摘要:

AbstractProjections of dorsal column, spinal, and cochlear nuclei upon the central nucleus of the torus semicircularis (otherwise known as nucleus mesencephalicus lateralis, pars dorsalis, or MLd) and upon other toral nuclei were investigated in pigeon by anterograde and retrograde tracing and electrophysiological methods. The anatomical results showed that caudal regions of the dorsal column nuclei and medial lamina V of the upper four cervical spinal segments have extensive projections upon the contralateral central auditory nucleus and upon other nuclei of the torus, in particular the core portion of the preisthmic superficial area of Puelles et al. (L. Puelles, C. Rrobles, M. Martiez‐de‐la‐Torre, and S. Martinez, 1994, J. Comp. Neurol. 340:98–125). The projections of nucleus angularis were found to terminate throughout most of the contralateral central nucleus except the dorsomedial portion at rostral levels, where the majority of the projections of nucleus laminaris were concentrated. Nucleus angularis (and to a lesser extent nucleus laminaris) was also found to have substantial projections to certain noncentral toral nuclei, in particular to the caudomedial shell nucleus of Puelles et al. (1994). As shown positively with both Nissl and cytochrome oxidase staining and negatively with substance P labeling, this nucleus is a medial extension of more caudal regions of the central nucleus, and it is suggested that it should be included as part of the auditory midbrain.The electrophysiological results confirmed the anatomical findings by showing that evoked potentials and multiunit activity can be recorded throughout the central and noncentral toral nuclei by using electrical stimulation of the radial nerve and auditory click stimuli. The core portion of the preisthmic superficial area, however, can be regarded as a distinct somatosensory nucleus of the midbrain.It is concluded that there is substantial convergence of somatosensory and auditory inputs within both central auditory and noncentral nuclei of the torus semicircularis in pigeon. © 1995 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903580402

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

年代:1995

数据来源: WILEY

摘要:

AbstractSkin innervation during wound healing was investigated using immunocytochemical staining with the panneuronal marker antiprotein gene product (PGP) 9.5, which labels the entire innervation of the skin throughout development and in the adult. Full‐thickness skin wounds in the hairy skin of the foot in neonatal rats result in pronounced hyperinnervation of the tissue that persists long after the wound has healed (at least 12 weeks). Quantification of this hyperinnervation by image analysis indicates that slcoin innervation density in the wounded area can increase up to 300%. The effect is greatest when wounds are performed at postnatal day (P) 0 or 7, declining when performed at P14 and P21 to resemble the weaker and transient effect in the adult. Staining with selective markers for different neuronal populations innervating skin (monoclonal anti‐RT97 staining the myelinated axons of large light sensory ganglion cells; anticalcitonin gene‐related peptide staining unmyelinated C axons, thinly myelinated Aδ axons, and a subpopulation of large A fibres) reveal that both A‐ and C‐fibre sensory axons contribute to this response. Destruction of the majority of the C‐fibre population with neonatal capsaicin pretreatment, which leaves large, A fibres intact, significantly reduces the hyperinnervation response at 14 days, confirming a major contribution from both A and C‐fibres. Sympathetic axons, stained with anti‐tyrosine hydroxylase, do not sprout into the wounded area. Furthermore, pretreatment of neonates with 6–hydroxydopamine, which destroys the sympathetic innervation, does not significantly reduce the overall sprouting response, as identified by anti‐PGP9. 5 staining. Behavioural sensory testing revealed a 50% drop in the mechanical threshold in the wounded area after 3 weeks. These remarkably long‐term and specific effects on sensory terminal axons following neonatal skin wounding indicate the plasticity of cutaneous innervation density following alterations in the target tissue at a critical stage of development.

ISSN:0092-7317    

DOI:10.1002/cne.903580403

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe distribution of vasopressin innervation in the brain of the jerboa (Jaculus orientalis)was investigated, with special attention to sex differences and seasonal variations. Vasopressin perikarya were observed in the paraventricular and supraoptic nuclei, the suprachiasmatic nucleus, the periventricular nucleus, the medial preoptic area, the bed nucleus of the stria terminalis, and the medial amygdaloid nucleus. In addition, vasopressin cell bodies were observed in the ventral retrochiasmatic area. After treatment with colchicine, vasopreasin perikarya were also observed around the organum vasculosum laminae terminalis, in the medial diagonal band of Broca, and in the dorsal medial preoptic nucleus.Vasopressin fibers were also found to be more widespread in the jerboa brain than in other rodents. Fibers were observed in the medial diagonal band of Broca, the stria medullaris, the tuber cinerum, the area postrema, the medial vestibular nucleus, and the dorsal motor nucleus of the vagus.Sexual dimorphism and seasonal variation in vasopressin immunoreactivity were observed in areas that not only showed a testosterone‐dependent vasopressin innervation in other rodents but also in the paratenial and mediodorsal thalamic nuclei, the tuber cinerum, the suprarnarnmillary complex, the zona incerta, the interpeduncular complex, and the dorsal and medial raphe nuclei. A denser vasopressin innervation was observed in spring/summer (sexual active period) than in autumn. Numerous brain structures contained vasopressin receptors (cerebral cortex, hypothalamus, substantia nigra, dentate gyrus, thalamic nuclei, superior colliculus, dorsal cochlear nucleus, and cerebellum); no sex‐ or season‐related differences were observed.These data indicate a high level of vasopressin in the jerboa brain, which may reflect an adaptation to its harsh bioclimatic environment. © 1995 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903580404

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe possible role that the hypothalamic arcuate nucleus might play in mediating the increase in paraventricular nucleus corticotropin‐releasing hormone mRNA levels following adrenalectomy was investigated in two series of experiments. In the first series, in situ hybridization histochemistry was used to quantify levels of eight arcuate nucleus neuropeptide and neurotransmitter mRNAs in neurons that potentially relay adrenal steroid feedback to the paraventricular nucleus. In the second series of experiments, arcuate neuropeptidergic projections to the hypothalamic paraventricular nucleus were characterized using retrograde tracing in combination with in situ hybridization histochemistry. Despite an increase in paraventricular nucleus corticotropin‐releasing hormone (60%) and pituitary proopiomelanocortin mRNA levels (sixfold), arcuate mRNA levels for proopiomelanocortin, neuropeptide Y, somatostatin, galanin, dynorphin, tyrosine hydroxylase, glutamate decarboxylase, and the glucocorticoid receptor were unchanged 14 days following adrenalectomy. Neuropeptidergic characterization of arcuatoparaventricular projections was achieved by injection of the retrograde tracer fluorogold into the paraventricular nucleus; retrogradely labeled neurons were characterized with polyclonal antisera against fluorogold in combination with oligonucleotide probes directed against neuropeptide Y, proopiomelanocortin, or somatostatin. Out of these three arcuate neuropeptides, neuropeptide Y mRNA was contained in 18% of the fluorogold‐positive neurons in the arcuate, proopiornelanocortin mRNA was contained in 8%, and somatostatin mRNA was contained in 6%. Overall, the results from both experiments suggest that the arcuatoparaventricular neuropeptide Y, proopiomelanocortin, and somatostatin projections are not sensitive to a chronic (14 day) lack of adrenal steroids. These projections as well as the other arcuate neurotransmitter and neuropeptide systems appear not to contribute to the persistent elevations in paraventricular nucleus corticotropin‐releasing hormone mRNA levels or pituitary proopiomelanocortin mRNA levels found in 14 day adremlectomized rats. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as in the public domain in the United States

ISSN:0092-7317    

DOI:10.1002/cne.903580405

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn the digestive system, substance P is an excitatory transmitter to muscle, a putative excitatory neuro‐neuronal transmitter, a vasodilator, and a mediator in inflammatory processes. Many of the biological effects of substance P are mediated by a high‐affinity interaction with the tachykinin receptor neurokinin‐1. The aim of the present study was to identify the sites of expression of this receptor in the rat stomach and intestine by immunchistochernistry with a polyclonal antiserum raised to the intracellular C‐terminal portion of the rat neurokinin‐1 receptor. Neurokinin‐1‐ receptor immunoreactivity is present in a large population of enteric neurons. The relative density of these neurons along the gut is colon>ileum ≫ stomach. In the intestine, stained neurons have a smooth cell body with processes that can be followed within and between plexuses, and make close approaches to other neuronal cells, but do not appear to project outside the plexuses, suggesting that they are interneurons. In the stomach, neurokinin‐1 receptor‐immunoreactive neurons are infrequent and have a poorly defined and irregular shapet Neurokinin‐1 receptor immunoreactivity is also localized to numerous non‐neuronal cells in the inner portion of the circular muscle layer of the small intestine, which have the appearance of small dark smooth muscle cells or interstitial cells of Cajal. These cells are postulated to form a “stretch‐sensitive” system with the deep muscular plexus and thus constitute an important site of regulation of muscle activity. Double labeling immunofluorescence was used to simultaneously localize neurokinin‐1 receptor and substance P/tachykinin immunoreactivities. These experiments demonstrate that in the enteric plexuses, substance P/tachykinin‐immunoreactive varicose fibers encircle the cell bodies of most neurokinin‐1 receptor‐containing neurons, and in the inner portion of the circular muscle layer of the small intestine they lie close to neurokinin‐1 receptor‐immunoreactive non‐neuronal cells. In addition, some enteric‐neurons express both neurokinin‐1 receptor and substance P/tachykinin immunoreactivities. The present study provides strong evidence that the neurokinin‐1 receptor is the tachykinin receptor mediating the actions of substance P on enteric

ISSN:0092-7317    

DOI:10.1002/cne.903580406

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

年代:1995

数据来源: WILEY

摘要:

AbstractA group of lineally related neurons in the grasshopper was studied to determine the number of efferent neurons in the group and their morphological types. The neurons arise from the median neuroblast of the third thoracic neuromere and comprise what is commonly known as the DUM or dorsal unpaired median group. Of some 92 neurons in the group, about 20 are efferent neurons, the remainder being local or intersegmental interneurons. As part of our continuing developmental studies, we wished to identify the efferent neurons within the lineage and to determine their number. Ten efferent DUM neurons had been described in earlier studies, where neurons were stained individually through microelectrodes. The remaining unidentified neurons might be novel types, multiples of known types, or both, possibilities that would not be readily distinguished through further staining of neurons individually. Rather, we used methods of retrograde staining and axon tracing that allowed us to examine the entire group of efferent DUM neurons. Nineteen efferent neurons were identified, comprising two DUM1s, five DUM3s, six DUM3,4s, three DUM3,4,5s, and three DUM5s, neurons were named according to the lateral nerves containing their axons. The efferent neurons were further divided by type according to the distribution of axonal branches in lateral nerves, the course of the primary neurite within the deep or superficial DUM tract, and the diameter of the cell body. © 1995 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903580407

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe supramedullary cells (SMCs) of teleosts have been studied for nearly 100 years, but their peripheral connectional have remained obscure. We examined the supramedullary cells of the puffer fish,Takifugu niphobles, using horseradish peroxidase transport. Horseradish peroxidase labeling was found bilaterally after application to the trigeminal, the posterior branch of the vagal, and thee spinal nerves, No labeled neurons were found after application to the anterior or visceral branches of the vagal nerve. Thus, labeled SMCs were found only after application to the nerves containing cutaneous branches.Some rostrocaudal topographical labeling was found after selective application to each of the four branches of the trigeminal nerve. Labeled neurons were more common in the rostral than in the central or caudal part of the SMC region. Some topographical labeling was also found after application to the first, second, and third spinal nerves, but the topography was not very clear, and there was considerable overlap in the distribution of labeled cells. The sum total of labeled SMCs after unilateral horseradish peroxidase application to each peripheral nerve was more than three times the total number of ipsilateral SMCs, indicating that a single SMC projects several peripheral processes into different nerves.From these results, and taking previous studies into consideration, we propose that supramedullary neurons have a phylogenetic relationship with the spinal dorsal cells of the lamprey and with the extramedullary cells of the amphibian embryo. © 1995 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903580408

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

年代:1995

数据来源: WILEY

摘要:

AbstractThis study provides quantitative descriptions of individual dendrites from electrophysiologically characterized and intracellularly labeled thalamocortical projection (TCP) neurons of the cat ventrobasal complex. One hundred nine dendrites from six ventral posterolateral (VPL) neurons and six ventral posteromedial (VPM) neurons were examined. Measurement of several parameters showed that the individual dendrites were very similar to each other in overall architecture even though they varied greatly in total length and number of dendritic branches. The mean path distance (length from soma to a dendritic tip) was very similar for a dendrites in each group (VPL or VPM) regardless of the number of branches found along the path distance. However, VPL dendrites had a longer mean path distance (VPL = 206 ± 36 μm; n = 51) than VPM dendrites (VPM = 182 ± 29 μm; n = 58; P<0.001). For all dendrites there was a strong correlation between the stem dendrite diameter and the dendritic length, which allows the estimation of dendritic length from dendrite diameter. Analysis of dendritic scaling shows that branches higher than first order do not follow Rall's ½ power rule, so these neurons cannot be modeled using the equivalent cylinder approximation.The data add to the qualitative descriptions of cat ventrobasal (VB) TCP dendrites currently available and provide a basis for future comparative, developmental, and plasticity studies. Analysis shows that many parameters of cat VB TCP dendrites fall within a narrow range, suggesting that, regardless of differences in length or superficial appearance, these dendrites share a stable underlying architecture. © 1995 Wiley‐Li

ISSN:0092-7317    

DOI:10.1002/cne.903580409

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

年代:1995

数据来源: WILEY

摘要:

AbstractCorrelated light and electron microscopic double‐immunostaining experiments for Leuenkephalin and calbindin were employed to determine the postsynaptic targets in the septal complex of Leu‐enkephalin fibers. Chronic surgical isolation of the septal complex from its hypothalamic afferents and retrograde tracer studies using wheat germ agglutinin‐conjugated horseradish peroxidase, both followed by an immunostaining for Leu‐enkephalin, were performed to elucidate the location of the origin of these axon terminals. Furthermore, a colocalization study for glutamic acid decarboxylase and Leu‐enkephalin was carried out on hypothalamic sections to determine their possible coexistence in cells projecting to the lateral septum.These studies revealed that (1) Leu‐enkephalin‐immunoreactive axons form pericellular baskets around a population of lateral septal area neurons; (2) they establish exclusively asymmetric synaptic contacts on their soma and initial dendritic segments; (3) 10% of the lateral septal area calbindin‐contatining cells, which are all of the γ‐aminobutyric acid (GABA)‐ergic somatospiny type, are innervated by Leu‐erikephalin‐immunoreactive baskets; (4) only 40% of the Leu‐enkephalin target neurons are calbindin immunopositive; 5) the septopetal Leuenkephalin fibers derive from neurons located in the ipsilateral perifornical area and anterior hypothalamus; and 6) none of their cells of origin cocontains the inhibitory transmitter GABA. These observations indicate that hypothalamic Leu‐enkephalin‐containing neurons are nonGABAergic excitatory cells. Hence, they can effectively stimulate a population of lateral septal area neurons, including the somatospiny cells, which are all GABAergic. Therefore, after stimulatory Leu‐enkephalin action, these neurons can inhibit their postsynaptic targets, including other projective lateral septal

ISSN:0092-7317    

DOI:10.1002/cne.903580410

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe present study characterized the projections of the anterodorsal (AD) and the anteroventral (AV) thalamic nuclei to the limbic cortex. Both AD and AV project to the full extent of the retrosplenial granular cortex in a topographic pattern. Neurons in caudal parts of both nuclei project to rostral retrosplenial cortex, and neurons in rostral parts of both nuclei project to caudal retrosplenial cortpx. Within AV, the magnocellular neurons project primarily to the retrosplenial granular a cortex, whereas the parvicellular neurons project mainly to the retrosplenial granular b cortex. AD projections to retrosplenial cortex terminate in very different patternsthan do AV projections: The AD projection terminates with equal density in layers I, III, and IV of the retrosplenial granular cortex, whereas, in contrast, the AV projections terminate very densely in layer Ia and less densely in layer IV. Further, both AD and AV project densely to the postsubicular, presubicular, and parasubicular cortices and lightly to the entorhinal (only the most caudal part) cortex and to the subiculum proper (only the most septal part). Rostral parts of AD project equally to all three subicular cortices, whereas neurons in caudal AD project primarily to the postsubicular cortex. Compared to AD, neurons in AV have a less extensive projection to the subicular cortex, and this projection terminates primarily in the postsubicular and presubicular cortices. Further, the AD projection terminates in layers I, II/III, and V of postsubiculum, whereas the AV projection terminates only in layers I and V. © 1995 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903580411

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

年代:1995

数据来源: WILEY