bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal development of cat hind limb motoneurons. I: Changes in length, branching structure, and spatial distribution of dendrites of cat triceps surae motoneurons
Authors: Ulfhake Brun , Cullheim Staffan , Franson Peter 
Published: January 2005

AbstractThe postnatal development of length, branching structure, and spatial distribution of dendrites of triceps surae motoneurons, intracellularly stained with horseradish peroxidase, was studied from birth up to 44–46 days of postnatal (d.p.n.) age in kittens and compared with corresponding data from adult cats.The number of dendrites of a triceps surae motoneuron was about 12, and the arborization of each dendrite generated an average of 12–15 terminal branches. There was no net change in the number of dendrites of a neuron or in the degree of branching of the dendrites despite the occurrence of both a transient remodeling of the dendritic branching structure and changes of the spatial distribution of the dendritic branches during postnatal development.The perisomatic territory in the transverse plane occupied by the dendritic branches of a motoneuron increased in parallel with the overall growth of the spinal cord. Thus, the relative size of the dendritic territory in this plane was kept almost constant, whereas dendritic branches projecting in the rostrocaudal direction grew much faster than the spinal cord and also became more numerous. At birth the rostro‐caudal dendritic span of individual motoneurons bridged 1:6 to 1:5 of the L7 spinal cord segment length; this figure was 1:3 at 22–24 d.p.n. Hence, in this direction, the growing dendritic branches invaded novel dendritic territories.The change in dendritic branch length from birth to 6 weeks of age corresponded to an average growth rate of 2 to 4 μm per dendritic branch and day, which implies that the total increase in length of the dendrites of a neuron could amount to 1 mm/day. The increase in branch length did not occur in a uniform or random manner; instead, it followed a spatiotemporal pattern with three phases: From birth to 22–24 d.p.n., growth was particularly prominent in ⩾3rd order preterminal and 2nd through 6th order terminal branches. From 22–24 to 44–46 d.p.n., a large increase in branch length confined to terminal branches of ⩾3rd branch orders was observed. As indicated by topological analysis, this length increase was probably due in part to a resorption of peripheral dendritic branches during this stage of development. From 44–46 d.p.n. to maturity, the increase of dendritic branch length was restricted to preterminal branches of low (⩽4th) branch order.Topological analysis revealed that the arborization pattern of triceps surae motoneuron dendrites resembled most a tree structure generated by an outgrowth of branches from terminal segments, but also that a transient change in dendritic branching structure appeared to occur during postnatal development.
Distribution and central projections of primary afferent neurons that innervate the masseter muscle and mandibular periodontium: A double‐label study
Authors: Capra Norman F. , Wax Tim D. 
Published: January 2005

AbstractA double‐label strategy was used to determine the distribution and central projections of primary afferent neurons that innervate the periodontium and muscles of mastication in cats. Central injections of either Fast Blue (FB) or a mixture of wheat germ agglutinin‐conjugated horseradish peroxidase (WGA‐HRP) and HRP were made into one of three cytoarchitectonically distinct regions of the spinal trigeminal nucleus. These regions included the subnucleus oralis (Vo), the subnucleus interpolaris (Vi), and the medullary dorsal horn (MDH). In each case, injections were also made into the periodontium of the ipsilateral mandibular teeth or into the ipsilateral masseter muscle. FB injections preceded the peroxidase injections by at least 48 hours and total survival time ranged from 72 to 96 hours. Animals were perfused with phosphate‐buffered paraformaldehyde (4%; pH 7.2). Serial frozen sections were made through the brainstem and trigeminal ganglion. Tetramethylbenzidine was used as a chromagen to demonstrate HRP and sections were viewed with brightfield and epifluorescent illumination. Cells containing peripherally injected tracer were observed in the lateral portion of the ganglion and in the mesencephalic nucleus (Vmes). Double‐labeled ganglion cells were observed in most cats that received periodontal injections in combination with central injections in the dorsal part of spinal trigeminal nucleus regardless of the rostrocaudal level of the central injection. In the animals that received intramuscular injections, double‐labeled ganglion cells were observed only in the animals that received central injections caudal to the Vo. Double‐labeled Vmes perikarya were observed in cats that received either intramuscular or periodontal injections in combination with central injections into the MDH and Vo but not in animals that received injections into the Vi. These results demonstrate that ganglion cell periodontal afferents project to the three major rostrocaudal subdivisions of the spinal trigeminal nucleus while ganglion cell muscle afferents have more limited central projections to caudal regions of the nucleus. Masseter and periodontal Vmes afferents also project to the spinal trigeminal nucleus‐specifically, to the Vo and MDH. These findings are consistent with physiological observations regarding the role of periodontal and masseteric afferents in oral and facial reflexes and somethetic mechanisms.
Regional specialisation for synaptic input and output on a locust intersegmental interneurone with multiple spike‐initiating zones
Authors: Watson A. H. D. , Pflüger H.‐J. 
Published: January 2005

AbstractA4I1 is a long intersegmental interneurone whose soma lies in the fourth abdominal ganglion and whose axon ascends through, and branches in the thoracic and suboesophageal ganglia and the brain. It receives sensory input in the prothoracic ganglion from wind‐sensitive hairs on the head and prosternum and in the fourth abdominal ganglion from cercal afferents (Pflüger: J. Comp. Neurol. 223:343–357, '84). Spikes can be initiated from both of these ganglia. In the present study the neurone was stained by intracellular injection of cobalt salts for light microscopy and of horseradish peroxidase for electron microscopy. The morphology of its neurites in the thoracic and fourth abdominal ganglia and the distribution of synapses upon them could then be observed and correlated. In the fourth abdominal ganglion the neurone receives input synapses but makes no outputs. In each thoracic ganglion the neurone has fine, varicose ventral neurites and thicker dorsal neurites. The ventral neurites are most abundant in the prothoracic ganglion where they receive only input synapses. In the meso‐ and metathoracic ganglia the ventral neurites also receive inputs, but in addition they make output synapses. In all three thoracic ganglia output synapses are abundant on the dorsal branches, but in the meso‐ and metathoracic ganglia a small number of inputs are also received here. The possibility that the function of the interneurone may not be the same in all of the thoracic ganglia is discussed in the light of its known physiological properties.
In situ localization of myosin and actin in dendritic spines with the immunogold technique
Authors: Morales Marisela , Fifková Eva 
Published: January 2005

AbstractThe in situ detection of macromolecules by means of immunoelectron microscopy provides information about their ultrastructural localization in cellular compartments. With this technique, we have demonstrated that the contractile proteins actin and myosin are both localized in dendritic spines at densities exceeding those of other neuronal compartments. Myosin was associated with actin filaments, with spine plasma membrane, and with membranes of the spine apparatus. Given the dynamic properties of actin and myosin, these data suggest that these proteins may be involved in the mechanism of synatpic plasticity in general and in morphometric change resulting from intense synaptic activation in particular.
Peripheral patterns of calcitonin‐gene‐related peptide general somatic sensory innervation: Cutaneous and deep terminations
Authors: Kruger Lawrence , Silverman James D. , Mantyh Patrick W. , Sternini Catia , Brecha Nicholas C. 
Published: January 2005

AbstractThe distribution of calcitonin‐gene‐related peptide (CGRP) immunoreactivity (IR) was studied in peripheral tissues of rats. The ganglionic origin, somatosensory nature, and anatomic relations of this thin‐axon population were evaluated with particular emphasis on possible nociceptive roles. In animals untreated with colchicine, CGRP‐IR is found in a vast proportion of small‐ and medium‐diameter sensory ganglion cells that give rise to numerous thinly myelinated and unmyelinated axons that display CGRP‐IR throughout the body.The integumentary innervation consists, in part, of an extensive subpapillary network largely traced to dermal blood vessels, sweat glands, and “free” nerve endings, some of which are found within regions containing only mast cells, fibroblasts, and collagen. Dermal papillae contain CGRP‐IR axons surrounding each vascular loop; other papillary axons end freely or occasionally surround Meissner corpuscles. Intraepithelial axons enter glabrous epidermal pegs, branching and exhibiting terminals throughout the stratum spinosum. A similar pattern is found in hairy skin with additional innervation entering the base and surrounding the lower third of each hair follicle, but apparently not supplying sebaceous glands and arrector pili muscle. Axons innervating nonkeratinized oral epithelium are similar or greater in number and distribution compared to epidermis, often with more extensive branching. The high density of intraepithelial CGRP‐IR innervation does not appear to correlate with the sensitive mechanoreceptor‐based increase in spatial sensory discriminative capacities in the distal portions of the limb.In deep somatic tissues, CGRP‐IR is principally related to vasculature and motor end plates of striated muscle, but there is an extensive network of thin axons within bone, principally in the periosteum, and focally in joint capsules, but not in relation to muscle spindles or tendon organs.These findings, together with the distribution in cranial tissues described in an accompanying paper (Silverman and Kruger: J. Comp. Neurol. 280:303–330, '89), are considered in the context of a “noceffector” concept incorporating the efferent role of these sensory axons in various tissues. It is suggested that involvement in tissue maintenance and renewal during normal function, as well as following injury, may predominate over the relatively infrequent nociceptive role of this peptidergic sensory system.
Distribution of neuropeptide y‐containing perikarya and axons in various neocortical areas in the macaque monkey
Authors: Kuljis Rodrigo O. , Rakic Pasko 
Published: January 2005

AbstractThe laminar and areal distribution of neuropeptide Y (NPY)‐containing perikarya and their processes was analyzed immunocytochemically in Brodmann's neocortical areas 17, 18, 7, 22, 3, 4, 24, and 9 (Walker's area 46) in seven macaque monkeys. Most NPY‐containing cells are distributed in two broad bands in layers II–III and V–VI in all areas; relatively few cells can be found in layer I and virtually none in layer IV. Numerous NPY‐containing cells are situated in the white matter immediately subjacent to the cortical gray. Severalfold regional and individual differences in the density of NPY‐positive somata were found in supra‐ and infragranular layers. However, the interareal variations in the density of NPY‐containing somata do not conform to a universal pattern, because of either individual variability or inherent difficulties in standardizing immunocytochemical labeling. In contrast, the laminar differences in the distribution of NPY‐containing axons among cortical areas are consistent in all animals. In general, primary sensory and motor areas have a lesser density of NPY‐containing axons than association and limbic areas. Within this general pattern, area‐specific laminar segregation of NPY‐containing axons occurs. The regional differences in the distribution of NPY‐like immunoreactivity in the neocortex may reflect innate characteristics of local neuronal circuits serving specialized functions.
Localization of Drosophila neurons that contain choline acetyltransferase messenger RNA: An in situ hybridization study
Authors: Barber Robert P. , Sugihara Hidemitsu , Lee Mariko , Vaughn James E. , Salvaterra Paul M. 
Published: January 2005

AbstractIn situ hybridization with radiolabeled complementary RNA (cRNA) probes was used to determine the location of the messenger RNA (mRNA) encoding choline acetyltransferase (ChAT) in Drosophila nervous system. Areas in the cell‐rich cortical regions of the cerebrum and optic lobes hybridized with substantial concentrations of the probe. This contrasted with the cell‐sparse neuropil areas where no significant concentrations of probe were observed. Although most of the cortical regions were substantially labeled, there were regions within all of the areas where labeling was sparse or nonexistent. For example in the lamina, even though the monopolar cell layer appeared to be heavily labeled, there were some neuronal profiles that were not associated with the probe. Moreover, the epithelial glia that form an arch of cell profiles subjacent to the monopolar cells were not labeled, nor were amacrine neurons in the apex of the lamina near the external optic chiasma. The highest concentration of probe (∼140 grains/400 μm2) was observed in the laminar monopolar cell region and the cerebral cortical rind. The next most heavily labeled region (∼90 grains/400 μm2) occurred over cortical cells of the medulla‐lobula. In the peripheral nervous system, label over the antennal sensory neurons amounted to about 75 grains/400 μm2, and the retinular cell layer of the compound eye exhibited about 60 grains/400 μm2. The control probe did not hybridize in significant quantities in either cellular or noncellular regions. This study presents evidence that large numbers of Drosophila cortical and primary sensory neurons contain the messenger RNA necessary for the production of ChAT, the acetylcholine‐synthesizing enzyme. Further, our findings provide baseline information for use in ontogenetic studies of cholinergic neurons in Drosophila, and they also provide normative data for studying the effects of mutant alleles at the Cha or Ace loci upon the transcription of ChAT messenger RNA.
Physiological, morphological, and cytochemical characteristics of a layer 1 neuron in cat striate cortex
Authors: Martin Kevan A. C. , Friedlander Michael J. , Alones Vinessa 
Published: January 2005

AbstractWe have recorded from a small neuron in layer 1 of the striate visual cortex in a 34‐day‐old kitten. It had a simple, orientation‐selective receptive field that was nondirectional and showed length summation. The neuron was injected intracellularly with horseradish peroxidase. Computer‐aided reconstruction revealed that it had a dense axonal plexus confined to layer 1, elongated in the anteroposterior dimension. By means of an antibody directed against a GABA‐like antigen, and postembedding immunocytochemistry, the neuron was found to be strongly immunoreactive. The main input to soma and dendrites of the neuron was from synapses that were not GABA‐L‐immunoreactive, and probably originated from pyramidal cells. The axon of the cell formed synapses on dendritic shafts and spines, whose most likely sources were the apical tufts of pyramidal cell dendrites. These data suggest that such neurons may be involved in local circuits that contribute to the formation of pyramidal cell receptive fields.
Structure‐Function relationships in the rat brainstem subnucleus interpolaris: VI. Cervical convergence in cells deafferented at birth and a potential primary afferent substrate
Authors: Jacquin Mark F. , Chiaia Nicolas L. , Klein Bradley G. , Rhoades Robert W. 
Published: January 2005

AbstractPossible substrates for peripheral injury‐induced receptive field (RF) changes were assessed in the trigeminal (V) subnucleus interpolaris (SpVi). In adult rats with infraorbital nerve section at birth, 449 cells were studied ipsilateral to the lesion by using electrophysiological methods. Of these, 33 (7.4%) had RFs that included facial vibrissae, guard hairs, and skin, as well as ipsilateral regions normally innervated by cervical primary afferents (ear, neck, shoulder, arm, forepaw). Such non‐V convergence was never seen in 373 normal SpVi cells or in 641 V ganglion cells ipsilateral to the lesion. SpVi cells with cervical RFs discharged to V ganglion shocks and their latencies (1.6 ± 0.7 ms, mean ± s.d.) did not differ from normal (1.4 ± 0.5). Most (71%) projected to the thalamus. None were nociceptive‐biased, and many had unusually discontinuous RFs (48%).Possible pathways by which cervical inputs might reach SpVi neurons were investigated in additional anatomical and electrophysiological experiments. Eight SpVi cells with cervical RFs were intracellularly labeled with HRP. Although all had dendrites that were polarized toward SpVi regions containing spared mandibular and/or ophthalmic primary afferents, none had dendrites which extended out of SpVi. In other neonatally nerve‐damaged adults, WGA‐HRP was injected bilaterally into forepaw, arm, and shoulder regions. Transganglionic transport was restricted to normal targets. However, WGA‐HRP injections into SpVi retrogradely labeled a total of 46 ± 20 (mean ± s.d.) cells in ipsilateral C1–3 dorsal root ganglia, and 24 ± 8 cells in C4–8 ganglia. In controls, labeled cells were seen only in C1–3 ganglia (32 ± 9). The distribution and number of labeled cells in the somatosensory cortex did not differ in experimental and control cases. No labeled cells were visible in the dorsal column nuclei of either the normal or experimental rats. Thus, retrograde labeling studies suggest that a cervical primary afferent projection to SpVi is a potential substrate for cervical convergence expressed in neonatally deafferented SpVi cells.
Axon‐myelin relationships in rat cranial nerves III, IV, and VI: A morphometric study of large‐ and small‐fibre classes
Authors: Fraher John P. 
Published: January 2005

AbstractThe primary objectives of this study were to determine (1) if quantitative axon‐myelin relationships are similar for large‐ and for small‐fibre classes within individual nerves and (2) if the same axon‐myelin relationships hold for equivalent fibre classes in closely similar nerves. The oculomotor, trochlear, and abducent nerves of the rat were examined since they each contain distinct large‐ and small‐fibre classes and are similar in a wide range of anatomical and developmental respects. Accordingly, morphometric analyses of axon‐myelin relationships were performed separately on large and small fibres of each of the three nerves.Withineach nerve, the setting of the relationship between the two parameters was found to be different for the two fibre classes: Scatterplots relating sheath thickness to axon perimeter for large fibres were shifted upwards relative to those for small fibres. These differences were also reflected in the positions of the regression lines fitted to the plots and in the g‐ratios.Significant differences were foundbetweennerves in relation to their large fibres: Those of the abducent nerve had significantly thicker sheaths, those of the oculomotor nerve had significantly smaller axon perimeters, and the myelin sheath–axon perimeter relationship of the abducent nerve differed significantly from that of the other two.This study therefore shows that morphometric axon‐myelin relationships may differ significantly between equivalent fibre classes of nerves that are closely similar in respect of morphological class, central origin, peripheral distribution, developmental environment, and function.
Deafferentation‐induced expansion of saphenous terminal field labelling in the adult rat dorsal horn following pronase injection of the sciatic nerve
Authors: LaMotte Carole C. , Kapadia Shanta E. , Kocol Christine M. 
Published: January 2005

AbstractWe have examined the effect of the degeneration of sciatic nerve afferents on the distribution of saphenous terminals in the adult rat dorsal horn. Deafferentation was produced by injection into the sciatic nerve of pronase, a combination of proteolytic enzymes, which causes death of ganglion cells and degeneration of their terminal fields. The saphenous terminal fields were labelled by exposing the cut nerve to a combination of horseradish peroxidase (HRP) and wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP). Terminals were mainly found in the superficial dorsal horn, indicating that small‐diameter afferents were heavily labelled. In one group of control animals, the normal sciatic and normal saphenous terminal fields were shown to be bilaterally symmetrical. In the experimental group, the initial injection of one sciatic nerve with pronase was followed 4 months later by bilateral HRP/WGA‐HRP labelling of both saphenous nerves. In each animals, the terminal field of the saphenous nerve on the lesioned side was expanded in the medial, lateral, and caudal directions. Medially and laterally, the expanded terminal field overlapped more of the sciatic territory than normal; caudally, saphenous terminals were found in the rostral portion of the L5 segment, in an area normally filled by sciatic terminals and devoid of saphenous terminals. The expansion resulted in a total saphenous area 26% larger than the control side. Electron microscopy demonstrated that the label in both the normal and expanded territories was primarily contained in axons and terminals, with minor transneuronal labelling. Labelled terminals in the expanded areas were both simple terminals with round, clear vesicles, and glomerular terminals with multiple synaptic contacts; these terminal types resemble those previously described for primary afferents in the superficial dorsal horn. Although the preexistence of “silent” synaptic terminals in the expanded areas cannot be disproven, the data support the hypothesis that primary afferents in the adult have the potential to sprout and establish synapses when the conditions of the deafferentation are favorable.
Organization of actin filaments and immunocolocalization of alpha‐actinin in the connecting cilium of rat photoreceptors
Authors: Arikawa Kentaro , Williams David S. 
Published: January 2005

AbstractA small discrete concentration of actin filaments in the connecting cilium of vertebrate photoreceptors appears to have a role in the morphogenesis of the phototransductive disk membranes (Williams et al., '88). We have visualized these actin filaments in rat rod photoreceptors by decorating them with myosin subfragment‐1. At the site of disk morphogenesis, we observed a cluster of short filaments, with various orientations and their faster growing (barbed) ends at the ciliary plasma membrane. Their association with the liplike structure of an early nascent disk is consistent with their apparent involvement in the initiation of disk môrphogenesis. A few longer decorated filaments extended along the core of the connecting cilium, away from the site of disk morphogenesis, implying that they might have some function other than the shaping of a new disk. Most of the antiactin label was found in the region of the short filaments. The alpha‐actinin immunolabel coincided with that of actin, suggesting that the filaments may be crosslinked by alpha‐actinin.