bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal development of cat hind limb motoneurons. III: Changes in size of motoneurons supplying the triceps surae muscle
Authors: Ulfhake Brun , Cullheim Staffan 
Published: January 2005

AbstractThe postnatal changes of neuronal dimensions were studied in cat triceps surae motoneurons intracellularly labeled with horseradish peroxidase.Systematic correlations were observed in the analysis of single dendrites at each studied stage, from birth to 44–46 days post natum (d.p.n.) age, between size parameters intrinsic to the dendrites as the diameter of a 1st‐order dendrite, the combined dendritic length, the dendritic membrane area, and the degree of branching. Some variability among samples was evident in each studied age group. The correlations were, however, sufficiently close to permit indirect estimations of both combined dendritic length and dendritic membrane area for larger samples of neurons from data on dendritic stem caliber.The total postnatal increase in dendritic membrane area was, on the average, 400%, i.e., from close to 100 × 103 μm2 to about 500 × 103 μm2. The corresponding increase in soma area amounted to 100%. Analysis revealed that there was a time lag between the increase in somatic and dendritic size. Thus, adult somatic dimensions were attained at age 44–46 d.p.n.; however, at this stage, the mean total dendritic membrane area was only about half of the adult value. The postnatal increase in size appeared to vary among neurons, yielding a wider neuronal size spectrum in the adult cat than that observed in kittens.The measured increase in size corresponded to a calculated average addition of dendritic membrane area of 3700 μm2/day from birth to 22–24 d.p.n. and from that stage to 44–46 d.p.n. of 2700 μm2 per day. Likewise, the increase in combined dendritic length could initially be as large as 1 mm/day down to 0.4 mm/day between 22–24 and 44–46 d.p.n., with a mean growth during the first 44–46 d.p.n. of 0.5 to 0.6 mm/day.The ratios of daughters to parent branch diameters (∑dd1.5: dp1.5) and the dendritic trunk parameter (∑d1.5) recorded along the proximodistal dendritic path distance revealed transient changes that might impact on the electronic properties of the dendrites during postnatal development. Computations from the measured changes in dendritic branch lengths and calibers indicated that if membrane and internal resistivity remain unaltered during postnatal development. the dendritic domain is electrotonically more compact inthe newborn kitten than in the adult cat.Based on the data we obtained on total neuronal membrane area available for synaptic junctions and previously published data on bouton packing density, it seems that any net change in the total number of synaptic boutons occurring postnatally should be small, and the mean number of boutons impinging on a triceps surae α‐motoneuron should be in the range of (50–60) × 103.
Topographic analysis of the retinal ganglion cell layer and optic nerve in the sandlance Limnichthyes fasciatus (Creeiidae, Perciformes)
Authors: Collin Shaun P. , Collin H. Barry 
Published: January 2005

AbstractThe sandlance or tommy fish Limnichthyes fasciatus (Creeiidae, Perciformes) is a tiny species that lives beneath the sand with only its eyes protruding and is found throughout the Indopacific region.The retina of the sandlance possesses a deep convexiclivate fovea in the central fundus of its minute eye (1.04 mm in diameter). A Nissl‐stained retinal whole mount in which the pigment epithelium had been removed by osmotic shock was used to examine the retinal topography of the ganglion cell layer. There was a foveal density of between 13.0 × 104 cells per mm2 (S.D. ± 1.8 × 104 cells per mm2), counted in the retinal whole mount, and 15.0 × 104 cells per mm2, counted in transverse sections, which diminished to a peripheral density of 4.5 × 104 cells per mm2 (S. D. ± 0.8 × 104 cells per mm2). The total population of axons within the optic nerve was assessed by electron microscopy. Optic axon densities ranged from 2 × 106 axons per mm2 in the caudal apex to over 16 × 106 axons per mm2 within a specialized region of unmyelinated axons in the rostral apex. The topography of the proportion of unmyelinated axon population (26%) follows closely that of the total population of optic nerve axons. There was a total of 104,452 axons within the optic nerve compared with 102,918 cells within the retinal ganglion cell layer. A close relationship is revealed between ganglion cell soma areas and axon areas where the organization in the optic nerve and retina may reflect some functional retinotopicity.
Transient projections from the lateral geniculate to the posteromedial lateral suprasylvian visual cortex in kittens
Authors: Bruce Laura L. , Stein Barry E. 
Published: January 2005

AbstractThe postnatal maturation of the projection from the lateral geniculate nucleus to the posteromedial lateral suprasylvian visual cortex (PMLS) was studied with injections of fluorescent dyes into the PMLS at various postnatal ages. Labeled neurons projecting to the PMLS were present in all laminae of the ipsilateral lateral geniculate on the day of birth. However, there was a conspicuous change in the distribution of labeled geniculo‐PMLS neurons by 11 days of age: now very few labeled neurons were present in lamina A, indicating a loss of geniculo‐PMLS connections. The loss of connections began at the peripheral margins of lamina A and proceeded through other laminae toward laminae C1‐3. By adulthood, labeled geniculo‐PMLS neurons were largely confined to laminae C1‐3; they were never observed in lamina A or A1 and were rarely observed in lamina C.To determine whether the lateral geniculate neurons survived after their projections to PMLS were lost, injections of fast blue were made at 1 or 2 days postnatally and the animals were allowed long postinjection survival times. Labeled neurons were found in all lateral geniculate laminae, thereby indicating that for many neurons the loss of connections could be attributed to a loss of their axon collaterals rather than to the death of the neurons themselves.After injections of fast blue into the PMLS and diamidino yellow dihydrochloride into area 17 shortly after birth, many double‐labeled neurons were present in all laminae, indicating that they have collaterals to both targets. Thus, the survival of many of the geniculo‐PMLS neurons contributing to the transient geniculo‐PMLS projection seems to be due to sustaining collateral projections to area 17 or other cortical targets.
Ultrastructure of ChAT‐immunoreactive synaptic terminals in the thalamic reticular nucleus of the rat
Authors: Hallanger Anne E. , Wainer Bruce H. 
Published: January 2005

AbstractThe thalamic reticular nucleus has been shown to receive cholinergic innervation from both the nucleus basalis of Meynert in the forebrain and the pedunculopontine and laterodorsal tegmental nuclei in the brainstem (Steriade et al.: Brain Res. 408:372–376, '87; Levey et al.: Neurosci. Lett. 74:7–13, '87). Relatively dense populations of choline acetyltransferase‐ (ChAT) immunoreactive axons and terminallike varicosities have been shown to be distributed throughout this nucleus (Levey et al.: J. Comp. Neurol. 257:317–332, '87). In this study, the ultrastructure of ChAT‐immunoreactive axons and of their synaptic terminals in the reticular nucleus was examined in the electron microscope. All ChAT‐immunoreactive axonal profiles in the reticular nucleus were presynaptic; the postsyaptic elements were exclusively dendritic profiles; and no axo‐axonic or axosomatic contacts from labelled axons were observed. Most ChAT‐immunoreactive synaptic contacts were made by profiles less than 0.25 μm in minor diameter. Single ChAT‐immunoreactive axons made synaptic contact with several dendritic profiles as the axons were followed through serial sections. These results suggest that the cholinergic innervation of the reticular nucleus will modulate the function of reticular neurons by synapsing onto the dendrites of its neurons without direct effect on the corticothalamic and thalamocortical terminals which also innervate the reticular nucleus.
Differential projections of B and C sympathetic axons in peripheral nerves of the bullfrog
Authors: Horn John P. , Fatherazi Sahba , Stofer William D. 
Published: January 2005

AbstractAccumulating evidence indicates that electrophysiologically distinct subsets of sympathetic neurons selectively innervate different classes of targets. The organization of this system may therefore be reflected in the sympathetic fiber contents of peripheral nerves. To test this possibility, we have mapped the pathways followed by three groups of postganglionic sympathetic axons in the bullfrog by recording compound action potentials and by retrograde tracing with horseradish peroxidase (HRP). The axons that were studied arise from fast B, slow B, and C‐type neurons in ganglia 9 and 10 at the lumbar end of the paravertebral sympathetic chain. They project to peripheral targets primarily by way of the sciatic nerve and can be distinguished by the velocities with which they conduct action potentials.Action potentials were recorded with suction electrodes from isolated preparations composed of paravertebral chain ganglia 7–10, the sciatic nerve, and branches of the sciatic nerve that supply striated muscles, skin, and the bladder. Preganglionic B fibers were selectively activated by stimulating the paravertebral chain rostral to ganglion 7, and preganglionic C fibers were selectively activated by stimulating spinal nerves 7 and 8 at points central to their rami communicantes. Compound action potentials recorded from the sciatic, peroneal, tibial, and sural nerves and from the primary trunk of the pelvic nerve were each found to contain three components produced, respectively, by fast B, slow B, and C‐type sympathetic axons. Similarly, action potentials recorded from cutaneous branches of the sciatic tree were found to contain three sympathetic components. By contrast, when compound action potentials were recorded from branches of the sciatic tree that directly enter and innervate striated muscles and also the bladder, the sympathetic responses were found to arise solely from C‐type axons.HRP was used to label the sympathetic neurons that project to the sartorius muscle and into the cutaneous lateral crural nerve. Retrograde transport of HRP from the sartorius muscle labeled 17 ± 4 (mean ± s.d.) sympathetic neurons and 27 ± 3 spinal motoneurons while transport from the lateral crural nerve labeled 68 ± 47 sympathetic neurons but no spinal neurons. The average somatic diameter of ganglion cells projecting to the sartorius muscle was significantly smaller than that of cells projecting to the lateral crural nerve.The electrophysiological results indicate that fast B and slow B sympathetic axons in the sciatic trunk and its primary branches project selectively into cutaneous nerves while sympathetic C axons project into all peripheral nerves. The HRP data support these findings given that C cells are, on average, smaller than B cells. Together the results provide an anatomical basis for the hypothesis that B and C neurons serve different physiological functions.
GABA‐like immunoreactivity in the cat retina: Light microscopy
Authors: Wässle H. , Chun M. H. 
Published: January 2005

AbstractSemithin sections of the cat retina were stained with antibodies against GABA conjugated to bovine serum albumin with glutaraldehyde. Labelled cells were visualized by means of the peroxidase‐antiperoxidase method. In the outer plexiform layer both A‐ and B‐type horizontal cells and the B‐type axon terminal system expressed GABA‐like immunoreactivity. Approximately 25–30% of all amacrine cells and the whole inner plexiform layer were heavily labelled. Two types of putative GABA‐ergic interplexiform cells could be distinguished. One of them also expressed tyrosine‐hydroxylase‐like immunoreactivity. A few bipolar cells were also GABA‐immunolabelled. GABA‐like immunoreactivity and 3H‐muscimol uptake were colocalized in 90% of the amacrine cells labelled. However, horizontal cells did not accumulate 3H‐muscimol.
Distribution of substance P‐like immunoreactivity in the goldfish brain
Authors: Sharma S. C. , Berthoud V. M. , Breckwoldt R. 
Published: January 2005

AbstractImmunohistochemical methods were used to study the distribution of SP‐like immunoreactivity (SPLI) in the brain of the common goldfish (Carassius auratus). SPLI cell bodies and fibers were seen in distant areas and nuclei throughout the brain. In the telencephalon, SPL1 was found in the area dorsalis telencephali pars centralis and pars lateralis, areas that have been compared to the basal ganglia of land vertebrates. In the diencephalon, SPLI somata were seen in the hypothalamus. Four primary visual centers contained SPLI fibers: the nucleus of the posterior commissure, the area pretectalis, the nucleus dorsolateralis thalami and the optic tectum; the origin of these fibers could not be determined. SPLI cell bodies were seen in the oculomotor nucelus; the possibility that this may be the Edinger‐Westphal nucleus is discussed. A high density of immunoreactive fibers was seen in the tractus retroflexus and the interpeduncular nucleus, though the habenula showed a few SP‐like immunopositive fibers. In the hindbrain, SPLI cell bodies and fibers were seen in the nuclei ambiguus and commissuralis of Cajal and in the dorsal motornucleus of the vagus nuclei; even though these nuclei are known to belong to the visceral and sensory motor columns, the exact role SP plays in processing this information is at present unknown.
Comparison of trigeminal receptor location and structure in the periodontal ligament of different types of teeth from the rat, cat, and monkey
Authors: Byers Margaret R. , Dong Willie K. 
Published: January 2005

AbstractThe periodontal ligament is richly innervated by mechanoreceptors whose cell bodies are located either in the trigeminal ganglion (TG) or the mesencephalic (MS) trigeminal nucleus. Both are sensitive to stretch of the ligament induced by tooth movement, but their thresholds, central connections, and functional significance differ. This study compared the location of TG and MS receptors in the periodontal ligament of cat teeth after labeling each by anterograde axonal transport. We also compared the location and ultrastructure of the feline TG receptors with labeled TG receptors in the periodontal ligament of monkey teeth and rat incisors in order to determine their location and ultrastructural properties.We found that the MS and TG receptors had a different distribution in the periodontal ligament of cat teeth; the MS terminals were concentrated below and next to the base of the roots, whereas the TG receptors were most numerous around the middle of the roots. The TG receptors of monkey teeth had a similar location to the feline TG receptors, but those of rat incisors were very different. Rat incisors are curved, continuously erupting teeth, and their TG receptors were located primarily on the lingual side in the alveolar (nonerupting) portion of the ligament. Ultrastructural comparisons found that most mechanoreceptors in the periodontal ligament of all the teeth had an unencapsulated branched Ruffini‐like structure. The TG receptors in the rat incisor ligament were the largest; those of monkey had the most varied form. Some coiled or encapsulated receptors were found in the monkey and cat ligament, but not in the rat incisor ligament. The TG receptors appear to be located at sites that would be most easily stretched during tooth contact. The different sites and intensity of the stretch forces occurring during the use of different types of teeth may determine the variations in the size and location of the TG mechanoreceptors and of their associated support cells. The different distribution of MS receptors may contribute to their response thresholds and static properties, which differ from those of TG receptors.
Telencephalic cholinergic system of the new world monkey (Cebus apella): Morphological and cytoarchitectonic assessment and analysis of the projection to the amygdala
Authors: Kordower Jeffrey H. , Bartus Raymond T. , Marciano Frederick F. , Gash Don Marshall 
Published: January 2005

AbstractWhile the cholinergic projection from the nucleus basalis to the cortical mantle has received considerable attention, a similar projection to the magnocellular basal nucleus of the amygdala has not been studied in such detail. The present study analyzed the cholinergic basal forebrain projection to the amygdala in the Cebus apella monkey by using combined tract‐tracing and immunocytochemical techniques. As a foundation for this assessment, the morphological and cytoarchitectonic organization of the cholinergic telencephalic system of the New World C. apella monkey was examined by using choline acetyltransferase (ChAT) immunocytochemistry. Although there were minor differences, the telencephalic cholinergic system of Cebus monkeys is similar to that seen in Old World nonhuman primates. ChAT‐immunoreactive neurons were observed throughout the Ch1‐4 regions of the basal forebrain, with subdivisions of the Ch4 region similar to those previously described (Mesulam et al., '83a). Most cholinergic neurons were hyperchromic and magnocellular; however, some neurons were parvicellular. Like most species, cholinergic neurons were also observed throughout the striatum. However, unlike in rodents, cholinergic perikarya were not observed within the cortex or hippocampus. To analyze the cholinergic fiber projections from the basal forebrain to the amygdala, monkeys received an intra‐amygdaloid injection of the retrograde tracer horseradish peroxidase conjugated to wheat germ agglutinin. Retrogradely labeled neurons that colocalized ChAT or acetylcholinesterase (AChE) were found predominantly in the anterolateral portion of the CH4 region. Fewer double‐labeled neurons were found in the anteromedial and intermediate portion of CH4 and in the CH3 region. Neurons that exhibited retrograde labeling were only occasionally discerned in the posterior portions of the CH4 region, in the medullary laminae of the globus pallidus, or lodged within the internal capsule. These data are discussed in terms of the putative role this cholinergic input might play in cognitive processing in primates.
Purkinje cell reduction in the reeler mutant mouse: A quantitative immunohistochemical study
Authors: Heckroth John A. , Goldowitz Dan , Eisenman Leonard M. 
Published: January 2005

AbstractWe have used the immunohistochemical detection of the Purkinje cell marker cGMP‐dependent protein kinase to identify Purkinje neurons in the cerebellum of the reeler mutant mouse. Our quantitative analysis of Purkinje cell number based on this marker indicates that reeler mice possess approximately 82,000 Purkinje cells, slightly less than half the number found in normal mice. Our analysis also shows that 5% of the Purkinje cells in reeler are located in a normal position (between molecular and granular layers), 10% are found in the granular layer, and the remainder form the deep cellular masses characteristic of the reeler cerebellum. The finding of a major Purkinje cell deficit in reeler was surprising in that most investigators consider this mutation to effect cell migration as opposed to cell number. Although we cannot determine whether the Purkinje cell loss in reeler is a primary or secondary gene effect, the possibility that the reeler gene has its effect on migration through a primary effect on neurogenesis or cell survival should be considered.
Development of the peripheral trigeminal system in the chick revealed by an isotype‐specific anti‐beta‐tubulin monoclonal antibody
Authors: Moody Sally A. , Quigg Mark S. , Frankfurter Anthony 
Published: January 2005

AbstractUsing a monoclonal antibody directed against a class III β‐tubulin isotype, cβ4, we studied the time course of the expression of this protein, the morphological differentiation of the immunoreactive cells, and the time course of peripheral axon outgrowth in the chick trigeminal (V) system. The neural crest precursors of the V ganglion neurons do not express the antigen until they begin to differentiate as neurons. The placodal precursors of the V ganglion neurons express the antigen while they still are cuboidal epithelial cells. They continue to be immunoreactive as they migrate from the placode and settle in the ganglion, prior to sprouting axons. The V motoneurons express the antigen near the time of their terminal mitotic division. Using this antibody to visualize axons, we demonstrate that both ganglionic and motoneuron axons grow out as individual fibers, much like pioneer axons. Both halt their extension for several hours once they attain the vicinity of their targets. During this pause many other axons join the nerve bundles. Finally, single pioneer axons split from the main trunk to begin local target innervation.
Ultrastructural localization of immunoreactive calbindin‐D28k in the rat and monkey basal ganglia, including subcellular distribution with colloidal gold labeling
Authors: DiFiglia Marian , Christakos Sylvia , Aronin Neil 
Published: January 2005

AbstractNormal cellular function depends on the controlled flux of Ca++ within intracellular compartments and across the plasma membrane. Proteins that bind Ca++ are thought to contribute to the regulation of intracellular Ca++ and, perhaps more importantly, signal functional changes in cell activity. In the brain, calbindin‐D28k is among a class of calcium‐binding proteins that are widely and heterogeneously distributed in select populations of neurons, among them neostriatal cells, but whose function is largely unknown. In this study of the monkey and rat neostriatum and globus pallidus, calbindin‐D28k was localized with immunoperoxidase and immunogold methods in order to identify striatal cell populations that contain this protein and the subcellular compartments in which it is likely to function.Light and electron microscopy showed intense and extensive labeling of immunoreactive calbindin‐D28k in the cell bodies, dendrites, and spines of medium‐sized neostriatal spiny neurons and in their axon terminals which end in the globus pallidus. More discrete labeling with a gold‐conjugated second antibody showed that the predominant site of calbindin‐D28k was the matrix of the cytoplasm. Gold label was also associated with the karyoplasm of spiny cells and with the neurofilaments and axoplasmic matrix of striatopallidal axons and terminals, respectively. Membranes were either sparsely labeled (endoplasmic reticulum, mitochondria) or devoid of gold particles (nuclear envelope and plasmalemma). Radioimmunoassays of striatal subcellular fractions supported the anatomical findings by indicating that the soluble fractions of neostriatal tissue homogenates contained most of the calbindin‐D28k immunoreactivity and that washes from forebrain synaptosomes treated with Triton X‐100 yielded high levels of immunoreactive calbindin‐D28k.These findings show that immunoreactive calbindin‐D28k is localized to spiny neurons of the striatopallidal pathway and are consistent with previous observations on subcellular localization in nonneuronal tissues. If, as recently speculated, calbindin‐D28k regulates calcium concentrations in neostriatal spiny neurons, this feature may be particularly involved with the high density of glutamatergic inputs to these cells. More work is needed to determine whether calbindin‐D28k, when complexed to Ca++ in neostriatal spiny cells, signals the activation of protein kinases, phosphorylation, and/or neurotransmitter release, as has been shown for other Ca++‐binding proteins in mammalian tissues.