摘要:

AbstractThe white matter of the rabbit flocculus is subdivided into five compartments by narrow sheets of densely staining acetylcholinesterase‐positive fibers. The most lateral compartment is continuous with the C2compartment of the paraflocculus and contains the posterior interposed nucleus. The other four compartments are numbered from lateral to medial as floccular compartments 1, 2, 3, and 4 (FC1−4). FC1−3continue across the posterolateral fissure into the adjacent folium (folium p) of the ventral paraflocculus. FC4is present only in the rostral flocculus. In the caudal flocculus FC1and FC3about dorsal to FC2. Fibers of FC1−4can be traced into the lateral cerebellar nucleus and the floccular peduncle. The presence of acetylcholinesterase in the deep stratum of the molecular layer of the flocculus and ventral paraflocculus distinguishes them from the dorsal paraflocculus. The topographical relations to the flocculus and the floccular peduncle with group y and the cerebellar nuclei are discussed. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903560102

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe localization and termination of olivocerebellar fibers in the flocculus and nodulus of the rabbit were studied with anterograde axonal transport methods [wheatgerm agglutinin‐horseradish peroxidase (WGA‐HRP) and tritiated leucine] and correlated with the compartments in the white matter of these lobules delineated with acetylcholinesterase histochemistry (Tan et al. J. Comp. Neurol., 1995, this issue). Olivocerebellar fibers originating from the caudal dorsal cap travel through floccular compartments FC2and FC4to terminate as climbing fibers in floccular zones FZIIand FZIV. Fibers from the rostral dorsal cap and the ventrolateral outgrowth traverse compartments FC1and FC3, which are interleaved with compartments FC2and FC4, and terminate in zones FZIand FZIII. Fibers from the rostral pole of the medial accessory olive traverse the C2compartment and terminate in the C2zone. FZI‐IIIextend into the adjoining folium (folium p) of the ventral paraflocculus. The C2zone continues across folium p into other folia of the ventral paraflocculus and into the dorsal paraflocculus. Four compartments and five zones were distinguished in the nodulus. Medial compartment XC1contains olivocerebellar fibers from the caudal dorsal cap and subnucleus β that terminate in the XZIzone. Olivocerebellar fibers from the rostral dorsal cap and the ventrolateral outgrowth occupy XC2and terminate in XZII. The XC4compartment contains fibers from both the caudal dorsal cap and from the rostral dorsal cap and the ventrolateral outgrowth. The latter terminate in a central portion of the XZIVzone. The dorsomedial cell column projects to the XZIIIzone, which is present only in the dorsal part of the nodulus, The rostral, medial accessory olive projects to the XZVzone, which occupies the lateral border of the nodulus. These results confirm and extend the conclusions of Katayama and Nisimaru ([1988] Neurosci. Res.5:424–438) on the zonal pattern in the olivo‐nodular projection in the rabbit. Additional observations were made on the presence of a lateral A zone (Buisseret‐Delmas [1988] Neurosci. Res.5:475–493) in the hemisphere of lobules VI and VII. Retrograde labeling of the nucleo‐olivary tract of Legendre and Courville ([1987] Neuroscience21:877–891) was observed after WGA‐HRP injections into the inferior olive including the rostral dorsal cap and the ventrolateral outgrowth. The anatomical and functional implications of these observations are discussed. ©

ISSN:0092-7317    

DOI:10.1002/cne.903560103

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractWith the use of retrograde transport of horseradish peroxidase we confirmed the observation of Yamamoto and Shimoyama ([1977] Neurosci Lett.5:279‐283) that Purkinje cells of the rabbit flocculus projecting to the medial vestibular nucleus are located in two discrete zones, FZIIand FZIV, that alternate with two other Purkinje cell zones, FZIand FZIII, projecting to the superior vestibular nucleus. The retrogradely labeled axons of these Purkinje cells collect in four bundles that occupy the corresponding floccular white matter compartments, FC1–4, that can be delineated with acetylcholinesterase histochemistry (Tan et al. [1995a] J. Comp. Neurol., this issue). Anterograde tracing from small injections of wheat germ agglutin‐hoseradish peroxidase in single Purkinje cell zones of the flocculus showed that Purkinje cell axons of FZIItravel in FC2to terminate in the medial vestibular nucleus. Purkinje cell axons from FZIand FZIIIoccupy the FC2and FC3compartments, respectively, and terminate in the superior vestibular nucleus. Purkinje cell axons from all three compartments pass through the floccular peduncle and dorsal group y. In addition, some fibers from FZIand FZII, but not from FZIII, arch through the cerebellar nuclei to join the floccular peduncle more medially. No anterograde tracing experiments were available to determine the projections of the FZIVand C2zones. The functional implications of these results are discussed. © 1995 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903560104

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe immunocytochemical distribution of salmon gonadotropin‐releasing hormone (sGnRH) and chicken GnRH‐II (cGnRH‐II) neurons in the brain of goldfish was examined using respective antisera. Salmon GnRH‐immunoreactive (ir) cell bodies were localized in the area between the olfactory nerve and the olfactory bulb (the terminal nerve ganglion), the ventral telencephalon, the preoptic area, and the hypothalamus. Chicken GnRH‐II‐ir cell bodies were observed in the same areas as were those of sGnRH, although the number of cell bodies were fewer than those of sGnRH. In addition, chicken GnRH‐II‐ir cell bodies were also observed in the midbrain tegmentum where no sGnRH‐ir cell bodies were found. Both sGnRH‐ir and cGnRH‐II‐ir fibers were distributed not only in the hypothalamus and the pituitary gland but also in various brain areas from the olfactory bulb to the spinal cord.The wide distribution of GnRH‐ir fibers suggests that in the goldfish, sGnRH and cGnRH‐II not only regulate gonadotropin release from the pituitary gland but also function as neuromodulators in various brain regi

ISSN:0092-7317    

DOI:10.1002/cne.903560105

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractFifth in star larvae ofManduca sextathat were parasitized by the braconid waspCotesia congregatafailed to develop after the parasitoid larvae emerged, and these host larvae lingered for 2–3 weeks in a quiescent, nonfeeding state without initiating a larval molt or metamorphosis. This study was focused on the neuroendocrine changes associated with the host's developmental arrest. Immunohistochemical studies suggested that the host brain neurosecretory cells as well as their axon terminals in the corpora cardiaca‐corpora allata complex accumulated multiple neuropeptides. The extent of accumulation in cells and axons increased with time, so that hosts examined 7–14 days after the wasps emerged showed the most intense staining with antibodies against prothoracicotropic hormone, bombyxin, allatotropin, allatostatin, diuretic hormone, eclosion hormone, proctolin, and FMRFamide. Increased levels of prothoracicotropic hormone and FMRFamide‐like peptides in the brains of parasitized larvae were confirmed using Western blots and enzyme‐linked immunosorbent assay (ELISA), respectively. Starvation of the unparasitized larvae induced some accumulation of the neuropeptides; however, the intensity of staining and number of immunopositive cells and axons were in most cases clearly higher in the parasitized larvae. Our results suggest that accumulation of the neuropeptides is associated with developmental arrest of parasitized larvae. Because a similar developmental arrest occurs in a wide range of parasitized insects, our findings may have relevance for many other species. Moreover, these data illustrate the potential value of using parasitizedM. sextalarvae as a model for studying the mechanisms governing the rates of neuropeptide expression, processing, packaging, and release, as well as providing a rich source of neuropeptides, thus facilitating their isolation and characterization. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903560106

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractSerotonin neurons are descending interneurons in the myenteric plexus of the guinea pig small intestine. Preembedding single‐ and double‐label immunocytochemistries at the ultrastructural level were used to identify the targets of these serotonin interneurons.Serial ultrathin sections were taken through a myenteric ganglion that had been processed for serotonin immunocytochemistry. The ganglion contained the cell bodies of 69 neurons, including 2 serotonin neurons and 6 neurons with the ultrastructural features of Dogiel type II cells. For each cell body in the ganglion, the number of serotonin inputs (synapses and close contacts) was determined. About 50% of the cell bodies did not receive any serotonin inputs. The most abundant serotonin terminals were related to two targets: other serotonin descending interneurons and a population of neurons with Dogiel type I morphology, but whose neurochemistry and function is unknown. The serotonin inputs to the serotonin cell bodies were located predominantly on the lamellar dendrites. Each of the Dogiel type II neurons received 3 or fewer serotonin inputs, and none of the serotonin inputs to Dogiel type II neurons formed a synapse. Overall, about 40% of the serotonin inputs formed synapses. The serotonin inputs to neurons that received many serotonin inputs were more likely to show synaptic specializations than serotonin inputs to neurons that received few serotonin inputs.Inhibitory motor neurons contain nitric oxide synthase (NOS). At the light microscope level, serotonin nerve fibers do not form dense pericellular baskets around NOS cell bodies. To determine whether there are serotonin input to NOS neurons, serial ultrathin sections were taken through a myenteric ganglion that had been processed for preembedding double‐label immunocytochemistry, in which the NOS neurons were labeled with peroxidase‐diaminobenzidine and the serotonin neurons with silver‐intensified 1 nm gold. Only 1 out of 9 NOS cells examined in serial section received more than 5 serotonin inputs. The results suggest that, in the guinea pig small intestine, the serotonin descending interneurons are not an essential element of the descending inhibitory reflex. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903560107

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the primate striate cortex, cytochrome oxidase (CO)‐rich puffs differ from CO‐poor interpuffs in their metabolic levels and physiological properties. The neurochemical basis for their metabolic and physiological differences is not well understood. The goal of the present study was to examine the relationship between the distribution of gamma aminobutyric acid (GABA)/non‐GABA synapses and CO levels in postsynaptic neuronal profiles and to determine whether or not a difference existed between puffs and interpuffs. By combining CO histochemistry and postembedding GABA immunocytochemistry on thesameultrathin sections, the simultaneous distribution of the two markers in individual neuronal profiles was quantitatively analyzed. In both puffs and interpuffs, GABA‐immunoreactive (GABA‐IR) neurons were the only cell type that received both non‐GABA‐IR (presumed excitatory) and GABA‐IR (presumed inhibitory) axosomatic synapses, and they had three times as many mitochondria darkly reactive for CO than non‐GABA‐IR neurons, which received only GABA‐IR axosomatic synapses. GABA‐IR neurons and terminals in puffs had a larger mean size, about twice as many darkly reactive mitochondria, and a higher ratio of non‐GABA‐IR to GABA‐IR axosomatic synapses than those in interpuffs (2.3:1 vs. 1.6:1;P<0.01). There were significantly more synapses of both non‐GABA‐IR and GABA‐IR types in the neuropil of puffs than of interpuffs; however, the ratio of non‐GABA‐IR to GABA‐IR synapses was significantly higher in puffs (2.86:1) than in interpuffs (2.08:1;P<0.01). Our results are consistent with the hypothesis that the level of oxidative metabolism in postsynaptic neurons and neuronal processes is tightly governed by the strength and proportion of excitatory over inhibitory synapses. Thus, the present results suggest that (1) GABA‐IR neurons in the macaque striate cortex have a higher level of oxidative metabolism than non‐GABA ones because their somata receive direct excitatory synapses and their terminals are more tonically active; (2) the higher proportion of presumed excitatory synapses in puffs imposes a greater energy demand there than in interpuffs; and (3) excitatory synaptic activity may be more prominent in puffs than in interpuffs because puffs receive a greater proportion of excitatory synapses from multiple sources including the lateral geniculate nucleus, which is not known to proj

ISSN:0092-7317    

DOI:10.1002/cne.903560108

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractParvalbumin (PV) is a calcium‐binding protein localized to selected neurons in the nervous system, including the retina. This investigation evaluated the distribution of PV immunoreactivity in the rabbit retina using immunohistochemistry with a monoclonal antibody directed to carp PV. In the inner nuclear layer (INL), PV immunoreactivity was present in horizontal and amacrine cells. In the ganglion cell layer, PV immunostaining was confined to somata that are likely to be both displaced amacrine cells and ganglion cells. PV‐immunoreactive (IR) amacrine cells were positioned in the proximal INL adjacent to the inner plexiform layer (IPL). These cells usually gave rise to a single primary process, which arborized into two distinct bands in the IPL. In sublaminaa, the processes were thin and had large, irregular endings. In sublaminab, multiple processes branched from the primary process and were characterized by varicosities and spines. PV‐IR amacrine cell bodies measured from 8 to 10 μm in diameter. Their density was highest in the visual streak and lowest in the periphery of the superior retina. The average number of PV‐IR amacrine cells was 464,045 cells per retina (N = 3), and the average regularity index of the PV‐IR cell mosaic was 3.23. PV‐IR amacrine cells were further characterized by double‐label immunofluorescence experiments using antibodies to PV and tyrosine hydroxylase (TH). Varicose TH‐IR processes were in close apposition to many PV‐IR amacrine cells and often formed “ring structures” around them. Together, these morphological, quantitative, and histochemical observations indicate that PV immunoreactivity in the INL is localized predominantly to AII amacrine cells, and therefore it is a valuable marker for the identification of this cell type.

ISSN:0092-7317    

DOI:10.1002/cne.903560109

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractA combined anterograde axonal degeneration and Golgi electron microscopic (Golgi‐EM) study was undertaken to identify thalamocortical synaptic connections between axon terminals from the mediodorsal thalamic nucleus (MD) and pyramidal cells in layers III and V of the agranular prelimbic cortex in the rat. The morphological characteristics of thalamocortical synapses from MD were also examined by labeling axon terminals with anterograde transport of wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP).WGA‐HRP labeled axon terminals from MD to the prelimbic cortex were small in size (0.5–1 μm in diameter), contained round synaptic vesicles, and formed axospinous synapses with asymmetrical membrane thickenings. With Golgi‐EM methods, gold‐toned apical dendrites in layer III were analyzed by reconstruction of serial ultrathin sections. Following lesions in the thalamus, degenerating thalamocortical axon terminals formed asymmetrical contacts exclusively on dendritic spines of the identified apical dendrites. More thalamocortical synapses were found on apical dendrites of layer V pyramidal cells than on apical dendrites of layer III pyramidal cells. In addition to thalamocortical synapses, a very few unlabeled symmetrical synapses were found on apical dendrites and somata of pyramidal cells, but they were not quantified and their sources are unknown. ©

ISSN:0092-7317    

DOI:10.1002/cne.903560110

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractSynaptosomal associated protein of 25 kDa (SNAP‐25) has been implicated in the membrane fusion machinery of neurotransmitter release and axonal growth. Using immunocytochemistry, we have analyzed the distribution and ultrastructural localization of SNAP‐25 in selected areas of the central and peripheral nervous systems of adult rats. We show that the protein is specifically expressed in the trans face of the Golgi apparatus and in the axonal compartment. In axons and nerve endings, SNAP‐25 is localized to discrete areas of the membranes of most organelles such as the axoplasmic reticulum, the axolemma, the outer membrane of mitochondria and synaptic vesicles. This wide distribution of SNAP‐25 suggests that the protein is involved in the fusion of membranes in the whole axonal compartment of neurons. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903560111

出版商:Wiley‐Liss, Inc.    

年代:1995

数据来源: WILEY