摘要:

AbstractGlucose utilization was measured in 74 brain regions of the cat during states of wakefulness or rapid eye movement (REM) sleep. These data were obtained from intact, unanesthetized animals which were instrumented for objectively measuring states of consciousness. Through a chronically implanted intravenous catheter, the cats received 250 μCi of [6−14C]glucose during REM sleep (N = 3) or during wakefulness (N = 3). After spending ≈8 min in REM sleep or in quiet wakefulness, the cats were administered a lethal dose of barbiturate and the brains were removed and processed for autoradiography. The results revealed site‐specific changes in glucose metabolism during REM sleep. Significant alterations in glucose use occurred in the thalamus, the limbic system, and specific regions of the pontine reticular formation. These data demonstrate for the first time that during states comprised entirely of REM sleep there are anatomically specific changes in cerebral glucose metabolism. The majority of brain regions exhibiting REM sleep‐dependent changes in glucose metabolism either overlapped with regions known to contain cholinergic cell bodies, or with areas that receive prominent cholinerg

ISSN:0092-7317    

DOI:10.1002/cne.903040402

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

年代:1991

数据来源: WILEY

摘要:

AbstractPrevious studies of the nerve terminal protein NT75 in the developing spinal cord have suggested an association between the appearance of NT75 immunoreactivity and the process of synaptogenesis. To examine the time course of NT75 expression further, the current study. Compared the localization of NT75 and the synaptic vesicle protein synaptophysin in the adult and developing rat cerebellum and in cerebellar tissue cultures. In the adult cerebellum, dense NT75 staining is confined to the molecular layer, where it is associated with parallel fiber endings of cerebellar granule cells. During development, NT75 immunoreactivity is first detectable in the cerebellar cortex as a dense band of staining in the deepest portion of the molecular layer at postnatal day 10. The stained zone expands to occupy a progressively greater portion of the molecular layer until about postnatal day 20. Synaptophysin staining occurs in granule cell processes earlier than NT75 and is found throughout the molecular layer by postnatal day 7. Quantitatively, rapid increases in both NT75 and synaptophysin occur in the first three postnatal weeks, with NT75 activity reaching levels exceeding the adult value by 50% over postnatal days 20 through 30, whereas synaptophysin plateaus at near adult levels by postnatal day 20. In cerebellar cultures, NT75 staining in neurites develops over several days, increasing coincidentally with development of synaptic contacts, whereas synaptophysin staining is already present in most neurites after only 1 day in vitro. The results indicate that NT75 expression in developing cerebellar granule cell nerve terminals is closely associated with the appearance of mature nerve terminals, suggesting that the protein may have a role in the formation/stabilization of the synaptic ending or in the mechanisms of synaptic transmission.

ISSN:0092-7317    

DOI:10.1002/cne.903040403

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

年代:1991

数据来源: WILEY

摘要:

AbstractSensory systems rely upon spatially organized projections for the faithful transfer of receptor activity into the central nervous system. While the mammalian olfactory nerve shows a regional topographical organization, data on the sources of variation within this projection are scarce. We evaluated the degree of precision of olfactory bulb glomerular innervation from the olfactory nerve layer (ONL) by making small cuts across the trajectory of the olfactory nerve fibers and assessing the resulting denervation by wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) labeling of primary nerve fibers. In control animals (no ONL cut), the ONL and glomerular layer showed intense labeling around the entire circumference of the bulb. Transneuronal labeling of the mitral cell layer and the external plexiform layer was also observed in animals surviving at least 2 days, which allowed us to study the nerve fiber innervation of second order cells as well. ONL cuts on the lateral face of the bulb produced a stripe of denervation, as evidenced by the absence of primary and transneuronal label in a well‐defined region. Fascicles of fibers within the ONL were never observed to enter the denervated region from more than one or two glomerular widths away, indicating a relatively tight limit of variation in the spatial termination of olfactory nerve fibers on the lateral bulb surface. This limit of variation does not hold around the circumference of the bulb since similar ONL cuts on the dorsal surface failed to produce a distinct stripe of denervation. Field potential measurements from the ONL after similar cuts supported the anatomic findings. These results show that primary olfactory axons and their terminals lie in parallel along the lateral face of the olfactory bulb. These spatial relationships of olfactory input to the bulb are maintained in the second order connections. This organization allows one to study the spatial aspects of interneuronally mediated synaptic mechanisms involved in olfactory c

ISSN:0092-7317    

DOI:10.1002/cne.903040404

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

年代:1991

数据来源: WILEY

摘要:

AbstractPlasticity of spinal systems in response to lumbosacral deafferentation has previously been described for the cat, by using immunocytochemistry to demonstrate plasticity of tachykinin systems and degeneration methods to demonstrate plasticity of descending systems. In this study, we describe the response to lumbosacral deafferentation in the adult rat. Application of immunocytochemical methods to visualize tachykinins (predominantly substance P [SP]), serotonin (5‐HT), and dopamine B‐hydroxylase (DBH), the synthesizing enzyme for norepinephrine, permits us to compare the response of SP systems in rat and cat spinal cord and to examine the response of two descending systems, serotoninergic and noradrenergic, to deafferentation. We used image analysis of light microscopic preparations to quantify the immunoreaction product in the spinal cord in order to estimate the magnitude, time course and localization of changes induced by the lesion. The distribution of SP, serotoninergic (5‐HT), and noradrenergic staining in the spinal cord of rat is very similar to that of the cat. Unilateral lumbosacral rhizotomy elicits a partial depletion, followed by a partial replacement of tachykinin immunoreactivity in laminae I and II. This response was similar to that described for the cat, although characterized by a longer time course, and, as in the cat, is likely due to plasticity of tachykinin containing interneurons. The same lesion elicits no depletion but a marked and permanent increase in 5‐HT immunoreactivity in laminae I and II, which develops more rapidly than the response by the SP system. These results indicate sprouting or increased production of SP and 5‐HT in response to deafferentation. No change was seen in DBH immunoreactivity, indicating that the noradrenergic system does not show plasticity in response to deafferentation. Our results demonstrate that dorsal rhizotomy evokes different effects in different systems in the adult spinal cord of the rat and thus suggests that the response of undamaged pathways to partial denervation of their target is regulated rather th

ISSN:0092-7317    

DOI:10.1002/cne.903040405

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe topographic organization of neostriatal connections was investigated by axonal transport of horseradish peroxidase, tritiated amino acids, or mixtures of both injected into the neostriatum of macaque monkeys. Striatal projections to pallidum and substantia nigra and the origin of projections to striatum from cerebral cortex and substantia nigra were examined. All striatal injections gave rise to projections to external and internal pallidum and to substantia nigra. Injections in caudate nucleus and in putamen both gave rise to substantial projections to pallidum and to substantia nigra, and the ratio of pallidal and nigral projections was generally similar.The striatopallidal projection showed prominent arborizations at right angles to the striatofugal pathway traversing the pallidum, forming in this manner terminal fields consisting of multiple bands or discs within a broad segment of the pallidum. Thus separate but neighboring regions of striatum appeared to have overlapping pallidal projection territories. In broad terms, rostral striatum projects to rostral pallidum, caudal striatum to caudal pallidum, and dorsal and ventral striatum, respectively, to dorsal and ventral pallidum. Inner (medial) and outer (lateral) putamen showed only subtle differences in pallidal projection patterns.The striatonigral projection from each injected area of striatum formed a longitudinal band extending over the entire length of the substantia nigra, with scattered, dense terminal fields occupying portions of pars compacta as well as pars reticularis. Rostral striatum projected to medial nigra and caudal striatum to lateral nigra. Terminal fields from ventral striatum were located somewhat more dorsally in the substantia nigra than those from dorsal striatum. Neighboring but separate regions of striatum appeared to have overlapping nigral projection territories, especially in caudal nigra. The nigrostriatal neurons projecting to an injected area of striatum generally were located in the same longitudinal band of the substantia nigra as the corresponding striatonigral projection. Labeled pars compacta neurons were often surrounded by a dense, labeled striatonigral terminal field, suggesting the existence of a striato‐nigrostriatal loop. The rostromedial pars compacta contained labeled neuronal cell bodies in most cases, suggesting a widely divergent projection to striatum from this cell group. A slight tendency for preferential cell labeling rostrally in nigra with rostral striatal injection and caudally in nigra with caudal injections was noted. The preferred relationship of lateral nigra with caudal striatum and medial nigra with rostral striatum has implications for clinical expression of Parkinson's disease, which may vary with differential involvement of different nigral cell groups along the medial to lateral axis.In cases of mid‐putamen injection, corticostriatal neuronal perikarya were labeled in a broad frontoparietal zone encompassing most motor and somatosensory areas, while a case of rostral caudate injection displayed labeled cells in four separate cortical zones: cingulate gyrus, prefrontal cortex medial to the sulcus principalis, superior temporal gyrus, and medial temporal cortex (including entorhinal cortex).The projections to pallidum from injected areas of caudate nucleus and from injected areas of putamen showed little overlap. This finding is consistent with the concept of parallel, segregated pathways through the basal ganglia involving regions of neostriatum and pallidum controlled by association cortex and sensorimotor cortex.Neither the striatopallidal projection, nor the striatonigral projection, nor the origin of the nigrostriatal projection, nor the origin of the corticostriatal projection showed a simple point‐to‐point topographical organization, but rather ended in multiple terminal fields of complex organization or originated in multiple cell groups. This complex mode of connectional organization is shared by many other non‐sensory neuronal circuits in the central nervous system and is likely to be a key feature in their

ISSN:0092-7317    

DOI:10.1002/cne.903040406

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

年代:1991

数据来源: WILEY

摘要:

AbstractIn the present study we employed light microscopic immunocytochemical techniques in order to investigate the temporal response of choline acetyltransferase (ChAT) and nerve growth factor receptor (NGFr) within hypoglossal motoneurons following unilateral transection or crushing of the XII nerve or after intraneural injections of ricin into the nerve. In control rats (i.e., sham operated) virtually all the motoneurons of the XII nucleus displayed intense immunolabeling for ChAT and were devoid of NGFr immunoreactivity. As early as 3 days post‐operative the intensity and the number of ChAT‐labeled neurons were reduced on the axotomized side compared to the non‐lesioned side. This decrease was maximal approximately two weeks post‐operative when virtually no ChAT‐labeled cells were present on the lesioned side. In contrast, no loss of hypoglossal neurons was found using Nissl stains. This absence of ChAT immunolabeling persisted for several days, yet by 30 days many of the motoneurons had begun to re‐express the enzyme.In contrast to the decrease in ChAT immunoreactivity, transection of the XII nerve also resulted in the expression of NGFr immunoreactivity within the lesioned motoneurons. This response was detected as early as one day post‐operatively and continued throughout all time points thus far examined including times after many of the motoneurons had begun to re‐express ChAT.Crushing of the XII nerve effected the expression of ChAT and NGFr in a manner comparable to, yet less intense than, that observed following transection.Ricin injected directly into the XII nerve resulted in the loss of hypoglossal motoneurons as demonstrated both in immunohistochemical and Nissl‐stained tissue preparations. The cell loss was readily apparent 3 days post‐operatively, and ChAT immunoreactivity permanently disappeared. NGFr immunolabeling was seen only in scattered surviving neurons but not in ricin poisoned cells.The possible mechanisms underlying the differential expression of ChAT and

ISSN:0092-7317    

DOI:10.1002/cne.903040407

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

年代:1991

数据来源: WILEY

摘要:

AbstractWe have used in situ hybridization techniques to describe the cellular distribution of transcripts from aDrosophilagene that encodes multiple FMRFamide‐related neuropeptides. TheDrosophila FMRFamidegene consists of two exons and is expressed predominantly as a ∼ 1.7 kb RNA throughout postembryonic stages (Nambu et al., '88; Schneider and Taghert, '88, '90). We used exon‐specific oligonucleotide probes to assay transcription in both embryonic and larval stages and found a pattern of hybridization signals that was restricted to the central nervous system and, within that tissue, was cell‐specific. The pattern included 36 distinct signals distributed throughout both the brain and segmental nerve cord (ventral ganglion). These observations suggest that the cell‐specific pattern of FMRFamide‐like neuropeptide expression in theDrosophilaCNS (White et al., '86; Taghert and Schneider, '90) is due to the restricted expression of specific gene transcripts. The results also indicate that, with few exceptions, all previously identified FMRFamide‐immunoreactive neurons inDrosophilalarvae expressFMRFamidegene transcripts. The 36 hybridization regions of the CNS could be divided into three categories, based on their signal intensities (strong, moderate, and weak). The differences in intensity were reproducible and suggest that steady‐state levels of specific neuropeptide RNA differ among individual neurons. The two exon‐specific probes produced patterns that were indistinguishable both in pattern and in intensity. This result supports the previous conclusion that the one detectableFMRFamidetranscript contains both exons (Schneider and Taghert, '90). A single identifiable signal was detected during embryogenesis (beginning at stage 16), but the mature complement of signals was not fully established until the fi

ISSN:0092-7317    

DOI:10.1002/cne.903040408

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

年代:1991

数据来源: WILEY

摘要:

AbstractWe have studied changes in the pattern of specific neuropeptide gene expression during the metamorphosis of theDrosophilanervous system. Prior to metamorphosis, theDrosophila FMRFamidegene is expressed exclusively within the central nervous system in a stereotyped pattern that comprises roughly 60 neurons (Schneider et al., '91). Using in situ hybridization, we found that theFMRFamidegene was continuously expressed throughout all stages examined: at each of 15 stages of adult development and through at least the first 10 days of adult life. There were no differences between the results observed with 2 exon‐specific hybridization probes, thus indicating little if any alternative splicing during postembryonic development. Despite many changes in the positions of individual hybridization signals due to the large‐scale reorganization of the nervous system, the continuous pattern of gene expression through adult development permitted many adult signals to be identified as larval signals. We concluded that the adult pattern ofFMRFamidegene expression was largely derived from persistent larval neurons. Adult‐specific hybridization signals in the brain and ventral ganglion were also detected and these corresponded to many of the ∼ 40 adult‐specific FMRFamide‐immunoreactive neurons. One specific larval signal was lost during adult development and the intensities of other signals fluctuated in reproducible manners. These stereotyped differences in hybridization signal intensity resemble similar observations made in larval stages (Schneider et al., '91) and support the hypothesis that the steady‐state levels ofFMRFamidetranscripts are differentially regulated among the diverse neurons that exp

ISSN:0092-7317    

DOI:10.1002/cne.903040409

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

年代:1991

数据来源: WILEY

摘要:

AbstractImmunohistochemical techniques were used to visualize areas of the brain and spinal cord containing a galaninlike peptide in the teleost fish, the sailfin molly. Galaninlike immunoreactivity (GAL‐LI) in both males and females was identified in neurons in the nucleus preopticus periventricularis, nucleus lateralis tuberis, and nucleus commissuralis. GAL‐LI fibers had a comparable distribution in the forebrain, preoptic, hypothalamic, and visceral sensory areas of both sexes. In striking contrast to these areas, the optic tectum, torus semicircular is, brainstem tegmentum, and spinal cord of the male contained much higher levels of GAL‐LI than the female. GAL‐LI in these dimorphic areas in the female was limited to single fiber bundles in the ventromedial tegmentum and in the trigeminal system. Additionally, a population of neurons in the preoptic nucleus was found to contain GAL‐LI in the male only.Sexual dimorphism was especially prominent in the spinal cord, where extensive GAL‐LI fibers were found in the male only. These fibers were oriented in the longitudinal plane and confined largely to the gray matter. Comparative studies were performed on the goldfish spinal cord, in which GAL‐LI was localized solely in the dorsal horn and exhibited no sexual dimorphism. Further, examination of spinal cord material from neonatal mollies revealed a lack of spinal GAL‐LI at this developmental stage. As the extent of GAL‐LI in the male molly spinal cord differs from both the goldfish and from that reported for the mammalian spinal cord, and a prominent sexual dimorphism in GAL‐LI extends from the diencephalon to the caudal spinal cord, it is suggested that a galaninlike peptide may play a unique, sex‐specific

ISSN:0092-7317    

DOI:10.1002/cne.903040410

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

年代:1991

数据来源: WILEY

摘要:

AbstractA galaninlike peptide has a sexually dimorphic distribution in the teleost fish, the sailfin molly. An extensive system of galanin‐like immunoreactive (GAL‐LI) fibers has been described in the brainstem and spinal cord of the male molly, which is absent in the female (Cornbrooks and Parsons, companion paper). As GAL‐LI in the mammalian spinal cord has been localized to neurons of origin in the dorsal root ganglia and dorsal and ventral horns, the present study was undertaken to determine whether the sexually dimorphic GAL‐LI in the male molly may originate in part from corresponding sources in this species.Colchicine treatments of the spinal cord and dorsal root ganglia did not result in GAL‐LI staining in neuronal somata in these regions. Following complete transection of the spinal cord and at any level of the spinal cord, there was a complete absence of GAL‐LI caudal to the lesion site. In fish that received unilateral spinal transection, there was a loss of GAL‐LI ipsilateral and caudal to the lesion. Finally, in fish that received lesions in the rostral hypothalamus, there was a complete loss of GAL‐LI in the sexually dimorphic fiber system in the brainstem and spinal cord, but not in non‐dimorphic GAL‐LI regions of the brainstem. Thus the sexually dimorphic fiber system in the male molly may originate in neurons of the preoptic nucleus that are sexually dimorphic for a GAL‐LI peptide. This preoptico‐spinal pathway may mediate sex‐specific

ISSN:0092-7317    

DOI:10.1002/cne.903040411

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

年代:1991

数据来源: WILEY