摘要:

AbstractPrevious studies in our laboratory have shown that microinjection of acetylcholine and non‐N‐methyl‐D‐aspartate (NMDA) glutamate agonists into the pontine inhibitory area (PIA) induce muscle atonia. The present experiment was designed to identify the PIA afferents that could be responsible for these effects, by use of retrograde transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA‐HRP), glutamate immunohistochemistry and NADPH‐diaphorase staining techniques. Experiments were performed in both decerebrate and intact cats. Dense retrograde WGA‐HRP labelling was found in neurons in the periaqueductal gray (PAG) and mesencephalic reticular formation (MRF) at the red nucleus (RN) level, ventral portion of paralemniscal tegmental field (VFTP), retrorubral nucleus (RRN), contralateral side of PIA (CPIA), pontis reticularis centralis caudalis (PoC), and most rostral portion of the nucleus parvicellularis (NPV) and nucleus praepositus hypoglossi (PH) at the level of the pontomedullary junction; moderate labelling was seen in pedunculopontine nucleus, pars compacta (PPNc), laterodorsal tegmental nucleus (LDT), superior colliculus (SC), MRF and PAG at the level caudal to RN, medial and superior vestibular nuclei, and principle sensory trigeminal nucleus (5P); and light labelling was seen in dorsal raphe (DR) and locus coeruleus complex (LCC). The projection neurons were predominantly ipsilateral to the injection site, except for both vFTP and RRN, which had more projection cells on the contralateral side. Double labelled WGA‐HRP/NADPH‐d neurons could be found in PPNc and LDT. Double labelled WGA‐HRP/glutamatergic neurons could be seen at high densities in MRF, RRN, vFTP, and cPIA, moderate densities in SC, LDT, PPNc, PoC, and NPV, and low densities in PH, 5P, DR, LCC, and PAG. No cells in LDT and PPNc were triple labelled with NADPH‐d, glutamate antibody and WGA‐HRP. The mesopontine efferents identified here may mediate the suppression of muscle tone in REM sleep and coordinate muscle tone during head and neck movements. © 1993 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in th

ISSN:0092-7317    

DOI:10.1002/cne.903360302

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe catecholaminergic (CA) innervation of the frontal lobe was visualized in 20‐ to 24‐week‐old human fetuses with immunocytochemical techniques, by use of antibodies raised against three synthetic enzymes of the CA pathway, tyrosine‐hydroxylase (TH), dopamine‐β‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT). DBH‐like immunoreactivity (IR) was probably labeling the noradrenergic (NA) fibers and terminals in the cerebral cortex since no PNMT‐IR fibers were detected. In double‐labeling TH‐DBH experiments, 92–95% of the DBH‐IR afferents were not labeled with TH antibodies, indicating that TH‐like immunoreactivity (TH‐IR) was found primarily in dopaminergic (DA) fibers. Although cortical layering had not yet occurred at this stage, the widespread CA innervation observed in the different areas and layers of the fetal frontal cortex was comparable to that previously described in the adult (Gaspar, Berger, Febvret, Vigny, and Henry: J. Comp. Neurol. 279:249–271, '89). At midgestation, the distribution of CA innervation was region and laminar specific: (1) The densest dopaminergic innervation in the cerebral cortex was located caudal to the genu of the corpus callosum: TH‐IR fibers were abundant throughout all layers, from the medial telencephalon (future cingulate) to the dorsal areas (presumed motor cortices) and the lateral insular areas; (2) TH‐IR fibers were less dense in the rostral prefrontal cortical anlage; (3) DBH‐IR noradrenergic afferents were less numerous than the dopaminergic ones in all the cortical areas studied; (4) in all areas, the highest amount of TH and DBH‐IR terminals was found in the upper subplate and in the lower part of the cortical plate, followed by the molecular layer and the intermediate zone. The deep subplate exhibited a lower number of positive fibers but contained TH‐IR cell bodies. The presence of dense CA innervation in the immature cortical anlage of the human frontal lobe does not exclude a reorganization of DA and NA innervations within the different cortical layers and areas during the protracted pre‐ and postnatal

ISSN:0092-7317    

DOI:10.1002/cne.903360303

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractPrevious reports from this laboratory and elsewhere have provided evidence that the locus coeruleus (LC) and dorsal raphe (DR) nuclei are topographically organized with respect to their efferent targets. Whereas most of these previous studies have focused on relationships between these monoamine‐containing brainstem nuclei and cerebral cortex, basal ganglia, and limbic structures, they have not systematically examined the distribution of LC and DR cells that project to multiple structures with common sensory or motor functions. The goal of the present study was to characterize and compare the distributions of LC and DR cells which project to different visual areas of the rat central nervous system. Long‐Evans hooded rats received unilateral pressure injections of the retrograde tracer wheat germ agglutinin‐horseradish peroxidase in either the dorsal lateral geniculate, ventral lateral geniculate, or lateral posterior nucleus of thalamus; superior colliculus, cortical area 17, cortical area 18a/b cerebellar vermis (lobules VI and VII); or paraflocculus. Transverse sections through the midbrain and pons were examined by light microscopy after performing routine tetramethyl benzidine histochemical procedures. For all cases studied, retrogradely labeled cells were observed throughout the rostrocaudal extent of the LC and DR; however, labeling patterns which were distinctive for different injection sites were noted in each of these brainstem nuclei. The major conclusion drawn from this work is that subsets of LC and DR cells which project to different target structures within the rat visual system are found in overlapping but not necessarily coextensive zones within these nuclei. These studies provide further evidence of a rough topographic ordering within both the LC and DR nuclei, as well as support a new hypothesis that the outputs from each of these nuclei are organized with respect to the sensory related functions of their efferent targets. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903360304

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe development of the uncrossed retinofugal pathways in normally pigmented and albinorats, aged from embryonic day (E) 14.5 to E18.5, was investigated. Dil was placed into one optic tract and the retinal origin of the uncrossed component, as well as its course in the optic stalk, was studied. The results show that, as in the mouse, the uncrossed retinal projection has two components. The first component is seen at E15.5 in normally pigmented animals. It develops exclusively in the central parts of the retina and is normal in albino littermates. The second component, which arises from the peripheral parts of the ventrotemporal retina, is seen two days later at E17.5 in all animals but is significantly smaller in albinos than in their pigmented littermates.Studies of axons in the optic stalk labelled retrogradely with DiI placed in the optic tract indicate that the uncrossed axons have no preference for any position in the stalk except when they approach the chiasm, where they tend to accumulate at the caudal region of the stalk. The uncrossed axons intermingle with the crossed axons along the entire length of the stalk. In albino embryos, no obvious difference in the prechiasmatic course of uncrossed axons was seen at any age examined.It is concluded that the albino mutation in rats affects the late ventrotemporal component of the uncrossed pathway selectively. It does not act on the early central component. Further, the intermingling of crossed and uncrossed axons in the stalk and the apparently unaffected prechiasmatic course of uncrossed axons in albinos indicate that the albino gene has its primary action in the retina. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903360305

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractProtein kinase C (PKC) is one of the major cellular signal transduction systems. Since at least nine different PKC isoenzymes have been described, the purpose of the present studies was to identify the regional, cellular, and subcellular distributions of PKCδ in the rat central nervous system (CNS) by light and electron microscopic immunocytochemistry. We have found that PKCδ immunoreactivity is present in all major subdivisions of the rat CNS. Within each of the subdivisions, PKCδ immunoreactivity is localized to perikarya that monitor sensory and motor functions. More specifically, PKCδ is found in the olfactory bulb, cerebral cortex, lateral septum, thalamus, vestibular and cochlear nuclei, inferior olive, nucleus of the solitary tract, cerebellum, and superficial layers of the dorsal horn in the spinal cord. In most cases, the distribution of this isoenzyme is distinct from that of the conventional isoforms. Within the CNS, PKCδ is localized primarily in neurons; however, neurons of the same type are not uniformly labeled. This is most evident in the cerebellum, where alternating columns of Purkinje cells are immunostained. While PKCδ is prominent in perikarya, occasional immunostaining is seen in dendrites, fibers or axons, and nerve terminals. Electron microscopic analysis of the posterolateral nucleus of the thalamus reveals that the cell nucleus, the rough endoplasmic reticulum, and the plasma membrane are all immunopositive. Since each of the PKC subspecies may have different substrate, lipid, and other co‐factor requirements, the regional, cellular, and subcellular distribution of each of these isoforms should help to define their functional environments. © 1993 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States

ISSN:0092-7317    

DOI:10.1002/cne.903360306

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractAlthough the structure and function of primate prefrontal cortex undergo substantial modifications during postnatal development, relatively little is known about the maturation of neurotransmitter systems in these cortical regions. In the primate brain, cholecystokinin is present in the greatest concentrations in prefrontal regions. Thus, in this study, we used immunohistochemical techniques to investigate the postnatal development of the cholecystokinin innervation of monkey prefrontal cortex.In animals aged 4 days through adult, cholecystokinin immunoreactivity was present in nonpyramidal neurons that appeared to represent at least two distinct cell types. The most common type was a vertically oval bitufted neuron, located in layers II‐superficial III, which typically had a radially descending axon that gave rise to short collaterals in layer IV. Another frequently observed cell type was a larger multipolar neuron located in the superficial half of layer III. The axon of these neurons branched locally in the vicinity of the cell body.The greatest density of cholecystokinin‐containing neurons and processes was present in monkeys less than 1 month of age. The density of immunoreactive structures in every prefrontal region then progressively declined with increasing age, with the most marked changes occurring during the first postnatal year. As a result, the density of labeled neurons in adult monkeys was less than one‐third of that in neonatal monkeys. However, labeled structures were significantly more dense in some ventromedial and orbital regions than in dorsal regions of the prefrontal cortex in neonatal, but not in older animals.In all animals, cholecystokinin‐containing neurons were present in highest density in layers II‐superficial III, and labeled terminal fields were observed in layers II, IV, and VI. In animals less than 1 month of age, fascicles of radial fibers traversed through layers III and V, whereas in animals 1 to 3 months of age, individual radial fibers rather than fiber bundles were present in layers III and V. In addition, immunoreactive pericellular arrays, which appeared to surround unlabeled nonpyramidal cells, were present in layers V and VI and the subcortical white matter in the youngest monkeys.Although many aspects of the cholecystokinin innervation of monkey prefrontal cortex remain constant during postnatal life, the distinct developmental changes in the cholecystokinin innervation of these regions suggest that it may play an important role in the maturation of the cortical circuitry that mediates the acquisition of certain cognitive abilities. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903360307

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe carotid body is an arterial chemoreceptor organ sensitive to blood levels of O2, CO2and pH. The present immunocytochemical and neurochemical study has demonstrated the presence of an extensive plexus of nitric oxide (NO)‐synthesizing nerve fibers in this organ. These nitric oxide synthase (NOS)‐containing axons are closely associated with parenchymal type I cells and with blood vessels in the carotid body. Denervation and retrograde tracing experiments have revealed that these fibers arise from NOS‐immunoreactive and nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase‐positive neuronal cell bodies located in the petrosal ganglion and the carotid body, and dispersed along the glossopharyngeal and carotid sinus nerves (CSN). Within the petrosal ganglion, these neurons are topographically segregated from the catecholaminergic cells, and they contain the neuropeptide, substance P. NOS‐positive autonomic microganglial cells in the carotid body and CSN also exhibit choline acetyltransferse (ChAT) immunoreactivity. Our results suggest that nitric oxide may be a novel neuronal messenger in the mammalian carotid body involved in the modulation of chemosensory transduction and transmission in this organ. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903360308

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe cytoarchitecture, fiber connections, and ultrastructure of the nucleus pretectalis superficialis pars magnocellularis (PSm) were studied in cypriniform teleosts (Cyprinus carpio). The PSm is an oval nucleus in the pretectum. Medium‐sized cells and synaptic glomeruli are the main components of the nucleus. A lesser number of small cells are also present. Most of the medium‐sized cells form one or two cell layers on the periphery of the nucleus, and some cells are scattered among synaptic glomeruli in the nucleus. Cell bodies in the peripheral cell layer are pyriform and sprout a thick dendrite directed inward. The dendrite gives off fine dendritic branches, which are postsynaptic elements in synaptic glomeruli.The PSm projects to the ipsilateral corpus mamillare (CM) and sends collaterals to the ipsilateral nucleus lateralis valvulae (NLV). Axons of the PSm neurons have terminals with many varicosities in the CM, and collaterals in the NLV have cup‐shaped terminals around the cell bodies of the NLV neurons. Following horseradish peroxidase (HRP) injections into the PSm, HRP‐labeled cells are found ipsilaterally in the optic tectum, the nucleus tractus rotundus of Schnitzlein, and the nucleus ruber of Goldstein. The tecto‐PSm projections are topographically organized. The rostral optic tectum projects mainly to the rostral portion of the PSm, and the caudal tectum projects to the caudal portion of the PSm. The ventral tectum sends fibers mainly to the ventral part of the PSm. The dorsomedial tectum projects to the medial part of the PSm, and the dorsolateral tectum projects to the lateral part of the PSm. Tectal projection neurons to the PSm are of only one type. The tectal cell body is pyriform and is situated in the superficial part of the ipsilateral stratum periventriculare (SPV). The tectal neurons have a long perpendicular dendrite, which branches out in the stratum opticum (SO). An axon emerges from the branching site in the SO. Judging from the dendritic branching pattern of the tectal projection neurons, we concluded that the PSm receives visual information from the optic tectum. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903360309

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe morphology, fine structure, and degree of colocalization with GABA, somatostatin, and neuropeptide Y of parvalbumin‐containing cells were studied with immunocytochemistry in the cerebral cortex of the lizardPodarcis hispanica. Parvalbumin‐containing cells make up a morphologically heterogeneous population of spine‐free neurons, displaying the morphological features of nonprincipal cells previously described in Golgi studies. Electron microscopically, parvalbumin‐immunoreactive cell bodies are similar in all cortical areas and layers. The perisomatic input is moderate in number, and boutons with either round clear vesicles or flattened vesicles were observed making asymmetric or symmetric synaptic contacts, respectively. Parvalbumin‐immunoreactive dendrites are smooth and almost completely covered with synaptic boutons of different types, most of which establish asymmetric contacts. Parvalbumin‐immunoreactive boutons are concentrated around cell bodies of principal cells. They are large, containing abundant mitochondria and small pleomorphic vesicles, and establishing symmetric synaptic contacts with somata, proximal dendritic shafts, and axon initial segments of principal cells. Colocalization studies revealed that all the parvalbumin‐containing cells are GABA‐immunoreactive, representing only a fraction of the GABA‐immunopositive cell population, and that parvalbumin‐ and peptide‐ (somatostatin and neuropeptide Y) containing cells show a negligible overlap.These results demonstrate that in the cerebral cortex of the lizardPodarcis hispanica, parvalbumin‐containing cells represent a subset of nonprincipal GABAergic neurons largely involved in perisomatic inhibition, which are different from the peptide‐containing cells, and suggest that they may include both axosomatic and axoaxonic cell

ISSN:0092-7317    

DOI:10.1002/cne.903360310

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractGanglion cells within the cat retina have been traditionally grouped by morphological criteria into three major classes: alpha, beta, and gamma. The gamma‐type cells have been least well characterized, but the available evidence indicates that this class comprises a relatively heterogeneous population of neurons. In the present study we demonstrate that an antibody for neuropeptide Y (NPY) recognizes a subpopulation of about 2,000 gamma‐type ganglion cells.The NPY‐immunoreactive (IR) neurons project to the superior colliculus and to the C layers of the lateral geniculate nucleus as demonstrated by retrograde labeling with fluorescent tracers (fluorogold or rhodamine latex microspheres). Virtually all of these cells disappear following lesions of the optic nerve. The NPY‐IR ganglion cells were identified as gamma cells on the basis of soma size and dendritic branching patterns. The somas of these neurons are small (8–22 μm in diameter), and each cell is characterized by sparsely branching dendritic processes, usually extending into the middle third of the inner plexiform layer, the physiologically defined ON sublamina. These neurons are distributed across the entire retina, with the highest density at the area centralis. Within local regions of the retina, however, there was no indication that the NPY‐IR gamma cells are arrayed in a regular mosaic pattern. These results provide the first evidence that the gamma class of ganglion cells of the cat retina can be subdivided on the basis of immunocytochemical properties. © 1993 Wi

ISSN:0092-7317    

DOI:10.1002/cne.903360311

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY