摘要:

AbstractThe present investigation demonstrates the morphological relationships among the main shoulder motor nuclei within the spinal cord of the cat. The intraspinal position of these nuclei has been revealed by retrograde labelling of spinal motor neurones via their peripheral nerves supplying anatomically identified shoulder muscles. Multiple pressure injection of up to four fluorescent tracers (Bisbenzimide, Fast Blue, Fluoro‐Gold, Rhodamine‐b‐isothiocyanate) in one experiment was used to show the longitudinal distribution and topographical relations of motor neurones projecting to muscles acting on the scapulo‐humerus joint. Tracer‐positive cells have been found from middle C5 to rostral Th2 in the cervical cord, forming coherent longitudinal cell clusters separated in medial and lateral projection fields in the ventral horn. The present data suggest that the anatomical organization of spinal shoulder motor neurones corresponds to the embryonic origin of their later target muscles. All medial motor nuclei project to muscles deriving from ventral embryonic origins, while those motor nuclei lying in lateral positions innervate muscles originating from dorsal muscle primordia. Therefore, the spinal topography of shoulder motor nuclei seems to be independent of both the position and the funciton of a given muscle in the adult animal. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903350302

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe enzyme NADPH diaphorase is present in many spinal neurons, and is thought to correspond to nitric oxide synthase. In order to determine which types of neuron in the spinal cord contain this enzyme, we have carried out a combined enzyme histochemical and immunocytochemical study with antibodies to GABA, glycine, and choline acetyltransferase. Two hundred and twenty‐four NADPH diaphorase‐positive neurons in midlumbar spinal cord from four rats were tested for GABA‐ and glycine‐like immunoreactivity. The majority of these neurons (207/224) were GABA‐immunoreactive and 139 were also glycine‐immunoreactive. NADPH diaphorase‐positive neurons in laminae I and II generally showed both types of immunoreactivity, while those in deeper laminae of the dorsal horn and around the central canal either showed both types or else were only GABA‐immunoreactive. Since GABA and acetylcholine are thought to coexist in spinal neurons, NADPH diaphorase staining was combined with immunostaining for choline acetyltransferase. Immunoreactive neurons in laminae III and IV were all NADPH diaphorase‐positive, while only some of those around the central canal and in the deeper laminae of the dorsal horn were positive. Choline acetyltransferase‐immunoreactive neurons in the intermediolateral cell column (presumed sympathetic preganglionic neurons) were often NADPH diaphorase‐positive, whereas those in the ventral horn (presumed motorneurons) were not. NADPH diaphorase‐positive cells in the intermediolateral cell column were not immunoreactive with GABA or glycine antibodies.These results suggest that NADPH diaphorase is largely restricted to GABAergic neurons in the lumbar spinal cord, and that it is mainly present in those neurons in which GABA coexists with glycine or acetylcholine. Since nitric oxide has been implicated in pain processing and hyperalgesia, while GABA, glycine, and acetylcholine are thought to be involved in analgesia and prevention of hyperalgesia, it is likely that nitric oxide synthase‐containing GABAergic neurons in dorsal horn have dual actions in transmission of nociceptive informatio

ISSN:0092-7317    

DOI:10.1002/cne.903350303

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe body surface representation in the gracile, cuneate, and spinal trigeminal nucleil of the little red flying fox (Pteropus scapulatus) was examined. As in other species, it was found that any single cross‐section through all three nuclei contains a representation of most, or all, of the body surface. In the little red flying fox, however, this representation is arranged as a series of dorsolateral to ventromedially oriented bands, within which there are no apparent topographies. These bands are arranged in such a way that the spatial relationships between body regions in the representation do not reflect those at the periphery. © 1993 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903350304

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe freshwater crayfishCherax destructorand the lobsterHomarus americanushave many similarities including life style, body form, and neural organization. However, the ontogenic history is very different in the two species. The development ofCheraxis short and direct whereas the development ofHomaruscomprises three pelagic larval stages and takes more than twice as long from extrusion to benthic stages at constant temperature. In order to determine the progression of maturation of the nervous system in each species and the potential implications of pelagic forms on brain structure, the timing of appearance of 22 general and neural developmental events clearly identifiable in both species was compared. The onset of serotonin antigenicity in the different parts of the brain was chosen as one marker of neural development.During the first month of embryogenesis the timing of morphological, physiological, and neural events is similar in the two species. Morphological development is then accelerated in the crayfish near hatching time and over the two postembryonic stages before the advent of the independent benthic stage. Such heterochronic processes can at least partly account for the different developmental patterns in the two decapods.Among the characters showing similar timing in the two species is the formation of glomeruli (presumptive zones of synaptic contact) in the olfactory lobes of the deutocerebrum, although this event is embryonic inHomarusbut postembryonic inCherax. In contrast, glomerular formation in the accessory lobes is heterochronic: in both species, the glomeruli of the accessory lobes are acquired postembryonically, that is, 3 to 4 months earlier inCheraxthan inHomarus. These data suggest that the development of the glomeruli in the olfactory lobes may depend primarily on internal developmental signals, whereas the triggering of glomerular formation in the accessory lobes may depend on external cues. The fact that, inHomarus, only the postlarval stages show mature accessory glomeruli may be a reflection of the functional requirements of benthic life. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903350305

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe axons of the primary sensory olfactory neurons project from the olfactory neuroepithelium lining the nasal cavity, onto glomeruli covering the surface of the olfactory bulb. Neuroanatomical studies have shown previously that individual olfactory glomeruli are innervated by neurons that are dispersed widely within the nasal cavity. The aim of the present study was to test the hypothesis that phenotypically unique subsets of primary sensory olfactory neurons, scattered throughout the nasal cavity, project to a subset of glomeruli in specific olfactory bulb loci. Immunochemical and histochemical analyses in neonatal mice revealed that the plant lectin,Dolichos biflorusagglutinin, bound to a subset of mature primary sensory olfactory neurons which express the olfactory marker protein. This subset of neurons was principally located in the rostromedial and dorsal portions of the nasal cavity and projected specifically to a subset of glomeruli in the rostromedial and caudodorsal portions of the olfactory bulb. Analysis ofDolichos biflorus‐reactive axons revealed that these axons coursed randomly, with no evidence of their selective fasciculation, within the olfactory nerve. It was only at the level of the rostral olfactory bulb that a significant reorganisation of their trajectory was observed. Within the outer fibre layer of the bulb, discrete bundles of lectin‐reactive axons began to coalesce selectively into fascicles which preferentially oriented toward the medial side of the olfactory bulb. These data demonstrated that a phenotypically distinct subset of primary sensory olfactory neurons exhibits a topographical projection from the olfactory epithelium to the olfactory bulb, and suggests that these, and other subsets, may form the basis of the mosaic nature of this pathway. Moreover, it appears that the outer nerve fibre layer in the rostral olfactory bulb plays an important instructive role in the guidance and fasciculation of olfactory sensory axons. © 1993 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903350306

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractGlutamate is the major excitatory neurotransmitter of the mammalian central nervous system. Two major classes of glutamate receptors have been reported. The actions of glutamate on itsN‐methyl‐D‐aspartate (NMDA)‐type receptor may underlie developmental and adult plasticity as well as neurotoxicity.The NMDA‐type of glutamate receptor in cat and monkey visual cortex was visualized by means of in vitro receptor autoradiography with the noncompetitive NMDA‐receptor antagonist [3H]‐MK‐801. The kinetics, performed on tissue sections, revealed an apparently single, saturable site with an approximate dissociation constant (KD) of 18.5 nM in cat and 15.9 nM in monkey visual cortex. Autoradiography, performed on frontal sections of cat and monkey visual cortex, revealed a heterogeneous laminar distribution of NMDA receptors.Cat areas 17,18,19, and the lateral suprasylvian areas exhibited a similar NMDA‐receptor distribution. In these areas, NMDA receptors were most prominent in layer II and the upper part of layer III. In monkey striate cortex, NMDA receptors were primarily concentrated in layers II, upper III, IVc, V, and VI. In monkey secondary visual cortex, [3H]‐MK‐801 labeling was most prominent in layers II, V, and VI; whereas in the temporal visual areas included in this study layer II displayed the heaviest receptor labeling.In neither cat nor monkey could we observe significant differences in NMDA‐receptor distribution between different retinotopic subdivisions within a single visual area. Neither did we detect any periodic changes in NMDA‐receptor distribution that would correspond to the compartments defined by cytochrome‐oxidase in monkey V1 and

ISSN:0092-7317    

DOI:10.1002/cne.903350307

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractDespite the pivotal clinical significance of the human anal canal, little is known about its total and specific innervation. This study assessed the comparative distribution and histotopology of nerve fibres immunoreactive for neural markers and a variey of regulatory active neuropeptides in the human anal canal by light microscopic immunohistochemistry. Depending on the epithelial zone and region of the anal canal, the neural elements were differentially immunoreactive for the pan‐neural marker protein gene product 9.5, the catecholamine marker tyrosine hydroxylase, the neuroendocrine marker chromogranin A, and various neuropeptides. Protein gene product 9.5‐immunoreactive nerve fibres were ubiquitously abundant in the anal canal. In the anal transitional zone, ectopic epithelial types were supplied by the same pattern of peptidergic nerves as the respective type of epithelium in normotopic location. In the dermis of the squamous zone and in the perianal epidermis, unusual distribution patterns of nerve fibres, referred to as areas of high nerve fibre density, were encountered. Double immunohistochemistry revealed region‐specific coexistence patterns of neuropeptidergic nerve fibres, and novel peptide coexistence patterns were detected in anal nerve fibres. Subsets of nerve fibres formed close spatial relationships with chromogranin A‐positive neuroendocrine cells, most frequently in the anal transitional zone. Chromogranin‐A positive cells were shown to be present in the epithelium of perianal eccrine sweat glands. The differential distribution, peptide phenpotypes and coexistence patterns of different nerve fibre populations in the human anal canal may reflect topospecific regulatory functions of neurally released neuropeptides in health and disease. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903350308

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractWith the objective of defining the relationship of descending inferior colliculus projections to the olivocochlear system in the guinea pig, inferior colliculus neurons were anterogradely labeled withPhaseolus vulgaris‐leucoagglutinin and olivocochlear neurons were retrogradely labeled with horseradish peroxidase in the same brain sections. Inferior colliculus neurons were found to project to many nuclei and regions of the hindbrain where olivocochlear neurons reside. The most substantial of these descending projections was to the ipsilateral medioventral periolivary region. Fewer descending projections terminated in the ipsilateral ventral nucleus of the lateral lemniscus, superior paraolivary nucleus, and rostral periolivary region; and even fewer ipsilateral projections terminated in the area surrounding the lateral superior olive, caudal periolivary region, and the lateroventral periolivary region. Descending neurons of the inferior colliculus also project to the contralateral hindbrain first via the lateral lemniscus and then the trapezoid body, to terminate in the contralateral medioventral periolivary region, superior paraolivary nucleus, rostral periolivary region, and the ventral nucleus of the lateral lemniscus. In addition to the projections into these regions that contain olivocochlear neurons, there are varicosities of inferior colliculus neurons that appear to contact the olivocochlear neurons themselves, both ipsilaterally and contralaterally, especially, but not only, in the ipsilateral medioventral periolivary region. We therefore conclude that descending inferior colliculus neurons do provide input to olivocochlear neurons and that the input is not limited to olivocochlear neurons of the ipsilateral medioventral periolivary region. However, given the robust nature of the projection to the ipsilateral medioventral periolivary region and the paucity of contacts observed in that region, we also conclude that the olivocochlear neuron is not the major target of descending inferior colliculus projections. © 1993 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903350309

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractWe employed a monoclonal antibody raised againstDrosophilabrain homogenate for a comparative immunocytochemical analysis of visual and olfactory pathways in brains of two insect species. On Western blots ofDrosophilaandApisnervous tissue, antibody fb45 recognized an antigen with an apparent molecular weight higher than 180 kD. Application of the antibody to sections ofDrosophilaandApisbrain stained certain interneurons which conspicuously fasciculate in common tracts or neuropilar compartments. Both inDrosophilaand inApis, the antigen was also expressed on the perineural sheath and granular cell compartments in the majority of neuronal cell bodies.The antibody stained monopolar cells in the visual system of both species, and inApisthose fibers of the anterior superior optic tract which link the medulla with the mushroom bodies. InDrosophila, bundles of Kenyon cells of the mushroom bodies were stained. In worker bees and drones, the relay neurons of the median and lateral antennoglomerular tracts were labelled.Since the recognition of the antigen does not require fixation, the antibody can be employed to label selectively living neurons in dissociated cell culture. This opens up the possibility for future functional studies on the role of the antigen in vitro. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903350310

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe 75 kDa protein nerve growth factor receptor [NGFr(p75)] is a neurotrophin receptor that is able to bind different members of the neurotrophin family of molecules implicated in affecting neruronal survival. Here we describe the light microscopic distribution of NGFr(p75)‐immunoreactivity (IR) within the feline trigeminal brainstem sensory nuclear complex and trigeminal ganglion of normal adult subjects and in subjects 10 and 30 days following retrogasserian rhizotomy. Within the trigeminal ganglion of normal subjects, numerous fibers and most of the neuronal cell bodies showed NGFr(p75)‐IR that varied in intensity, while cells and fibers with NGFr(p75)‐IR were less numerous within the mesencephalic trigeminal nucleus. Within the main sensory and spinal trigeminal nuclei, NGFr(p75)‐IR formed a reproducible pattern that varied between the different subnuclei. The NGFr(p75)‐IR consisted both of dense pockets and a low level NGFr(p75)‐IR that was selective to the trigeminal neuropil. Following rhizotomy, most of the NGFr(p75)‐IR was lost from the main sensory and spinal trigeminal nuclei, except in regions where the upper cervical roots and cranial nerves VII, IX, and X project. In contrast, examination of the central root that was still attached to the trigeminal ganglion showed increased NGFr(p75)‐IR in fibers and supporting cells, as did the motor root within the peripheral mandibular division. These results indicate that the majority of the NGFr(p75)‐IR within the main sensory and spinal trigeminal nuclei originates from primary trigeminal afferents and that retrogasserian rhizotomy leads to an up‐regulation of NGFr(p75)‐IR in the part of the central root that is contiguous with the ganglion.

ISSN:0092-7317    

DOI:10.1002/cne.903350311

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY