bluuebunny/crossref_metadata_2025_split huggingface dataset:
GABAergic projection from the intercalated cell masses of the amygdala to the basal forebrain in cats
Authors: Paré D. , Smith Y. 
Published: January 2005

AbstractThe intercalated cell masses (ICMs) are dense clusters of small GABAergic cells interposed between the basolateral and centromedial nucles groups of the amygdala. Until now, the ICMs have been largely ignored in anatomical studies of the amygdaloid complex. Thus, this study was undertaken to ientify some of their targets by means of tract‐tracing methods combined with immunohistochemical teniques.Wheat‐germ agglutinin conjegated to horseradish peroxidase (WGA‐HRP) was injected into numerous cortical areas and dorsal thalamic nuclei, in the anterior commissure and/or stria terminalis nuclei, and in the caudate nucleus, as wel as into latera and preoptic hypothalamic areas. Very few retrogradely labeled cells were seen in the ICMs following these injections. In contrast, massive retrograde labeling was found in the rostral groups of ICMs after WGA‐HRP injections involving the substantia innominata and horizontal limb of the diagonal band. Furthermore, these retrogradely labeled intercalated cells were also GABA immunoreactive. Results of iontophoretic injections of Phaseolus vulgaris‐leucoagglutinin (PHA‐L) in the rostral ICMs confirmed that they contribute a massive projection to the entire extent of the substance innominata and horizontal limb of the diagonal band. Electron microscopic observations of ultrathin sections prepared for postembedding GABA or glutamate immunocytochemistry revealed that the ICM terminals labeled with PHA‐L displayed GABA, but not glutamate immunoreactivity, and formed symmetric synapses with dendritic profiles.The present findings constitue the first direct demonstration of an amygdalofgal GABAergic projection to the basal forebrain. Considering that the basal forebrain contains a group of cholinergic and GABAergic neurons collectively projecting to the entire cortical mantle, this GABAergic projection of the ICMs could allow the amygdaloid complex to influence the activity of widespread cortical regions to which it is not directly connected, at least in the cat. © 1994 Wiley‐Liss, Inc.
Dopamine in the lobster Homarus gammarus. I. Comparative analysis of dopamine and tyrosine hydroxylase immunoreactivites in the nervous system of the juvenile
Authors: Cournil Isabelle , Helluy Simone M. , Beltz Barbara S. 
Published: January 2005

AbstractAs a catecholamine, depamine belogs to a class of molecules that have multiple transmitter and hhormonal functions in vertebrate and invertebrate nervous systems. However, in the lobster, where many central beurons have been identified and the peripheral innervation pattern is well known, the distribution of dopamine‐containing neurons has not been examined in detail. Therefore, immunocytochemical methods were used to identify neurons likey to contain dopamine and tyrosine hydroxylase in the central nervous system of the juvenile lobster Homarus gammarus.Approximately 100 neuronal somata stain for the catecholamine and/or its synthetic enzyme in the brain and ventral nerve cord. The systems of neurons labeled with dopamine and tyrosine hydroxylase natibodies have the following characteristic: (1) the two systems are nearly identical; (2) every segmental ganglion contains at least one pair of labeled neurons; (3)the positions and numbers of cell bodies labeled with each antiserum are similar in the various segmental ganglia; (4) six labeled neurons are anatomically identified; two interneurons from the brain project within the ventral cord to reach the last abdominal ganglion, two neurons from the commissural ganglia are presumably neurosecretory neurons, and two anterior unpaired medial abdominal neurons project to the hindgut muscles; and (5) nocell bodies are labeled in the stomatogastric ganglion, but fibers and terminals in the neuropil are stained. The remarkably small numbers of labeled neurons and the presence of very large labeled somata with far‐reaching projections are distinctive features consistent with other modulatory aminergic systems in both vertebrates and invertebrates. © 1994 Wiley‐Liss, Inc.
Evidence for prenatal competition among Ahe central arbors of trigeminal primary afferent neurons: Single axon analysis
Authors: Chiaia Nicolas L. , Zhang Shujie , King Tod D. , Rhoades Robert W. 
Published: January 2005

AbstractPrevious studies from this laboratory have demonstrated that prenatal damage to vibrissae follicles results in significant increases in the brainstem representations of the remaining vibrissae as demonstrated by staining for the mitochondrial enzyme cytochrome oxidase (CO). Because CO is primarily a postsynaptic marker, these results do not directly address the question of whether there were changes in the projections of primary afferent fibers. To address this issue, we made intra‐axonal recordings from individual vibrissa‐related primary afferents in rats that sustained damage to vibrissae follicles oil embryonic day 17, and then injected horseradish peroxidase (HRP) into these axons to visualize their terminal arbors in the brainstem at the level of trigeminal subnucleus interpolaris (SpI). All vibrissae‐related primary afferents responded to deflection of one and only one vibrissa, and the terminal arbors of axons (N = 47) recovered from animals that sustained fetal peripheral lesions were significantly larger than those (N = 23) from normal rats. Fibers from fetally damaged animals had increased total fiber lengths and numbers of branch points. These results indicate that reduced competition among primary afferent axons results in increases in the terminal arbors that remain. These increases occur without any significant alteration in their peripheral receptive fields. © 1994 Wiley‐Liss, Inc.
Programmed cell death during the earliest stages of spinal cord development in the chick embryo: A possible means of early phenotypic selection
Authors: Homma Shunsaku , Yaginuma Hiroyuki , Oppenheim Ronald W. 
Published: January 2005

AbstractThe spatiotemporal distribution of cell death in the chick embryo neural tube and spinal cord (brachial region) was examined between stage (St.) 12 and 22, in plastic semithin sections. Between St. 12 and 16, the total number of pycnotic cells per segment was low, whereas after St. 16 the number of pycnotil cells was substantially increased. Between St. 17 and 19 three cell death foci or regions could be recognized. One region, the dorsal pycnotic zone, was located in the most dorsal part of the spinal cord, including the neural crest, with the highest number of pycnotic cells observed at St. 18. The second region, or ventral pyenotic zone, was located between motoneurons and the floor plate and had the highest number of dying cells at St. 17. The third region, the floor plate pycnotic zone, was located in the midportion of the floor plate and had the greatest amount of cell death at St. 19. Although low numbers of pycnotic cells were also observed in other regions between St. 17 and 19, no pycnotic cells were found in the ventrolateral region that gives rise to motoneurons. Ultrastructural observations as well as data from in situ nick end labeling indicate that the pycnotic cells observed in the neural tube die by apoptosis and that the debris from the dead cells is phagocytized primarily by adjacent healthy neuroepithelial cells.Although the spatiotem poral distribution of pycnotic cells suggests that cell death at these early stages could play a role in establishing the pioneer axonal pathway for spinal commissural neurons, preliminary observations following perturbations of cell death do not support this notion. Alternatively, early cell death may be involved in the regulation of cellular patterning along the dorsoventral axis of the neural tube by a kind of negative selection of specific progenitor cells. © 1994 Wiley‐Liss, Inc.
Homogeneity of intracellular electrophysiological properties in different neuronal subtypes in medial preoptic slices containing the sexually dimorphic nucleus of the rat
Authors: Hoffman Neil W. , Kim Yang I. , Gorski Roger A. , Dude F. Edward 
Published: January 2005

AbstractThe sexually dimorphic nucleus of the preoptic area (SDN‐POA) is larger in male than in female rats, the male phenotype requiring the presence of circulating androgens perinatally. These experiments investigated the intracellular electrophysiology and morphology of SDN‐POA neurons and compared these properties with those of other medial preoptic area (MPOA) neurons. Biocytin‐injected cells in the SDN‐POA either had one or two primary dendrites, or they had multipolar dendritic arrays; dendrites were aspiny or sparsely spiny and displayed limited branching. Neurons in other parts of the MPOA were similar morphologically. Regardless of morphology, neurons situated in either the SDN‐POA or surrounding MPOA had low‐threshold potentials and linear or nearly linear current‐voltage relations. In most (73%) cells, stimulation of the dorsal preoptic region evoked a fast excitatory postsynaptic potential followed by a fast inhibitory postsynaptic potential (IPSP). Bicuculline blocked the fast IPSPs, which reversed near the Cl2 equilibrium potential (‐71 ± 5mV), indicating their mediation by gamma‐aminobutyric acid (GABA)A receptors.Neurons in the SDN‐POA have electrophysiological properties similar to those of other medial preoptic cells. When compared with the hypothalamic paraventricular nucleus, the MPOA appears relatively homogeneous electrophysiologically. This is despite the morphological variability within this population of neurons and heterogeneities that are also apparent at other levels of analysis. Finally, GABA‐mediated, inhibitory synaptic contacts are widespread among medial preoptic neurons, consistent with indications from earlier reports that GABA provides a link in the feedback actions of gonadal steroids on the release of gonadotropic hormones. © 1994 Wiley‐Liss, Inc.
Motor neurons in onuf's nucleus and its rat homologues express the p75 nerve growth factor receptor: Sexual dimorphism and regulation by axotomy
Authors: Koliatsos Vassilis E. , Price Donald L. , Clatterbuck Richard E. 
Published: January 2005

AbstractThe present study establishes that populations of neurons in the lumbosacral cord, which innervate pelvic striated muscles, express p75NGFR throughout their life spans. These neuronal groups comprise the Onuf's nucleus in humans and its principal rat homologues, dorsolateral (DL) and dorsomedial (DM) nuclei, as well as the cremasteric (CRE) nucleus. The p75NGFR in these neurons is localized in the rough endoplasmic reticulum, Golgi complex, and lysosomes. Almost all neurons that project to striated perineal muscles in the male rat express p75NGFR; very low levels of p75NGFR are detected in neurons that innervate perineal sphincters of the female. In the female rat, p75NGFR expression is masculinized with perinatal androgen treatment. In addition, the expression of p75NGFR in DM and DL neurons in the adult is up‐regulated by injury (i. e., pudendal axotomy) but is not influenced by gonadectomy. The results of this study establish that neurons of Onuf s nucleus and its rat homologues differ from general somatic motor neurons in that they express p75NGFR from early postnatal life (i. e., when all motor neurons express p75NGFR) into the adult (when the former, but not the latter, express the receptor). In view of growing evidence for the role of neurotrophins in the physiology of motor neurons, the above differentiating feature between general somatic and sexually dimorphic motor neurons suggests that p75NGFR may be involved in motor neuron plasticity and may participate in mechanisms by which neurons can protect themselves from degenerative insults. © 1994 Wiley‐Liss, Inc.
A physiological and structural study of neuron types in the cochlear nucleus. I. Intracellular responses to acoustic stimulation and current injection
Authors: Feng Jane J. , Kuwada Shigeyuki , Ostapoff E.‐Michael , Batra Ranjan , Morest D. Kent 
Published: January 2005

AbstractNeurons in the cochlear nucleus differ in their discharge patterns when stimulated by tones. They also differ in their responses to depolarizing current injection in vitro. We made intracellular recordings from neurons in the cochlear nucleus of gerbils and chinchillas. The responses to tones and to depolarizing current were compared for the same neurons. Three categories of response patterns to tones were observed: chopper, primary‐like, and onset. Chopper neurons responded with regularly spaced action potentials to stimulation with tones and to injections of depolarizing current. Their response rate rose with increasing levels of current to a maximum, which was comparable to that evoked by suprathreshold tones. These observations suggest that the regularity and maximal firing rate of these neurons are determined by voltage‐dependent membrane properties. Primary‐like neurons responded with irregularly spaced action potentials to tones. Injection of depolarizing current into these neurons produced a single action potential at current onset, which could be followed by a few irregularly spaced action potentials. The response rate showed little relation to current level. These suggest that the membrane characteristics of primary‐like neurons are different from those of chopper neurons. Onset neurons produced action potentials only at the beginning of the stimulus for both tones and depolarizing current, even though there was a sustained depolarization throughout the duration of the tone. The findings suggest that cochlear nucleus neurons have different membrane properties and that these properties may play a critical role in a neuron's temporal response pattern to acoustic stimulation. © 1994 Wiley‐Liss, Inc.
Innervation of footpads of normal and mutant mice lacking sweat glands
Authors: Rao M. S. , Jaszczak E. , Landis S. C. 
Published: January 2005

AbstractFootpads of normal adult mice are innervated by sympathetic and sensory fibers. The sympathetic fibers associated with sweat glands contain acetylcholinesterase and immunoreactivity for vasoactive intestinal peptide. Although catecholamine histofluorescence is absent, the gland innervation exhibits immunoreactivity for tyrosine hydroxylase. A distinct population of sympathetic fibers, which possess catecholamines and neuropeptide Y as well as tyrosinehydroxylase immunoreactivity, innervates blood vessels. Sensory fibers containing immunoreactivity for substance P and calcitonin gene‐related peptide course beneath the epidermis and some form endings in it. Treatment of neonatal mice with the adrenergic neurotoxin, 6‐hydroxydopamine, results in loss of sympathetic innervation of sweat glands and blood vessels, permits growth of sensory axons into sweat glands, but does not alter the peptidergic sensory innervation of the dermis and epidermis. Three mouse mutations, Tabby (Ta), crinkled (cr), and downless (dl), disrupt the interactions between the mesenchyme and epidermis that are required for normal development of specific epidermal derivatives, including sweat glands. The sympathetic innervation of blood vessels and sensory innervation of footpad skin of the three mutant mice that lack sweat glands is indistinguishable from normal. The sympathetic fibers that normally innervate sweat glands, however, are not present. These results indicate that in the absence of their normal target, the sympathetic fibers that innervate sweat glands are lacking. Furthermore, they suggest that, although sensory fibers may sprout into sympathetic targets in the footpad, the domains occupied by sensory fibers are not normally accessible to sympathetic axons. © 1994 Wiley‐Liss, Inc.
Preoptic projections to Barringon's nucleus and the pericoerulear region: Architecture and terminal organization
Authors: Rizvi Tilat A. , Ennis Matthew , Aston‐Jones Gary , Jiang Maorong , Liu Wei‐Lin , Behbehani Michael M. , Shipley Michael T. 
Published: January 2005

AbstractThe medial preoptic area (MPO), a sexually dimorphic region, plays a pivotal role in neuroendocrine function and reproductive behavior. We recently reported that MPO projects heavily to the midbrain periaqueductal gray (PAG). We also noted that MPO projects to the dorsolateral pontine tegmentum. Here we identified the cells of origin of the MPO→tegmental projection and delineated the terminal organization of MPO projections to Barrington's nucleus, locus coeruleus (LC), and the rostromedial pericoerulear region (pLCrm). Correlative cyto‐ and chemoarchitectonic studies were done to define better the nuclear groups of the dorsolateral pontine tegmentum.Retrograde tracing revealed that MPO neurons projecting to the dorsolateral pontine tegmentum are preferentially distributed in distinct subregions of MPO, including the sexually dimorphic medial preoptic nucleus (MPN). Anterograde tracing with wheat germ agglutininhorseradish peroxidase or Phaseolus vulgaris leucoagglutinin demonstrated considerable target specificity in projections from MPO to the dorsolateral pontine tegmentum. Barrington's nucleus receives a dense focal input along its entire rostrocaudal axis. In addition, pLCrm is heavily targeted by MPO inputs; pLCrm contains a concentrated plexus of extranuclear dendrites of LC neurons. The lateral dorsal tegmental (LDT) nucleus and LC proper receive only sparse input from MPO.MPO projections to Barrington's nucleus could regulate micturition reflexes during reproductive behavior. The MPO→pLCrm projection could influence noradrenergic LC neurons in relation to reproductive and/or gonadal steroid function. Given the strong established connections from olfactory structures to MPO, it is possible that the MPO→LC pathway provides an anatomical substrate for olfactory modulation of arousal. © 1994 Wiley‐Liss, Inc.
Ontogeny and effect of activity on proenkephalin mRNA expression during development of the chick spinal cord
Authors: Garner L. K. , Mendelson B. , Albers K. M. , Kindy M. , Overbeck T. L. , David B. M. 
Published: January 2005

AbstractNumerous studies have shown in the adult nervous system that mRNA expression can be regulated by neuronal activity. To examine the effect of activity during embryogenesis, the ontogeny of proenkephalin mRNA expression and expression following activity blockade was investigated during development of chick spinal cord. A cDNA fragment (ca. 0.5 kb) coding for chick proenkephalin was cloned and sequenced. With this cDNA, a cRNA probe was made to examine proenkephalin mRNA expression in the spinal cord during embryogenesis. Proenkephalin mRNA was expressed in spinal cord in clusters of cells located in the developing dorsal horn and intermediate lamina at the earliest stages examined (stage 22; E4). Proenkephalin‐positive cells in the intermediate lamina were located immediately adjacent to the ventricular zone. At stage 28 (E6) an additional cluster of proenkephalin mRNA‐positive cells was seen at the lateral border of the developing intermediate lamina. At stage 33 (E7. 5–8) the pattern of hybridization positive cells was similar to earlier stages, but individual cells could be identified. At stage 39 (E13) densely labeled cells were seen throughout the dorsal horn and intermediate laminae including the column of Terni. To determine whether neural activity affects proenkephalin mRNA expression, d‐tubocurarine (an inhibitor of neural activity) was injected into developing embryos. Following administration of d‐tubocurarine a dramatic decrease was seen in proenkephalin mRNA hybridization in the dorsal horn and intermediate lamina of the spinal cord. This study demonstrates in vivo that changes in the level of neural activity can alter gene expression during embryogenesis and suggests that activity is required for expression of nervous system‐lspecific genes. © 1994 Wiley‐Liss, Inc.
Distribution of corticospinal motor neurons in the postnatal rat: Quantitative evidence for massive collateral elimination and modest cell death
Authors: Oudega Martin , Varon Silvio , Hagg Theo 
Published: January 2005

AbstractThe postnatal development of rat corticospinal motor neurons (CSMN) was studied by retrograde tracing with cholera toxin B subunit (CTB) injected into the upper cervical dorsal spinal cord on the first postnatal day (P0), P3, P10, P20, and at adulthood. CTB‐labeled neurons were visualized by immunocytochemistry and extensively quantified throughout the cortex. At P0, CSMN were found to an extent similar to that reported in P3 animals with other neuronal tracers, now permitting in vitro studies of neonatal CSMN. Between P0 and P3, the number of labeled neurons increased by 30% to a total maximum of approximately 185,000 in both cortices. The increase occurred throughout the cortex. At P10, the number of labeled CSMN had decreased to 60% of the number at P3. Fewer CSMN were evident particularly in the perirhinal cortex. Between P10 and P20, the number of CSMN decreased further to 52% of the maximal number at P3. This decrease occurred predominantly in the cingulate and parietal cortex. The number of labeled CSMN in rats injected at P0 and analyzed at P20 was 10% lower than the number in P0‐injected littermates that were analyzed at P3, which suggests that only a small portion of the “disappearing” CSMN undergoes developmental neuronal death. Thus, the spinal projection of the remaining 38% is apparently eliminated between P3 and P20. Detailed quantitative analysis of the CSMN distribution demonstrated that neuronal death occurs predominantly in the perirhinal cortex. In contrast, axonal elimination of corticospinal projections occurred throughout the CSMN field, i. e., primarily in the frontal, occipital, and perirhinal cortex between P3–P10 and in the cingulate and parietal cortex between P10–P20. © 1994 Wiley‐Liss, Inc.
Extrasynaptic localization of taurine‐like immunoreactivity in the lamprey spinal cord
Authors: Shupliakov Oleg , Brodin Lennart , Srinivasan Meera , Grillner Sten , Cullheim Staffan , Storm‐Mathisen Jon , Ottersen Ole Petter 
Published: January 2005

AbstractTaurine is an endogenous amino acid that can occur in nerve terminals in the central nervous system and that can produce inhibitory neuronal responses. It is unclear, however, whether this amino acid can function as a synaptic transmitter. To examine the distribution of taurine at high anatomical resolution in a vertebrate, light and electron microscopic immunocytochemical postembedding techniques were applied to the lamprey spinal cord (Ichtyomyzon unicuspis and Lampetra fluviatilis), which contains many large, unmyelinated axons. The most intense immunolabeling occurred in a population of liquor‐contacting cells (tanycytes), located around the central canal, which extended processes to the dorsal, lateral, and ventral margins of the spinal cord. In addition, a proportion of the taurine‐immunoreactive cells contained gamma‐aminobutyric acid (GABA)‐like immunoreactivity. A moderate level of taurine immunoreactivity was also present in ependymal cells, located around the central canal, as well as in astrocytes throughout all regions of the spinal cord. At the ultrastructural level, the taurine immunoreactivity showed an even distribution in the cytoplasm of the labeled cells. In contrast to the glial labeling, neuronal cell bodies and axons exhibited very low levels of taurine labeling, which were similar to the level of background labeling. The synaptic vesicle clusters within the axons did not show any clear accumulation of taurine immunoreactivity.These results suggest that taurine may have metabolic roles in the lamprey spinal cord, and, as in other systems, it may take part in osmoregulation. However, the lack of immunolabeling in presynaptic elements is not consistent with a role of taurine as a synaptic transmitter. © 1994 Wiley‐Liss, Inc.