摘要:

AbstractThe relationship between leucine5‐enkephalin‐containing nerve terminals and midbrain dopaminergic neurons was studied in the adult rat by light and electron microscopy. For light microscopy, alternate midbrain sections were immunostained with rabbit polyclonal antibodies against leucine5‐enkephalin and tyrosine hydroxylase, by means of the peroxidase antiperoxidase technique. Leucine5‐enkephalin stained fibers and terminals were observed with varying density in the retrorubral field (dopaminergic nucleus A8 region), substantia nigra pars compacta (dopaminergic nucleus A9 region), and ventral tegmental area and related nuclei (dopaminergic nucleus A10 region). For electron microscopy, midbrain sections were immunostained with a mouse monoclonal antibody against leucine5‐enkephalin and a rabbit polyclonal antibody against tyrosine hydroxylase, by means of the peroxidase antiperoxidase technique and silver‐intensified colloidal gold reactions, respectively. The nucleus A10 area was examined at the electron microscopic level, and there were (a) both symmetric (75%) and asymmetric (25%) synapses made between leucine5‐enkephalin axon terminals and dopaminergic dendrites, and also synaptic contacts with unlabeled dendrites; (b) leucine5‐enkephalin synaptic contacts with dopaminergic dendrites that were covered with astrocytic membranes; and (c) leucine5‐enkephalin appositions with unlabeled nerve terminals that made synaptic contacts with dopaminergic dendrites, suggestive of axo‐axonic connections. These findings provide the structural basis for both direct and indirect control of A10 dopaminergic neurons by enkephalin‐containing nerve terminals.

ISSN:0092-7317    

DOI:10.1002/cne.903320302

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractSulfoglucuronylglycolipids (SGGLs) and glycoproteins, reacting with monoclonal antibody HNK‐1, are developmentally and spatially regulated in the mammalian cortex and cerebellum. It has been proposed that the HNK‐1 carbohydrate epitope is involved in intercellular adhesion and cell‐cell interactions. Biochemical analysis and immunocytochemical localization of SGGLs and other neolacto series glycolipids were studied in the leaner mutant mouse cerebellum, where a slow and progressive rostral to caudal degeneration occurs with a gradual loss of both granule cells and Purkinje cells. Biochemical analyses showed that SGGLs and other neolacto series of glycolipids were significantly decreased in the adult leaner cerebellum; however, HNK‐1‐reactive glycoproteins were not affected. By an immunocytochemical method which selectively localizes the lipid antigens, it is shown that SGGLs are primarily associated with Purkinje cell bodies and their dendrites in the molecular layer and in cerebellar nuclei where Purkinje cell axons terminate. At postnatal day 30 (P30), SGGL immunoreactivity (rSGGL‐ir) in the leaner cerebellum was reduced moderately compared to normal littermates, which correlated with the minimal degree of Purkinje cell degeneration at this age in leaner and with the biochemical data. At P67 and P90, the SGGL‐ir was significantly more reduced in the leaner as Purkinje cell degeneration proceeded. There was a direct correlation between loss of Purkinje cells and SGGL‐ir in the cerebellar molecular layer. In both normal and young leaner cerebella, the SGGL‐ir in different lobules was not uniform; there were distinct rostrocaudal and mediolateral differences. SGGL‐ir was markedly more intense in rostral than in caudal lobules in the vermis, the dividing line being the region immediately caudal to the primary fissure and rostral to the declival sulcus. In the lateral cerebellum, the SGGL‐ir was less intense than in the vermis and the rostrocaudal difference was not as pronounced. There was also nonuniformity in the intensity of staining in different folia. The rostrocaudal as well as mediolateral differences in the intensity of SGGL‐ir were confirmed independently by biochemical analysis. The differential phenotypic expression of SGGLs and the selective susceptibility to Purkinje cell death in leaner mutant are discussed in relation to the known embryologic and ontogenetic compartmentation of cerebellum.

ISSN:0092-7317    

DOI:10.1002/cne.903320303

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe efferent projections of the suprachiasmatic nucleus (SCN) in the golden hamster have been examined by using the anterograde tracer Phaseolus vulgaris leucoagglutinin (Pha‐L). SCN projections were further localized through a combination of restricted SCN‐lesions and immunocytochemistry for three well‐known peptidergic transmitters contained in SCN neurons, viz. vasopressin (VP), vasoactive intestinal peptide (VIP), and gastrin‐releasing peptide (GRP). Thus, major terminal fields of SCN‐derived VP were detected in the medial preoptic nucleus, the anterior part of the paraventricular nucleus of the thalamus (PVA), the medial parvicellular part of the paraventricular nucleus of the hypothalamus (PVN), and the medial part of the dorsomedial nucleus of the hypothalamus (DMH). VIP‐containing projections from the SCN were discovered in the PVA, anterior and dorsal parvicellular divisions of the PVN, subparaventricular area, and medial DMH. Efferent fibers from the SCN containing GRP were restricted to the subparaventricular area, medial DMH, and supraoptic nucleus. In addition, Pha‐L tracing indicated the existence of SCN projections which could not be ascribed to one of the presently investigated peptides. Furthermore, a pronounced innervation of the contralateral SCN was observed, of which the neurotransmitter remains to be established.The results of the present study indicate that the different neuronal populations in the SCN, as characterized by their transmitter content, also show a clear diversity in their preferential target areas. © 1993 W

ISSN:0092-7317    

DOI:10.1002/cne.903320304

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractIn guinea pigs, intracellular labeling of the dorsal root ganglion (DRG) cells withPhaseolus vulgaris‐leucoagglutinin (PHA‐L) was used to demonstrate the central projections of somatic and visceral afferent C‐fibers. The terminations of the afferent fibers were analyzed qualitatively and quantitatively with the aid of camera lucida drawings. Terminal branches of C‐fibers of both somatic and visceral origin were, in general, distributed in accord with the organization of the neuropil in lamina of the spinal cord. Terminal boutons arranged from longitudinally coursing fibers were distributed in lamina I, while boutons in lamina II were scattered in an apparent random fashion. The synaptic enlargements were counted in gray matter of the spinal dorsal horn and measured on each terminal branch of a fiber. All synaptic boutons (over one thousand) of somatic fibers were found in the superficial dorsal horn (laminae I and II). More than 60% of the synaptic enlargements of the visceral afferents also were localized superficially (lamina I and adjacent dorsal funiculus) while 10–20% of the visceral enlargements appeared in deeper layers of the spinal cord. Boutons of somatic C‐fibers were larger than those of visceral orgin. Quantitative data of the unmyelinated afferent fibers are discussed in the context of the sensory functions of myelinated afferent fibers. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903320305

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractTwo morphological types of neurons in the rostral nucleus of the solitary tract (NST) in the hamster send axons to the parabrachial nucleus (PBN). Elongate cells have oval cell bodies and 2 mediolaterally oriented primary dendrites. Large stellate cells have polygonal cell bodies and 3–5 radiating primary dendrites. Both cell types are located in the rostral central subdivision of the NST, surrounded by primary afferent axons from the oral cavity. This study uses electron microscopy to evaluate the synaptic inputs to horseradish peroxidase (HRP)‐labelled elongate and stellate PBN projection cells.Three types of axon terminals provide most of the synapses on the labelled cells. Primary‐like terminals contain large, clear, round vesicles and engage in asymmetrical synaptic junctions; they resemble gustatory (facial) afferent terminals identified previously (Whitehead, J. Comp. Neurol. 244:72, 1986). Axon terminals containing small, pleomorphic vesicles (SP terminals), form symmetrical junctions, and resemble Golgi II endings. Terminals containing medium‐sized pleomorphic vesicles (MP terminals) form asymmetrical junctions. These types of axon terminals distribute differentially on the labelled cells. Primary‐like inputs are largely restricted to distal dendrites and their spines. SP terminals provide more synaptic coverage than primary‐like or MP terminals; for both cell types the SP inputs are concentrated proximally on dendrites and cell bodies. The data suggest that elongate and large stellate cells function as second‐order projection neurons in the ascending taste system. The density, spatial distribution, and timing of activation of the various types of synapses could relate to the electrophysiological response properties of the projection neurons. © 1993 W

ISSN:0092-7317    

DOI:10.1002/cne.903320306

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe hamster periventricular hypothalamic area has been the focus of functional research concerning photoperiodic time measurement. These studies have relied upon the extensive analysis of rat paraventricular nucleus because there has been a general absence of anatomical description in the hamster. The present work southt to remedy this problem by investigating the structure of the hamster paraventricular nucleus with respect to the localization of cells immunoreactive to vasopressin, oxytocin, or cotricotropin‐releasing factor and of cells projecting to the spinal cord or to vascular sites outside the blood‐brain barrier.The hamster paraventricular nucludus includes the medial, lateral, and posterior magnocellular divisions, the main parvicellular division, as well as the periventricular area and dorsal cap, which are also parvicellular. The magnocellular divisions are characterized by many large neurons immunoreactive to oxytocin and vasopressin, which are generally absent from the parvicellular divisions. In contrast, corticotrophin‐releasing hormone‐immunoreactive cells are plentiful in most of the parvicellular areas. Spinally projecting cells are found in two rostral areas, one dorsally and a second, more ventral area. More caudally, the two regions merge within the posterior magnocellular division. Cells of the ventral group are frequently immunoreactive for one of the three peptides. Cells identified by peripheral injection of retrograde label are found in the rostral magnocellular divisons but not in the caudal posterior magnocellular division. Areas in which these cells also contain peptide are also described. The features of the hamster paraventricular nucleus are compared to those in the rat and apparent species differences are discussed. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903320307

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe brain (supraoesophageal ganglion) is the most complex of the segmental ganglia composing the nerve cord of the locustsSchistocerca gregariaandLocusta migratoria. In this paper, we describe the ground plan of the commissures crossing the midline of the brain and propose a nomenclature with the aim of making a complex neuropil more understandable at the level of individual neurons. For developmental and comparative reasons the neuroarchitecture of the brain is related to the neural axis, not to the body axis. We have identified 73 commissural fiber bundles belonging to the adult brain, and these are named according to their location (ventral, dorsal, anterior, posterior, medial) with respect to the central complex as reference point. Reconstructions of identified neurons from intracellular stainings, cobalt backfills, or immunohistochemical studies demonstrate the various configurations in which fibers cross the brain. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903320308

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractRats that sustained forelimb removal on either embryonic day (E) 16, on the day of birth (P‐0), or transection of the brachial plexus in adulthood had brainstem sections stained for galanin, calcitonin gene‐related peptide (CGRP), or substance P (SP) at various intervals after these lesions were made. In normal adult rats, only a few galanin‐immunoreactive fibers are present in the cuneate nucleus and most are located in its caudal portion. CGRP‐positive axons are also sparse in the cuneate and are distributed mainly in the periphery of the nucleus. SP‐positive axons are seen throughout the cuneate nucleus. In rats that sustained forelimb removals at birth or transection of the brachial plexus in adulthood, dense galanin immunoreactivity was present throughout the cuneate nucleus at all rostrocaudal levels on the side of the brainstem ipsilateral to the lesion. The changes after lesions that were made in the adult animals were apparent within 1 week, the earliest time analyzed. Increases in galanin immunoreactivity in the cuneate of animals that sustained forelimb removals on P‐0 were first visible on P‐2. Neither forelimb removal at birth nor brachial plexus lesions in adulthood had any qualitative effect upon the distribution or density of CGRP‐ or SP‐immunoreactivity in the cuneate nucleus.Removal of a forelimb on E‐16 didnotincrease the density of galanin‐immunoreactive fibers in the cuneate nucleus. Such lesions also failed to produce any appreciable change in the density of either CGRP‐ or SP‐positive fibers in the cuneate nucleus. The present data raise the possibility that large caliber, non‐peptidergic primary afferent axons which innervate the cuneate nucleus may express galanin after damage at birth or in adulth

ISSN:0092-7317    

DOI:10.1002/cne.903320309

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.903320301

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY