摘要:

AbstractThe present study was undertaken in an attempt to better understand the abnormalities of cutaneous sensibility that are present in patients following nerve injury with concomitant cutaneous denervation and subsequent reinnervation. Reinnervated intervibrissal pelage of the rat mystacial pad was studied in silver‐impregnated sections 3 and 5 months after transecting and 2 and 5 months after crushing the infraorbital nerve. The sensory terminals on guard and vellus hairs were analyzed in serial paraffin sections and in thick frozen sections. In normal rat mystacial skin, approximately nine/ten of innervated guard hairs have a typical piloneural complex consisting of a palisade of highly regular lanceolate terminals surrounded by circularly arranged Ruffini terminals and free nerve endings (FNEs). The remaining one of ten innervated guard hairs has only circularly arranged presumptive FNEs and Ruffini terminals. Vellus hairs, either singly or in clusters, typically have only circularly arranged terminals that in many cases are simple FNEs. We first recognized abnormalities in innervation of hairs following nerve transection and fully expected nerve terminals to be completely normal following nerve crush. Almost all reinnervated sensory nerve terminals associated with guard hairs were markedly abnormal following nerve transection and quantitatively abnormal following nerve crush. Following nerve transection, lanceolate terminals were almost completely absent, and they were remarkably reduced in number following nerve crush. Vellus hairs when reinnervated typically lacked the complex circular presumptive Ruffini terminals. These findings may be in part the basis for the abnormal cutaneous sensory perceptions (dysasthesias and paresthesias) noted in human subjects following damage to nerves with subsequent sensory reinnervation of the skin. Our findings are in accord with the reports of subtle physiologic abnormalities following nerve transection and crush. Morphologically abnormal reinnervated sensory terminals may retain modality specificity but in addition respond abnormally. These conclusions may be in part the basis for abnormal sensibilities that have been reported following crushing damage to peripheral nerve

ISSN:0092-7317    

DOI:10.1002/cne.902830202

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe morphology and dendritic distribution of terminals that synapse onto a type of large‐field ganglion cell in the retina of the goldfish are described. Electron microscopy was combined with retrograde labelling of cells with horseradish peroxidase (HRP). Synapses from both amacrine (four types) and bipolar cells contacted the dendrites (all orders) of these cells. In contrast to a recent report describing the synaptic organization of large‐field ganglion cells in the catfish (Sakai et al., '86), the synapses were relatively evenly distributed throughout the dendritic arbor, not clustered at discrete sites, and no presynaptic specializations were seen in the dendrites of the ganglion ce

ISSN:0092-7317    

DOI:10.1002/cne.902830203

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

年代:1989

数据来源: WILEY

摘要:

AbstractA new population of spiking local interneurones is described in the metathoracic ganglion of the locust. All have their cell bodies in a cluster at the ventral, anteromedial portion of the ganglion close to the inner edge of an anterior connective. Their branches are restricted to the same half of the ganglion as their cell bodies.Fifteen types of these unilateral interneurones have been characterized by their morphology, as revealed by intracellular injection of dye, and by their physiology, as revealed by intracellular recording. Each interneurone has a characteristic shape and physiological action, but they form three distinct subgroups according to their gross morphology and their mode of operation. Interneurones of the first subgroup have ventral branches that extend over most of one‐half of the metathoracic neuropil and receive inputs mainly from exteroceptors on the ipsilateral hind leg. Typically, they have extensive and reciprocal receptive fields along the dorsoventral axis of the hind leg. Interneurones of the second subgroup have two main ventral branches which extend either medially or laterally and receive inputs mainly from proprioceptors of the hind leg. Interneurones of the third subgroup have few ventral branches and are inhibited by inputs anywhere on the hind le

ISSN:0092-7317    

DOI:10.1002/cne.902830204

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

年代:1989

数据来源: WILEY

摘要:

AbstractSomatostatin‐containing neurons and terminals have been analyzed in monkey temporal and occipital cortex by using light and electron microscopic immunohistochemistry. An antibody against Somatostatin‐28(1–12), that was shown previously preferentially to label fibers (Morrison et al.:Brain Research262:344–351, 1983), was utilized. As expected, few cell bodies were labeled. At the electron microscopic level, labeled cells presented a characteristic asymmetric position of the nucleus and very few symmetric or asymmetric synapses on the somatic surface. In all areas examined, somatostatin fibers formed a dense plexus in the most superficial layers (I‐upper III). The density of labeled fibers in intermediate (deep III–IV) and deep layers (V–VI) varied considerably among areas. The synaptic relationships of the immunoreactive fibers were analyzed and postsynaptic targets quantified in V1, V2, and the superior and inferior temporal gyrus (STG and ITG, respectively). The synapses formed by somatostatin‐labeled boutons were of the symmetric type (type II) and the primary postsynaptic targets were dendritic shafts. No regional differences were found in the distribution of the postsynaptic targets in layers I‐upper III. The pattern of synapses in the deep layers was examined in STG. The frequency and distribution of postsynaptic targets was similar to the superficial layers of STG and the other temporal and occipital regions. In intermediate layers of the temporal cortex areas there was an increase in the proportion of synapses on dendritic spines. In a correlated light and electron microscopic analysis we examined synapses made by radial fibers in these regions and found that although the main targets are distal dendritic shafts, almost 40% of synapses were on dendritic spines. We suggest that the radial fibers may originate from a specialized interneuron, previously described as the double bouquet cell, and that this particular subset of somatostatin‐containing double bouquet cells is likely to exhibit a very high degree of regional heterogeneity with a preference for association cortices with extensive cortico

ISSN:0092-7317    

DOI:10.1002/cne.902830205

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

年代:1989

数据来源: WILEY

摘要:

AbstractHorseradish peroxidase (HRP) was injected into cells from which intracellular recordings were made in slices of the dorsal cochlear nucleus (DCN) in order to correlate physiology with morphology. In general, the morphology of cells labeled intracellularly with HRP corresponded to those made with Golgi impregnations in mice and other mammals. The following cells were labeled: one granule cell, four cartwheel cells, eight fusiform cells, two other cells in the fusiform cell layer, and two tuberculoventral association cells in the deep layers of the DCN The axon of the granule cell runs parallel to isofrequency laminae with collaterals branching perpendicularly and running along the tonotopic axis. The cartwheel cells have dendrites in the molecular layer that are densely covered with spines. The axon of one cell terminates just dorsally to the cell body. Fusiform cells have the characteristic spiny, apical and smooth, basal dendrites. The basal dendrites are conspicuously oriented parallel to isofrequency laminae. Axons of the fusiform cells exit through the dorsal acoustic stria without branching. The two tuberculoventral association cells in the deep DCN have axons that terminate both in the deep DCN, within the same isofrequency lamina that contains the cell body, and in the ventral cochlear nucleus (VCN).Intracellular recordings from 11 of these cells show that they cannot be distinguished on the basis of their responses to intracellularly injected current. All cell types fired large action potentials that were followed by a fast and a slower undershoot, distinguishing them from cells of the VCN but not from one another. Most cells responded to shocks of the auditory nerve root with early EPSPs and later IPSPs. The latencies of EPSPs show that some were monosynaptic and others polysynaptic. That there was no systematic relationship between the latencies of EPSPs and the cell types from which they were recorded shows that shocks to the nerve root may have activated more than just the large, myelinated, auditory nerve fibers.

ISSN:0092-7317    

DOI:10.1002/cne.902830206

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe aim of this study was to map the viscerotopic representation of the upper alimentary tract in the sensory ganglia of the IXth and Xth cranial nerves and in the subnuclei of the solitary and spinal trigeminal tracts. Therefore, in 172 rats 0.5–65 μl of horseradish peroxidase (HRP), wheat germ agglutinin‐HRP, or cholera toxin‐HRP were injected into the trunks and major branches of the IXth and Xth cranial nerves as well as into the musculature and mucosa of different levels of the upper alimentary and respiratory tracts.The results demonstrate that the sensory ganglia of the IXth and Xth nerves form a fused ganglionic mass with continuous bridges of cells connecting the proximal and distal portions of the ganglionic complex. Ganglionic perikarya were labeled in crude, overlapping topographical patterns after injections of tracers into nerves and different parts of the upper alimentary tract. After injections into the soft palate, pharynx, esophagus, and stomach, anterograde labeling was differentially distributed in distinct subnuclei in the nucleus of the tractus solitarius (NTS). Palatal and pharyngeal injections resulted primarily in labeling of the interstitial and intermediate subnuclei of the NTS and in the paratrigeminal islands (PTI) and spinal trigeminal complex. Esophageal and stomach wall injections resulted in labeling primarily of the subnucleus centralis and subnucleus gelatinosus, respectively.The distribution of upper alimentary tract vagal‐glossopharyngeal afferents in the medulla oblongata has two primary groups of components, i.e., a viscertopic distribution in the NTS involved in ingestive and respiratory reflexes and a distribution coextensive with fluoride‐resistant acid‐phosphatase‐positive regions of the PTI and spinal trigeminal nucleus presumably involved in visceral reflexes mediated by nociceptive or chemosens

ISSN:0092-7317    

DOI:10.1002/cne.902830207

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

年代:1989

数据来源: WILEY

摘要:

AbstractA study was made of the distribution of sympathetic preganglionic neurons identified by retrograde labeling with horseradish peroxidase from various peripheral nerve trunks and of the distributions of monoaminergic terminals in the spinal cord of the rat. Nerve terminals were stained immunohistochemically by using antisera raised against tyrosine hydroxylase, phenylethanolamine‐N‐methyl‐transferase, neuropeptide Y, and 5‐hydroxytryptamine and by using formaldehyde‐induced fluorescence. The three‐dimensional distribution of sympathetic preganglionic neurons was described by using computer reconstruction and compared with the arrangement of each population of immunohistochemically stained terminals in the intermediate zone. Although monoaminergic terminals are associated with most sympathetic neurons, particularly in the intermediolateral column, the relationship of many terminals to sympathetic neuron somata in other parts of the intermediate zone is tenuous. Some of the descending innervation may terminate on interneurons. The data are consistent with the coexistence of phenylethanolamine‐N‐methyl‐transferase and neuropeptide Y in terminals arising from cell bodies in the C1 region in the ventrolateral medulla and with the presence of at least two populations of catecholaminergic terminals as well as the adrenergic one. Serotoninergic terminals are denser and have a different arrangement from those of catecholaminergic terminals in the

ISSN:0092-7317    

DOI:10.1002/cne.902830208

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

年代:1989

数据来源: WILEY

摘要:

AbstractUsing a sensitive double immunostaining technique with unconjugated cholera‐toxin B subunit as a retrograde tracer, the authors determined the nuclei of origin of monoaminergic, peptidergic, and cholinergic afferent projections to the cat facial nucleus (FN). The FN as a whole receives substantial afferent projections, with relative subnuclear differences, from the following areas: (1) the perioculomotor areas, the contralateral paralemniscal region, and the mesencephalic reticular formation dorsal to the red nucleus; (2) the ipsilateral parabrachial region and the nucleus reticularis pontis, pars ventralis; and (3) the nuclei reticularis parvicellularis, magnocellularis, ventralis, and dorsalis of the medulla.In addition, the present study demonstrated that the lateral portion of the FN receives specific projections from the contralateral medial and olivary pretectal nuclei and the ipsilateral reticular formation of the pons. It was also found that the FN receives: (1) serotoninergic inputs mainly from the nuclei raphe obscurus, pallidus, magnus, and the caudal ventrolateral bulbar reticular formation; (2) catecholaminergic afferent projections from the A7 noradrenaline cell group located in the Kölliker‐Fuse, parabrachialis lateralis, and locus subcoeruleus nuclei; (3) methionin‐enkephalin‐like inputs originating in the pretectal complex, the nucleus paragigantocellularis lateralis and the caudal raphe nuclei; (4) substance P‐like afferent projections mainly from the Edinger‐Westphal complex and the caudal raphe nuclei; and (5) cholinergic afferents from an area located ventral to the nucleus of the solitary tract at the level of the obex.In the light of these anatomical data, the present report discusses the physiological significance of FN inputs relevant to tonic and phasic events occurring at the level of the facial musculature during the period of paradoxical slee

ISSN:0092-7317    

DOI:10.1002/cne.902830209

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo study the connections of the neurons of the rabbit retina that accumulate indoleamines, we injected 5,7‐dihydroxytryptamine into the vitreous body. It accumulated within a subset of amacrine cells and could be visualized there by aldehyde‐induced fluorescence. The fluorescent labeling was photoconverted to an insoluble, osmiophilic product by irradiation in the presence of diaminobenzidine, and the tissue was examined by electron microscopy. Preservation of the structure of the tissue after photoconversion was satisfactory and the dendrites of the indoleamine‐accumulating cells could easily be identified. They form a dense plexus near the junction of the inner plexiform and ganglion cell layers, where they exhibit large synaptic endings that occupy a substantial fraction of the surface of rod bipolar terminals. The dendrites of the indoleamine‐accumulating cells receive input from rod bipolars at dyad synapses, where the other postsynaptic partner is a dendrite of a narrow‐field, bistratified amacrine cell; in addition, they receive amacrine cell input throughout the inner plexiform layer. The only outputs we observed are reciprocal synapses onto the rod bipolar endings. Thus, these amacrine cells appear to exert an important effect on the transmission of scotopic information through t

ISSN:0092-7317    

DOI:10.1002/cne.902830210

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

年代:1989

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902830201

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

年代:1989

数据来源: WILEY