摘要:

AbstractThe relationships both between cholinergic neurons and substance P (SP) and between cholinergic neurons and calcitonin gene‐related peptide (CGRP) terminals were examined in the rat sacral intermediolateral nucleus at the light and electron microscopic levels by means of double‐immunostaining methods. Cholinergic neurons were labeled by a monoclonal antibody to choline acetyltransferase (CAT) with the avidin‐biotin technique and stained bluish‐green by indolyl‐β‐galactoside reaction products with β‐galactosidase as a marker. On the same sections, SP or CGRP fibers were labeled by polyclonal antisera to SP or CGRP after application of the peroxidase‐antiperoxidase (PAP) method and stained brown by the p‐dimethylaminoazobenzene (DAB) reaction. After embedding in Epon, light and electron microscopic sections were examined. At the light microscopic level, CGRP‐like immunoreactive (CGRP‐I) fibers and SP‐like immunoreactive (SP‐I) fibers were found to pass through the lateral edge of the dorsal horn and then into the dorsal region of the sacral intermediolateral nucleus. In addition, SP‐I fibers also extend from the dorsolateral funiculus into the entire sacral intermediolateral region. At the electron microscopic level, many axosomatic and axodendritic synapses were found between CAT‐I structures and SP‐I terminals in the intermediolateral nucleus, whereas most of the CGRP‐I terminals in this area made axodendritic synapses with CAT‐I dendrites. These results indicate that cholinergic neurons in the sacral intermediolateral nucleus receive direct synaptic input from SP‐I and CGRP‐I terminals. Therefore, it is likely that both SP‐I and CGRP‐I fibers from dorsal root ganglia and intrinsic SP‐I fibers make direct synapses with sacral parasympathetic preganglionic neurons and thus have great importan

ISSN:0092-7317    

DOI:10.1002/cne.902850102

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

年代:1989

数据来源: WILEY

摘要:

AbstractCorrelation of the somatotopic organization of the facial lobe (FL), a primary medullary gustatory nucleus in the channel catfishIctalurus punctatus, with its lobular substructure was investigated to examine a possible structural basis for the excellent ability of ictalurid catfishes to localize a food source in the environment. The FL in the channel catfish is composed of six longitudinal columns (ie., lobules) extending rostrocaudally and differing from each other in their length and location within the lobe. Each lobule receives segregated input from discrete portions of the external body surface. The three more medial lobules in the FL receive input (from medial to lateral) from the medial mandibular barbel, the lateral mandibular barbel, and the maxillary barbel, respectively. The proximal‐distal axis of each of the barbels is represented in a posteroanterior lobule axis. The largest lobule, the face‐flank lobule, is located dorsolaterally in the FL, whereas the anteroposterior body axis is represented in the posteroanterior lobule axis. This indicates that the neural representation of the external body surface of the channel catfish faces caudally in the FL. The two shortest lobules, positioned ventral to the face‐flank lobule, receive input from the nasal barbel and the pectoral fin, respectively. The rostrocaudal dimensions of each of the barbel lobules correlate well with the relative lengths of the barbels. Taste‐sensitive portions within the three barbel lobules examined were generally confined to the dorsal regions, whereas tactile responses were observed throughout the lobules. The present findings indicate that the FL of the channel catfish is highly organized to localize tactile and taste stimulation of the external body surface and further suggest that the barbel lobules of the FL are differentiated into two portions: a dorsal taste and tactile region, and a ventral, primarily tactil

ISSN:0092-7317    

DOI:10.1002/cne.902850103

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

年代:1989

数据来源: WILEY

摘要:

AbstractA group of readily recognized amacrine cells were observed in Golgi‐impregnated and flat‐mounted macaque, baboon, and human retinas. These cells had roughly circular or oval dendritic fields that were narrowly stratified within the inner plexiform layer (IPL). Most of these cells stratified in the inner half (sublamina b) of the IPL, and they had their somata in the ganglion‐cell layer; a few stratified in the outer half (sublamina a) of the IPL and had their somata in the amacrine‐cell layer.Typically, a single dendrite issued from the soma, and, after passing for 10 μm or so, gave rise to five or more radiate processes. As these processes neared the edge of the dendritic field they branched, turned, and became varicose. Most showed no evidence of an axon, although a few had a short process extending inward, toward the optic‐fiber layer. Dendritic‐field diameters were about 100 μm near the fovea and increased to about 350 μm in the peripheral retina. Mean somal diameter also increased slightly from near the fovea (7.8 μm) to the periphery (8.7 μm).Although the primate cells are smaller, and there are some minor differences in the form of the dendritic fields, these cells appear to be morphologically equivalent to thestarburstamacrines of the rabbit retina, whose counterparts have also been observed in the retinas of rats and cats.Presuming that these cells correspond to the choline acetyltransferase immunoreactive primate cells described by Mariani and Hersh (J. Comp. Neurol. 267:269–280, '87), their overlap factor is about ten for the type whose somata lay in the ganglion‐cell layer and about 0.25 for those whose somata lay in the

ISSN:0092-7317    

DOI:10.1002/cne.902850104

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe stomach and small intestine receive an efferent innervation from the dorsal motor nucleus of the vagus (DMX). The current experiments were undertaken as a partial test of the hypothesis that the CNS innervates only a small number of command neurons in a restricted number of enteric ganglia. The anterograde tracerPhaseolus vulgarisleucoagglutinin (PHA‐L) was injected into the DMX by iontophoresis, and 10–21 days later PHA‐L was visualized in the bowel by immunofluoresence. Varicose vagal efferent fibers, labeled by PHA‐L, were found in the myenteric plexus as far distally as the ileo‐colic junction. PHA‐L‐labeled varicose axons were rare in comparison to nonlabeled fibers, entered a minority of myenteric ganglia, and contacted a small proportion of the neurons. Ganglia thus innervated by vagal efferent fibers were more numerous in the stomach than in the small intestine. Within the stomach, these ganglia were more common in the antrum than in the corpus and none were found in the wall of the rumen. Innervated ganglia in the small intestine became progressively more sparse distally. No PHA‐L‐labeled axons were observed in the submucosal plexus, thus raising the possibility that vagal modulation of secretomotor responses involves an intermediate synapse in the myenteric plexus. Nonvaricose bundles of PHA‐L‐labeled fibers were also observed. These bundles appeared to utilize the connectives of the myenteric plexus as a pathway within which to descend within the bowel. Vagal efferent bundles were found to pass through the pyloric sphincter to enter the small intestine from the stomach; thus vagal fibers can reach the distal intestine by an intraenteric route that is not lesioned by crushing mesenteric nerves. The existence of this pathway affects the interpretation of experiments seeking to utilize such lesions to distinguish intrinsic from extrinsic neurites. Possible target neurons of the vagal efferent innervation were identified by simulatneously demonstrating the immunoreactivities of 5‐hydroxytryptamine (5‐HT), vasoactive intestinal polypeptide (VIP), enkephalin (ENK), galanin (GAL), and tyrosine hydroxylase (TH) along with that of PHA‐L. Vagal terminals in the myenteric plexus appeared selectively to contact 5‐HT‐ and, to a significantly lesser extent, VIP‐, but not ENK‐ or GAL‐immunoreactive neurons. Apparent vagal innervation of 5‐HT‐immunoreactive neurons was significantly more common in the duodenum, where a majority of the 5‐HT‐immunoreactive cells were encircled by varicose PHA‐L‐labeled axons, than in the stomach. Some identified vagal efferent axons contained GAL immunoreactivity and a subset of the neurons of the DMX that were labeled by retrograde transport of Fluro‐Gold from the stomach were GAL‐immunoreactive; therefore, a GAL‐like peptide is present in neurons of the DMX that innervate gastric myenteric ganglia. Although TH‐immunoreactive fibers were observed in the vagus nerves, none were found to be doubly labeled by PHA‐L. Most of the TH‐containing axons in the vagus nerves, therefore, are probably not derived from the DMX but are sympathetic postganglionic axons. These observations are consistent with the hypotheses that the vagus nerve innervates a small number of command neurons in the myenteric plexus, that some of these neurons contain 5‐HT or VIP, an

ISSN:0092-7317    

DOI:10.1002/cne.902850105

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn the present study, the anterograde tracerPhaseolus vulgaris‐leucoagglutinin (PHA‐L) was injected into area V2 in order to demonstrate the precise morphology of individual axons from area V2 to V1. On the basis of 28 complete axon reconstructions, several characteristic features have been identified. (1) Individual axons arborize in multiple layers: 1, 2, 5, and (inconstantly) 3. A single axon may have numerous terminal clusters in layers 1 and 2, but at most one in layer 3. (2) Axons typically ascend to layer 1, turn asymmetrically in one direction, and travel for long distances in this layer (1.10–4.30 mm; dimensions uncorrected for shrinkage). A few axons (three of 28 reconstructed) were found to have a single terminal cluster (0.3–0.5 mm wide) in layers 1 and 2. (3) Collaterals in layer 5 seem to extend over shorter distances (0.60 mm or less). (4) Delicate sprays of boutons (both beads and spines) are clustered along the main trunk. Spacing is variable but usually ranges from 0.35 mm to 0.65 mm. (5) In addition to clustered boutons, there can be linear collaterals, continuously studded with boutons, parallel to the main axon in layer 1.These results indicate that axons from V2 have complex radial and tangential distributions in V1. Terminations in different layers may be directed to different sets of neurons or to different portions of the dendritic tree (for example, distal portions of pyramidal neuron apical dendrites in layers 1 and 2, but more proximal portions in layer 3). Clustered terminations over wide tangential areas may imply a divergent innervation by a single axon of multiple compartmental structures, such as ocular dominance columns or cytochrome oxidase

ISSN:0092-7317    

DOI:10.1002/cne.902850106

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe terminal field of cholecystokinin‐8 (CCK)‐like immunoreactive (CCK‐IR) tufted cells in the rat main olfactory bulb was examined by means of immunohistochemistry combined with either an anterograde tracer or a degeneration method. CCK immunostaining was carried out in animals in whichPhaseolus vulgarisagglutinin (PHA) had been injected into the main olfactory bulb. Pairs of adjacent sections were processed for CCK and PHA immunostaining, respectively. Dense CCK‐IR terminallike staining was noted in layer Ia of the anterior olfactory nucleus and lateral part of the olfactory tubercle; weaker staining was also observed in the transitional area between the anterior olfactory nucleus and the piriform cortex, in the medial part of the olfactory tubercle, and in the cortical amygdaloid nucleus. The CCK‐IR staining was limited to the area containing PHA‐labeled terminals and was diminished in these sites after unilateral olfactory bulbectomy. Immuno‐electron microscopic analysis showed that CCK‐IR profiles in such regions made asymmetric synaptic contacts, mainly with dendritic spines. These results suggest that CCK‐IR tufted cells project mainly to the anterior olfactory nucleus and lateral part of the olfactory tubercle, and act mainly via ax

ISSN:0092-7317    

DOI:10.1002/cne.902850107

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

年代:1989

数据来源: WILEY

摘要:

AbstractEight nonspiking interneurons were identified that are elements of the central pattern generator controlling ventilation in the shore crab,Carcinus maenas.Intracellular recordings from these neurons in an isolated ganglion preparation revealed that these cells exhibit large amplitude oscillations in their membrane potentials, which are in‐phase with the ventilatory motor pattern. These oscillations are present during the expression of the two distinct ventilatory motor output patterns corresponding to forward and reversed ventilation, and the oscillations stopped during pauses in the ventilatory rhythm. Injection of intracellular current pulses into these interneurons caused a resetting of the ongoing ventilatory rhythm, indicating that these cells are part of the ventilatory central pattern generator. The structure of each interneuron was determined by the intracellular injection of Lucifer Yellow dye. These neurons have a large diameter main neurite ranging from 10 to 20 μm in diameter with very restricted primary and secondary branching from the main neurite. All of the interneurons are restricted to a single hemiganglion and perturbation of these cells with intracellular current pulses only affect the motor output of the hemiganglion containing the interneuron. These eight nonspiking interneurons appear to be the primary components of the central pattern generator underlying ventilation in the cr

ISSN:0092-7317    

DOI:10.1002/cne.902850108

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

年代:1989

数据来源: WILEY

摘要:

AbstractA combined retrograde transport‐double immunohistochemical staining method was used to determine the extent to which rat liver glucocorticoid receptor‐immunoreactivity (GR‐ir) is contained within phenylethanolamine‐N‐methyltransferase (PNMT)‐ir neurons that project to the paraventricular nucleus of the hypothalamus (PVH) or the spinal cord. The results confirmed that cells in the C1, C2, and C3 adrenergic cell groups each contribute to the adrenergic innervation of the PVH, and indicated that the great majority of retrogradely labeled neurons in each group (80% overall) also express GR‐ir. Following injections in the upper thoracic segments of the spinal cord, the bulk of adrenergic neurons that were retrogradely labeled were found in the C1 cell group, though 31% of the total number PNMT‐ir cells that could be retrogradely labeled following spinal injections were localized in the C2 and C3 regions. Of these spinally projecting PNMT‐ir neurons, 62% displayed GR‐ir. The results suggest all three medullary adrenergic cell groups contribute projections to the spinal cord and/or the PVH, and that the capacity to express the GR phenotype is a common, though perhaps not universal, attribute of PNMT‐ir neurons. No pronounced differences in the expression GR‐ir were observed in adrenergic neurons as a function of their location or efferent projections. Brainstem adrenergic neurons may play a role in integrating neuronal and hormonal controls of adrenal function via ascending and

ISSN:0092-7317    

DOI:10.1002/cne.902850109

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe innervation of the guinea pig trachea was studied in wholemount preparations stained for acetylcholinesterase, catecholamines, and substance P immunoreactivity and by electron microscopy. The majority of parasympathetic and afferent nerve fibres arrive from the vagus via branches of the recurrent laryngeal nerves. The recurrent laryngeal nerves are composed of several fascicles comprising 600–700 small myelinated fibres (2–5 μm diameter) and about 1,000–2,000 unmyelinated fibres; both components exit from the nerve and project in fine branches to the trachea. A separate component of 200–250 large myelinated fibres (more than 5 μm diameter) runs the full length of the nerve and innervates the striated muscles of the larynx. The recurrent laryngeal nerves are slightly asymmetric in their origin, length, number, and composition of fibres, with the right nerve being shorter but with more numerous and thinner myelinated fibres. At the distal end of the recurrent nerve, a fine branch called the ramus anastomoticus connects it to the superior laryngeal nerve. In the tracheal plexus, there are on average 222 ganglion cells (range 166–327), distributed mostly in small ganglia of 12 or fewer neurons. The ganglionated plexus is situated entirely outside the tracheal wall, overlying the smooth muscle. Ligation experiments show that sympathetic nerve fibres reach the trachea with the recurrent nerves via anastomoses between the sympathetic chain and vagus nerves, or occasionally with recurrent nerves directly, the largest being at the level of the ansa subclavia. There are also perivascular sympathetic nerve plexuses. Substance P immunoreactive fibres enter the trachea from the vagus nerves and by pathways similar to those of sympathetic nerves. There are also paraganglion cells within the recurrent laryngeal nerve that contain catecholamines and are surrounded by substance P immunoreactive fibres.After cervical vagotomy, all the large myelinated fibres of the ipsilateral recurrent laryngeal nerve degenerate and so do all but 10 or 20 small myelinated fibres and all but a few unmyelinated fibres. Degenerating fibres are found within the entire tracheal plexus, indicating bilateral innervation. The small myelinated fibres that survive cervical vagotomy probably represent sympathetic or afferent nerves with their cell bodies located in sympathetic or dorsal r

ISSN:0092-7317    

DOI:10.1002/cne.902850110

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe distribution of enkephalin (ENK) immunoreactivity has been examined in the cat superior colliculus (SC) by means of light and electron microscope immunocytochemistry. The antisera were directed against leucine enkephalin but also recognized methionine enkephalin. Colocalization of ENK with gamma aminobutyric acid (GABA) was studied with a two‐chromagen double‐labeling technique. Enkephalin antiserum labeling was highly specific. Dense neuropil labeling was found only in a thin band 75–100 μm wide within the upper superficial gray layer of SC. Negligible neuropil labeling was seen deeper, except for patches of label within the intermediate gray layer. Intensely labeled neurons also had a specific distribution. Forty‐seven percent were located within the upper 200 μm of SC, 40% within the deep superficial gray layer, 11% in the optic layer, and only 2% below that layer. Almost all ENK‐labeled cells were small (mean area of 117 μm2). Some of these had horizontal fusiform cell bodies and horizontally oriented dendrites. Others had small round somata and thin, obliquely oriented dendrites. In double‐labeling experiments, 18% of anti‐ENK‐labeled cells were also immunoreactive for GABA.Four distinct types of ENK‐labeled profile were identified with the electron microscope. Presynaptic dendrites (PSD) with loose accumulations of synaptic vesicles were densely labeled with the antiserum. Conventional dendrites were also labeled. Both types of labeled profile received input from unlabeled synaptic terminals, including those from the retina that contained pale mitochondria and round synaptic vesicles and formed asymmetric synaptic contacts. Retinal terminals were never labeled with the antisera. However, some axon terminals with round synaptic vesicles, dark mitochondria, and symmetric synaptic densities were labeled by the antisera, as were some thinly myelinated axons. These results show that there is a small population of enkephalinergic neurons in the cat SC, some of which also contain GABA. Because not all cells with identical morphologies were double labeled, it appears that neurons of like morphology are chem

ISSN:0092-7317    

DOI:10.1002/cne.902850111

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

年代:1989

数据来源: WILEY