bluuebunny/crossref_metadata_2025_split huggingface dataset:
GABA‐immunoreactive neurons in the nematode Ascaris
Authors: Guastella John , Johnson Carl D. , Stretton Antony O. W. 
Published: January 2005

Abstractγ‐Aminobutyric acid (GABA) immunoreactive neurons in the cephalic, somatic, and caudal regions of the Ascaris nervous system were visualized with serial section and whole‐mount GABA immunocytochemistry. In the ventral and dorsal nerve cords, GABA‐ like immunoreactivity (GLIR) is localized to the neurites and cell bodies of identified inhibitory motor neurons and to two fibers, one in each cord, that arise from neurons in the nerve ring. GLIR is absent from identified excitatory motor neurons and from ventral cord interneurons. In neurons containing GLIR, immunoreactivity was present throughout the cell, which argues against an exclusive localization of GABA at conventional synapses.In whole mounts, ten GABA‐immunoreactive neurons were present in the cephalic region. These include four nerve ring‐associated cells (the RME‐like cells), two bilaterally symmetrical pairs of lateral ganglia neurons (the amphid‐GABA and deirid‐GABA cells) and one bilaterally symmetrical pair of ventral ganglion cells (the VG‐GABA cells). In sections, the RME‐like cells and the VG‐GABA cells were consistently stained through the cephalic region. However, anti‐GABA staining of the lateral ganglia cells in sections was light, thus suggesting that they contain less GLIR than the other more intensely stained GABA‐immunoreactive neurons. In the caudal region, a single GABA‐immunoreactive neuron was present in the dorsal rectal ganglion. Our data suggest that these ten cephalic neurons, and a single dorsal rectal ganglion neuron, use GABA as a neurotransmitter.
Parabrachial nucleus projection towards the hypothalamic supraoptic nucleus: Electrophysiological and anatomical observations in the rat
Authors: Jhamandas Jack H. , Harris Kim H. , Krukoff Teresa L. 
Published: January 2005

AbstractIt has been proposed that the pontine parabrachial nucleus (PBN) participates in the regulation of body fluid balance and the release of vasopressin from the neurohypophysis, although the pathways mediating the latter response are uncertain. This study in the rat, utilizing anatomical and electrophysiological methods, describes a projection from the lateral PBN towards the hypothalamic supraoptic nucleus (SON). Rats received iontophoretic injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA‐L, 2% solution). After 14–17 days, rats were sacrificed and their brains prepared for immunofluorescent visualization of projections to the SON region. PHA‐L‐labelled terminals were found primarily in perinuclear regions immediately dorsal to the SON. In contrast, injections within the medial PBN and the nearby Kölliker‐Fuse nucleus did not reveal labelling in or around the SON. Extracellular recordings from 86 of 118 antidromically identified neurons in anaesthetized rats revealed a set of complex synaptic responses after stimulation in the PBN. Excitatory responses (in 82 of 86 cells) of short (< 100 msec, 39/82 cells) and long (> 100 msec, 43/82) duration were observed in both vasopressin‐ and oxytocin‐secreting cells of the SON, while 4/86 cells displayed a depressant response to PBN stimulation. In the adjacent perinuclear zone, 22/39 nonneurosecretory cells responded with an increase in their excitability consequent to an identical stimulus. These data suggest a predominantly facilitatory influence of lateral PBN neurons on SON neurosecretory cells in the rat, and that the PBN‐SON projection is an indirect one that utilizes an interneuronal network located in the perinuclear zone adjacent to the SON.
From embryo to adult: Anatomy and development of a leg sensory organ in Phormia regina meigen (Insecta: Diptera). I. Anatomy and physiology of a larval “Leg” sensory organ
Authors: Lakes‐Harlan R. , Pollack G. S. , Merritt D. J. 
Published: January 2005

AbstractNeurons within the precursor of the adult leg, the imaginal disc, innervate a larval sense organ, Keilin's organ. Electron microscopical investigations of first instar larvae show that five dendrites end at the organ: three insert at the bases of the three hairs of the organ and two end against the cuticle, without any apparent cuticular specialization. In third instar larvae, the imaginal leg discs invaginate into the body cavity, and only four of the dendrites (the outer segments of which become greatly elongated) remain in contact with Keilin's organ. The axons of the neurons that supply Keilin's organ project into a ventral neuropile region of the central nervous system, with a pattern that resembles the projections of other larval sensilla. Electrical activity can be recorded from neurons of the imaginal disc in response to mechanical stimulation.
Unmyelinated axons of the auditory nerve in cats
Authors: Ryugo D. K. , Dodds L. W. , Benson T. E. , Kiang N. Y. S. 
Published: January 2005

AbstractThis paper describes some central terminations of type II spiral ganglion neurons as labeled by extracellular injections of horseradish peroxidase (HRP) into the auditory nerve of cats. After histological processing with diaminobenzidine, both thick (2–4 μm) and thin (0.5 μm) fibers of the auditory nerve were stained. Whenever traced, thick fibers always originated from type I spiral ganglion neurons and thin fibers always from type II ganglion neurons. Because the labeling of type II axons faded as fibers projected into the cochlear nucleus, this report is limited to regions of the ventral cochlear nucleus near the auditory nerve root. The central axons of type II neurons are unmyelinated, have simple yet variable branching patterns in the cochlear nucleus, and form both en passant and terminal swellings. Under the light microscope, most swellings are located in the neuropil but they are also found in the vicinity of cell bodies, nodes of Ranvier of type I axons, and blood vessels. Eighteen en passant swellings in the neuropil were located by light microscopy and resectioned for electron microscopy; two of these swellings exhibited ultrastructural features characteristic of chemical synapses. The data indicate that inputs from outer hair cells might be able to influence auditory processing in the cochlear nucleus through type II primary neurons.
Different postnatal development profiles of neurons containing distinct GABAA receptor β subunit mRNAs (β1, β2, and β3) in the rat forebrain
Authors: Zhang Jian‐Hua , Sato Makoto , Tohyama Masaya 
Published: January 2005

AbstractThe expression of three β subunit (β1, β2, and β3) mRNAs for γ‐aminobutyric acidA receptor in the postnatal rat forebrain was examined by in situ hybridization h istochemistry with probes synthesized for the respective subunit mRNAs. The developmental expression of these subunit mRNAs conformed to one of three patterns. Pattern I was high expression of the mRNA at birth and a constant or increasing expression thereafter. In contrast, pattern II was no or very low expression of the mRNA at birth, with expression quickly increasing to reach the adult level in the early postnatal period. Pattern III was the transient expression of the subunit mRNA or else a marked decrease of its expression after a peak in the early postnatal period.On the basis of this classification, the expression of β3 subunit mRNA followed pattern I in most regions of the forebrain, such as the isocortex, the olfactory bulb and some of its related areas, the hippocampal formation, the amygdala, the septum, the bed nucleus of the stria terminalis, the caudate‐putamen, the nucleus accumbens, the globus pallidus, the ventral pallidum, and the hypothalamus. In some areas, such as the magnocellular preoptic nucleus, the thalamus, and the subthalamic nucleus, pattern III was seen for this subunit. However, none of the regions of the brain showed pattern II expression of β3 subunit mRNA. In contrast, the expression of β1 and β2 subunit mRNAs followed pattern II in most regions of the forebrain. These included the expression of β1 subunit mRNA in the isocortex, the olfactory bulb, the hippocampal formation, the amygdala, the septum, the bed nucleus of the stria terminalis, the thalamus, and the hypothalamus, and the expression of β2 subunit mRNA in the isocortex, the olfactory bulb and some of its related areas, the amygdala, the nucleus of the diagonal band, the caudate‐putamen, the thalamus, and the hyothalamus. Pattern I was not found for β1 subunit mRNA, although it was seen in some areas for β2 subunit mRNA, such as the ventral pallidum, the globus pallidus, and the magnocellular preoptic nucleus. On the other hand, pattern III was followed by β1 subunit mRNA in the anterior olfactory nucleus, the olfactory tubercle, and the piriform cortex, and the same pattern for the β2 subunit was also found in the olfactory tubercle, the hippocampal formation, the septum, the bed nucleus of the stria terminalis, and the nucleus accumbens.These results indicate that all three β subunit mRNAs are under developmental regulation, and that the different mRNAs are differentially regulated in various regions of the forebrain. In addition, the present study also showed that β3 subunit mRNA is highly expressed in both the neonatal and adult stages, indicating an important role for this subunit in brain development.
Identification of a retinal protein in Drosophila with antibody to the α subunit of bovine brain Go protein
Authors: Garen‐Fazio Suzanne , Neer Eva J. , Schmidt Carl J. 
Published: January 2005

AbstractAn antibody directed against the αo subunit of bovine brain Go (R4) was used to identify a Drosophila retinal protein which may be the analogue of vertebrate transducin. The immunoreactivity appears predominantly in the retinal and occellar rhabdomeres. On a Western blot, the antibody recognizes a 41 kDa protein that is present in the heads of yellow white flies, but not in the heads of eyeless mutant flies, eyes absent. This protein is not recognized by an antibody raised against Drosophila αo.Antibody R4 intensely stains rhabdomeres and, to a lesser extent, the neuropil of the central nervous system in tissue sections of adult flies. Antibody to Drosophila αo stains the neuropil of the central nervous system, but does not stain rhabdomeres. In developing flies, faint immunoreactivity appears in the retinal rhabdomeres at about 70% of the time through pupal development and increases to its apparent adult maximal level about 1 day after eclosion. Tissue sections from a phototransduction mutant, norp A, have retinal immunoreactivity at normal levels up to about 1 week after eclosion, but by 2 weeks, immunoreactivity has largely disappeared. This disappearance parallels the degeneration of the retina in norp A mutants.In Drosophila and other invertebrates, light activates a phospholipase C in the retina. The identification of a protein in Drosophila rhabdomeres with an antibody raised against a mammalian G protein α subunit thought to be involved in phospholipase C activation suggests that there may be common structural features between the putative Drosophila transducin and α0, The identification of regions common to mammalian α0 and Drosophila transducin may then provide clues to the structural requirements for PLC activation.
Postnatal development of thalamic recipient neurons in the monkey striate cortex: Somatic inhibitory synapse acquisition by spiny stellate neurons of layer 4C
Authors: Lund Jennifer S. , Harper Thomas R. 
Published: January 2005

AbstractThe development of type 2 (Colonnier,1981) synapses on the cell bodies of thalamic recipient spiny stellate neurons in layers 4C alpha and 4C beta of primary visual cortex neurons was examined over the first 36 postnatal weeks and in the adult monkey. The type 2 synapses, known to be GABAergic (Ribak, 1978) and therefore presumed to be inhibitory, developed faster on the alpha neurons than the beta neurons. Both neuron groups show a marked increase and then decline in the percentage of the somatic membrane covered by type 2 synaptic appositions during this 36‐week time period. The time course of the type 2 synapses development is compared to that of the spine synapse development described in previous studies (Lund and Holbach, 1991; Lund et al., 1991), and it is clear that on both neuron groups this inhibitory synapse population is put in place and refined later than the spine synapses. These findings suggest that each cortical neural circuit has a unique time course for its early development within an overall time window (Rakic et al., 1986), or sensitive period (Hubel and Wiesel, 1970). Visual deprivation, although causing the alpha and beta neurons to adopt a more similar temporal and numerical developmental pattern than normal, did not prevent acquisition and loss phases of type 2 synapses or the assumption of a normal numerical loading by 36 weeks of age.
Neurogenesis in the brain auditory pathway of a marsupial, the northern native cat (dasyurus hallucatus)
Authors: Aitkin Lindsay , Nelson John , Farrington Moyra , Swann Sue 
Published: January 2005

AbstractNeurogenesis in the auditory pathway of the marsupial Dasyurus hallucatus was studied. Intraperitoneal injections of tritiated thymidine (20–40 m̈Ci) were made into pouch‐young varying from 1 to 56 days pouch‐life. Animals were killed as adults and brain sections were prepared for autoradiography and counterstained with a Nissl stain.Neurons in the ventral cochlear nucleus were generated prior to 3 days pouch‐life, in the superior olive at 5–7 days, and in the dorsal cochlear nucleus over a prolonged period. Inferior collicular neurogenesis lagged behind that in the medial geniculate, the latter taking place between days 3 and 9 and the former between days 7 and 22. Neurogenesis began in the auditory cortex on day 9 and was completed by about day 42. Thus neurogenesis was complete in the medullary auditory nuclei before that in the midbrain commenced, and in the medial geniculate before that in the auditory cortex commenced.The time course of neurogenesis in the auditory pathway of the native cat was very similar to that in another marsupial, the brushtail possum. For both, neurogenesis occurred earlier than in eutherian mammals of a similar size but was more protracted.
Position‐ and fibre type‐dependent selectivity by regenerating motor axons in reformation of the topographical projection to the glutaeus muscle in the adult toad (bufo marinus)
Authors: Brown David R. , Everett Alan W. 
Published: January 2005

AbstractThe toad glutaeus magnus muscle receives a topographical innervation dependent on the rostrocaudal origins of glutaeus motor axons on the spinal cord. The same projection is re‐established in adult animals after cutting the glutaeus muscle nerve and allowing regenerating axons to reinnervate the muscle (Brown and Everett (1990) J. Comp. Neurol. 292:363–372). To determine whether the topographically selective reinnervation of the glutaeus muscle comes about because of genuine positional qualities associated with the pre‐ and post‐synaptic tissues, we undertook two different experimental procedures: first, the nerve supply to the muscle was cut and redirected to ensure that regenerating axons entered the muscle via entirely novel pathways; and second, the triceps femoris nerve was cut so that the glutaeus muscle was reinnervated from a large pool of motor axons which were mostly foreign but segmentally appropriate. The motor projection to the muscle was determined by the glycogen depletion procedure; single glutaeus motor axons were repetitively stimulated in vitro to deplete muscle fibres of their stores of glycogen. The spatial location of fibres belonging to single motor units could then be determined by staining sections of the muscle histochemically for glycogen. A similar to normal projection was re‐established after both experiments in that rostrally located motor axons innervated mostly the ventral portion of the muscle and caudal axons mostly the dorsal portion of the muscle. “Intermediate” axons synapsed predominantly with fibres in the middle of the muscle. Furthermore, the arrangement of fibre types in the muscle could not fully account for the reformation of the topographical projection by a type matching mechanism, although a secondary role for fibre types in the subsequent refinement of the projection was clearly suggested by our findings. Our results provide evidence for a distinction between at least two determinants that influence the reinnervation of muscle: positional cues and fibre types, with the former taking precedence over the latter.
Glycinergic interplexiform cells make synaptic contact with amacrine cell bodies in goldfish retina
Authors: Yazulla Stephen , Studholme Keith M. 
Published: January 2005

AbstractRecent works utilizing glycine‐immunoreactivity (IR) and combined Golgi impregnation and 3H‐glycine uptake autoradiography indicate that glycinergic interplexiform cells (IPC) may synapse upon cell bodies in the inner nuclear and ganglion cell layers in fish retina. This possibility was investigated with immunocytochemical techniques using presynaptic and postsynaptic markers for glycinergic neurons: a monoclonal antibody (mAb 7A) against the 93 kDa subunit of the strychnine‐sensitive glycine receptor and a polyclonal antiserum against a glycine/BSA conjugate. Synaptic contacts onto the lateral and proximal surfaces of amacrine cell bodies and onto the distal surface of cells in the ganglion cell layer were identified with both probes. The contacts were rare with one contacted amacrine cell/section of 500 linear μm. Serial 1‐μm sections were processed alternately for glycine and GABA antisera using postembedding techniques at the light microscopic level. Glycine‐IR processes + boutons were apposed to GABA‐IR cell bodies in 16 of 17 examples, indicating that the dendro‐somatic contacts were onto GABA‐immunoreactive amacrine cell bodies. In context of other published morphological data, we suggest that the dendro‐somatic synapses were derived from glycinergic IPCs. Glycinergic IPCs receive input from GABAergic horizontal cells and, via a shunt conductance produced by the dendro‐somatic contacts, may be involved in controlling the sensitivity, temporal, or spatial properties of amacrine cell responses to large field illuminatio.
Immunohistochemical localization of calretinin in the rat hindbrain
Authors: Arai Ryohachi , Winsky Lois , Arai Mari , Jacobowitz David M. 
Published: January 2005

AbstractThe localization of calretinin in the rat hindbrain was examined immunohistochemically with an antiserum against calretinin purified from the guinea pig brain. Calretinin immunoreactivity was found within neuronal elements. The distribution of calretinin‐immunoreactive cell bodies and fibers is presented in schematic drawings and summarized in a table. Major calretinin immunoreactive neurons were found in the lateral and medial geniculate nuclei, substantia nigra, ventral tegmental area, interpeduncular nucleus, periaqueductal gray, mesencephalic trigeminal nucleus, superior and inferior colliculi, pontine nuclei, parabrachial nucleus, dorsal and laterodorsal tegmental nuclei, cochlear nuclei, vestibular nuclei, medullary reticular nuclei, nucleus of the solitary tract, area postrema, substantia gelatinosa of the spinal trigeminal nucleus, and cerebellum. These results show that distinct calretinin‐immunoreactive neurons are widely distributed in the rat hindbrai.
Synaptic organization of cortico‐cortical connections from the primary visual cortex to the posteromedial lateral suprasylvian visual area in the cat
Authors: Lowenstein Pedro R. , Somogyi Peter 
Published: January 2005

AbstractThe synaptic organization of the projection from the cat striate visual cortex to the posteromedial lateral suprasylvian cortical area (PMLS) was examined. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA‐L) was iontophoretically delivered into area 17, and anterogradely labeled fibers were revealed in PMLS by means of an immunocytochemical detection method. Most axons and presumptive terminal swellings were found in layers III and IV. The neuronal elements (n = 190) that were postsynaptic to anterogradely labeled boutons were quantitatively analyzed. All anterogradely labeled cortico‐cortical boutons (n = 182) established type 1 synapses. The results show that 83% of the postsynaptic targets were dendritic spines, probably belonging to pyramidal cells. Dendritic shafts constituted 17% of the targets. The dendritic shafts postsynaptic to cortico‐cortical boutons were studied for the presence of gamma‐aminobutyric acid (GABA) with a postembedding immunogold method. Most dendritic shafts (85%) that were tested were found to be GABA‐positive, demonstrating that they originate from local inhibitory neurons. Taking into account that most postsynaptic targets were spines and extending the results of the immunocytochemical testing to the total population of postsynaptic dendrites, it was calculated that at least 14% of targets originated from GABA‐positive cell.Thus cortico‐cortical axons establish direct monosynaptic connections mainly with pyramidal and to a lesser extent with GABAergic nonpyramidal neurons in area PMLS, providing both feedforward excitation and feedforward inhibition to a visual associational area known to be involved in the processing of motion information. The results are consistent with previously demonstrated deficits in physiological properties of neurons in PMLS following removal of cortico‐cortical afferent.
Electron‐microscopic analysis of synaptic input from the perigeniculate nucleus to the A‐laminae of the lateral geniculate nucleus in cats
Authors: Cucchiaro Josephine B. , Uhlrich Daniel J. , Sherman S. Murray 
Published: January 2005

AbstractThe perigeniculate nucleus of carnivores is thought to be a part of the thalamic reticular nucleus related to visual centers of the thalamus. Physiological studies show that perigeniculate neurons, which are primarily GABAergic, provide feedback inhibition onto neurons in the lateral geniculate nucleus. However, little is known about the anatomical organization of this feedback pathway. To address this, we used two complementary tracing methods to label perigeniculate axons for electron microscopic study in the geniculate A‐laminae: intracellular injection of horseradish peroxidase (HRP) to fill an individual perigeniculate cell and its axon; and anterograde transport of Phaseolus vulgaris leucoagglutinin to label a population of perigeniculate axons. Labeled perigeniculate terminals display features of F1 terminals in the geniculate neuropil: they are small, contain dark mitochondria, and form symmetric synaptic contacts. We found that most of the perigeniculate terminals (> 90%) contact geniculate cell dendrites in regions that also receive a rich innervation from terminals deriving from visual cortex (e.g., “cortico‐recipient” dendrites). The remainder of the perigeniculate synapses (10%) contacted dendrites in regions that also received direct retinal input (e.g., “retino‐recipient” dendrites). Serial reconstruction of segments of dendrites postsynaptic to perigeniculate terminals suggests that these terminals contact both classes of relay cell in the A‐laminae (X and Y), although our preliminary conclusion is that an individual perigeniculate cell contacts only one class. Finally, our quantitative comparison between labeled perigeniculate terminals and unlabeled Fl terminals indicates that these perigeniculate terminals form a distinct subset of Fl terminals. We quantitatively compared the labeled perigeniculate terminals to unlabeled F1 terminals. Although the parameters of the perigeniculate terminals fell entirely within the range of those for the unlabeled F1 terminals, as populations, we found consistent differences between these two groups. We thus conclude that, as populations, other sources of F1 terminals are morphologically distinct from perigeniculate terminals and innervate different target.