immunohistochemical techniques, we mapped these proteins in fish brain.Ryanodine receptor‐like immunoreactivity was found in nerve cell bodies as well as dendrites and axonal processes. The ryanodine‐binding protein is distributed throughout the neuraxis in specific cell types of the gymnotiform brain. In the telencephalon, immunoreactive cells were found in the glomerular layer of the olfactory bulb, in the supracommissural subdivision of the ventral telencephalon, and in the intermediate rostral subdivision of the ventral telencephalon. In the diencephalon, immunoreactive cells or fibers were observed in the nucleus prethalamicus and the habenula, within the nucleus at the base of the optic tract and the adjacent dorsal tegmental nucleus, the pretectal nuclei A and B, and the nucleus electrosensorius. In addition, immunopositive cells were seen in several nuclei of the hypothalamus, with the inferior and lateral subdivision of the nucleus recessus lateralis displaying the highest concentration of neurons. In the mesencephalon, the optic tectum contained the greatest number of immunopositive cells. In the rhombencephalon, labelling was seen in the nucleus of the lateral valvula, central gray, lateral tegmental nucleus, in boundary cells of the nucleus praeminentialis, efferent octavolateral nucleus, an area adjacent to the medial edge of the lateral reticular nucleus, nucleus medialis, and electrosensory lateral line lobe. As in avian brain, cerebellar Purkinje cells were positive for ryanodine‐binding protein, although only subsets of Purkinje cells were labelled. © 1992 Wiley‐Liss, Inc.
Transient expression of GABA immunoreactivity in the developing rat spinal cord
Authors: Ma Wu , Behar Toby , Barker Jeffery L. 
Published: January 2005

AbstractThe development of GABAergic neurons in the spinal cord of the rat has been investigated by immunocytochemical staining of frozen sections with anti‐γ‐aminobutyric acid (GABA) antiserum. In the cervical cord, GABA‐immunoreactive fibers first appeared at embryonic day (E) 13 in the presumptive white matter within the ventral commissure, ventral funiculus, and dorsal root entrance zone, and in the ventral roots. There were no GABA‐immunoreactive cell bodies detected at this age. By E14, motoneurons, the earliest generated spinal cells, were the first cell population to become GABA‐immunoreactive at the cell body level. Thereafter, GABA‐immunoreactive neurons increased progressively in number and extended from ventral to dorsal regions. GABA‐immunoreactive relay neurons within lamina I of the dorsal horn were initially detected at E17. Interneurons in the substantia gelatinosa, the latest generated cells in the spinal cord, were also the last to express the GABA immunoreactivity at E18. Immunoreactive neurons peaked in intensity and extent at E18 and 19. GABA immunoreactivity was only detectable in neurons within the intermediate and marginal zones 1–3 days after they withdrew from the cell cycle. This contrasts to glutamate decarboxylase immunoreactivity, which is detected in precursor cells in the ventricular zone prior to, or during, withdrawal from the cell cycle. Toward the end of gestation, GABA immunoreactivity declined in intensity and extent. This regression began in the ventral horn of the cervical region and ended in the dorsal horn of the lumbosacral region. During the first week after birth, immunoreactivity in motoneurons and in many other neurons within the ventral horn, intermediate gray, and deeper layers of the dorsal horn disappeared, and only in those neurons predominantly within the superficial layers of the dorsal horn did it persist into adulthood. Thus, the expression and regression of GABA immunoreactivity in the spinal cord followed ventral‐to‐dorsal, rostral‐to‐caudal, and medial‐to‐lateral gradients. These observations indicate that the majority of embryonic spinal neurons pass through a stage of transient expression of GABA immunoreactivity. The functional significance of this transient expression is unknown, but it coincides with the period of intense neurite growth of motoneurons, sensory neurons, and interneurons, and of neuromuscular junction formation, suggesting that the transient presence of GABA may play an important role in the differentiation of sensorimotor neuronal circuits. © 1992 Wiley‐Liss, Inc.