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J D Coulter

Publications and source records attributed to J D Coulter.

At least 19 recordsLinked to original sources
PubMed1991

Distribution and developmental expression of the nerve terminal protein NT75 in the rat cerebellum.

Previous studies of the nerve terminal protein NT75 in the developing spinal cord have suggested an association between the appearance of NT75 immunoreactivity and the process of synaptogenesis. To examine the time course of NT75 expression further, the current study compared the localization of NT75 and the synaptic vesicle protein synaptophysin in the adult and developing rat cerebellum and in cerebellar tissue cultures. In the adult cerebellum, dense NT75 staining is confined to the molecular layer, where it is associated with parallel fiber endings of cerebellar granule cells. During development, NT75 immunoreactivity is first detectable in the cerebellar cortex as a dense band of staining in the deepest portion of the molecular layer at postnatal day 10. The stained zone expands to occupy a progressively greater portion of the molecular layer until about postnatal day 20. Synaptophysin staining occurs in granule cell processes earlier than NT75 and is found throughout the molecular layer by postnatal day 7. Quantitatively, rapid increases in both NT75 and synaptophysin occur in the first three postnatal weeks, with NT75 activity reaching levels exceeding the adult value by 50% over postnatal days 20 through 30, whereas synaptophysin plateaus at near adult levels by postnatal day 20. In cerebellar cultures, NT75 staining in neurites develops over several days, increasing coincidentally with development of synaptic contacts, whereas synaptophysin staining is already present in most neurites after only 1 day in vitro. The results indicate that NT75 expression in developing cerebellar granule cell nerve terminals is closely associated with the appearance of mature nerve terminals, suggesting that the protein may have a role in the formation/stabilization of the synaptic ending or in the mechanisms of synaptic transmission.

Animals↗
PubMed1990

Immunolocalization and quantitation of a novel nerve terminal protein in spinal cord development.

In the adult spinal cord, the neuron-specific protein NT75 is located in nerve terminals synapsing in the superficial laminae of the dorsal horn. The present study examines the occurrence of NT75 in the developing rat spinal cord. NT75 immunoreactivity is detectable in primary afferent axons at the dorsal root entry zone on embryonic day 15. Subsequently, staining of presumptive nerve terminals appears in the deeper laminae of the dorsal horn, expanding into the superficial laminae during the first postnatal week. NT75 staining also appears in developing corticospinal tract axons in the brainstem at birth, and at lumbosacral levels by postnatal day 5. As NT75-positive nerve terminals approach the adult distribution, staining of primary afferent and corticospinal axons decreases, becoming undetectable by postnatal day 30. Dense transient staining of presumed nerve terminals in the ventral horn is also apparent during early postnatal development. Quantitative analysis of developing spinal cord shows a low level of NT75 immunoreactivity at birth. NT75 activity then increases substantially, reaching values by the third and fourth postnatal weeks up to 2.5 times that seen in adults. The occurrence of NT75 immunoreactivity correlates with the reported time course of synaptic development in the spinal cord. In addition, the results suggest that NT75 immunoreactivity is maintained at high levels in the nerve terminals of certain neural pathways into adulthood, whereas in other systems NT75 immunoreactivity may be detectable only during development.

Aging↗
PubMed1989

A nerve terminal protein with a selective distribution in spinal cord and brain.

A monoclonal antibody, designated S-7B8, recognizes a protein antigen localized to highly selected populations of nerve terminals in spinal cord and brain. The antibody produces dense immunocytochemical staining of primary afferent endings that synapse in superficial laminae of the spinal cord dorsal horn. Electron microscopy shows staining to be localized in nerve terminals where reaction product is associated primarily with spherical vesicles. In brain, S-7B8 immunoreactivity occurs in nerve terminals in sensory relay nuclei, most thalamic nuclei, and other selected areas, including the cerebellar molecular layer, the substantia nigra, the globus pallidus, and certain synaptic layers of the hippocampus and dentate gyrus. Endocrine glands and other tissues do not exhibit S-7B8 immunoreactivity. Although the antibody localizes to certain populations of nerve terminals that may use excitatory amino acid neurotransmitters, the distribution of S-7B8 immunoreactivity in the CNS does not correspond to that of any previously identified nerve terminal protein. Experiments to characterize the S-7B8 antigen indicate it may be an integral membrane component since extraction of synaptosomes with alkaline pH or high ionic strength does not release the antigen from the membranes. To identify the molecular weight of the S-7B8 antigen, synaptosomal membranes were solubilized in CHAPS and sequentially chromatographed on hydroxylapatite and then on DEAE anion-exchange resin to produce enriched fractions. When enriched fractions were separated on SDS-PAGE and Western blotted, the S-7B8 antibody specifically stained a protein migrating at 75,000 Da. This protein has been designated NT75. Preliminary studies of developing pathways show that the appearance of S-7B8 immunoreactivity in growing nerve endings corresponds closely to the time when synaptic connections are formed. Thus, the NT75 protein recognized by the S-7B8 antibody may have a role in the development and maintenance of specific synaptic endings.

Animals↗
PubMed1986

Axonal transport of monoclonal antibodies.

Three monoclonal antibodies against rat brain synaptosomes, produced by conventional hybridoma techniques, were screened for their ability to undergo uptake and axonal transport in vivo. Injections of ascitic fluid or of purified immunoglobulin G (IgG) were made into the vitreal chamber of the eye in anesthetized rats to test for anterograde transport in retinal afferents to the contralateral superior colliculus. Retrograde transport by facial nucleus motoneurons was evaluated after injections of antibody into the mystatial vibrissal skin and musculature. Transported immunoglobulins were localized in tissue sections using a modification of the peroxidase-antiperoxidase technique. One monoclonal antibody, S-2C10, was found to undergo anterograde transport in retinal ganglion cells and retrograde axonal transport in facial motoneurons. Transported immunoglobulins were detectable even after injections of dilute antibody solution (0.01-0.05% IgG), and the uptake-transport process for this antibody appeared saturable. Two other antibodies tested, S-4E9 and S-1G10, exhibited the ability to undergo retrograde transport, but only after injections at relatively high antibody concentrations (greater than or equal to 1.0% IgG). Neither of these antibodies was shown to undergo anterograde transport. Following retrograde transport in motoneurons, the S-2C10 antibody was localized in neuronal perikarya, proximal dendrites, and the adjacent neuropil of the facial motor nucleus. In contrast, the S-4E9 and S-1G10 antibodies were localized in punctate granules within neuronal cell somata following transport. The findings suggest that the uptake-transport process for the S-2C10 antibody is mediated by adsorptive endocytosis following binding of the antibody to a plasma membrane component (or components) present in somadendritic and nerve terminal membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Transneuronal transport of lectins.

Axonal and transneuronal transport of the plant lectins wheat germ agglutinin (WGA), Pisum sativum agglutinin (PSA), Lens culinaris agglutinin (LCA), soybean agglutinin (SBA), peanut agglutinin (PNA), Concanavalin A agglutinin (Con A), and Ulex europeus agglutinin (UEA) were examined and compared using an immunocytochemical staining method. WGA, which binds to N-acetylglucosamine and sialic acid carbohydrate residues, and the 3 mannose binding lectins (Con A, PSA and LCA) were found to undergo retrograde transport to the facial nucleus after injection into the facial muscles, and anterograde transport to the optic tectum after injection in the vitreous, and to the spinal trigeminal nucleus caudalis after injection into the mystatial vibrissae. SBA showed a slight tendency to be transported retrogradely, but not in the anterograde direction, whereas UEA and PNA were not axonally transported in any of these systems. All lectins which were transported in the anterograde direction labeled neuronal somata in their respective terminal fields indicating that transneuronal transport had taken place. Axonal and transneuronal transport of the lectins appears to be dependent upon their respective carbohydrate affinities. Transneuronal transport which can be demonstrated for certain lectins indicates that mechanisms exist whereby neurons exchange large molecules which could be involved in mediating trophic and other influences on target cells.

Animals↗
PubMed1985

Axonal transport of antibodies to subcellular and protein fractions of rat brain.

Experiments examined the feasibility of using the axonal transport of antibodies as a possible means to characterize nerve membrane composition and the fate of internalized macromolecules. Polyspecific antibodies were generated in rabbits against rat brain synaptosomal and microsomal subcellular fractions and against wheat germ agglutinin-binding proteins isolated by lectin affinity chromatography. Antisera were injected into the vitreal chamber of the eye and into the facial musculature of anesthetized rats to test, respectively, for anterograde transport in retinotectal neurons and for retrograde transport in facial motoneurons. Control injections of preimmune serum were made into the opposite side. After survival for 4-168 h, animals were perfused and the axonally transported rabbit immunoglobulins detected in frozen sections of the brainstem using a modified peroxidase-antiperoxidase immunocytochemical procedure. Antisera against all 3 classes of neuronal antigens contained antibodies that underwent retrograde axonal transport. No evidence of anterograde transport was seen. Neurons containing retrogradely transported immunoglobulins exhibited punctate as well as diffuse staining of the cytoplasm and proximal dendrites, exclusive of the nucleus. Following retrograde transport of antibodies to the synaptosomal fraction, staining of the neuropil around motoneurons was also observed, suggesting transcellular transport of these antibodies. Concentrations of injected antibodies as low as 1% of whole antiserum led to detectable retrograde transport. Increasing concentrations of antibodies above the amount in whole antiserum did not increase the intensity of staining in retrogradely labeled neurons, suggesting saturation. The findings support the view that antibodies to neural membranes are taken up and transported by binding to specific sites on nerve terminals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

The central distribution of vagal catecholaminergic neurons which project into the abdomen in the rat.

A double labeling technique employing retrograde labeling of vagal neurons with horseradish peroxidase from injections into the stomach wall and immunocytochemistry for dopamine-beta-hydroxylase revealed catecholaminergic neurons in the medulla oblongata which project into the abdomen. The great majority of such neurons were located in the dorsal motor nucleus of the vagus, particularly in its rostral third.

Abdomen↗
PubMed1979

Cells of origin of long descending propriospinal fibers connecting the spinal enlargements in cat and monkey determined by horseradish peroxidase and electrophysiological techniques.

The cells of origin of the long descending propriospinal tract (LDPT) in the cervical enlargement were studied in cat and monkey by using the retrograde transport of horseradish peroxidase (HRP). Their distribution was confirmed electrophysiologically in cat by recording their antidromic action potentials. In cats and monkeys unilateral injections of HRP were made into the gray matter of the lumbosacral enlargement, but there was some spread to the contralateral side. In cats labeled somas were found in greatest numbers in lamina VIII and medial lamina VII, bilaterally. Labeled cells also were found bilaterally in laminae I, IV--VI, and X, but few were in IV and VI. Those in lamina V were usually in the lateral part of the lamina near the reticulated region. The cross-sectional areas of 20 neurons from each of laminae I and V--VIII were measured. Cells in lamina I were smallest and the largest were in VII and VIII. In cats with the spinal cord hemisected between the injection site and the cervical enlargement containing the somas, the bilaterality of the LDPT neurons in laminae VII and VIII was confirmed anatomically and physiologically. Contralaterally projecting neurons in laminae VIII and medial VII constituted a majority of LDPT cells in those laminae. The LDPT neurons in the dorsal horn appeared to project mainly ipsilaterally, but the number of labeled dorsal horn cells in these preparations was small. The distribution of antidromically localized cells of the LDPT was found to be in good agreement with the anatomical results. Their conduction velocity was 59 +/- 22 m/s (mean +/- s.d., n = 245). Histograms of the conduction velocity by laminae are given. In monkey the distribution of labeled somas was similar to that in the cat, except that the concentration of labeled somas in the ventral horn was more medially and dorsally located. Labeled somas were found bilaterally in laminae I, IV--VIII, and X, but more appeared to be ipsilateral to the side of the injection, especially in the dorsal horn. The bilaterality of the LDPT in the monkey was not tested with hemisections of the spinal cord. Neurons of the LDPT are ideally situated for conveying sensory information from the forelimb for eliciting reflexes in the hindlimb, as has been observed after stimulating afferents in the forelimb, and for coordinating, in general, motor functions between the two pairs of limbs.

Action Potentials↗
PubMed1979

Commissural columns in the sensory-motor cortex of monkeys.

Callosally projecting cells and the terminal ramifications of their axons were identified in the monkey sensory-motor cortex by retrograde and anterograde labeling techniques, often by double labeling cells and axons in the same animal. Bundles of callosal fibers terminate in small column-like zones 0.5-1 mm wide in the motor cortex (area 4) and in the first (SI) and second (SII) somatic sensory areas. Such columns are aligned in register to form elongated strips extending mediolaterally in the long axes of the pre- and postcentral gyri. Significant portions of area 4, SI and SII, in regions corresponding to the representations of the hand and foot, are not callosally connected. The cells of origin of callosal fibers in SI are largely confined to layer IIIB and form columns and strips corresponding to the above. In connected zones of SI, the callosal connection is reciprocal and precisely point-to point. This and the laminar distribution of the terminal ramifications of callosal fibers (to layers I-IV) suggest that callosal fibers may arise from the terminate upon exactly homotopic, column-like groups of layer IIIB pyramidal cells. Commissurally projecting cells and their terminal ramifications are not limited to particular architectonic fields or particular parts of fields in SI. All architectonic fields of SI project heterotopically to the contralateral SII.

Animals↗
PubMed1978

Intracortical connectivity of architectonic fields in the somatic sensory, motor and parietal cortex of monkeys.

Anterograde and retrograde transport methods were used to study the corticocortical connectivity of areas 3a, 3b, 1, 2, 5, 4 and 6 of the monkey cerebral cortex. Fields were identified by cytoarchitectonic features and by thalamic connectivity in the same brains. Area 3a was identified by first recording a short latency group I afferent evoked potential. Attempts were made to analyze the data in terms of: (1) routes whereby somatic sensory input might influence the performance of motor cortex neurons; (2) possible multiple representations of the body surface in the component fields of the first somatic sensory area (SI). Apart from vertical interlaminar connections, two types of intracortical connectivity are recognized. The first, regarded as "non-specific," consists of axons spreading out in layers I, III and V-VI from all sides of an injection of isotope; these cross architectonic borders indiscrimininately. They are not unique to the regions studied. The second is formed by axons entering the white matter and re-entering other fields. In these, they terminate in layers I-IV in one or more mediolaterally oriented strips of fairly constant width (0.5--1 mm) and separated by gaps of comparable size. Though there is a broadly systematic topography in these projections, the strips are probably best regarded as representing some feature other than receptive field position. Separate representations are nevertheless implied in area 3b, in areas 1 and 2 (together), in areas 3a and 4 (together) and in area 5; with, in each case, the representations of the digits pointed at the central sulcus. Area 3b is not connected with areas 3a or 4, but projects to a combined areas 1 and 2. Area 1 is reciprocally connected with area 3a and area 2 reciprocally with area 4. The connectivity of area 3a, as conventionally identified, is such that it is probably best regarded not as an entity, but as a part of area 4. Areas identified by others as area 3a should probably be regraded as parts of area 3b. Parts of area 5 that should be more properly considered as area 2, and other parts that receive thalamic input not from the ventrobasal complex but from the lateral nuclear complex and anterior pulvinar, are also interconnected with area 4. More posterior parts of area 5 are connected with laterally placed parts of area 6. A more medial part of area 6, the supplementary motor area, occupies a pivotal position in the sensory-motor cortex, for it receives fibers from areas 3a, 4, 1, 2 and 5 (all parts), and projects back to areas 3a, 4 and 5.

Animals↗
PubMed1978

Organization of corticospinal neurons in the cat.

The cells of origin of the corticospinal tract of the cat were identified using the retrograde horseradish peroxidase (HRP) labeling technique. Cortical neurons labeled from the spinal cord were confined to layer V and included large Betz cells, as well as many smaller neurons of this layer. Collections of 5-10 labeled neurons concentrated in areas of 300-500 micrometer diameter were observed, suggesting a columnar-type of organization of corticospinal neurons. Injections of HRP into different spinal segments were used to determine the somatotopic distribution of corticospinal neurons. Cortical neurons projecting to the cervical spinal enlargement were found in the lateral hemisphere, with more caudal spinal levels being represented successively more medial. There appeared to be little, if any, overlap in the distributions of neurons labeled from the cervical versus the lumbosacral spinal cord. Neurons projecting to the spinal enlargements were most abundant in the primary area 4, motor cortex (MI), but substantial populations of neurons were located in each of the subfields, areas 3a, 3b, 1 and 2, of the primary somatic sensory cortex (SI), plus area 2 pre-insularis of the second somatic sensory region (SII), and area 5 of the suprasylvian gyrus. This suggested, in view of the differences in inputs and response properties of neurons in these cortical regions, that the corticospinal projections from the different areas could represent multiple, independent functions in spinal cord sensory and motor control. The soma diameters of HRP-labeled corticospinal neurons varied widely, with a distinct, large-celled (Betz-type) and a small-celled population being present in the area 4 motor cortex. The largest labeled neurons of the somatic sensory cortical areas were intermediate in size. Three types of corticospinal neurons may exist, corresponding to the giant pyramidal (Betz) cells, the largest pyramidal neurons of the somatic sensory regions, and the abundant, smaller pyramidal cells which are found throughout the sensory and motor cortical fields.

Animals↗