摘要:

AbstractTo determine hypophysiotrophic thyrotropin‐releasing hormone (TRH)‐producing neurons in the rat hypothalamus, we employed a combination of the immunohistochemistry for TRH prohormone (pro‐TRH) and the retrograde tracing of neurons that project to the median eminence (ME) by injecting biotinylated wheat germ agglutinin (WGA) into the ME. In intact rats, immunoreactive pro‐TRH‐positive neurons occurred in the parvicellular paraventricular nucleus (parvi‐PVN), basal part of the anterior and lateral hypothalamus, perifornical area and dorsomedial nucleus, especially accumulating in the parvi‐PVN. Twenty‐four hours after injection of the WGA into the middle portion of the ME., we found neurons that incorporated the lectin in the anterior periventricular area, the PVN, and the arcuate nucleus. When we examined serial sections consecutively stained. with anti‐WGA, anti‐pro‐TRH, and anti‐WGA, most of the pro‐TRH‐labeled neurons in the medial parvi‐PVN and a part of the neurons in the anterior periventricular area and in the anterior, lateral, and dorsal parvi‐PVN appeared to incorporate WGA. These neurons may correspond with the hypophysiotrophic TRH‐synthesizin

ISSN:0092-7317    

DOI:10.1002/cne.903070402

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

年代:1991

数据来源: WILEY

摘要:

AbstractCentral axons of sensory ganglion (SG) neurons of theXenopustail enter the spinal cord via the ventral roots and travel dorsally and rostrally following a diagonal course within the lateral marginal zone (LMZ) to reach the dorsolateral fasciculus (DLF) (Nordlander et al.:Brain Res., 440:391–395, 1988). Axons are dispersed as they cross the cord. At the DLF they turn and travel together rostrally, sharing the fascicle with axons of primary sensory neurons (Rohon‐Beard cells) already present in the tract. In this paper we analyze the growth patterns of the central projections of SG axons in the tail by using HRP applied to proximal branches of tail spinal nerves. Growth cones of the diagonal route are variable in configuration, often bearing processes that spread within the LMZ. Once in the DLF, growth cones change shape, becoming distinctly linear. While growth cones navigating the diagonal part of the route never contact or fasciculate with other diagonal SG axons, SG growth cones and axons of the DLF are more closely associated with their fellows. Measurements of the slopes of SG axons in the diagonal route indicated a limited range with a mean of 23° with respect to the cord axis. On the basis of these observations, we conclude that 1) navigational patterns for growth cones of this pathway differ for the diagonal versus the DLF part of its course, and 2) fasciculation is not a mechanism used by SG axons to reach the DLF, but that instead, each axon is able to find its way independe

ISSN:0092-7317    

DOI:10.1002/cne.903070403

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe synaptic relationships of glycine immunoreactive amacrine cells in the cat retina were studied through the use of postembedding immunogold techniques. Glycine immunoreactive amacrine cells were found to synapse extensively with other amacrines and ganglion cells, particularly in strata 1–3 of the inner plexiform layer. This contrasts with GABA immunoreactive amacrine cells which provide major input to bipolar cells in strata 3–5. Glycine containing amacrine terminals exhibited diversity with respect to the morphology of their synaptic vesicles. The three types of terminals which could be distinguished were characterized by small pleomorphic (32–35 nm), medium‐sized flattened (38–45 nm), or larger rounded (48–55 nm) vesicles.Comparison of retinal sections processed for glycine immunoreactivity with adjacent sections stained for GABA reactivity revealed a colocalization of glycine and GABA in 3% of the cells in the amacrine layer and approximately 40% of the cells in the ganglion cell layer, The amacrine terminals in which glycine and GABA were colocalized typically contained the small pleomorphic type

ISSN:0092-7317    

DOI:10.1002/cne.903070404

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study its connections with the diencephalon and corpus striatum. The specificity of SEF pathways was determined with horseradish peroxidase (HRP) histochemistry to compare its connections with those of the arcuate frontal eye field (FEF), contiguous dorsocaudal area 6 (6DC), and primary motor cortex (M1, arm/hand region). Results indicate that patterns of SEF connectivity were similar to the FEF and markedly different from areas GDC and Ml. Primary reciprocal thalamic pathways of the SEF were with the magnocellular ventral anterior (VA) nucleus, medial parvicellular VA, medial area X, and paralaminar medialis dorsalis (multi‐formis and parvicellularis). FEF showed similar connections but its most robust pathway was with MD rather than VA. In contrast, area 6DC showed the most extensive reciprocal connections with lateral VApc and lateral area X with only sparse connections with paralaminar MD. Area 6DC also exhibited reciprocal connections with the ventral lateral (VL) complex and the ventral posterior lateral nucleus, pars oralis (VPLo). M1 showed dense bidirectional connections with VPLo, and to a lesser extent, with VL. M1 pathways with the medial dorsal nucleus were negligible. All areas exhibited connections with the paracentral and central lateral nuclei and only M1 lacked connections with the central superior lateral nucleus.SEF and FEF exhibited similar efferent projections to the caudate and putamen. In the caudate, terminal fields were restricted to a central longitudinal core while those from area 6DC were more widely distributed. Eye field efferents were restricted to the putamen's face region while 6DC projections were more exuberant. The arm/hand region of Ml projected to the arm/hand region of the putamen.Pathways are discussed with respect to their significance in oculomotor contro

ISSN:0092-7317    

DOI:10.1002/cne.903070405

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

年代:1991

数据来源: WILEY

摘要:

Abstractγ‐Aminobutyric acid (GABA) immunoreactive neurons in the cephalic, somatic, and caudal regions of theAscarisnervous system were visualized with serial section and whole‐mount GABA immunocytochemistry. In the ventral and dorsal nerve cords, GABA‐ like immunoreactivity (GLIR) is localized to the neurites and cell bodies of identified inhibitory motor neurons and to two fibers, one in each cord, that arise from neurons in the nerve ring. GLIR is absent from identified excitatory motor neurons and from ventral cord interneurons. In neurons containing GLIR, immunoreactivity was present throughout the cell, which argues against an exclusive localization of GABA at conventional synapses.In whole mounts, ten GABA‐immunoreactive neurons were present in the cephalic region. These include four nerve ring‐associated cells (the RME‐like cells), two bilaterally symmetrical pairs of lateral ganglia neurons (the amphid‐GABA and deirid‐GABA cells) and one bilaterally symmetrical pair of ventral ganglion cells (the VG‐GABA cells). In sections, the RME‐like cells and the VG‐GABA cells were consistently stained through the cephalic region. However, anti‐GABA staining of the lateral ganglia cells in sections was light, thus suggesting that they contain less GLIR than the other more intensely stained GABA‐immunoreactive neurons. In the caudal region, a single GABA‐immunoreactive neuron was present in the dorsal rectal ganglion. Our data suggest that these ten cephalic neurons, and a single dorsal rectal ganglion neuron, us

ISSN:0092-7317    

DOI:10.1002/cne.903070406

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe distribution of uptake sites for the inhibitory neurotransmitter γ‐aminobutyric acid (GABA) in the nematodeAscaris suumwas examined by autoradiography of3H‐GABA uptake. Single neural processes in both the ventral and dorsal nerve cords were labeled with3H‐GABA. Serial section analysis identified the cells of origin of these processes as the RMEV‐like and RMED‐like neurons. These cells belong to a set of four neurons in the nerve ring, all of which are labeled by3H‐GABA.3H‐GABA labeling of at least two other sets of cephalic neurons was seen. One of these pairs consists of medium‐sized lateral ganglia neurons, located at the level of the amphid commissure bundle. A second pair is located in the lateral ganglia at the level of the deirid commissure bundle. The position and size of these lateral ganglia cells suggest that they are the GABA‐immunoreactive lateral ganglia cells frequently seen in whole‐mount immunocytochemical preparations (Guastella et al., J Comp Neurol307:584–597, 1991).Four neuronal cell bodies located in the retrovesicular ganglion were also labeled with3H‐GABA. These cells, which are probably cholinergic excitatory motor neurons, do not contain detectable GABA‐like immunoreactivity. Heavy labeling of muscle cells was also observed. The ventral and dorsal nerve cord inhibitory motor neurons, which are known to contain GABA‐like immunoreactivity, were not labeled above background with3H‐GABA.Together with the experiments reported previously (Guastella et al., J Comp Neurol307:584–597, 1991), these results define three classes of GABA‐associated neurons inAscaris: 1) neurons that contain endogenous GABA and possess a GABA uptake system; 2) neurons that contain endogenous GABA, but that either lack a GABA uptake system or possess a GABA uptake system of low activity; 3) neurons that possess a GABA uptake sys

ISSN:0092-7317    

DOI:10.1002/cne.903070407

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

年代:1991

数据来源: WILEY

摘要:

AbstractMethods involving the anterograde and retrograde transport of wheat‐germ agglutinin conjugated horseradish peroxidase and the retrograde transport of Fluoro‐Gold were used in rats to examine the distribution within the spinal trigeminal nucleus of trigeminal neurons projecting to the nucleus submedius (Sm) of the thalamus, as well as the distribution of axon terminals within the Sm. Following injections into the trigeminal nucleus, axon terminals were seen in the dorsal part of the anterior Sm; the terminals occurred bilaterally but had an obvious contralateral dominance. To help determine the precise location of the Sm‐petal neurons, the border between trigeminal subnuclei interpolaris and caudalis was examined by the use of immunohistochemical procedures for calcitonin gene‐related peptide (CGRP). The Sm‐petal neurons that were labeled retrogradely occurred only at the caudal interpolaris and rostral caudalis levels; the number of labeled neurons on the contralateral side was approximately six times that on the ipsilateral side. Most of these neurons were located in the ventral part of the caudal interpolaris and rostral caudalis and spinal trigeminal tract; in caudalis, the neurons were almost exclusively localized to its superficial layers. There were approximately three times more labeled neurons in interpolaris than in caudalis. In the experiments combined with immunohistochemistry for CGRP, many neurons (34%) were seen in proximity to CGRP‐like immunopositive fibers. These results suggest that the Sm of the rat receives its orofacial afferent inputs from brainstem neurons that are localized to the caudal interpolaris and rostral caudalis. In view of previous studies that have implicated these three structures in somatosensory function, and in particular nociception, our data point to a role for this direct projection from interpolaris and caudalis to Sm in the central process

ISSN:0092-7317    

DOI:10.1002/cne.903070408

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe development of immunoreactivity for the calcium‐binding proteins parvalbumin (PV) and calbindin‐D28K (Cal) was studied inMacaca nemestrinastriate, cortex from fetal (F) 60 days to postnatal (P) 5 + years. We correlated changes in PV and Cal staining patterns with the well‐documented developmental sequence for primate striate cortex neuron generation and maturation, synaptogenesis, and thalamocortical axon interactions in an attempt to deduce a functional role for these proteins.Our major finding is that Cal and PV have diametrically opposed developmental patterns except in layer 1. At F60 days both are present only in neurons of layer 1 and the number of labeled cell bodies and processes increases up to F125 days. Almost all Cal+ and PV+ cells in layer 1 disappear by P12 weeks. Cal is present by F113 days in pyramidal and stellate neurons, particularly layers 4–6. The number and staining density of cells in layers 2–6 increases up to birth and then both decline by P9–12 weeks. Supragranular layers show a second increase in Cal labeling from P20–36 weeks, and then there is a slow decline to the adult pattern which is reached by P1–2 years. Cell bodies in layers 4A, 4Cα, and deep 4Cβ are heavily Cal+ during pre‐and early post‐natal periods, but upper 4Cβ remains unlabeled.PV is not seen until F155–162 days in layers 2–6. Large stellate and a few pyramidal cells appear first in layers 5/6 and 4Cα, but PV + stellate neurons are found in all layers except 4Cβ by P6 weeks. Layer 4Cβ contains a few PV+ cell bodies at P3 weeks, and light neuropile staining at P6 weeks, but then PV labeling rapidly increases so that by P12 weeks the density of 4Cβ exceeds that of 4Cα. Striate cortex has an adult pattern of cell number and neuropile density by P20 weeks.These developmental patterns suggest that the highest density of Cal cell body staining does not correlate with synaptogenesis, or the postnatal critical period of visually driven, binocular interactions. Rather Cal appears when lateral geniculate axons arrive in cortex, persists over the entire span of thalamocortical interactions, and disappears during the decline of cortical plasticity. The appearance of PV is highly correlated with the onset of complex visually driven activity at birth, while both the number of PV+ cell bodies and the density of PV+ neuropile reach adult levels coincident with the completion

ISSN:0092-7317    

DOI:10.1002/cne.903070409

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes the distribution of histamine‐like immunoreactivity in the midbrain and suboesophageal ganglion of the sphinx mothManduca sexta.Intense immunocytochemical staining was detected in ten bilateral pairs of neurons in the median protocerebrum and in one pair of neurons in the suboesophageal ganglion. Whereas most areas of the brain and suboesophageal ganglion are innervated by one or more of these neurons, typically no immunoreactive fibers were found in the mushroom bodies, the protocerebral bridge, and the lateral horn of the protocerebrum. The 11 histamine‐immunoreactive neurons were reconstructed from serial sections. Ten neurons have bilateral arborizations, often with axonal projections in symmetric areas of both hemispheres. One neuron, whose soma resides in the lateral protocerebrum, has only unilateral projections. Of the 11 neurons, 6 occur in pairs with similar morphological features. In addition to these neurons, weak histamine‐like immunoreactivity was detected in 7–13 interneurons that were not reconstructed individually. The central projections of the ocellar nerves from the intracranial ocelli also exhibit histamine‐like immunoreactivity. The single‐cell reconstructions reveal similarities between the organization of histamine‐ and serotonin‐immunoreactive neurons in the brain and suboesophageal ganglion

ISSN:0092-7317    

DOI:10.1002/cne.903070410

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe olfactory glomeruli represent morphological and functional units in which olfactory information is processed in specialized synaptic arrangements established between the central processes of sensory neurons, whose cell bodies are located in the olfactory epithelium, and the terminal (intraglomerular) portions of the dendrites of periglomerular, tufted, and mitral cells. The olfactory glomeruli are surrounded by distinctive glial formations in which the peripheral glia interacts with the central glia. We have studied the morphology and organization of neuroglial cells in the layer of olfactory nerves and the glomerular layer of the olfactory bulb in the insectivorous hedgehog (Erinaceus europaeus) with the electron microscope, Golgi method, and immunohistochemistry by using antibodies to glial fibrillary acidic protein (GFAP) and “rip,” a monoclonal antibody that stains oligodendrocytes and their processes in the rat (Friedman et al.: Glia 2:380–390, 1989).The peripheral glia is represented by a special category of cells that are closely related to astrocytes and known as sheathing cells. They accompany olfactory axons to their entrance in the glomeruli where they interact with the central glia, represented by astrocytes and oligodendrocytes. The sheathing cells typically display indented nuclei and protoplasmic expansions forming laminar processes wrapping several axons together. Astrocytes surrounding the glomerular neuropil belong to the velate type. They display numerous sheet‐like processes enveloping dendritic segments and periglomerular cell bodies. Oligodendrocytes were found surrounding the glomeruli and at the interstices separating different glomeruli. Myelinated dendritic segments and cell bodies were found surrounding the olfactory glomeruli. These myelin coverings probably derive from oligodendrocytes. Together with the astrocytic lamellar expansions, they provide a rigid structural support that contributes to the segregation of groups of different cells while remaining relatively isolated from other influences at the periphery of the gl

ISSN:0092-7317    

DOI:10.1002/cne.903070411

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

年代:1991

数据来源: WILEY