摘要:

AbstractThe aim of this study was to investigate the neurochemical coding of myenteric neurons in the guinea pig gastric corpus by using immunohistochemical methods. Antibodies and antisera against calbindin (CALB), calretinin (CALRET), choline acetyltransferase (ChAT), calcitonin gene‐related peptide (CGRP), dopamine β‐hydroxylase (DBH), β‐endorphin (ENK), neuropeptide Y (NPY), neuron‐specific enolase (NSE), nitric oxide synthase (NOS), protein gene product 9.5 (PGP), parvalbumin (PARV), serotonin (5‐HT), somatostatin (SOM), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. Double‐ and triple‐labeling studies revealed colocalization of certain transmitters and enabled the identification of distinct subpopulations of gastric enteric neurons. NPY/VIP/NOS/ENK were present in 28% of all neurons, whereas 11% had NPY/VIP / DBH / ChAT; NOS‐only neurons made up 2% of the population. The combination SP/ChAT/ENK occurred in 21% of the population, whereas SP/ChAT/ENK/CALRET and SP/CHAT/SOM/ ± CALRET was identified in 5% and 6% of all cells, respectively. 5‐HT‐containing neurons comprised 2% of all cells and could be further classified by the presence of additional antigens as 5‐HT/SP/(ChAT) or 5‐HT/VIP/(ChAT). Approximately 21% of all neurons contained only ChAT with no additional antigen present and are referred to as ChAT/–. Gastric myenteric ganglion cells were not immunoreactive for CALB, PARV, CGRP, or TH. The results of this study indicate that gastric myenteric neurons can be characterized on the basis of different chemical coding. Neurochemical coding of corpus myenteric neurons revealed some similarities and significant differences in comparison with other regions of the gut. These differences might reflect adaptation of enteric nerves according to regional specialization and the distinct functions of the proximal stomach as a gastric reser

ISSN:0092-7317    

DOI:10.1002/cne.903530202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe examined the number, spatial distribution, and size of ganglion cells in the retinae of normal Syrian hamsters and hamsters with retinal projections to the auditory and somatosensory nuclei of the thalamus, induced by neonatal surgery. As revealed by retrograde filling with horseradish peroxidase, there are about 64,600 contralaterally projecting retinal ganglion cells (RGCs) and 1,700 ipsilaterally projecting RGCs in the retinae of normal adult hamsters. Contralaterally projecting RGCs are distributed throughout the retina and have two local density peaks located within a central streak of high RGC density that is oriented approximately along the nasal‐temporal axis. RGC density falls above and below the central streak, with a steeper gradient towards the upper retina. Ipsilaterally projecting RGCs are diffusely distributed within a crescent at the inferotemporal retinal periphery and are most dense at the internal border of the crescent. The soma diameter of contralaterally projecting RGCs ranges from 6 to 25 μm; the diameter distribution is unimodal, with a peak in the 10–13 μm range and is skewed toward smaller values, with an elongated tail towards higher values. Contralaterally projecting RGCs tend to be smaller in regions of higher density. Ipsilaterally projecting RGCs tend to be larger than contralaterally projecting RGCs both globally and within the temporal crescent, and their size distributions tend to be less regular and less well related to local density.The retinae of neonatally operated hamsters with novel retinal projections to the auditory and somatosensory systems contain about one‐fourth the normal number of contralaterally projecting RGCs, whose relative density distribution is approximately normal despite the drastic reduction of absolute RGC density. The range and distribution of RGC soma diameters are similar in normal and neonatally operated hamsters, and, in operated as in normal hamsters, contralaterally projecting RGC somata tend to be smaller in regions of higher density.Our results in normal hamsters suggest a role for intraretinal mechanisms in the determination of RGC size. Our findings in neonatally operated hamsters suggest that, despite the reduced number of RGCs in these animals, the same types of RGCs are found in the retinae of normal and neonatally operated hamsters. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903530203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractNeurons in the striatum that project to the substantia nigra contain the opioid peptide dynorphin. Stimulation of D1 dopamine receptors results in increased expression of mRNA encoding dynorphin as well as expression of immediate‐early genes such asc‐fosin these neurons. Levels of dynorphin vary in different regions of the normal rat striatum, being highest in ventral and medial striatum. In a prior study, we have shown that both regional and temporal patterns ofc‐fosinduction following treatment with the indirect dopamine receptor agonist cocaine are inversely related to those of dynorphin expression. These results suggested that dynorphin is involved in regulating the responsiveness of these neurons to dopamine input. In the present experiments, we examined such a potential role for dynorphin by analyzing the influence of the dynorphin (kappa opioid receptor) agonist spiradoline on immediate‐early gene induction by cocaine, and we determined that this immediate‐early gene response is mediated by D1 dopamine receptors located in the striatum. As a marker of neuron activation, expression ofc‐fosandzif 268immediate‐early genes was assessed with quantitative in situ hybridization histochemistry. Results showed that (1) intrastriatal infusion of the D1 dopamine receptor antagonist SCH‐23390 (2.5–250 pmol) resulted in a dose‐dependent blockade of immediate‐early gene induction by cocaine (30 mg/kg); (2) systemic administration of the kappa opioid receptor agonist spiradoline (0.5–10.0 mg/kg) decreased cocaine‐induced expression ofc‐fosandzif 268mRNAs in striatum in a dose‐dependent manner; (3) intrastriatal infusion of spiradoline (1–50 nmol) also suppressed immediate‐early gene induction by cocaine, demonstrating that kappa opioid receptors located in the striatum mediate such an effect; and (4) systemic and intrastriatal administration of spiradoline also affected immediate‐early gene expression in cortex. These results demonstrate that, in striatum, immediate‐early gene induction by cocaine is a D1 dopamine receptor‐mediated process that is inhibited by activation of kappa opioid receptors. Therefore, these findings suggest that the striatal dynorphin opioid system acts directly and/or indirectly to inhibit dopamine input to striatonigral neurons through kappa opioid receptor‐mediated processe

ISSN:0092-7317    

DOI:10.1002/cne.903530204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWhereas in mammals postnatal neurogenesis, gliogenesis, and angiogenesis appear to be kept at low rates, in fish the capability for the production of new brain cells during adulthood is very pronounced. Many of the newly generated cells originate from germinal layers that maintain their proliferative activity during adulthood. By employing incorporation of the thymidine analogue 5‐bromo‐2′‐deoxyuridine (BrdU) into mitotic active cells, we have quantitatively mapped such proliferation zones in the brain of adultApteronotus leptorhynchus(Gymnotiformes, Teleostei).In the telencephalon, diencephalon, mesencephalon, and rhombencephalon, the total number of BrdU‐labelled cells was low, making up approximately 25% of all mitotic active cells in the brain. Many of these cells were scattered over wide areas. Otherwise, zones of high proliferative activity were typically located at or near the surface of ventricular, paraventricular, and cisternal systems. Approximately 75% of all BrdU‐labelled cells found in the brain of adultApteronotus leptorhynchuswere situated in the cerebellum. Zones displaying proliferative activity were restricted to small areas, such as narrow stripes around the midline of corpus cerebelli and valvula cerebelli, the boundary between corpus and valvula, and a large portion of the area covered by the eminentia granularis medialis.Counts indicate that, on average, 100,000 cells, corresponding to approximately 0.2% of the total population of cells in the brain of adultApteronotus leptorhynchus, are in S‐phase within a period of 2 hours. At least part of these newly generated cells is added to the population of already existing cells. This leads to a permanent growth of the brain with increasing size of the fish, a process that appears to slow down only in individuals of relatively advanced age. © 1995 W

ISSN:0092-7317    

DOI:10.1002/cne.903530205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractProjections from the central cervical nucleus (CCN) to the cerebellar nuclei were examined following injections ofPhaseolus vulgaris‐leucoagglutinin or cholera toxin subunit B into the C1–C3 segments in the rat. Labeled axons and terminals were immunohistochemically demonstrated. Labeled spinocerebellar fibers arising from the CCN entered the cerebellum through the inferior and the superior cerebellar peduncles. Labeled mossy fiber terminals were seen in lobules I–VI, sublobule VIIb, lobules VIII and IX, and the copula pyramidis of the cerebellar cortex. Labeled axons ran toward the cerebellar cortex, through and between the medial and the interpositus nuclei, and gave off collateral axons and terminal axons to the cerebellar nuclei. The projections to the cerebellar nuclei were predominantly contralateral to the cells of origin. Labeled terminals were distributed from the medial to the ventrolateral part of the middle subdivision of the medial nucleus throughout its rostrocaudal extent. Labeled terminals were also seen in the lateral part of the medial nucleus and in the border region between the medial nucleus and the interpositus nuclei, which corresponds to the rostromedial extension of the posterior interpositus nucleus. In the anterior interpositus nucleus, labeled terminals were distributed dorsoventrally in the middle third of the mediolateral extent. They were more numerous in the rostrodorsal part of this area. Labeled terminals were distributed dorsally and caudally in the medial third of the posterior interpositus nucleus. No labeled terminals were seen in the caudomedial subdivision and the dorsolateral protuberance of the medial nucleus, the dorsolateral hump region and the lateral nucleus. The present study demonstrates that the CCN projects to specific areas of the cerebellar cortex and the medial and the interpositus nuclei. © 1995 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903530206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe literature on the anatomical organization of primary sensory afferents, though extensive, contains relatively little information about the longitudinal extent of the central collateral projections. Our understanding of intersegmental sensorimotor integration in the spinal cord and of the developmental mechanisms that establish its underlying circuitry could be significantly enhanced by a more complete description of these projections. To address this issue from a developmental perspective, we labeled the central projections of lumbar primary afferents in fixed preparations of the chicken embryo with the lipophilic tracer DiI. At late embryonic stages, the afferent projections had the following characteristics: Primary afferents originating from a single lumbar dorsal root ganglion bifurcated to project longitudinally in the dorsal funiculus or Lissauer's tract. Dorsal funiculus axons extended up to seven segments caudally and to at least ten segments rostrally, whereas axons in Lissauer's tract extended up to seven segments in each direction. Collaterals branched off the longitudinal axons over a range of about seven segments in each direction. Within this range, collaterals to specific terminal fields exhibited more restricted ranges.The development of these longitudinal patterns during earlier embryonic stages was followed from the time the afferents first reached the neural tube on day 4 of embryogenesis. The longitudinal axons lengthened as a single bundle up to day 10, with medial axons consistently longer than lateral axons. After day 10, the longitudinal axons were segregated into the dorsal funiculus and Lissauer's tract. Collaterals sprouted after about 2 days of longitudinal axon growth, by which time the axons had extended several segments in each direction. The segmental range over which collaterals were present reached a maximum of 20 segments at day 10. Collaterals to the different terminal areas differed in their segmental ranges already by this time. After day 10, the total segmental range of collaterals decreased to the stable level of about seven segments in each direction, which is characteristic of late‐stage embryos. © 1995 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903530207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe dendritic branching pattern and the distribution of dendritic spines were studied in hippocampal neurones with an improved technique. In slices taken from adult Wistar rats, CA1 pyramidal cells were filled with Lucifer yellow and examined under a laser‐scanning confocal microscope.The basal dendrites were found evenly distributed inside a regular cupola‐shaped volume. Their total length was about 4,500 μm. The branches divided between one and three times, with the initial segments comprising less than 2%, and the long terminal segments (mean length, 119 μm) including more than 80% of the total length of the basal dendrites. The apical dendritic branches emerged obliquely from the main shaft, ran for a distance of 50 to 250 μm, and made up a total length of about 5,100 μm in stratum radiatum and between 1,100 and 3,200 μm in stratum lacunosum‐moleculare. The mean total length of the dendritic tree was 11,900 μm. All values were corrected for shrinkage. Shrinkage was measured in three dimensions and was 20.2% in the horizontal (x/y) plane and 40.9% in the vertical (z) plane.Both the basal and the apical dendritic branches were covered by regularly spaced spines. When corrected for dehydration‐induced shrinkage and for hidden spines, the density was 1.80 and 2.00 spines/μm dendritic length for the basal and apical dendritic branches, respectively. Apart from the initial parts of the branches, which had few or no spines, the spines were remarkably evenly spaced. In particular, the distance between spine heads was significantly different from a random distribution, suggesting a regulatory process for the spacing of spines. © 1995

ISSN:0092-7317    

DOI:10.1002/cne.903530208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractSecretoneurin is a novel 33‐amino‐acid neuropeptide produced by endoproteolytic processing from secretogranin II, which is a member of the chromogranin/secretogranin family. In this mmunocytochemical study, we compared the distribution pattern of secretoneurin immunoreactivity with that of tyrosine hydroxylase, calbindin, substance P, and Leu‐enkephalin in adjacent sections of rat forebrain. Secretoneurin appeared mainly in varicosities and fibers. Only a few cell bodies were stained. In the nucleus accumbens, a partial overlap of secretoneurin‐immunoreactive patches with enkephalin‐immunopositive areas was found. Secretoneurin displayed low to moderate levels of immunoreaction in calbindin‐rich as well as in calbindin‐immunonegative areas of the caudate‐putamen. In the globus pallidus, entopeduncular nucleus, and substantia nigra, secretoneurin immunoreactivity was oriented ventromedially preferentially in woolly fibers. The dense immunostaining in the medial nucleus accumbens was directly continuous with dense secretoneurin immunoreactivity in the bed nucleus of the stria terminalis. Two strongly secretoneurin‐immunopositive bands, one in the sublenticular portion and a smaller one along the posterior limb of the anterior commissure, interconnected the highly secretoneurin‐immunopositive centromedial amygdala with the bed nucleus of the stria terminalis. Thus, the distribution pattern of secretoneurin immunoreactivity provides a marker of the extended amygdala that forms a continuum between the centromedial amygdala and the bed nucleus of the stria terminalis. ©

ISSN:0092-7317    

DOI:10.1002/cne.903530209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractFrontal eye field (FEF) projections to posterior cortical areas were mapped by autoradiography of tritiated amino acids (Leu, Pro) in six macaque monkeys. In three monkeys, the large saccade part of the FEF (IFEF) was identified by microstimulation and injected with tracers. In a fourth monkey, the small saccade part of the FEF (sFEF) was identified by microstimulation and injected with tracer. Tracer injections were placed into the sFEF region of two other monkeys using anatomical landmarks. The IFEF and sFEF generally had distinct and largely segregated projections to posterior cortical areas, and the overall pattern of labeling in visual areas with established topology indicates that IFEF neurons preferentially project to areas having large and eccentric receptive fields, whereas sFEF neurons project to areas having smaller, more centrally located fields. The terminal fields from the sFEF were more widespread than those from IFEF. Projections from sFEF terminated in the lateral intraparietal area (LIP), the ventral intraparietal area (VIP), and the parietal part of visual area V3A, in the fundus of the superior temporal visual area (TST), the middle temporal area (MT), the medial superior temporal area (MST), the temporal part of visual area V4, the inferior temporal area (IT), and the temporal‐occipital area (TEO) and in occipital visual areas V2, V3, and V4. Projections from IFEF terminated in parietal areas 7a, LIP, and VIP and the medial part of parietal area PE; in temporal areas MST and the superior temporal polysensory area (STP); and in occipital area V2 and posterior cingulate area 23b. Projections from IFEF and sFEF appeared to terminate in different parts of common target areas in MST, LIP, and V2. The topography of IFEF and sFEF projections to LIP suggests that this posterior eye field may also be organized by saccade amplitude. Most terminal labeling from FEF injections was bilaminar to layers I and V/VI, but labeling in area LIP, area MT, the medial part of area PE, and area 23b was columnar‐form to all layers. © 1995 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903530210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractRetinogeniculate projections in the ferret are refined during postnatal development so that inputs from the two eyes become segregated into eye‐specific laminae, and each eye‐specific lamina is further divided into sublaminae containing inputs from on‐center or off‐center afferents. Segregation into eye‐specific laminae and on/off sublaminae is dependent on neuronal activity; sublamination depends on activation of N‐methyl‐d‐aspartate (NMDA) receptors. By analogy with the suggested role of nitric oxide in NMDA‐mediated long‐term potentiation in the hippocampus, we investigated a possible role for nitric oxide in ferret retinogeniculate development. The expression of NADPH‐diaphorase, a nitric oxide synthase, was examined histologically in the lateral geniculate nucleus of ferrets at several postnatal ages. At birth, neuropil is labeled in the nucleus, although no cell bodies are visible. After the first postnatal week, some labeled cells appear, predominantly in the C laminae. By three postnatal weeks, cell bodies are clearly labeled in all geniculate laminae. Staining reaches a peak in density at about four postnatal weeks, then declines such that by six postnatal weeks labeled cells are no longer visible. This transient expression of NADPH‐diaphorase activity is consistent with a role for nitric oxide in the development of mature connections within the ferret lateral geniculate nucleus.

ISSN:0092-7317    

DOI:10.1002/cne.903530211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY