bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuropeptide‐immunoreactive neurons projecting to the paraventricular hypothalamic nucleus in the rat
Authors: Moga Margaret M. , Saper Clifford B.
Published: January 2005

The paraventricular nucleus of the hypothalamus (PVH) is innervated by a variety of types of neuropeptide‐immunoreactive fibers. The cells of origin for many of these inputs are not known. In the present study, the combined retrograde fluorescence–immunofluorescence method was used to determine the cells of origin for neurotensin‐, corticotropin‐releasing factor‐, brain natriuretic peptide‐, somatostatin‐, and met‐enkephalin‐like immunoreactive (‐ir) fibers in the PVH. After injections of the fluorescent tracer Fluorogold into the PVH, the pattern of retrograde labeling was as previously reported (Sawchenko and Swanson, 1983, J. Comp. Neurol. 218:121–144; McKellar and Loewy, 1981, Brain Res. 217:351–357). The distribution of each type of double‐labeled neuron was unique. Retrogradely labeled enkephalin‐ir neurons were concentrated in two locations: the ventral part of the lateral septal nucleus and the lateral anterior nucleus within the AHA. A small cluster of corticotropin‐releasing factor‐ir neurons in the ventral lateral subnucleus of the bed nucleus of the stria terminalis were retrogradely labeled. Notable concentrations of somatostatin‐ir double‐labeled neurons were found in the ventral part of the lateral hypothalamic area and the medial part of the arcudte hypothalamic nucleus. Neurotensin‐ir double‐labeled neurons were most numerous in the anteroventral periventricular nucleus and in the retrochiasmatic area. Many brain natiuretic peptide‐ir neurons in the tuberomammillary nucleus of the hypothalamus and in the pedunculopontine and laterodorsal tegmental nuclei were retrogradely labeled. The specificity of these chemically defined projections helps lay the groundwork for examining the functional organization of PVH afferents. © 1994 Wiley‐Liss, Inc.
Growth of central nervous system auditory and visual nuclei in the postnatal gerbil (Meriones unguiculatus)
Authors: Rübsamen R. , Gutowski M. , Langkau J. , Dörrscheidt G. J.
Published: January 2005

The objective of the present study was, by using the Mongolian gerbil (Meriones unguiculatus) as an animal model, to provide data on the growth dynamics of central auditory and visual nuclei and to relate the growth of these structures to the growth of the entire brain. So far, no such systematic study has been performed in any mammalian species. The knowledge of the rates of development of central nervous sensory structures might be useful for understanding the contribution of the central nervous system to maturation of sensory processing.

Increases in volumes of nuclei and changes in their shape were analyzed for animals at the day of birth (P0); at postnatal days P7, P15, P22, P28; and in the third month (P90). The auditory nuclei investigated were the cochlear nucleus, the superior olivary complex, the nuclei of the lateral lemniscus, the inferior colliculus, and the medial geniculate body. From the visual system, the superior colliculus and the lateral geniculate body were studied.

At P15 (shortly after the onset of central auditory responsiveness), the volumes of all auditory nuclei examined reached only 60–70% of their adult sizes; i.e., they showed considerable growth afterwards. At the same time (shortly before the animals open their eyes), the visual nuclei had almost reached their adult sizes (superior colliculus, 91%; lateral geniculate nucleus, 97%).

These data demonstrate that different sensory nuclei contribute in highly different fashions to brain growth. There are system‐specific differences in growth dynamics between central auditory and visual nuclei. However, the absolute growth of nuclei in both sensory systems relates to the brain regions. The data do not support the idea of a peripheral‐to‐central gradient in the growth of central auditory nuclei. © 1994 Wiley‐Liss, Inc.
Brainstem network controlling descending drive to phrenic motoneurons in rat
Authors: Dobbins Elizabeth G. , Feldman Jack L.
Published: January 2005

Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second‐order) neurons projecting to phrenic motoneurons and propriobulbar (third‐order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Bötzinger complex. An intervening region, the pre‐Bötzinger complex, contained essentially no phrenic premotoneu rons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kölliker‐Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical, spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third‐order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Bötzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kölliker‐Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second‐ and third‐order neurons form the output network for diaphragm motor control which includes numerous behaviors (e. g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons. © 1994 Wiley‐Liss, Inc.
Distribution of histamine‐, 5‐hydroxytryptamine‐, and tyrosine hydroxylase‐immunoreactive neurons and nerve fibers in developing rat brain
Authors: Vanhala Anu , Yamatodani Atsushi , Panula Pertti
Published: January 2005

Although the general patterns of the developing histaminergic system in the rat brain are known, no comparative studies between the development of the brain histaminergic system and the development of other neuroactive substances have yet been published. Interestingly, separate immunohistochemical studies on the development of the 5‐HT system and on the catecholaminergic system in the rat imply common features in the different aminergic systems. Therefore, the spatial distribution of histamine‐immunoreactive (HA‐ir) neurons and nerve fibers was compared to the distribution of 5‐hydroxytryptamine (5‐HT)‐, and tyrosine hydroxylase‐immunoreactive (TH‐ir) ones in the developing rat brain between embryonic days 12, (E12) and 20 (E20) by using a double‐immunostaining method. The high‐pressure liquid chromatography (HPLC) fluorometric method was used for determination of histamine concentration in different brain regions during the same period of development and synthetic oligonucleotide probes complementary to the rat histidine decarboxylase (HDC) to determine the origin of HA in the brain during the development with in situ hybridization. The immunohistoch6mical results revealed co‐localization of HA and 5‐HT within a subgroup of cells in the developing raphe nuclei between E14 and E18. From E18 onwards HA immunoreactivity started to gradually disappear from the rhombencephalon, and was totally abolished by E20, while 5‐HT‐ir cells continued to establish their adult positions. No significant colocalization of RA and TH immunoreactivities was detected. The biochemical results were in agreement with the immunohistochemical ones and confirmed that histamine detected in the early developing brain is authentic. A positive in situ hybridization signal for HDC was detected in a small area in the ventrolateral pons in the same areas as HA‐ and HDC‐ir cell bodies at E16, suggesting that at least some HA may be synthesized locally. These results confirm that HA is one of the first neurotransmitters to appear in the developing brain. In addition, the transient co‐localization of HA and 5‐HT immunoreactivities and the transient HDC expression at E16 within the developing pontine raphe nuclei may imply an interesting and a more general role for HA in modification of brain development. © 1994 Wiley‐Liss, Inc.
Serotonin‐immunoreactive neurons and endogenous serotonin in the opisthosomal ventral nerve cord of the horseshoe crab, Limulus polyphemus
Authors: Washington Benny , Higgins Denise E. , McAdory Brenda , Newkirk Robert F.
Published: January 2005

It has been suggested that serotonin serves as a neurotransmitter in the horseshoe crab, Limulus polyphemus. While some studies of identified groups of central neurons have been conducted, little is known concerning the neuronal organization in Limulus central ganglia. This study was undertaken to determine the localization of serotoninergic neurons in the opisthosomal ventral nerve cord of Limulus and to construct a basis for further comparative biochemical and pharmacological studies of the specific function of these neurons. Endogenous serotonin was, detected in the ventral nerve cord (chain of abdominal ganglia) by high performance liquid chromatography and electrochemical detection (HPLC‐EC). Endogenous serotonin was quantified in the 9th through 13th ganglia, anterior (hemal) nerves, posterior (branchial) nerves, and connectives. The serotonin content in the abdominal ganglia was significantly reduced when the ganglia were incubated for 24 hours in Leibovitz's (L‐15) medium containing reserpine or 5, 7‐dihydroxytryptamine (5, 7‐DHT), neurotoxins that block the uptake of serotonin into storage vesicles. The distribution of serotonin‐immunoreactive neurons in the ventral nerve cord was determined by indirect immunocytochemistry. Treatment of the chain of ganglia with an anti‐serotonin antiserum followed by treatment with a fluorescent‐labeled antiserum raised against the primary antibody demonstrated specific staining in each, ganglion, the ganglionic roots, and connectives. Clusters of serotonin immunoreactive neurons were observed anteriolaterally and posteriorly in each ganglion. Processes from dense fiber bundles extended from these clusters of neurons to the central region of each ganglion. These results demonstrate that serotonin‐immunoreactive neurons are present in the opisthosomal ventral nerve cord of the horseshoe crab and that serotonin may function as a neurotransmitter. © 1994 Wiley‐Liss, Inc.
Effect of altered neuronal activity on cell size in the medial nucleus of the trapezoid body and ventral cochlear nucleus of the gerbil
Authors: Pasic Thomas R. , Moore David R. , Rubel Edwin W.
Published: January 2005

Activity‐dependent transneuronal regulation of neuronal soma size has been studied in the medial nucleus of the trapezoid body and ventral cochlear nucleus of adolescent gerbils. Cochlear ablation or tetrodotoxin has been used to eliminate afferent electrical activity in auditory nerve fibers permanently or for 24 or 48 hours. Previous studies have shown that the cross‐sectional area of spherical cell somata in the ipsilateral anteroventral cochlear nucleus decreases within 24 hours of electrical activity blockade with tetrodotoxin, which is fully reversible when activity is restored. The present findings extend this work by directly comparing the results of unilateral blockade of auditory nerve action potentials or unilateral cochlear ablation on the size of spherical and globular cell bodies in the ventral cochlear nucleus with changes produced by the same manipulations in third‐order cells, principal neurons in the medial nucleus of the trapezoid body. Soma size in both ventral cochlear nucleus cell types decreases reliably by 24 hours after cochlear removal or eighth nerve activity blockade by tetrodotoxin. Soma size of neurons in the contralateral medial nucleus of the trapezoid body decreases 48 hours, but not 24 hours, after either manipulation. When activity in auditory nerve fibers is allowed to resume for 7 days following a 48‐hour activity blockade, soma size fully recovers in the medial nucleus of the trapezoid body as well as in ventral cochlear nucleus neurons. We also report that the cross‐sectional area of neuronal soma in the medial nucleus of the trapezoid body is larger in lateral regions of medial nucleus of the trapezoid body (low‐frequency representation) than in the medial regions of the nucleus (high‐frequency representation). We conclude that cell body size changes in brainstem auditory neurons are reversible and that the signals associated with the loss and subsequent recovery of soma size are activity related. However, the delayed effect of activity deprivation in the medial nucleus of the trapezoid body suggests that trophic substances released by afferent axons may contribute to the maintenance of anatomical characteristics. © 1994 Wiley‐Liss, Inc.
Connectivity of the lobus parolfactorius of the domestic chicken (Gallus domesticus): An anterograde and retrograde pathway tracing study
Authors: Székely Andrea D. , Boxer Margaret I. , Stewart Michael G. , Csillag András
Published: January 2005

In 1–week‐old domestic chicks, the connectivity of the lobus parolfactorius (LPO), part of the avian basal ganglia, was investigated using Phaseolus vulgaris leucoagglutinin and horseradish peroxidase for anterograde and retrograde pathway tracing, respectively. Tyrosine hydroxylase immunocytochemistry was applied in combination with Phaseolus lectin to assess the overlap between LPO efferents and diencephalic and meseticephalic catecholamine centres. Anterograde projections from LPO were detected in the hyperstriatum, neostriatum, and paleostriatum. Intranuclear connections were also apparent within the LPO. Descending LPO efferents innervated the lateral mammillary and intramedial nuclei and the dorsomedial thalamic complex. Fibres from LPO were observed in the tectal gray, substantia nigra, area ventralis tegmentalis of Tsai, and the adjacent nucleus mesencephalicus profundus. Further caudally, projections from LPO reached the nucleus papillioformis, locus coeruleus, and subcoeruleus ventralis. LPO efferents were coextensive with tyrosine hydroxylase‐positive cells in the nuclei mamillaris lateralis and intramedialis of the hypothalamus, area ventralis tegmentalis, substantia nigra, locus coeruleus, and subcoeruleus ventralis of mesencephalic and pontine tegmentum. Close contacts between LPO fibres and catecholamine cells were visible in the nigra and the area ventralis tegmentalis. Retrograde labelling from LPO was found in the archistriatum, dorsomedial thalamic complex, nuclei lateralis anterior and superficialis parvicellularis thalami, substantia nigra, central gray, area ventralis tegmentalis of Tsai, and locus coeruleus and in cells dorsal to the decussation of brachium conjunctivum. Reciprocal connections were verified between the LPO and the following areas: dorsomedial thalamic complex, central gray, substantia nigra, area ventralis of Tsai, and locus coeruleus. © 1994 Wiley‐Liss, Inc.
GABAergic projection from the basal forebrain to the visual sector of the thalamic reticular nucleus in the cat
Authors: Bickford M. E. , Günlük A. E. , van Horn S. C. , Sherman S. M.
Published: January 2005

We examined the projection from the basal forebrain to thalamic and cortical regions of the visual system in cats, with particular reference to the visual sector of the thalamic reticular nucleus, the lateral geniculate nucleus, and the striate cortex. First, we made injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP) into the visual sector of the thalamic reticular nucleus and found cells labeled by retrograde transport in the lateral nucleus basalis magnocellularis. Injection of biocytin into the basal forebrain resulted in the anterograde labeling of a dense band of fibers and terminals within the entire thalamic reticular nucleus; this labeling extended through the visual sector including the perigeniculate nucleus. No orthograde labeling was found in the lateral geniculate nucleus. Next, we addressed the issue of putative neurotransmitters used by this pathway using a variety of immunocytochemical and histochemical markers. In this fashion, we identified two populations of cells in the nucleus basalis magnocellularis of the cat: large cholinergic cells that contain choline acetyltransferase, NADPH‐diaphorase, and calbindin and that project to striate cortex and smaller cells that contain gamma‐aminobutyric acid (GABA), glutamic acid decarboxylase, and parvalbumin and that project to the visual sector of the thalamic reticular nucleus. We also examined at the electron microscopic level terminals in the visual sector of the thalamic reticular nucleus that were labeled from a biocytin injection in the basal forebrain. Most of these terminals form symmetric contacts onto dendrites and were revealed by postembedding immunocytochemical staining to be positive for GABA. © 1994 Wiley‐Liss, Inc.
Developmental plasticity of reticulospinal and vestibulospinal axons in the north american opossum, Didelphis virginiana
Authors: Wang X. M. , Qin Y. Q. , Xu X. M. , Martin G. F.
Published: January 2005

We have shown previously that rubral axons grow around a lesion of their spinal pathway in the North American opossum if it is made at early stages of development. In the present experiments, we have asked whether reticular and vestibular axons have the same ability. The spinal cord was hemisected at postnatal day 20, 12, or 5, well within the critical period for rubrospinal plasticity, and, approximately 30 days later, bilateral injections of fast blue were made about four segments caudal to the lesion. The pups were killed 4 or 5 days after the injections. In most of the animals lesioned on postnatal day 20, labeled neurons were not found in the medial part of the pontine reticular nucleus or the dorsal part of the lateral vestibular nucleus ipsilateral to the lesion. The spinal projections from both areas are exclusively ipsilateral. When the lesions were made at postnatal day 12 or 5, however, labeled neurons were present in both areas, suggesting that they supported axons that had grown caudal to the lesion. As was expected from previous studies, rubral neurons were labeled contralateral to the lesion in all three groups. In the opossum, as in other species, the red nucleus projects contralaterally. We conclude that reticular and vestibular axons, like axons from the red nucleus, grow around a lesion of their pathway during development and that the critical period for their plasticity ends earlier than that for rubrospinal axons. © 1994 Wiley‐Liss, Inc.
Glial domains and axonal reordering in the chiasmatic region of the developing ferret
Authors: Reese B. E. , Maynard T. M. , Hocking D. R.
Published: January 2005

This study has examined the developing glial architecture of the optic pathway and has related this to the changing organization of the constituent axons. Immunocytochemistry was used to reveal the distribution of glial profiles, and DiI was used to label either radial glial profiles or optic axons. Electron microscopy was used to determine the distribution of glial profiles, axons, growth cones, and wrists at different locations along the pathway.

Three different glial boundaries were defined: Two of these are revealed as changes in the distribution of vimentin‐immunoreactive profiles occurring in the prechiasmatic optic nerve and at the threshold of the optic tract, respectively, and one by the presence of glial fibrillary acidic protein (GFAP)‐immunoreactive profiles at the chiasmatic midline. The latter, midline boundary may be related to the segregation of nasal from temporal optic axons. The boundary at the threshold of the optic tract coincides with the segregation of dorsal from ventral optic axons that emerges at this location in the pathway. The segregation of old from young optic axons is shown to occur only gradually along the pathway. Glial profiles are most frequent in the deeper parts of the tract, coursing parallel to the optic axons and orthogonal to their usual radial axis. These are suggested to arise from later‐growing radial glial fibers that are diverted to grow amongst the older optic axons. Those glial profiles may subsequently impede axonal invasion, thus creating the chronotopic reordering by forcing the later‐arriving axons to accumulate superficially. © 1994 Wiley‐Liss, Inc.
Colocalization of prosomatostatin‐derived peptides in the caudate‐putamen of the rat
Authors: Rushlow W. , Naus C. C. G. , Flumerfelt B. A.
Published: January 2005

In the striatum of rat, somatostatin 14, somatostatin 28, and somatostatin 28 (1–12) have previously been localized within a small population of medium aspiny local circuit neurons. Because all three peptide fragments are generated through the cleavage of prosomatostatin by different converting enzymes, the possibility for differential expression of these peptides exists. In order to investigate this possibility, frozen sections were collected from the brains of adult female Wistar rats fixed with 4% paraformaldehyde and double labelled using immunocytochemistry and in situ hybridization. Sections were first processed for somatostatin 14, somatostatin 28, or somatostatin 28(1–12) by using the avidin‐biotin complex immunocytochemical technique followed by in situ hybridization using 35S‐labelled antisense riboprobes to somatostatin mRNA. The results of such analysis revealed that somatostatin 28 and somatostatin mRNA are 100% colocalized. Somatostatin 14 and somatostatin 28(1–12), in contrast, are only present within 66% of the neurons that express somatostatin mRNA. Examination of the anatomical distribution of neurons that express both somatostatin mRNA and somatostatin 14 or somatostatin 28(1–12) protein reveals that these neurons are present throughout the caudate‐putamen of rat but are more prevalent in the ventromedial regions. Neurons that express somatostatin mRNA but not somatostatin 14 or somatostatin 28(1–12) are also present throughout the caudate‐putamen but are most numerous within a dorsolateral strip just beneath the corpus callosum. These results suggest that the somatostatin neuron population within the rat caudate‐putamen is actually composed of two smaller subpopulations based on neuropeptide content. The first subpopulation contains somatostatin 28 and constitutes one‐third of the total somatostatin population, whereas the other contains somatostatin 28, somatostatin 14, and somatostatin 28(1–12) and represents the remaining two‐thirds of the cells that express somatostatin mRNA. © 1994 Wiley‐Liss, Inc.
Ipsi‐ and contralateral commissural growth cones react differently to the cellular environment of the ventral zebrafish spinal cord
Authors: Bernhardt Robert R.
Published: January 2005

Early commissural axons in the zebrafish spinal cord extend along a pathway consisting of a ventrally directed ipsilateral, a contralateral diagonal, and a contralateral longitudinal segment. The midline floor plate cell is one important cue at the transition from the ipsilateral to the contralateral pathway segments. In order to identify additional guidance cues, the interactions between commissural growth cones and their substrates were examined at the electron microscopic level in the different pathway segments. The growth cones extended near the superficial margin of the spinal cord, within filopodial reach of three bilateral longitudinal axon pathways that were ignored irrespective of whether other axons were already present. Ultimately the commissural growth cones pioneered an additional independent longitudinal pathway in the dorsolateral spinal cord. Neuroepithelial cells were extensively contacted in the lateral marginal zone of the dorsal spinal cord and are thus in a position to contribute to the establishment of the longitudinal commissural pathway segment. The extent of contact with neuroepithelial cells in the ventral spinal cord was dependent on whether commissural growth cones had already crossed the ventral midline: ipsilateral, but not contralateral, growth cones showed extensive contacts with neuroepithelial processes and minor contacts with the basal lamina. In marked contrast, commissural growth cones that had already crossed the ventral midline and entered the diagonal pathway segment showed major appositions to the basal lamina. Extensive contact with the basal lamina was first established in the ventral midline region, where crossing growth cones always inserted between the basal lamina and the base of the midline floor plate cells. This indicates that a change occurs in the response characteristics of commissural growth cones as they cross the ventral midline of the spinal cord. Such a change could help to explain why the growth cones extend first toward but then away from the ventral midline. 1994 Wiley‐Liss. Inc.
Immunocytochemical localization of the β2subunit of the gamma‐aminobutyric acidAreceptor in the rat brain
Authors: Moreno Juan I. , Piva Marta A. , Miralles Celia P. , de Blas Angel L.
Published: January 2005

An antiserum to the β2subunit of the rat gamma‐aminobutyric acid (GABAA) receptor was prepared by immunizing a rabbit with a fusion protein expressed in bacteria. The fusion protein had the large, intracellular loop expanding between the putative M3 and M4 transmembrane domains of the β2subunit fused to staphylococcal protein A (SPA). The antiserum immunoprecipitated both the solubilized and the affinity‐purified GABAAreceptors. The anti‐β2antibodies were affinity purified on immobilized β2intracellular loop peptide. The antibodies recognized a 55–57 kDa peptide in immunoblots of either crude membranes from rat cerebral cortex or affinity‐purified GABAAreceptors from bovine cerebral cortex. Immunocytochemistry with the affinity‐purified antibody has revealed for the first time the localization of the β2subunit in the rat brain. A comparative study of the regional and cellular immunoreactivities of the affinity‐purified anti‐β2antibody and the monoclonal antibody 62‐3G1 (which recognizes both β2and β3subunits) is presented. The procedure described for generating and preparing specific anti‐β2subunit antibodies that are valuable for immunocytochemistry could be extended to other GABAAreceptor subunits. © 1994 Wiley‐Liss, Inc.
Two types of interneuron in the dorsal lateral geniculate nucleus of the rat: A combined NADPH diaphorase histochemical and GABA immunocytochemical study
Authors: Gabbott Paul L. A. , Bacon Sarah J.
Published: January 2005

The rationale for this study was to provide a comprehensive light microscopical description of the morphology of diaphorase‐reactive neurons and neuropil elements in the dorsal lateral geniculate nucleus (dLGN) of the rat. An additional objective was to quantitatively assess whether a subpopulation of the diaphorase‐reactive neurons, previously shown to be GABA‐immunoreactive, constitute a distinct type of local‐circuit neuron in the rat dLGN.

Diaphorase activity was localised in a population of predominantly bipolar fusiform neurons. These cells were weak to moderately stained and possessed the morphological features of intrinsic inhibitory neurons, previously called class B neurons in the rat dLGN. Quantitative estimates indicated that the diaphorase‐reactive neurons constituted approximately 10% of the total neuron composition of the dLGN. The majority (about 83%) of the diaphorase‐reactive cells were located in the lateral half of the nucleus. In addition, a dense plexus of diaphorase‐reactive varicose fibres was found throughout the dLGN lying between the oriented fibre bundles coursing dorsoventrally through the LGN.

Diaphorase‐reactive punctae were found to be closely associated with the somata and proximal dendritic segments of nonreactive neurons and also with the stained proximal dendritic segments of diaphorase‐reactive dLGN neurons. The source of the diaphorasereactive varicose fibres in the dLGN was unknown. Evidence suggests, however, that they are of extrinsic origin.

The GABA‐immunoreactive nature of the diaphorase neurons in the dLGN was demonstrated by colocalising GABA immunoreactivity within the somata of diaphorase‐reactive cells. The majority (> 90%) of diaphorase‐reactive dLGN neurons were GABA‐immunopositive. Also present was a distinct population of GABA‐immunopositive neurons that were not diaphorase‐reactive. In this study, cells that were solely GABA‐immunopositive have been called class B1neurons, while cells that were both diaphorase‐reactive and GABA‐immunoreactive have been called class B2neurons. Size‐frequency distributions of somatic profile areas established that the two populations of GABA‐immunoreactive neuron were significantly different. Class B1neurons constituted 57%, with class B2cells representing 43% of all GABA‐immunostained neurons in the rat dLGN.

The characteristic morphological features, neurochemical identity and frequency of the diaphorase‐reactive neurons in the rat dLGN indicate that they represent a subpopulation of inhibitory interneurons with the ability to affect intrinsic dLGN operations and thalamocortical interactions using the neuromodulator nitric oxide.
Distribution of β‐endorphin‐like‐immunoreactive structures in the chicken and quail brain as demonstrated with a new homologous antibody directed against a synthetic peptide
Authors: van Gils Jelle , Absil Philippe , Moons Lieve , Grauwels Luc , Vandesande Frans , Balthazart Jacques
Published: January 2005

A polyclonal rabbit antibody was raised against a synthetic peptide fragment located at the C‐terminal end of turkey β‐endorphin (β‐END) and used to analyze the distribution of β‐END‐immunoreactive‐like structures in the quail and chicken brain. Three major groups of immunopositive cells were detected in the preoptic area‐hypothalamus complex. A thin layer of immunopositive cells was parallel and adjacent to the ventral edge of the brain in the preoptic and anterior hypothalamic region, a more numerous group of immunoreactive perikarya was located along the walls of third ventricle in these same regions, and, finally, a few scattered cells were found in a more lateral position on both the internal and external sides of the tip of the fasciculus prosencephali lateralis. The periventricular cell population extended in the caudal direction unti the posterior hypothalamus. Labelled fibers were always associated with these immunoreactive perikarya, and they were also found in the adjacent hypothalamic regions. A dense innervation of the median eminence was also detected. These data are compared with previous studies in mammals and birds that had identified more restricted populations of immunoreactive cells and the possible sources of the observed discrepancy are discussed. The functional significance of the present data is also briefly analyzed.
Perirhinal and parahippocampal cortices of the macaque monkey: Cortical afferents
Authors: Suzuki Wendy L. , Amaral David G.
Published: January 2005

Neuropsychological studies have recently demonstrated that the macaque monkey perirhinal (areas 35 and 36) and parahippocampal (areas TH and TF) cortices contribute importantly to normal memory function. Unfortunately, neuroanatomical information concerning the cytoarchitectonic organization and extrinsic connectivity of these cortical regions is meager. We investigated the organization of cortical inputs to the macaque monkey perirhinal and parahippocampal cortices by placing discrete injections of the retrograde tracers fast blue, diamidino yellow, and wheat germ agglutinin conjugated to horseradish peroxidase throughout these areas. We found that the macaque monkey perirhinal and parahippocampal cortices receive different complements of cortical inputs. The major cortical inputs to the perirhinal cortex arise from the unimodal visual areas TE and rostral TEO and from area TF of the parahippocampal cortex. The perirhinal cortex also receives projections from the dysgranular and granular subdivisions of the insular cortex and from area 13 of the orbitofrontal cortex. In contrast, area TF of the parahippocampal cortex receives its strongest input from more caudal visual areas V4, TEO, and caudal TE, as well as prominent inputs from polymodal association cortices, including the retrosplenial cortex and the dorsal bank of the superior temporal sulcus. Area TF also receives projections from areas 7a and LIP of the posterior parietal lobe, insular cortex, and areas 46, 13, 45, and 9 of the frontal lobe. As with area TF, area TH receives substantial projections from the retrosplenial cortex as well as moderate projections from the dorsal bank of the superior temporal sulcus; unlike area TF, area TH receives almost no innervation from areas TE and TEO. It does, however, receive relatively strong inputs from auditory association areas TE and TEO. It does, however, receive relatively strong inputs from auditory association areas on the convexity of the superior temporal gyrus. © 1994 Wiley‐Liss, Inc.
Inhibitory axoaxonal and neuromuscular synapses in the crayfish opener muscle: Membrane definition and ultrastructure
Authors: Govind C. K. , Atwood H. L. , Pearce Joanne
Published: January 2005

The specific inhibitory motoneuron to the crayfish (Procambarus clarkii) opener muscle provides neuromuscular synapses to the muscle fibers and axoaxonal synapses to the excitatory motor nerve terminals. Freeze fracture of the membrane in both types of synapses show that the presynaptic active zone consists of clusters of large particles (putative calcium channels), which are often encircled by large depressions representing fused synaptic vesicles on the internal leaflet or P face of the presynaptic membrane. Corresponding pits and protrusions mark the external leaflet or E face of the presynaptic membrane. The postynaptic receptor‐bearing surface, characterized for neuromuscular synapses only, consists of rows of particles on both leaflets of the muscle membrane. The organization differs from that seen at excitatory synapses where particles occur only on the E‐face leaflet. Serial thin sections of nerve terminals reveal that neuromuscular synapses are significantly larger in proximal fibers than in their central counterparts and support a greater number of presynaptic dense bars (active zones). Axoaxonal synapses also show regional differences; almost three times as many occur in the proximal region compared with the central region. Most synapses possess a single dense bar. The majority of synapses formed by the inhibitory axon are neuromuscular; a minority are axoaxonal. The latter occur in various locations along the excitatory nerve terminals as well as on branches of the axon itself. This preterminal or, “off‐shore” location could act to cut off entire populations of excitatory synapses or reduce the amplitude of the preterminal action potential. © 1995 Willy‐Liss, Inc.
The efferent projections of the periaqueductal gray in the rat: A Phaseolus vulgaris‐leucoagglutinin study. II. Descending projections
Authors: Cameron Adrian A. , Khan Iqbal A. , Westlund Karin N. , Willis William D.
Published: January 2005

The descending projections of the periaqueductal gray (PAG) have been studied in the rat using the anterograde tracer Phaseolus vulgaris‐leucoagglutinin. The tracer was injected into the dorsolateral or ventrolateral subdivisions of the PAG at rostral or caudal sites. It was found that the patterns of the descending projections of the rostral and caudal parts of the dorsolateral PAG were the same and that the patterns of the descending projections of the rostral and caudal parts of the ventrolateral PAG were the same. However, the patterns of projections of the dorsolateral and ventrolateral PAG subregions were substantially different. These results suggest that the dorsolateral and ventrolateral parts of the PAG are organized into longitudinal columns that extend throughout the length of the PAG. The axons of PAG neurons descended through the pons and medulla via two routes. A small fiber bundle was present in the periaqueductal gray and in the periventricular area. This bundle distributed fibers and terminals locally within the periaqueductal gray and in the locus coeruleus and Barrington's nucleus. A larger bundle had a diffuse arrangement in the pontine reticular formation, however, and it had a more restricted distribution in the medulla, where it occupied a position dorsolateral to the pyramid. This bundle supplied structures in the pontine and medullary tegmentum. The dorsolateral column preferentially supplied the locus coeruleus, subcoeruleus, the gigantocellular nucleus pars alpha, the rostral part of the paragigantocellular nucleus, and the region of the A5 noradrenergic cell group. The ventrolateral column preferentially supplied the nucleus raphe magnus, the caudal part of the lateral paragigantocellular nucleus, and the rostroventrolateral reticular nucleus. © 1995 Willy‐Liss, Inc.
Phaseolus vulgaris –leucoagglutinin tracing of commissural fibers to the rat dentate gyrus: Evidence for a previously unknown commissural projection to the outer molecular layer
Authors: Deller T. , Nitsch R. , Frotscher M.
Published: January 2005

Numerous studies have shown a lamina‐specific termination of commissural fibers to the dentate gyrus in the inner molecular layer. However, the exact course and arborization pattern of individual fibers remained unknown. In this study, the commissural fiber tract to the dentate gyrus of the rat has been studied using the anterograde tracer Phaseolus vulgaris ‐leucoagglutinin (PHA‐L), which labels individual axons and their collaterals. Following iontophoretic application of the tracer, anterogradely labeled fibers were followed through the posterior basal fornix and medial fimbria where they formed a dense fiber bundle. Labeled fibers then entered the dentate gyrus close to the medial blade of the granule cell layer where they separated and traversed the hilus. Only in those cases where the injection also involved CA3 pyramidal cells could axons arborizing in the hilus be observed. Typically, fibers that continued into the molecular layer did not arborize in the hilus. Upon their entrance into the molecular layer, these fibers changed direction, gave off several collaterals, and followed a new path parallel to the granule cell layer where they preferentially formed en passant contacts. These commissural fibers to the inner molecular layer terminated in a wide septotemporal (longitudinal) extension. However, a considerable number of fibers reached the outer molecular layer where some of them formed extensive arborizations. Moreover, these commissural fibers to the outer molecular layer appeared to be restricted to the hippocampal lamella, corresponding to the level of the contralateral injection site. These data suggest the existence of three commissural projections to the rat dentate gyrus: (1) commissural fibers to the hilus arising from CA3 neurons, (2) commissural fibers to the inner molecular layer, and, (3) commissural fibers to the outer molecular layer. © 1995 Wiley‐Liss, Inc.
Heterogeneous topographical distribution of the striatonigral and striatopallidal neurons in the matrix compartment of the cat caudate nucleus
Authors: Desban Marcel , Gauchy Christian , Glowinski Jacques , Kemel Marie‐Louise
Published: January 2005

The topographical organization of the striatonigral projection was investigated in the cat by comparing the localization and the intensity of labelling of retrogradely labelled cells in the caudate nucleus following one or multiple injections of horseradish peroxidase‐wheat germ agglutinin into the center or along the rostrocaudal axis of the substantia nigra pars reticulata. Second, the localizations of retrogradely labelled striatopallidal neurons and of clusters of aggregated striatonigral neurons (as outlined by the transportof 14C‐material) were compared in cats that received four horseradish peroxidase‐wheat germ agglutinin injections into the internal segment of the globus pallidus and three nigral injectionsof 14C‐amino acids into the substantia nigra pars reticulata. Two types of striatonigral neurons located predominantly within the matrix compartment were identified: poorly collateralized aggregated cells distributed in clusters and more numerous collateralized cells distributed outside the clusters. In addition, two cell types were distinguished within each cluster of aggregated neurons. Those innervating the center of the substantia, nigra pars reticulata were observed after a single nigral injection of the tracer, whereas those projecting to distinct sites of the substantia nigra pars reticulata along a rostrocaudal axis were observed only after multiple injections. Striatal neurons innervating the internal segment of the globus pallidus were heterogeneously distributed predominantly within the matrix but outside the clusters of aggregated striatonigral neurons. Together, these results provide further evidence for the heterogeneity of the matrix and for the complexity of matrix striatonigral connections that send both diverging and converging signals to the substantia nigra pars reticulata. © 1995 Wiley‐Liss, Inc.
The retinohypothalamic tract originates from a distinct subset of retinal ganglion cells
Authors: Moore Robert Y. , Speh Joan C. , Patrick Card J.
Published: January 2005

The retinal ganglion cells giving rise to retinohypothalamic projections in the rat were identified using retrograde transport of horseradish peroxidase (HRP) or Fluoro Gold injected into the suprachiasmatic nucleus (SCN), and using transneuronal transport of the Bartha strain of the swine herpesvirus (PRV‐Bartha). When PRV‐Bartha is injected into one eye, it is taken up by retinal ganglion cells, replicated, transported to axon terminals in the SCN, and released. There the virus may take one, or both, of two paths to retinal ganglion cells in the contralateral eye: (1) uptake by SCN neurons, replication, and release from the neurons with uptake and retrograde transport in retinal afferents originating in the contralateral retina; (2) transneuronal passage through axo‐axonic appositions between retinal afferents in the SCN with subsequent retrograde transport of virus to the contralateral retina. The ganglion cells thus labeled are a homogeneous population of small neurons (mean diameter, 12.8 ± 2.2 μm an mean area, 81.8 ± 21.8 μm2) with sparsely branching dendrites that are widely distributed over the retina. This population is best identified when virus labeling of retinal projections in areas beyond the hypothalamus is eliminated by lateral geniculate lesions that transect the optic tract at its entry into the geniculate complex. The same population is labeled with retrograde tracers but, with both HRP and Fluoro Gold, other ganglion cells are labeled, presumably from uptake by fibers of passage, indicating that the virus is a more reliable marker for ganglion cells giving rise to retinohypothalamic projections. The ganglion cells identified correspond to a subset of type III, or W, cells. © 1995 Wiley‐Liss, Inc.
NADPH‐Diaphorase in the central nervous system of the tench (tinca tinca L., 1758)
Authors: Arévalo R. , Alonso J. R. , García‐Ojeda E. , Briñón J. G. , Crespo C. , Aijón J.
Published: January 2005

The distribution and morphological characterization of nicotinamide adenine dinucleotide phosphate‐diaphorase (ND)–positive cells and fibers in the tench central nervous system was mapped by using a direct histochemical method. This enzyme was observed in specific cell populations throughout all main divisions of the tench brain.

In the telencephalon, we found strongly labeled olfactory fibers, as well as positive cells and fibers in the area ventralis of the telencephalic lobes. Positive staining was observed in the following diencephalic nuclei: nucleus preopticus magnocellularis pars magnocellularis, nucleus recessus lateralis, nucleus recessus posterioris, nucleus posterior tuberis, and nucleus diffusus torus lateralis, as well as small cells with a diffuse distribution surrounding the diencephalic ventricle. In the mesencephalon, heavily stained ND‐positive neurons were observed in the nucleus fasciculi longitudinalis medialis, nucleus nervi oculomotorius, and nucleus nervi trochlearis. In the hindbrain the most evident staining was observed as large neurons located in the nuclei of the cranial nerves, scattered positive cells located between the negative fibers of the cranial nerves, and in the nucleus fasciculi solitari. Finally, in the spinal cord, ND‐positive cells and fibers were mainly located in the ventral horn.

This distribution of ND labeling in the brain of the tench is significantly different from previous data on ND activity in the brain of terrestrial vertebrates and does not correlate with the presence and distribution patterns of several neurotransmitters and neuroactive substances in the teleost brain. © 1995 Wiley‐Liss, Inc.
Morphology of ganglion cells in the neotenous tiger salamander retina
Authors: Toris Carol B. , Eiesland Jodi L. , Miller Robert F.
Published: January 2005

The morphology of retinal ganglion cells in the neotenous tiger salamander (Ambystoma tigrinum) was analyzed with the aid of morphometric techniques to determine the diversity of cell types and to evaluate the widely held notion that this form of Ambystoma has a simple retina, with little variance among its cell morphologies. Single‐cell staining was achieved through retrograde labeling with horseradish peroxidase injected around the optic nerve sheath followed by a period of several days before tissue processing; 83 well‐labelled cells with axons were studied in detail with light microscopy and a computer‐aided reconstruction system. Five different morphological cell classes were devised based on broad morphometric criteria such as the dendritic area of influence; the number, length, and complexity of dendritic branches; and the amount of overlap between neighboring dendrites. These classes included small simple, small complex, medium simple, medium complex, and large cells. In addition, a class of cells with numerous varicosities among the dendrites was separately analyzed. These swellings did not stain for catecholamines.

Based on optical determinations of the dendritic sublamination pattern within the inner plexiform layer, presumed On‐Off cells are present in all subclasses, whereas On cells predominate in the smaller cell groups. Presumed Off cells are well represented in the large field units, although the small total number of cells in this latter class leads to uncertainty regarding the significance of this observation. The diversity of ganglion cell morphology revealed in the present study argues against the assumption that the neotenous tiger salamander has a simple retina, with a relatively invariant set of ganglion cells. On the contrary, it appears that this aquatic form shows morphological diversity in the retinal ganglion cell population rivaling that reported for other vertebrates, including mammals. A functional role for the different cell classes is briefly considered. © 1995 Wiley‐Liss, Inc.