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B Droz

Publications and source records attributed to B Droz.

At least 37 records · Page 2Linked to original sources
PubMed1989

Calbindin-immunoreactive sensory neurons of dorsal root ganglion project to skeletal muscle in the chick.

In the chicken dorsal root ganglia, two neuronal subpopulations referred to as A1 and B1 share in common an immunoreactivity to antisera raised to calbindin D-28k but are distinguished by their cytological and ultrastructural characteristics. To determine the peripheral targets innervated by calbindin-immunoreactive neurons in lumbosacral dorsal root ganglia, cryostat sections of various hindlimb tissues were treated with anticalbindin antisera. Calbindin-immunostained axons were clearly detected in skeletal muscle. Large myelinated nerve fibres and afferent axon terminals in neuromuscular spindles were calbindin-immunoreactive; thin unmyelinated nerve fibres were also immunostained in nerve bundles of the perimysium. Since motoneurons and neurons of the autonomic nervous system were devoid of calbindin immunostaining, it was suggested that the immunoreactive axons found in skeletal muscle originate from sensory neurons expressing a calbindin immunoreaction in the dorsal root ganglia. This hypothesis was corroborated after introduction of wheat germ agglutinin coupled with horseradish peroxidase or colloidal gold particles into the sartorius muscle. The retrogradely transported tracer was collected only in ganglion cell bodies which displayed the ultrastructural characteristics of A1 and B1 sensory neurons. On the basis of calbindin immunoreaction and of tracer retrograde transport, it is concluded that ganglion cells of subclasses A1 and B1 contribute to the sensory innervation of skeletal muscle in the chicken.

Afferent Pathways↗
PubMed1989

Maintenance of neuronal expression of calbindin by a muscular extract in cultures of chick dorsal root ganglion cells.

Calbindin D-28K is a calcium-binding protein which is expressed by subpopulations of dorsal root ganglion cells cultured from 10-day-old (E10) chick embryos. After 7 or 10 days of culture, more than 20% of the ganglion cells are immunostained by an anticalbindin-antiserum; however, after 14 days of culture, the proportion drops to 10%. This fall can be prevented by addition of muscle extract to cultures at 10 days. Thus the transitory expression of calbindin-immunoreactivity by responsive sensory neurons would be not only induced but also maintained by a differentiation factor of muscular origin.

Animals↗
PubMed1989

Inducing effect of skeletal muscle extracts on the appearance of calbindin-immunoreactive dorsal root ganglion cells in culture.

Calbindin D-28k is a calcium-binding protein which is not expressed by dorsal root ganglion cells cultured from 6-day-old (E6) chick embryos. When soluble muscle extracts from embryos at E11, E18 or chickens 2 weeks after hatching were added immediately after seeding, dorsal root ganglia cells grown at E6 displayed neuronal subpopulations expressing calbindin immunoreactivity with time; the effect of muscle extract on the percentage of calbindin-immunoreactive dorsal root ganglia cells followed a dose-response curve. When muscle extract was added to cultures after a 3 day delay, the percentage of calbindin-expressing neurons was unchanged. The effect produced by muscle extract and, to a lesser degree, skin extract on the appearance of calbindin-positive neurons was not reproduced by brain or liver extracts while all four exerted a trophic action on cultured neurons. Hence it is assumed that muscle extract contains a factor which produces an inductive effect on the initiation of calbindin-expression by uncommitted subpopulations of sensory neurons rather than a trophic influence on the selective survival of covertly committed neuronal subpopulations. The fact that muscle extract promoted calbindin expression by dorsal root ganglia cells in neuron-enriched as well as in mixed dorsal root ganglion cell cultures indicates that the factor would act directly on sensory neurons rather than indirectly through mediation of non-neuronal cells. Since the active muscular factor was non-dialysable, heat-inactivated, trypsin-sensitive and retained by molecular filters with a cut-off of 30 K, this factor is probably a protein.

Animals↗
PubMed1988

Calbindin D-28k-immunoreactive neurons in chick dorsal root ganglion: ontogenesis and cytological characteristics of the immunoreactive sensory neurons.

The expression of calbindin (28,000 mol. wt Vitamin D-dependent calcium binding protein) was studied in sensory neurons of the chick dorsal root ganglion by combining immunocytochemical and ultrastructural features. In the chick embryo at E10, about 20% of the neuroblasts were immunostained with antibodies raised to calbindin. After hatching, two subpopulations of primary sensory neurons were labeled with calbindin-antibodies and could be identified: the large Al cell bodies (6%) mainly characterized by huge blocks of rough endoplasmic reticulum and the small B1 cell bodies (14%) which contain parallel cisternae of rough endoplasmic reticulum. The other neuronal cell types A2 and B2 were devoid of any immunostaining. Thus, calbindin is an early and reliable marker of two subclasses of primary sensory neurons in the chick dorsal root ganglion.

Animals↗
PubMed1988

Influence of peripheral and central targets on subpopulations of sensory neurons expressing calbindin immunoreactivity in the dorsal root ganglion of the chick embryo.

The influence of central and peripheral target tissues on the expression of calbindin D-28k by sensory neurons of the chick dorsal root ganglia was tested under various experimental conditions. Firstly, dorsal root ganglia of chick embryos were transplanted at two stages of development onto the chorioallantoic membrane of a host embryo for a period of 4 or 8 days. In dorsal root ganglia grafted at E12, 20% of the ganglion cell bodies were immunoreactive to calbindin 4 and 8 days later; the percentage of calbindin-immunostained neurons in grafted dorsal root ganglia was similar to that observed in control dorsal root ganglia of the same embryonic age (E16 or 20). In contrast, when grafted dorsal root ganglia were taken from a donor embryo at E8, no calbindin-immunoreactive neuron was found 4 or 8 days later. However, when dorsal root ganglia at E8 were cotransplanted with musculature cells, 14% of the grafted ganglion cell bodies were again immunoreactive to calbindin 4 or 8 days later. Secondly, peripheral targets of sensory neurons were suppressed by excision of one hindlimb. After excision at E6, virtually all the ipsilateral dorsal root ganglia cells were free of calbindin immunoreaction after 6 days of reincubation. In contrast, when the excision was performed at E11, calbindin was expressed in about 9% of the nerve cell bodies. Thirdly, central connections were destroyed by cauterization of the lumbosacral spinal cord at E6 or E11. Six days after deprivation of central connections, the percentage of calbindin-immunoreactive ganglion cells was the same as in control dorsal root ganglia of the same age.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantois↗
PubMed1988

Expression of calbindin immunoreactivity by subpopulations of primary sensory neurons in chick embryo dorsal root ganglion cells grown in coculture or conditioned medium.

Primary sensory neurons which innervate neuromuscular spindles in the chicken are calbindin-immunoreactive. The influence exerted by developing skeletal muscle on the expression of calbindin immunoreactivity by subpopulations of dorsal root ganglion (DRG) cells in the chick embryo was tested in vitro in coculture with myoblasts, in conditioned medium (CM) prepared from myoblasts and in control cultures of DRG cells alone. Control cultures of DRG cells grown at the 6th embryonic day (E6) did not show any calbindin-immunostained ganglion cell. In coculture of myoblasts previously grown for 14 days, about 3% of calbindin-immunoreactive ganglion cells were detected while about 1% were observed in some cultures grown in CM. Fibroblasts from various sources were devoid of effect. Skin or kidney cells were more active than myoblasts to initiate calbindin expression by subpopulations of DRG cells in coculture or, to a lesser degree, in CM. The results suggest that cellular factors would rather induce calbindin expression in certain sensory neurons than ensure a selective neuronal survival.

Animals↗
PubMed1988

Substrate-dependent migration of myelin-associated glycoprotein immunoreactive cells in cultured explants of dorsal root ganglia from chick embryos.

The aim of this study was to investigate the influence of collagen or polyornithine substrates on cell migration in explant cultures of dorsal root ganglia (DRG) by means of light microscopy and immunocytochemistry. Myelin-associated glycoprotein (MAG) immunoreactivity was used to characterize the subpopulation of small B ganglion cells, whereas neuron-specific enolase (NSE) immunoreactivity acted as a general neuronal cell marker. After a few days in culture, DRG explants grown on collagen substrate showed a flattened shape consisting of a core surrounded by a crown of neurites, which were mixed up with migrating cells of different types. These migrating cells were immunostained for both MAG and NSE and were observed after 7 days in the vicinity of the explant core, then after 14 days also at a distance from the explant core. In contrast, even after 14 days in culture, explants grown on polyornithine substrate maintained a globular shape. The MAG-positive ganglion cells were confined to the explant core and no cell migration was observed on this type of substrate. MAG immunoprecipitates located at the ganglion cell surface were observed in explants cultured on polyornithine, but rarely on collagen substrate. In conclusion, it is suggested that this pattern of intracellular distribution of MAG immunoreactive material could reflect interactions between cell surface and extracellular matrix, and could condition the migratory ability of small ganglion cells.

Animals↗
PubMed1987

Differentiation of postmitotic neuroblasts into substance P-immunoreactive sensory neurons in dissociated cultures of chick dorsal root ganglion.

Counts performed on dissociated cell cultures of E10 chick embryo dorsal root ganglia (DRG) showed after 4-6 days of culture a pronounced decline of the neuronal population in neuron-enriched cultures and a net gain in the number of ganglion cells in mixed DRG cell cultures (containing both neurons and nonneuronal cells). In the latter case, the increase in the number of neurons was found to depend on NGF and to average 119% in defined medium or 129% in horse serum-supplemented medium after 6 days of culture. The lack of [3H]thymidine incorporation into the neuronal population indicated that the newly formed ganglion cells were not generated by proliferation. On the contrary, the differentiation of postmitotic neuroblasts present in the nonneuronal cell compartment was supported by sequential microphotographs of selected fields taken every hour for 48-55 hr after 3 days of culture. Apparently nonneuronal flat dark cells exhibited morphological changes and gradually evolved into neuronal ovoid and refringent cell bodies with expanding neurites. The ultrastructural organization of these evolving cells corresponded to that of primitive or intermediate neuroblasts. The neuronal nature of these rounding up cell bodies was indeed confirmed by the progressive expression of various neuronal cell markers (150 and 200-kDa neurofilament triplets, neuron specific enolase, and D2/N-CAM). Besides a constant lack of immunoreactivity for tyrosine hydroxylase, somatostatin, parvalbumin, and calbindin-D 28K and a lack of cytoenzymatic activity for carbonic anhydrase, all the newly produced neurons expressed three main phenotypic characteristics: a small cell body, a strong immunoreactivity to MAG, and substance P. Hence, ganglion cells newly differentiated in culture would meet characteristics ascribed to small B sensory neurons and more specifically to a subpopulation of ganglion cells containing substance P-immunoreactive material.

Acetylcholinesterase↗
PubMed1986

Carbonic anhydrase activity in primary sensory neurons. I. Requirements for the cytochemical localization in the dorsal root ganglion of chicken and mouse by light and electron microscopy.

Subpopulations of primary sensory neurons in mammalian dorsal root ganglion (DRG) exhibit carbonic anhydrase (CA) activity. To identify these subpopulations in DRG cells of mouse and chicken, the reliability of the cytochemical localization of the enzyme requires that several conditions be fulfilled: Preservation of the enzyme activity in glutaraldehyde-containing fixative; accessibility of the cytoenzymatic reaction throughout 20-micron thick Vibratome sections; retention of the reaction product in situ during OsO4 post-fixation; specificity of the cytoenzymatic reaction for CA activity as corroborated by the immunocytochemical detection with antibodies anti-CA II in mouse DRG; strict correlation between the CA activity and the cytological characteristics in a given subclass of neurons. On the basis of these criteria, it is concluded that the CA activity may be used as a cell marker to identify cytologically defined neuronal subpopulations and their axons in mouse DRG. In chicken DRG, CA activity is not consistently expressed in a given subclass of ganglion cells and their axons. Hence, it is assumed that the expression of CA activity by DRG cells in chicken is modulated by functional or environmental conditions.

Animals↗
PubMed1986

Carbonic anhydrase activity in primary sensory neurons. II. Influence of environmental factors on the phenotypic expression of the enzyme in dissociated cultures of chicken dorsal root ganglion cells.

Neuronal subpopulations of dorsal root ganglion (DRG) cells in the chicken exhibit carbonic anhydrase (CA) activity. To determine whether CA activity is expressed by DRG cells maintained in in vitro cultures, dissociated DRG cells from 10-day-old chick embryos were cultured on a collagen substrate. The influence exerted by environmental factors on the enzyme expression was tested under various conditions of culture. Neuron-enriched cell cultures and mixed DRG-cell cultures (including numerous non-neuronal cells) were performed either in a defined medium or in a horse serum-supplemented medium. In all the tested conditions, subpopulations of cultured sensory neurons expressed CA activity in their cell bodies, while their neurites were rarely stained; in each case, the percentage of CA-positive neurons declined with the age of the cultures. The number and the persistence of neurons possessing CA activity as well as the intensity of the reaction were enhanced by addition of horse serum. In contrast, the expression of the neuronal CA activity was not affected by the presence of non-neuronal cells or by the rise of CO2 concentration. Thus, the appearance and disappearance of neuronal subpopulations expressing CA activity may be decisively influenced by factors contained in the horse serum. The loss of CA-positive neurons with time could result from a cell selection or from genetic repression. Analysis of the time curves does not support a preferential cell death of CA-positive neurons but suggests that the eventual conversion of CA-positive neurons into CA-negative neurons results from a loss of the enzyme activity. These results indicate that the phenotypic expression of cultured sensory neurons is dependent on defined environmental factors.

Acetylcholinesterase↗
PubMed1986

Myelin-associated glycoprotein immunoreactive material: an early neuronal marker of dorsal root ganglion cells during chick development.

Immunostaining of myelin-associated glycoprotein (MAG) was performed in chick dorsal root ganglia (DRG) during development. The MAG-immunoreactive material appeared first around 7 days of incubation in immature neurons of DRG. Immunoprecipitates first confined to one pole of nucleus were gradually redistributed in the perinuclear Golgi apparatus of small DRG cells. Thus MAG may be used in the chick embryo as an early marker of primary sensory neurons of class B.

Animals↗
PubMed1985

Neuronal subpopulations in the dorsal root ganglion of the mouse as characterized by combination of ultrastructural and cytochemical features.

The neuronal population of dorsal root ganglia in mouse consists of various classes of ganglion cells which may be divided in turn into subclasses by using several criteria. In class A cells, membrane-bound organelles are distributed ubiquitously throughout the large perikarya. Subclass A alpha (12%), which is characterized by large clumps of Nissl substance separated by narrow strands of neuroplasm, lacks detectable carbonic anhydrase activity. Subclass A beta (16%) displays small clusters of Nissl substance isolated by broad channels of neuroplasm and a moderate activity of carbonic anhydrase. Subclass A gamma (8%) shows the most intense carbonic anhydrase activity and a lack of uptake for [3H]L-glutamine. In class B cells (63%), the small perikarya display a zonal distribution of the organelles. Subclass B alpha contains parallel cisternae of rough endoplasmic reticulum and acid phosphatase isoenzymes present in long and curved Golgi saccules. Subclass B beta displays straight Golgi saccules rich in acid phosphatase isoenzymes and a high affinity uptake for glutamine. Subclass B gamma is characterized by the absence of acid phosphatase isoenzymes and by the presence of substance P-immunoreactivity. Class C cells (1%) have the smallest size and the highest affinity uptake for glutamine. Thus subtypes of primary sensory ganglion cells may be identified by the concomitant use of multiple criteria.

Acid Phosphatase↗
PubMed1985

Expression of myelin-associated glycoprotein by small neurons of the dorsal root ganglion in chickens.

Biochemical and immunocytochemical investigations have shown that myelin-associated glycoprotein (MAG) is exclusively related to myelin and myelin-forming cells in mammals. In the present study it was found that dorsal root ganglia in young chickens display MAG-immunoreactive material in most small sensory neurons. The presence of MAG at the surface of small sensory neurons raises the question of whether this glycoprotein acts as a cell adhesion molecule in lower vertebrates.

Animals↗
PubMed1985

Influence of environmental factors on the expression of phenotypic characters by chicken dorsal root ganglion cells in culture.

Primary sensory neurons were grown under four conditions of culture. The influence of nonneuronal cells, horse serum or both was studied on the phenotypic expression of certain neuronal subpopulations. The number of neurons expressing acetylcholinesterase, alpha-bungarotoxin-binding sites or a high uptake capacity for glutamine was enhanced by nonneuronal cells. The horse serum increases the neuronal subpopulation exhibiting a carbonic anhydrase activity. Certain phenotypic changes fit conditions consistent with an epigenetic induction rather than a cell selection.

Acetylcholinesterase↗
PubMed1982

[Alterations in axonal transport. Role in peripheral neuropathies (author's transl)].

In peripheral nerves, the use of radioisotopes or enzyme markers makes it possible to study the traffic of molecules and cell organelles, which flow along the axons in both directions. Such axonal transports ensure the renewal of most macromolecular components in the axons and hence contribute to maintain healthy peripheral nerve fibers. A lasting alteration of the mechanisms, which sustain transport or distribution of axonal constituents, could therefore initiate or reinforce pathological processes responsible for various human axonopathies. Investigation of axonal transport in genetic or toxic neuropathies in animals drows attention to the key-role played by neuronal dynamics in pathogenesis of nerve lesions.

Animals↗