摘要:

AbstractAt least two types of large neurons (somatic cross‐sectional areas, SA>300 μm2) and five types of medium neurons (SA between 100 and 300 μm2) were distinguished in Golgi preparations of the adult rat neostriatum. Type I large cells had aspinous somata with long, radiating, sparsely spined dendrites which were sometimes varicose distally, whereas type II large cells had spines on both somatic and dendritic surfaces. Type I medium cells had aspinous somata and proximal dendrites, but their distal dendrites were densely covered with spines. Type II medium cells had somatic spines, and their radiating dendrites were sparsely spined. Other medium cells had no somatic spines: Type III cells had poorly branched and sparsely spined dendrites. Type IV cells had profusely branched, sparsely spined dendrites. Type V cells had radiating and varicose dendrites which could also be sparsely spined.Several small neurons (SA mostly less than 100 μm2) were also found in the rat neostriatum: Some had aspinous soma with sparsely spined dendrites; others had somatic spines.Except for the type II large cells, intrinsic axon collaterals were observed for every type of neuron, indicating that they all had local integrating funct

ISSN:0092-7317    

DOI:10.1002/cne.902080202

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractSpinocerebellar tract (SCT) neurons projecting to lobules III to V of the cerebellar anterior lobe were identified by the retrograde horseradish peroxidase technique.SCT neurons projecting to lobule III with crossed ascending axons were located mainly in the central cervical nucleus (CCN), the medial part of lamina VII of L6 to the caudal segments, and the dorsal horn (lamina V) and ventral horn (lamina VIII) of the sacral‐caudal segments. Spinal border cells with crossed ascending axons also projected to lobule III. SCT neurons projecting to this lobule with uncrossed ascending axons were located in the medial part of lamina VI of the cervical segments and the middle part of lamina VII of C6 to T1, lamina V of the lower cervical, thoracic and the lumbar segments, Clarke's column including marginal neurons, and the medial part of lamina VI of L5 and L6. These neuronal groups also projected to lobule IV, except for those present caudal to L6 (in the medial part of lamina VII, and laminae V and VIII of the sacral‐caudal segments). A far smaller number of similar neurons projected to lobule V.Injections of HRP restricted to the vermal region labeled mainly neurons in the CCN and Clarke's column while restricted injections to the intermediate‐lateral regions labeled ipsilaterally spinal border cells, lamina V neurons, and Clarke column neurons, especially of the lumbar segments as well as marginal neurons of this c

ISSN:0092-7317    

DOI:10.1002/cne.902080203

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe distribution of indoleamine‐accumulating amacrine cells and their synaptic connections in the retina of the cat were analyzed in the fluorescence, phase‐contrast, and electron microscopes. The findings were compared to recently characterized morphological subclasses of amacrine cells.The indoleamine‐accumulating neurons were visualized after labeling with an exogenous indoleamine, 5, 6‐dihydroxytryptamine. The intravitreal injection of the labeling drug was preceded by treatment with the neurotoxic dopamine‐analogue, 6‐hydroxydopamine, in order to destroy the otherwise interfering dopaminergic processes.The analysis in the fluorescence and phase‐contrast microscopes confirmed earlier reports that the indoleamine‐accumulating cell bodies and processes have a distribution consistent with that of amacrine cells. A stratified branching pattern of the indoleamine‐accumulating processes in the outer half of the inner plexiform layer was discovered. In the inner half of that layer the branching pattern is diffuse.In the electron microscope the indoleamine‐accumulating neurons were seen to have synapses of the conventional type. Their main synaptic contacts are reciprocal synapses with rod bipolar terminals in sublamina b of the inner plexiform layer. They also have synapses with flat cone bipolar terminals in sublamina a, and occasionally with amacrine cells and ganglion cells throughout the inner plexiform layer. Synapses with invaginating cone bipolar terminals, in sublamina b, appear to be rare. The synaptic arrangement with reciprocal synapses with rod bipolar terminals is similar to that of the recently reported AI amacrine cells. It is also similar to that of the indoleamine‐accumulating neurons in the retinae of other mammals

ISSN:0092-7317    

DOI:10.1002/cne.902080204

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractRecent evidence suggests that ganglion cell size and its regional variation may be an important feature of vertebrate retinas. Accordingly, we have examined Nissl‐stained, whole‐mountedPseudemys scriptaretinas to determine the soma size spectrum of ganglion cells at different retinal loci. Cell size histograms reveal that at any given point on the retina, a majority of ganglion cells are small (6–10 μm), and in peripheral samples there is some evidence for a second, larger size class (12–15 μm). Comparison of samples along the dorsoventral and nasotemporal axes suggests that there are two major trends in soma size variation. Along the dorsoventral axis, ganglion cell diameter increases sharply from the visual streak (6–7 μm, cf. Peterson and Ulinski, 1979) to the dorsal and ventral periphery (9–10 μm). These changes reflect a tendency towards increased size for the entire distribution as well as a relative decrease in the frequency of small ganglion cells. This soma size variation is significantly correlated with changes in ganglion cell density. Along the nasotemporal axis, temporal ganglion cells are significantly larger than those at more nasal retinal loci. This differences reflects an overall increase in the size of ganglion cells in temporal retina and a small but significant increase in the percentage of neurons la

ISSN:0092-7317    

DOI:10.1002/cne.902080205

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractMature Purkinje cells in mouse cerebellar tissue cultures were morphologically analyzed by electron microscopy. Explants maintained for 19 to 31 days in vitro contained Purkinje cells that were similar in most respects to those described in vivo except for incomplete arborization of the dendritic trees. Typical features included (1) absence of Purkinje cell perisomatic spines; (2) a paucity of naked Purkinje cell dendritic spines; (3) a 1:1 relationship of Purkinje cell dendritic spines to parallel fiber terminals; and (4) almost complete astroglial investment of Purkinje cell somata and dendrites. Minimal extracellular space was present in the neuropil of the explants and unusual synapses involving Purkinje cells were absent. Atypical features described by some investigators may be a function of retarded development in suboptimal culture conditions and do not represent the limit of tissue culture methodology.

ISSN:0092-7317    

DOI:10.1002/cne.902080206

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe ontogeny of the neurotensin (NT) neuron system in the forebrain and diencephalon of the rat was investigated by means of indirect immunofluorescence. NT‐positive structures first appear in the primordium of the olfactory bulb, anterior amygdaloid area, piriform cortex, amygdaloid complex, nucleus tractus diagonalis, lateral preoptic area, and lateral hypothalamus, etc., of the fetus of gestational day 16. From this day, NT‐positive structures appear gradually in various areas of the forebrain and diencephalon and reach their maximum content on postnatal day 7. In contrast, NT‐positive structures decrease slightly in number as the rat grows. However, even in adult rats, numerous NT‐positive structures are still identifiable in various areas of the forebrain and dienc

ISSN:0092-7317    

DOI:10.1002/cne.902080207

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractFollowing an olfactory bulb lesion in guinea pig (2 to 3 days), neuronal degeneration occurs in several olfactory‐bulb‐related areas, primarily in the piriform cortex. The degenerating neurons, which are argyrophilic, are also found in the posterolateral cortical amygdaloid nucleus and the ventrolateral entorhinal cortex. It is suggested that the neurons degenerate because of a transneuronal effect due to a sudden loss of afferent input from the the olfactory bulb, although a retrograde effect acting in concert with transneuronal factors cannot be excluded.Terminal degeneration can be identified in several areas outside the olfactory bulb projection area, and is interpreted as degeneration in the axons of the degenerating cortical neurons. Such terminal degeneration, which is best seen 3 to 4 days postoperatively, has been identified in part of the basolateral amygdaloid complex, in the basomedial amygdaloid nucleus, and in the temporal parts of the fascia dentata of the hippocampal formation. Terminal degeneration has also been observed in the deep layers of the anterior olfactory nucleus, the olfactory tubercle, the nucleus of the lateral olfactory tract, and the anterior amygdaloid area. All these projections, apparently, represent the second link in two‐neuron pathways, where mitral or tufted cells in the olfactory bulb make up the first neuron. This interpretation was confirmed in control experiments in which areas of argyrophilic neurons coincided with the location of retrogradely labeled neurons following injection of flurorescent substances into several of the abovementioned areas of terminal degener

ISSN:0092-7317    

DOI:10.1002/cne.902080208

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractFollowing morphine treatment, an autoradiographic study investigated the uptake of3H‐thymidine by the subependymal cells in the rat brain.3H‐thymidine was administered subcutaneously to adult, male Sprague‐Daw‐ley rats 30 minutes after saline or morphine (10 mg/kg) injection. The animals were sacrified 1 hour after3H‐thymidine administration. In some experiments the opioid antagonist, naloxone, was given alone 45 minutes before3H‐thymidine or 15 minutes before morphine treatment. Three areas of the subependyma were evaluated in terms of the percentage labeled cells and number of grains per nucleus, and a dorsal‐to‐ventral gradiant was described. Morphine treatment significantly increased the number of3H‐thymidine labeled subependymal cells and number of grains/nucleus within labeled cells. Examination of the distribution of grains/nucleus showed that morphine‐treated animals had significantly more cells labeled with 30 or more grains than did saline‐injected controls. Prior administration of naloxone blocked the increased3H‐thymidine uptake in morphine‐treated animals but had no significant influence on cell proliferation when administered alone. The data are discussed in terms of morphine's possible dual influence on mechanisms which enhance cell transition from G to S phase and/or which accelerate DNA synthesis once these cells have entered the S

ISSN:0092-7317    

DOI:10.1002/cne.902080209

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902080201

出版商:Alan R. Liss, Inc.    

年代:1982

数据来源: WILEY