摘要:

AbstractThis study has analyzed variations in the number of nucleoli and nuclear bodies, as well as in their ultrastructural and cytochemical organization, after the osmotically induced activation of supraoptic nucleus (SON) neurons of the rat. The number of nucleoli and nuclear bodies and also the nucleolar size were determined on smear preparations of previously block‐impregnated SON. The mean number of nucleoli per cell was 1.35 ± 0.6 (mean ± SDM) in control rats. No significant variations in this value were registered either in dehydrated or rehydrated rats. The mean nucleolar volume and the total nucleolar volume per cell showed a significant increase in dehydrated rats with respect to the controls, whereas these two parameters tended to return to control values in rats rehydrated after dehydration. The mean number of nuclear bodies per cell increased significantly from 0.56 ± 0.50 (mean ± SDM) in control rats to 1.54 ± 1.1 after 6 days of dehydration. By electron microscopy, SON neurons displayed a reticulated nucleolar configuration. After the osmotically induced neuronal activation, there was an increase in the proportion of the total nucleolar area occupied by the granular component, and also a reduction in the mean fibrillar‐center area. The most characteristic nucleolar features in rehydrated rats were the tendency for the granular component to be segregated and the occurrence of intranucleolar vacuoles. Ultrastructural cytochemistry with a specific silver method revealed a selective silver reaction on the coiled threads of the nuclear bodies—identified as “coiled bodies”—and on the nucleolar fibrillar components in all animal groups studied. Since nucleoli play a major role in ribosome biogenesis, a relationship between these nucleolar changes and the level of cellular activity of SON neurons is proposed. Furthermore, the response of nuclear “coiled bodies” to neuronal activation suggests their participation in the processing and transpor

ISSN:0092-7317    

DOI:10.1002/cne.903080302

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

年代:1991

数据来源: WILEY

摘要:

AbstractComputer‐assisted image analysis was used to map the regional distribution of glial fibrillary acidic protein‐immunoreactive (GFAP‐IR) astrocytes in the rat forebrain, and mesencephalon. A complete survey of packing densities of GFAP‐IR structures was performed. Computer maps revealed high values in the outer and inner layers of the cortex, some hippocampal and olfactory bulb layers, prepiriform cortex, dorsal part of the caudate‐putamen, globus pallidus, lateral septum, reticular thalamic nucleus, lateral habenular nucleus, circumventricular organs, nuclei of the medial hypothalamus, substantia nigra, interpeduncular nucleus, and mamillary body. These correspond to regions of the embryonic pial and ventricular brain surfaces, which undergo developmental alterations including growth and various forms of internalization. From this we conclude that in the adult brain, astrocytes of high GFAP‐IR are derivatives of surface‐contact glia, whereas those located in areas having developed by the local thickening of the neural tube wall show reduced

ISSN:0092-7317    

DOI:10.1002/cne.903080303

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis study was designed to investigate the developmental profile of tyrosine hydroxylase‐like immunoreactive structures in the chick retina in both frozen sections and wholemount preparations. In frozen sections, cells with tyrosine hydroxylase‐like immunoreactivity were first detected in 10 to 15 cell rows from the innermost part of the inner nuclear layer on embryonic or incubation day 11. They were seen in the inner cell rows of the inner nuclear layer during later periods; by embryonic day 18, the immunoreactive cells were located 1 to 3 cell rows outward from the innermost part of the inner nuclear layer where mature immunoreactive cells mainly exist. The immunoreactive cells began to give rise to processes on embryonic day 13. The processes (possibly dendrites) gradually increased in number and intensity in sublayers 1 and 4 of the inner plexiform layer during prenatal life. Several days after hatching, an abrupt increase in immunoreactive processes was noted in sublayer 1 but not in sublayer 4. On the sixth postnatal day, retinal neural elements immunoreactive for tyrosine hydroxylase seemed to exhibit a distribution pattern similar to that of the adult chick. In wholemount retinas, immunoreactive cells were initially detected at the earliest stage of embryonic day 12 in a small circle termed “starting area” occupying the ventral part of the temporal retinal field. The closer to the “starting area” the earlier the retinal area began to express many immunoreactive cells. Thus tyrosine hydroxylase cell density in individual retinal areas, as represented by cell number per square millimeter, peaked in different developmental periods varying from embryonic day 12 to day 14. At this stage, immunoreactive cells were arranged irregularly in the retina. Thereafter, the cell density as well as total cell number gradually declined and reached a plateau around embryonic day 20 when tyrosine hydroxylase‐like immunoreactive cells, like those in the mature retina, showed an even distribution throughout the retina. These findings suggest that: (1) early appearing immunoreactive cells in outer parts of the inner nuclear layer migrate toward inner portions of the inner nuclear layer during development, (2) the developmental profile of tyrosine hydroxylase‐like immunoreactive processes in the inner plexiform layer differs from sublayer to sublayer and might be dependent, in part, on light stimuli at birth, (3) the time of origin of immunoreactive cells in discrete retinal areas depends on the distance from the “starting area” as a possible trigger zone of tyrosine hydroxylase cell differentiation, and (4) immunoreactive cells and processes begin to exhibit a regular arrangement and an even distribution in the chick retina by embryonic day 20, possibly as a result of an intricate organization of tyrosine hydroxylase‐like immunoreactive cell development. Thus the present study shows a complex developmental profile of tyrosine hydroxylase‐containing cells in the chick retina, which is not necessarily identical with the ontogeny of retinal dopamine cells or with that of tyrosine hydroxylase immunoreactive cells in the retinas of other

ISSN:0092-7317    

DOI:10.1002/cne.903080304

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe insoluble matrix domain of the interphotoreceptor matrix (IPM) from normal dog, cat, and mouse retinae were characterized using lectin cytochemistry. The lectins WGA (wheat germ agglutinin) and PNA (peanut agglutinin) were used to label interphotoreceptor matrix microdomains in cryosections of retinal tissue and in extracted insoluble matrix. Retinal cryosections and extracted matrix were examined by epifluorescence microscopy and scanning confocal laser microscopy, the latter allowed for the removal of all background fluorescence and gave increased resolution. The insoluble matrix was extracted as a continuous sheet that was comprised of two photoreceptor‐specific matrix domains distinguished both by the size of the domains, and by differential binding of WGA and PNA lectins. Each domain encloses a photoreceptor inner and outer segment. Individual rod‐associated domains were connected into a hexagonal lattice and this pattern was regularly interrupted by the larger cone‐associated domains which have 8–10 surrounding rod domains. The PNA lectin primarily labeled the cone‐associated matrix with faint binding to the rod matrix; the WGA lectin labeled both the rod‐ and cone‐asso

ISSN:0092-7317    

DOI:10.1002/cne.903080305

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe calcium‐binding proteins calbindin‐D28K (CaBP) and parvalbumin (PV) were localized in the “normal” and “epileptic” human hippocampus to address the possible relationship between the expression of these constitutive cytosolic calcium‐binding proteins and the resistance or selective vulnerability of different hippocampal neuron populations in temporal lobe epilepsy. Compared to rodents and a baboon (Papio papio), the pattern of CaBP‐like immunoreactivity (LI) in the “normal” human hippocampus is unique. CaBP‐LI is present in the dentate granule cells, neurons of the “resistant zone” (area CA2), and presumed interneurons of all regions. Unlike rodent and baboon CA1 pyramidal cells, human CA1 pyramidal cells appear to be devoid of CaBP‐LI. Thus, the relatively resistant dentate granule cells and CA2 pyramidal cells are the only human hippocampal principal cells that contain CaBP‐LI normally. As in lower mammals, PV‐LI is present exclusively in interneurons of all human hippocampal subregions.CaBP‐ and PV‐LI were localized in hippocampi surgically removed in the treatment of intractable temporal lobe epilepsy to determine whether surviving hippocampal cells were those that express these calcium‐binding proteins. Hippocampi removed from patients with tumors or arteriovenous malformations that were associated with complex partial seizures arising from this region appeared relatively normal histologically. CaBP‐ and PV‐LI in this patient group appeared similar to that seen in autopsy controls. Conversely, “cryptogenic” epileptics, who exhibit hippocampal sclerosis as the only lesion associated with the epilepsy, exhibited a preferential survival of hippocampal cells that were CaBP‐ or PV‐immunoreactive. In the dentate hilus, which normally contains few CaBP‐LI neurons, most of the few surviving hilar neurons were CaBP‐immunoreactive. Their number and darkness of staining suggests that CaBP synthesis may be increased in cells that survive. Despite an obvious decrease of PV‐LI specifically in the damaged parts of the sclerotic hippocampi, PV‐immunoreactive interneurons were often among the few surviving cells. Nevertheless, large expanses of the surviving granule cell layer appeared to have lost the PV‐immunoreactive axosomatic fiber plexus.These results reveal a unique and striking correlation between the human hippocampal cells that normally express these calcium‐binding proteins

ISSN:0092-7317    

DOI:10.1002/cne.903080306

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe aim of the present study was to analyze the distribution and characteristics of NPY immunoreactive structures in the cerebral cortex of lizards and to investigate the degree of co‐existence of this neuropeptide with somatostatin and GABA. The immunoperoxidase method was applied to vibratome sections as well as to semithin sections.NPY neurons are multipolar or fusiform and were unevenly distributed throughout the brain cortex. Within the medial, dorsomedial and dorsal cortices, most NPY perikarya were located in the plexiform layers, especially in the deep one. This suggests that these cells could be regarded as interneurons. In the lateral cortex, NPY neurons were found throughout all layers. The dorsomedial cortex displayed the highest NPY cell density. Here, neuronal perikarya projected many immunoreactive processes toward two distinct zones: the deep plexiform layer of the medial cortex and the superpositio medialis. The NPY neurons of the dorsomedial cortex differed from the other NPY cortical immunoreactive cells in that the latter displayed very few immunoreactive processes.A high degree of co‐existence among NPY, somatostatin, and GABA (approx. 80%) was found. This co‐existence rate is very similar to that reported in mammals and suggests that co‐localization is a phylogenetically ancient phe

ISSN:0092-7317    

DOI:10.1002/cne.903080307

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe distribution of zinc was described in the dentate area, a part of the hippocampal region, of the domestic pig. A modification of Timm's sulphide silver procedure, the Neo‐Timm method, was used for the histochemical demonstration of zinc. The staining of the dentate area exhibited a well‐defined stratified pattern, the predominant part of the staining being restricted to the neuropil, although weakly stained nerve cell bodies were observed in the hilus fasciae dentatae.In the molecular layer, three distinct sublaminae were seen at most septotemporal levels. The outer and inner sublaminae displayed medium staining intensity, whereas the intermediate sublamina appeared extremely pale. The granular cell layer was well stained in its superficial two thirds, because of dense masses of staining occupying the interstices between the unstained granular cells. In the hilus fasciae dentatae, extreme differences in staining intensity were seen between the layers, ranging from very intense staining of the outer hilar cell layer to generally weak staining of the inner plexiform layer.The distribution of zinc in the pig was compared with that in the guinea pig and rat, described previously. The staining pattern of the molecular layer showed striking species differences, whereas the granular cell layer appeared very near identical. The stratified staining pattern seen in the hilus of the pig is very similar to the distribution observed in the guinea pig, but differs from the essentially homogeneous staining of the rat hilus. However, the differences in hilar staining pattern between the pig and guinea pig on the one hand and the rat on the other essentially display variation in the cytoarchitectural organization of the hilus, rather than expressing a true species differe

ISSN:0092-7317    

DOI:10.1002/cne.903080308

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe central course and the projections of the first and the second cervical dorsal root ganglia and of suboccipital muscle primary afferent fibers in the guinea pig were studied by means of anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA/HRP) or aqueous solution of horseradish peroxidase (HRP).Injections of WGA/HRP into the second cervical dorsal root ganglion produced labeling in the dorsal and ventral horns. Within the spinal cord, the largest amount of HRP reaction product was found within the lateral third of the substantia gelatinosa and within the central cervical nucleus. The main area of termination in the medulla was the external cuneate nucleus. However, HRP reaction product was also found within the medial and inferior vestibular nuclei, cell group x, the perihypoglossal nuclei, the nucleus of the solitary tract, and the nucleus of the spinal trigeminal tract. Descending fibers could be detected as caudal as spinal segment T5.Injections of WGA/HRP into the first cervical dorsal root ganglion produced heavy terminal label within the central cervical nucleus but not within the substantia gelatinosa. Again, the external cuneate nucleus was the main area of termination within the medulla. Label could not be observed within the vestibular nuclear complex or within the spinal trigeminal nucleus.Injections of aqueous HRP into the suboccipital muscles produced heavy transganglionic label within the central cervical nucleus, whereas the substantia gelatinosa totally lacked terminal label. Ascending proprioceptive fibers reached the external cuneate nucleus and group x. Scanty projections could be detected within the vestibular nuclei as well as within the perihypoglossal nuclei except for the nucleus prepositus hypoglossi. Label was absent, in the spinal trigeminal nucleus.

ISSN:0092-7317    

DOI:10.1002/cne.903080309

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

年代:1991

数据来源: WILEY

摘要:

AbstractPatterns of connections underlying cross‐modality integration were studied by injecting distinguishable, retrograde tracers (Fluoro‐Gold and diamidino yellow) in pairwise manner into different sensory representations (visual, somatosensory, and auditory) in the cerebral cortex of the rat.In agreement with previous single tracer studies, our results indicate that the central core of sensory areas receives projections mainly from a set of association areas located in a ringlike fashion along the margin of the cortical mantle. The visual cortex received projections from areas 48/49, area 29d, posterior agranular medial cortex (AGm), area 11, area 13, and area 35. All these areas were also connected to the auditory cortex with the exception of areas 29d and AGm. However, lateral to area 29d and posterior AGm, a band of neurons projecting to the auditory cortex was present. Somatosensory cortex was connected mainly with the more anterior aspect of the hemisphere, which included primary motor area, area 11, and area 13.The patterns of intermodality relationships revealed in the present study were of two main categories. In the anterior, and lateral areas, an intermingling of cells projecting to different sensory modalities was observed. In contrast, in areas located along the medial aspect of the hemisphere, cells connected to different sensory modality representations tended to be segregated from each other. Postsubicular cortex (areas 48/49) contained both intermingled and segregated groups of cells. The incidence of clearly identified double‐labeled cells concurrently projecting to two different sensory representations was extremely rare. These patterns may form a substrate for different levels of cross‐modal sensory integration in the rat

ISSN:0092-7317    

DOI:10.1002/cne.903080310

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe aim of these experiments was to establish the number and location of connectionally distinct areas in the medial frontal lobe of the cat. Thirty deposits of distinguishable retrograde tracers were placed at restricted sites spanning the medial frontal lobe in 16 cats. Following each deposit, the number of retrogradely labeled neurons in each of 17 thalamic nuclei was determined. Variations of the thalamic labeling pattern dependent on the location of the cortical tracer deposit were then analyzed by a quantitative procedure.The results indicate that the medial frontal lobe contains three fundamental divisions: the anterior cingulate area, medial area 6, and the medial prefrontal district. The anterior cingulate area derives its strongest thalamic input from the anteromedial nucleus. Medial area 6 is the target of afferents originating in a dorsolateral sector of the mediodorsal nucleus and in the ventroanterior nucleus. Medial prefrontal cortex is heavily innervated by pathways originating in the core of the mediodorsal nucleus and in the principal ventromedial nucleus. Within each major district, thalamic connectional patterns exhibit graded regional variation, with the result that, whereas the connections of the district are not uniform, it is difficult to define further discrete subdivisions.We discuss these results in relation to previously proposed schemes for parcellation of the cat's medial frontal lobe and conclude that the infralimbic and prelimbic areas (areas 25 and 32) of previous systems are best understood not as discrete areas but as ventral and intermediate sectors of a continuous medial prefrontal domain.

ISSN:0092-7317    

DOI:10.1002/cne.903080311

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

年代:1991

数据来源: WILEY