摘要:

AbstractAntibodies to the intracellular calcium binding protein parvalbumin were shown to label specifically a distinct group of neostriatal GABAergic neurons. These neurons corresponded to the intensely staining subclass of neostriatal GABAergic neurons that have previously been shown to be a class of aspiny interneurons in the neostriatum. The parvalbumin neurons were aspiny neurons with varicose dendrites distributed throughout the neostriatum in a pattern identical to the intensely stained GABA neurons, and both populations of neurons showed increased numbers in the lateral part of the neostriatum. Double labeling of single neurons with both the GABA and parvalbumin antisera showed that all parvalbumin neurons were positive for GABA, but some GABA labelled neurons were not immunoreactive for parvalbumin. These parvalbumin‐negative GABAergic neurons were morphologically similar to the spiny projection neurons, which are GABAergic but usually are not so heavily stained. The relationship of the GABA‐containing parvalbumin neurons to the striatal mosaic organization was determined by using immunocytochemistry for another calcium binding protein, calbindin D28K, to label the matrix compartment of the striatum. The distribution of parvalbumin‐positive neurons relative to the calbindin‐positive matrix and calbindin‐poor patches was determined by using pairs of adjacent sections stained with the calbindin and parvalbumin antisera. This analysis showed that the somata of the parvalbumin neurons were present in both patch and matrix compartments, and their axons and dendrites crossed the boundaries between compartments. A quantitative analysis of the number of neurons in each compartment revealed that the neurons showed no preferential distribution in either compartment, but instead were present according to the area occupied by that compartment. Approximately 10% of parvalbumin neurons were in the patch compartment, and in these same sections, the patch compartment occupied approximately 10% of the area of those sections. Staining with parvalbumin antibodies can therefore be used to identify a single class of GABAergic aspiny interneurons that is present in both patch and matrix compartments, and whose processes cross the borders between these com

ISSN:0092-7317    

DOI:10.1002/cne.903020202

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe three‐dimensional organization of dentate granule cell dendritic trees has been quantitatively analyzed with the aid of a computerized microscope system. The dendrites were visualized by iontophoretic injection of horseradish peroxidase into individual granule cells in the in vitro hippocampal slice preparation. Selection criteria insured that the analyzed cells were completely stained and that only neurons with two or fewer cut dendrites in the distal portion of the molecular layer were analyzed. Twenty‐nine of the 48 sampled granule cells had no cut dendrites.The granule cells had between one and four primary dendrites. Granule cell dendritic branches were covered with spines and most extended to the hippocampal fissure or pial surface. The mean total dendritic length was 3,221 μm with a range from 2,324 μm to 4,582 μm. The dendrites formed an elliptical plexus with the transverse spread averaging 325 μm and the spread in the septotemporal axis averaging 176 μm. On individual neurons, the maximum branch order ranged from four to eight and the number of dendritic segments ranged from 22 to 40. Approximately 63% of the dendritic branch points occurred in a zone that included the granule cell layer and the inner one‐third of the molecular layer. The dendritic tree was organized so that, on average, 30% of the length was in the granule cell layer and proximal third of the molecular layer, 30% was in the middle third, and 40% was in the distal third. Comparisons were made between the dendrites of granule cells in the suprapyramidal and infrapyramidal blades of the dentate gyrus. Suprapyramidal cells had a significantly greater total dendritic length than infrapyramidal cells, their transverse spread was higher, and they had a greater number of dendritic segments. When neurons in the suprapyramidal blade were further subdivided on the basis of somal position within the depth of the cell body layer, superficial neurons were found to have a greater number of primary dendrites, more elliptical trees, and larger transverse spreads of their dendrites. There were no significant differences in dendritic segment number or total dendritic length between superficial and

ISSN:0092-7317    

DOI:10.1002/cne.903020203

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe highest molecular weight neurofilament protein (NF‐H) is multiply phosphorylated at epitopes which can be distinguished by specific monoclonal antibodies on Western blots. Eight characterized antibodies were used in immunocytochemistry to examine the tissue distributions of phosphorylated variants of NF‐H in axons of the adult rat spinal cord. The most striking difference in staining was found between axons in the cuneate tract and those in the neighboring dorsal corticospinal tract. Axons in the cuneate tract reacted intensely with antibodies to phosphorylated epitopes of NF‐H and poorly with antibodies to dephosphorylated epitopes of NF‐H, whereas the reverse was the case for the axons of the dorsal corticospinal tract. These differences showed that systematic variations in the phosphorylation of NF‐H in long‐tract axons in the central nervous system occur as a function of cell type. When the cytoskeletons of these axons were compared by electron microscopy, the neurofilaments of the cuneate fibers were seen to be more abundant and formed a latticework, more compactly organized than the neurofilaments of the dorsal corticospinal axons. By comparison, the dorsal corticospinal axons were relatively richer in microtubules than the cuneate axons. Although the cuneate fiber tract contained many more large (greater than 2.0 (μm2) in cross section) axons than did the dorsal corticospinal tract, these differences in cytoskeletal organization were apparent even when myelinated axons of similar sizes (0.4 μm2to 2.0 μm2) were compared. In addition, the number of neurofilaments in cuneate axons in the 0.4 to 2.0 (μm2) size range was significantly better correlated with axon size than was the case for this size range of dorsal corticospinal axons. Thus, the differences seen in the organization of the neurofilament latticework and the phosphorylation of NF‐H between axons found in these two tracts both appeared to be correlated with cell type, and were independent of length or cal

ISSN:0092-7317    

DOI:10.1002/cne.903020204

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe organisation of the olivocerebellar projection to lobules VI, VIII, and IX of the posterior lobe of the rat cerebellum was investigated in detail by using the retrograde tracer wheat germ agglutinin‐horseradish peroxidase. Small, well‐defined rostro‐caudally orientated columns of olive cells were found to project to different parasagittal areas in the posterior lobe. A column of olive cells about 2,000 μm in rostro‐caudal length in subnucleus “c” and nucleus β of the caudal medial accessory olive (MAO) provides climbing fibre input to the most medial part of lobules VI and IX, but this projection is displaced laterally in lobule VIII by a projection from a column of cells about 600 μm in rostro‐caudal length in lateral caudal MAO (subnucleus “a”). It is possible that each of these columns of olivary neurones may be further subdivided in the rostro‐caudal axis so that different sections project to different medio‐lateral parts of the cortex. A fine‐grain ‘sublobular’ localisation may also exist: the projection to midline lobule VIc arises at caudal levels of the olive from a band of cells in the transition region between subnucleus “c” and nucleus β, whilst by comparison the projection from caudal levels of the olive to lobules VIa and VIb arises from cells located more ventrally in nucleus β. Evidence is also presented to confirm that the posterior lobe vermis in the rat extends further laterally than in other mammals and that part of it receives a projection from a column of olive cells, 1,000 μm in rostro‐caudal length, in a newly defined regio

ISSN:0092-7317    

DOI:10.1002/cne.903020205

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe synapses between the filiform hair sensory afferents and giant interneurons (GIs) 1–6 of embryonic and first instar cockroaches,Periplaneta americana, were used to investigate the role of neuronal anatomy in determining synaptic specificity. The pattern of afferent‐to‐GI synapses was first determined by intracellular recording of excitatory postsynaptic potentials (EPSPs). The lateral (L) axon synapses only with GIs 3, 4, and 6, while the medial (M) axon synapses with the contralateral dendrites of all six GIs but with the ipsilateral dendrites only of GIs 1, 2, and 4. The three‐dimensional anatomy of the filiform afferents and GIs was determined by injection of cobalt. There is little anatomical segregation of the filiform afferents; consequently, there is no correlation between the anatomy of the GIs and their synaptic inputs. The M axon and ipsilateral GI3 were studied in more detail by light and electron microscopy. Despite the presence of an anterior M axon branch which loops around the ipsilateral GI3 neurite at a distance of 2 μm, no synapses are formed between them. This lack of synapses is not due to the presence of physical barriers. Investigation of filiform afferents and GIs in embryonic ganglia shows that at no stage are the afferents sufficiently separated for their anatomy to be an important factor in determining the specificity of the synaptic inputs of the GIs. It was postulated that two pairs of complementary cell surface labels would be sufficient to code for this specificity, and that, in GIs 3, 5, and 6, spatial differences in the expression of these labels allow the M axon to distinguish ipsilateral dendrites from contr

ISSN:0092-7317    

DOI:10.1002/cne.903020206

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractCut dorsal root axons regenerate into transplants of embryonic spinal cord and form synapses that resemble those found in the dorsal horn of normal spinal cord. One aim of the present study was to determine whether these axons also regenerate into and establish synapses within transplants of embryonic brain. A second aim was to compare the patterns of growth in embryonic brain and spinal cord transplants.Embryonic spinal cord or brain was transplanted into the lumbar enlargement of adult Sprague‐Dawley rats, the L4 or L5 dorsal root was cut, and the cut root was juxtaposed to the transplant. The transplants included whole pieces or dissociated cell suspensions of embryonic day 14 (E14) spinal cord, or whole pieces of E14 neocortex, E18 occipital cortex, E15 cerebellum, or E18 hippocampus. One month later the regenerated dorsal root axons were labeled by immunocytochemical methods to demonstrate calcitonin gene‐related peptide (CGRP).CGRP‐immunoreactive axons regenerated into all the transplants examined and formed synapses in the neocortex and cerebellum transplants in which they were sought. Synapses were far rarer in neocortex and cerebellum than we had observed previously in transplanted spinal cord, and the patterns of growth differed in transplants of spinal cord and brain. In solid transplants of spinal cord, regenerated axons remained relatively close to the interface with the dorsal root, branched, and formed bundles. Areas of dense ingrowth were separated by regions with few labeled axons. In transplants of brain regions, the regenerated axons were few, unbranched, and appeared as individual fibers rather than in bundles, but they were distributed widely in neocortex transplants. The results of quantitative studies confirmed these observations. The area fraction occupied by regenerated axons in solid spinal cord transplants was significantly larger than in occipital cortex or cerebellum transplants. Distribution histograms of the area occupied in transplants demonstrated that regenerated axons were distributed sparsely but homogeneously in transplants of brain, whereas spinal cord transplants were heterogeneous for regenerated axons and contained areas in which growth was dense or sparse. In contrast, several measurements of axon distribution, including area, longest axis, and length of lateral extension, indicated that CGRP‐labeled axons spread more widely in occipital cortex transplants than in solid transplants of spinal cord or cerebellum.The results indicate that embryonic CNS tissues that are not normal targets support or enhance the growth of severed dorsal roots and suggest that the conditions that constitute a permissive environment for regenerating axons are relatively nonspecific. Embryonic spinal cord, the normal target of dorsal roots, appears to supply additional, more specific cues that enable regenerating axons to grow and arborize within the transplant and to establish relatively normal numbers of synapses. These cues appear to depend at least in part on the integrity of transplant structure, since growth into solid transplants of spinal cord exceeds growth into cell susp

ISSN:0092-7317    

DOI:10.1002/cne.903020207

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractAfferent pathways from the uterus of the cat were labeled by injections of horseradish peroxidase (HRP), wheat germ agglutinin‐HRP, or fluorescent dyes into the uterine cervix and uterine horns. Afferent input to the uterus arises from small to medium size neurons (average size 31 × 28 um) in dorsal root ganglia at many levels of the spinal cord (T12‐S3). The segmental origin correlates with the location of the afferent terminal field in the uterus. Eighty‐seven percent of the dorsal root ganglion cells (average, 822 on one side) innervating the cervix are located in sacral ganglia, whereas 97% of the cells innervating the uterine horn (average 479 on one side) are located in lumbar ganglia. Double dye labeling experiments indicate that, a small percentage (average 15%) of lumbar neurons innervating the uterine cervix also innervate the uterine horn. The majority (70‐80%) of afferent input to the uterine cervix passes through the pelvic nerve and the remainder through the pudendal nerve, whereas afferent input to the uterine horn must travel in sympathetic nerves. Ovariectomy (10‐14 days) did not change significantly the number, sizes, or segmental distribution of uterine afferent neurons. In some cats (25%) injections of WGA‐HRP into the uterine cervix labeled neurons (90‐125 per animal) in lamina VII in the S2spinal segment in the region of the sacral parasympathetic nucleus.Central projections of uterine horn afferent neurons were not labeled; however, afferent projections from the cervix were detected in the sacral spinal cord. The most prominent labeling was present in Lissauer's tract and in lamina I and outer lamina II on the lateral edge of the dorsal horn. From this region some labeled axons extended through lamina V into the dorsal gray commissure. Very few afferents were labeled on the medial side of the dorsal horn. These results are discussed in regard to the physiological function of uterine afferents and the possible transmitter role of vasoactive intestinal polypeptide, which is present in a large percentage (70%) of cervical af

ISSN:0092-7317    

DOI:10.1002/cne.903020208

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThis study deals with the neurochemical characterization of the rat lateral septal area (LSA) somatospiny neurons and their innervation by hippocamposeptal, Catecholaminergic, and GABAergic fibers. Electron microscopic single and double immunostaining methods were used to label Catecholaminergic fibers and GABAergic cells and boutons. Axon terminals originating in the hippocampus were labeled by acute anterograde axon degeneration induced by fimbria‐fornix transection 36 hours before sacrifice. Three types of experiments were performed. The convergent Catecholaminergic and hippocamposeptal innervation of LSA somatospiny neurons was studied by combining immunostaining for tyrosine hydroxylase (TH) with fimbria‐fornix transection. GABAergic neurons and their hippocamposeptal afferents were identified and characterized in colchicine pretreated animals immunostained for glutamic acid decarboxylase (GAD) combined with fimbria‐fornix transection. The third experiment aimed at simultaneously visualizing the relationships between Catecholaminergic boutons, hippocamposeptal excitatory amino acid containing axon terminals and GABAergic profiles by double immunostaining for TH (the PAP technique) and GAD (the immunogold method) combined with fimbria‐fornix transection. The results are summarized as follows: (1) The same LSA somatospiny neurons receive synaptic inputs from the hippocampus and TH immunoreactive fibers which form pericellular baskets around these cells. (2) LSA somatospiny neurons are GABAergic and are postsynaptic targets of GABAergic boutons with unknown origin and hippocamposeptal axon terminals. (3) The double immunostaining experiment, finally, provided direct evidence that thesameGABAergic somatospiny neurons are postsynaptic targets of both Catecholaminergic and hippocamposeptal afferents. The synaptic interconnections described in this study provide anatomical basis for a better understanding of the action of catecholamines, excitatory amino acids, and GABA on the activity of LSA

ISSN:0092-7317    

DOI:10.1002/cne.903020209

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of tyrosine hydroxylase‐like immunoreactivity was mapped in whole‐mount preparations of the brain of fifth instarRhodnius prolixusStål. Immunoreactivity was limited to neuronal cell bodies and processes, which were distributed over both ventral and dorsal surfaces of the CNS. The brain, excluding the optic lobes, contained about 160 tyrosine hydroxylase‐like immunoreactive cells. Each optic lobe contained two groups of small round cell bodies, which were too numerous to count. The wide distribution of immunoreactivity suggests that tyrosine hydroxylase is present in neurons with diverse central functions. Tyrosine hydroxylase is the rate‐limiting enzyme in catecholamine synthesis in vertebrates. A comparison of a map of the distribution of catecholamine‐induced fluorescence obtained using the glyoxylic‐acid technique (Flanagan;J. Insect Physiol.30(9):697‐704, 1984) with that generated for tyrosine hydroxylase reveals considerable overlap between the two systems, suggesting that tyrosine hydroxylase is used in the catecholamine pathway in this insect. The mapping of these reactive neurons is an important step for identification of unique tyrosine hydroxylase‐containing neurons, and is our initial step in the analysis of identified catecholamine‐containing neu

ISSN:0092-7317    

DOI:10.1002/cne.903020210

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractAfferent and efferent connections of the fastigial oculomotor region (FOR) were studied in macaque monkeys by using axonal transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA‐HRP). When injected HRP is confined to the FOR, retrogradely labeled cells appear in lobules VIc and VII of the ipsilateral vermis and in group b of the contralateral medial accessory olive (MAO). In reference to the maps of topographical organization, the extent of the effective site in the fastigial nucleus (FN) could be assessed from the distributions of labeled Purkinje cells (P cells) in the vermis and labeled olivary neurons in the MAO.In contrast to the unilateral nature of the P‐cell and climbing‐fiber projections, those from the other brainstem regions to the FOR were bilateral. Following the injection of HRP into the FOR, the largest number of retrogradely labeled cells appeared in the pontine nuclei. Although the number of labeled cells was greater on the contralateral side in both the peduncular and dorsomedial pontine nuclei (DMPN), the number on each side was virtually identical in the dorsolateral pontine nucleus (DLPN). In the nucleus reticularis tegmenti pontis(NRTP), labeled cells were located only in its medial and dorsolateral portions bilaterally. In the vestibular complex, labeled cells appeared in the superior (SVN), medial (MVN), and inferior vestibular nuclei (IVN) bilaterally. The lateral vestibular nucleus (LVN), including y group and the ventrolateral vestibular nucleus, were free of labeled cells. Labeled cells appeared also in the perihypoglossal nucleus (PHN) bilaterally. In the pontine raphe (PR) and paramedian pontine reticular formation (PPRF), labeled cells appeared bilaterally in the caudal third of the area between the oculomotor and abducens nuclei. Labeled cells appeared also in the mesencephalic and medullary reticular formation.Tracing of anterogradely labeled axons demonstrated that most fibers from the FOR decussated within the cerebellum and entered the brainstem via the contralateral uncinate fasciculus. Some crossed fibers ascended with the contralateral brachium conjunctivum and terminated in the midbrain tegmentum. A small contingent of fibers advanced further to the thalamus. In the mesodiencephalic junction, labeled terminals were found contralaterally in the rostral interstitial nucleus of medial longitudinal fasciculus (riMLF) and a medial portion of Forel's H Field. They appeared also in the central mesencephalic reticular formation (cMRF), the periaqueductal gray (PAG), the posterior commissure nucleus, and the superior colliculus. The oculomotor and trochlear nuclei, the red nucleus, and the interstitial nucleus of Cajal were free of labeled terminals.The projections from the FOR to the vestibular complex were bilateral and were mainly to the ventral portions of the LVN and IVN. The ipsilateral fibers emerged with the juxtarestiform body. The PHN, the SVN, and the MVN were free of terminals. Crossed fibers arising from the FOR terminated in a caudal portion of the PR, the PPRF, the DMPN, the NRTP, and the dorsomedial portion of the medullary reticular formation (DMRF). Labeled terminals in the DMRF were also found on the ipsilateral side, although the contralateral side was predominant. When the HRP injection involved a fastigial area rostral to the FOR, labeled terminals appeared also in the PHN, SVN, MVN, and DLPN of the contralateral

ISSN:0092-7317    

DOI:10.1002/cne.903020211

出版商:Wiley‐Liss, Inc.    

年代:1990

数据来源: WILEY