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F Vandesande

Publications and source records attributed to F Vandesande.

At least 55 records · Page 3Linked to original sources

Effect of sensory deafferentation on the GABAergic circuitry of the adult cat visual system.

The effect of bilateral central retinal lesions on the GAD67 and GAD65 messenger RNA levels in the dorsal lateral geniculate nucleus, the perigeniculate nucleus and the visual cortex of the adult cat was investigated by in situ hybridization. Three days post-lesion, a decrease in the number of GAD67-expressing cells was apparent in the deafferented dorsal lateral geniculate nucleus. This decrease persisted until 7.5 months post-lesion and was more pronounced with longer survival times. The decrease in GAD67 mRNA was mirrored by a decrease in glutamate decarboxylase-immunoreactive cells. GAD65 messenger RNA expression levels were low in the dorsal lateral geniculate nucleus of both control and retinally-lesioned cats. In the perigeniculate nucleus the messenger RNA levels of both glutamate decarboxylase isoforms were clearly decreased over a restricted region. In the lesion-affected visual cortex, no changes at the messenger RNA level were observed for either GAD67 or GAD65 although changes in glutamate decarboxylase immunoreactivity have been previously described. Hence, in the dorsal lateral geniculate nucleus, the perigeniculate nuclcus and the visual cortex, different intracellular mechanisms seem to lead to decreased GABAergic inhibition in response to sensory deafferentation.

Animals↗

Determination of serotonin, catecholamines and their metabolites by direct injection of supernatants from chicken brain tissue homogenate using liquid chromatography with electrochemical detection.

An isocratic liquid chromatographic method with electrochemical detection for the determination of L-3,4-dihydroxyphenylalanine, dopamine, norepinephrine, epinephrine, serotonin, and their major metabolites, 3,4-dihydroxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid and 5-hydroxyindole-3-acetic acid in chicken brain tissue is described. Chickens were killed at different ages, the brains were quickly frozen and 300-microm cryostat sections were made. From these sections, two to six tissue micropunches (1 mm in diameter) were punched out from 20 different areas of the hypothalamus and homogenated in 100 microl 0.1 M perchloric acid which included 0.01% cysteine as antioxidant. Fifty-microl supernatants were injected directly onto the LC system, separated on a 3-microm Phase II ODS column (100 x 3.2 mm I.D.) and detected by an electrochemical detector at a potential of +0.75 V. Standard curves, recoveries, analytical precision and detection limits were investigated for each monoamine neurotransmitter and its metabolites. The method was applied to study the influence of food restriction on the concentration of monoamine neurotransmitters in different brain areas, known to be involved in feeding and reproductive behaviour of female broiler chickens. Over 1000 micropunched tissue samples from ad libitum fed and food-restricted female broiler chickens were analyzed. Our results provide a possible role for catecholamines and indolamines in the altered feeding and reproductive behaviour of the broiler chicken.

3,4-Dihydroxyphenylacetic Acid↗

Isolation and structural characterization of two novel peptides derived from proopiomelanocortin in the pituitary of the rainbow trout.

The trout possesses two POMC genes as a result of duplication of its genome some 25-100 million years ago. One of the POMC molecules exhibits a unique C-terminal extension of 25 amino acid residues which is not found in any other POMC characterized so far. In order to isolate possible novel peptides derived from trout POMC-A, we have raised antibodies against two synthetic epitopes derived from the C-terminal region of the precursor. Two native decapeptides were isolated in pure form from an extract of trout pituitary. The primary structures of these peptides were established as Glu-Gln-Trp-Gly-Arg-Glu-Glu-Gly-Glu-Glu and Ala-Leu-Gly-Glu-Arg-Lys-Tyr-His-Phe-Gln-NH2. The structure of the trout POMC-A cDNA reveals that both peptides are flanked by pairs of basic amino acids or a glycine residue, indicating that they can actually be generated during post-translational processing of POMC-A.

Amino Acid Sequence↗

Characterization of a novel alpha-amidated decapeptide derived from proopiomelanocortin-A in the trout pituitary.

Two complementary DNAs encoding distinct forms of POMC have been characterized in the trout pituitary. One of the POMC variants (POMC-A) possesses a C-terminal extension of 25 amino acids, which has no equivalent in other POMCs described to date. This C-terminal peptide contains three pairs of basic amino acids, suggesting that it may be the precursor of multiple processed peptides. In addition, the presence of a C-terminal glycine residue suggests that some of the processing products may be alpha-amidated. To characterize the molecular forms of the peptides generated from the C-terminal domain of trout POMC-A, we have developed specific antibodies against the C-terminal pentapeptide YHFQG and its alpha-amidated derivative YHFQ-NH2. Immunocytochemical labeling of pituitary sections with antibodies against YHFQ-NH2 revealed the presence of numerous immunoreactive cells in the pars intermedia and the rostral pars distalis. In contrast, the antibodies against YHFQG produced only weak immunostaining. HPLC analysis combined with RIA detection revealed that extracts of the pars intermedia and pars distalis contain several peptides derived from the C-terminal extension of trout POMC-A, with the predominant molecular form exhibiting the same retention time as ALGERKYHFQ-NH2. Tryptic digestion of this major form produced a peptide that coeluted with YHFQ-NH2. These data indicate that the processing of the C-terminal extension of trout POMC-A generates several novel peptides including the decapeptide amide ALGERKYHFQ-NH2.

Amino Acid Sequence↗

Long-term effects of retinal lesions on growth-associated protein 43 (GAP-43) expression in the visual system of adult cats.

We have investigated the role of growth-associated protein 43 (GAP-43) in synaptic reorganization in the visual system of adult cats that received binocular central retinal lesions. Different survival times between 3 and 8 months after induction of the lesion were chosen. In the deafferented part of the dorsal lateral geniculate nucleus (dLGN) we found a long-lasting increase in GAP-43 protein, while glial fibrillary acidic protein (GFAP) immunoreactivity, which initially increased due to the degeneration of retinal ganglion cells, slowly subsided over this period. In area 17, the pattern of GAP-43 expression did not provide indications for morphological changes in the cortical architecture following retinal lesions.

Animals↗

One-step immunoaffinity purification and partial characterization of hypophyseal growth hormone from the African catfish, Clarias gariepinus (Burchell).

Growth hormone (GH) was purified from African catfish (Clarias gariepinus) pituitary extracts in a single step by use of immunoaffinity chromatography. A monoclonal antibody to chicken GH, which labels the catfish hypophyseal somatotropes in immunocytochemistry, was coupled to CNBr-activated Sepharose, and crude alkaline pituitary extracts were run over the immunoadsorbent. Reversed-phase high-performance liquid chromatography analysis of the eluted material suggested heterogeneity, whereas silver staining upon SDS-polyacrylamide gel electrophoresis showed one single band with an estimated molecular weight between 22,000 and 23,000 Da. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the same preparation revealed the presence of several components with molecular weights ranging from 20,170 to 20,900 Da. The amino terminus of the protein was homogeneous, and the first 50 residues matched the proposed sequence of GH from two other siluran species (Ictalurus punctatus and Pangasius pangasius), except for one substitution at position 3. These data unequivocally confirm the identity of the purified molecule as suggested by immunochemical evidence. The bioactivity of the GH preparation was demonstrated by the short-term effect of GH on T3 plasma levels in juvenile catfish.

Amino Acid Sequence↗

Autoradiographic localization of receptors for neuropeptide Y (NPY) in the brain of broiler and leghorn chickens (Gallus domesticus).

Broiler and leghorn chickens show an extreme difference in ingestive and reproductive behavior. As neuropeptide Y (NPY) influences both behaviors the goal of this study was to elucidate the distribution, expression and affinity of NPY binding sites in broiler and leghorn chicken brain. By means of in vitro autoradiography, sections of chicken brains were incubated with 3H-NPY as tracer and NPY as displacer. Scatchard analysis revealed a curvilinear plot suggesting two subtypes of the NPY binding site in the chicken brain, a high affinity one (KD = 2-4 nM) and one with a lower affinity (KD = 18-24 nM). Binding sites for NPY are localized with high density in the different subdivisions of the neostriatum and the hyperstriatum, the cerebellum, the nucleus septalis lateralis and medialis, the nucleus ruber and the nucleus tractus solitarii. A lower density of NPY binding sites was found in the different subdivisions of the striatum, the nucleus mesencephalicus lateralis pars dorsalis, the paleostriatum, the archistriatum intermedium pars ventralis, the nucleus geniculatus lateralis, the nucleus taeniae, the locus ceruleus, the nucleus rotondus, the nucleus habenularis medialis, the nucleus dorsomedialis anterior (rostralis) thalami, the pituitary and the area of the hypothalamus with its nuclei such as the nucleus paraventricularis magnocellularis and the nucleus preopticus medialis. Comparison of the localization of NPY binding sites in the brains of broilers and leghorns showed no differences but the density of both receptor types is two to three times higher in broilers than in leghorns.

Animals↗

Variability of energy metabolism and nuclear T3-receptors within the skeletal muscle tissue of pigs different with respect to the halothane gene.

Energy metabolism of skeletal muscle tissue of pigs growing from approximately 12 to 18 kg (12 homozygous halothane negative, HH; 16 heterozygotes, Hh; 17 homozygous halothane susceptible, hh) was measured in vivo using 31P nuclear magnetic resonance (NMR) spectroscopy. Data for intracellular pH, phosphocreatine (PCr), phosphomonoesters (PME), and ATP were analyzed by canonical discriminant analysis, an artificial neural network approach, and analysis of variance. Within the hh pigs, two subpopulations could be distinguished before the application of halothane treatment. Some of the hh pigs had a high PME concentration in the biceps femoris muscle (hh(pme+)), whereas others had a low concentration (hh(pme-)) (2.18 +/- .12 for hh(pme+) vs 1.68 +/- .12 mM for hh(pme-), P < .004). The hh(pme+) pigs were statistically different from HH pigs for pH (P < .03), PME (P < .004), and PCr (P < .008) before halothane treatment. The hh(pme-) pigs were not different from the Hh and HH pigs with respect to PME when measured before halothane treatment (P > .05). However, intracellular pH (P < .03) and PCr (P < .008) of the hh(pme-) pigs were different from those of HH pigs (7.15 vs 7.19 for pH and 38.7 vs 35.1 for PCr, respectively). When combining intracellular pH, PME, and PCr within a canonical discriminant analysis, all were measured before halothane treatment, Hh pigs were found to be different from HH pigs (Mahalanobis distance different from zero, P < .02). In a second experiment, growth rate, depth of longissimus muscle, and maximal binding capacity of nuclear T3-receptors of skeletal muscle tissue were different (P < .05, P < .002, and P < .02, respectively) among pigs selected from the same genetic lines. Of the variability in depth of the longissimus muscle, 22% was explained by variability in maximal binding capacity of nuclear T3-receptors. These results, if confirmed with a large number of pigs, might open new possibilities for selection procedures for leanness because, with respect to halothane susceptibility, a shift between genotypic and phenotypic variability was observed.

Adenosine Triphosphate↗

Distribution of two molecular forms of gonadotropin-releasing hormone (GnRH) in the central nervous system of the frog Rana ridibunda.

Two molecular forms of gonadotropin-releasing hormone (GnRH) have been recently characterized in the brain of the frog Rana ridibunda i.e. mammalian GnRH (mGnRH) and chicken GnRH-II (cGnRH-II). Using highly specific antisera against each form of GnRH, we have investigated the distribution of these two neuropeptides in the frog brain by the indirect immunofluorescence and the peroxidase-antiperoxidase techniques. mGnRH-immunoreactive cell bodies were restricted to a well defined region corresponding to the septal-anterior preoptic area. mGnRH-containing fibers projected through the ventral diencephalon and ended in the median eminence. In contrast, cGnRH-II-immunoreactive structures were widely distributed in the frog brain. In the telencephalon cGnRH-II-positive elements formed a ventromedial column extending from the olfactory bulb to the septal area, a pathway which corresponds to the terminal nerve. A dense accumulation of cGnRH-II-immunoreactive cell bodies was also found in the septal-anterior preoptic area; these neurons sent processes towards the median eminence via the hypothalamus. Double immunostaining revealed that, in this area, mGnRH- and cGnRH-II-like immunoreactivity co-existed in the same neurons. In the mid-diencephalon, numerous cGnRH-II-immunoreactive perikarya were found, surrounding the third ventricle, in the posterior preoptic and infundibular areas. Many of these neurons sent processes towards the ventricular cavity. More caudally, a dense population of cGnRH-II-immunoreactive perikarya was also observed in the nucleus of the paraventricular organ and the posterior tubercle. Dorsally, the thalamus, the tegmentum, the tectum and the granular layer of the cerebellum were richly innervated by cGnRH-II-positive fibers. In the medulla oblongata, numerous cGnRH-II-immunoreactive perikarya were seen in several cranial nerve nuclei. Ventrally, a dense plexus of immunoreactive fibers projected rostrocaudally into the spinal cord. The occurrence of mGnRH- and cGnRH-II-like immunoreactivity in the septal-anterior preoptic area and the hypothalamo-pituitary pathway supports the view that both peptides act as hypophysiotropic neurohormones. The widespread distribution of cGnRH-II-immunoreactive elements in the central nervous system of the frog strongly suggests that this peptide may also exert neuromodulator and/or neurotransmitter activities.

Animals↗

Noradrenergic system in the chicken brain: immunocytochemical study with antibodies to noradrenaline and dopamine-beta-hydroxylase.

A light microscopic immunocytochemical study, using antisera against noradrenaline (NA) and dopamine-beta-hydroxylase (DBH), revealed the noradrenergic system in the brain of the chicken (Gallus domesticus). NA- and DBH-immunoreactive (ir) elements showed a similar distribution throughout the whole brain. The neurons immunoreactive for the monoamine were confined to the lower brainstem, the pons, and the medulla. In the pons, a rather dense group of cells was found in the dorsal, most posterior part of the locus coeruleus and in the caudal nucleus subcoeruleus ventralis. A few labeled cells appeared in and around the nucleus olivaris superior in the most caudal part of the metencephalic tegmentum. In the medulla oblongata, noradrenergic cells could be visualized at the level of the nucleus of the solitary tract and in a ventrolateral complex. Virtually all regions of the brain contained a rather dense innervation by NA- and DBH-immunopositive varicose fibers. Noradrenergic fibers and terminals were especially abundant in the ventral forebrain and in the periventricular hypothalamic regions. DBH-ir and NA-ir fibers, varicosities, and punctate structures could be observed in close association with immunonegative perikarya in several brain regions, more specifically in the ventral telencephalon, in the mid- and tuberal hypothalamic region, and in the dorsal rostral pons. Some perikarya in these brain areas were completely surrounded by noradrenergic structures that formed pericellular arrangements around the cells. The present study on the distribution of the noradrenergic system in the brain of the chicken combined with the results of a previous report on the distribution of L-Dopa and dopamine in the same species (L. Moons, J. van Gils, E. Ghijsels, and F. Vandesande, 1994, J. Comp. Neurol. 346:97-118) offers the opportunity to differentiate between the various catecholamines in the brain of this vertebrate. The results are discussed in relation to catecholaminergic systems previously reported in avian species and in the mammalian brain.

Adrenergic Fibers↗

Effect of sensory deafferentation on immunoreactivity of GABAergic cells and on GABA receptors in the adult cat visual cortex.

To investigate the effects of sensory deafferentation on the cortical GABAergic circuitry in adult cats, glutamic acid decarboxylase (GAD) and gamma-aminobutyric acid (GABA) immunoreactivity and GABA receptor binding were studied in the visual cortex of normal cats and compared with cats that had received restricted binocular central lesions of the retina and had survived for 2 weeks postlesion in a normal visual environment. In the visual cortex of lesioned cats, two changes were observed in the number of GAD-immunoreactive elements in the regions affected by the retinal lesions: the number of GAD-positive puncta decreased, whereas that of GAD-immunoreactive somata increased. In contrast, no detectable changes were measured in the number of GABA-immunopositive somata or puncta. At the receptor level, we observed no differences in either the laminar distribution or the affinity of cortical GABAA and GABAB receptors labeled with [3H]-muscimol and [3H]-baclofen, respectively, in the lesioned versus normal cats. We present the hypothesis that sensory deafferentation in these adult cats (1) leads to a reduction of cortical GABAergic inhibition in the deafferented region, and (2) that this decreased inhibition may permit changes in efficiency of synapses and (3) that these changes may represent a first stage of events underlying the retinotopic reorganization preceeding the structural changes.

Afferent Pathways↗

Decrease of zif-268 and c-fos and increase of c-jun mRNA in the cat areas 17, 18 and 19 following complete visual deafferentation.

We used in situ hybridization to investigate the effect of complete visual deafferentation on immediate early gene expression in adult cat visual cortex. Deafferentation was obtained by unilateral section of the optic tract and sections of both the corpus callosum and anterior commissure. In this model, one hemisphere served as control for the other within the same animal. A decrease in zinc finger protein (zif)-268 and c-fos mRNA was observed in the superficial and deep layers of areas 17 and 18, and all layers of area 19 in the deafferented hemisphere. This decrease, present 3 days after surgery, was maximal after 30 days. An increase of c-jun mRNA was observed in the deep layers of areas 17, 18 and 19 in the deafferented hemisphere 3, 10 and 30 days after surgery. These results suggest that visual input activates zif-268 and c-fos expression and tonically depresses c-jun expression in the primary visual complex yielding similar levels of c-jun and c-fos expression in normal conditions.

Animals↗

Nature and distribution of gonadotropin-releasing hormone (GnRH) in the brain, and GnRH and GnRH binding activity in serum of the spotted dogfish Scyliorhinus canicula.

The distribution of different molecular forms of gonadotropin-releasing hormone (GnRH) in the brain and serum of the spotted dogfish, Scyliorhinus canicula, was investigated by an indirect immunofluorescence method, using antisera against salmon (s-), chicken-II (cII-) and mammalian (m-) GnRHs, and by reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with radioimmunoassays. Five GnRH molecular forms were demonstrated on the basis of the retention time in the RP-HPLC system. The characteristics of four of these GnRH peptides are consistent with those of m-, cII-, dogfish (df-), and sGnRH. The fifth form appears to be novel. Immunoreactive sGnRH structures were confined to the diencephalon; whereas cIIGnRH and mGnRH were found in the telencephalon and diencephalon. cIIGnRH- and dfGnRH-like molecules were detected in the serum. Moreover, a specific, low-affinity GnRH binding protein (GnRH-BP) was found in the serum of the spotted dogfish. The binding of [125I]sGnRHA to the serum GnRH-BP was dependent on incubation time, equilibrium being reached within 1 hr at 4 degrees; binding was rapid and completely reversible. Scatchard analysis yielded a linear plot with a Kd of 7.9 x 10(-7) M. The presence of a GnRH-BP in spotted dogfish serum suggests a probable action of GnRH via the general circulation.

Animals↗

Localization of the two protein kinase C beta-mRNA subtypes in cat visual system.

Protein kinase C (PKC) consists of a family of different subtypes encoded by different PKC genes. We investigated the distribution of PKC beta 1 and PKC beta 2 in the visual system of the adult cat by in situ hybridization using oligonucleotide probes complementary to the PKC beta 1 and PKC beta 2 mRNAs, two splicing variants of the same gene transcript. In the primary visual cortex PKC beta 1 and PKC beta 2 were both present. The laminar distribution patterns found for the two PKC subtypes were identical. A remarkable finding was the difference between the laminar distribution of the PKC beta s in areas 17 and 18 when compared with area 19. In all three areas the highest expression levels were found in layer VI, moderately high levels were found in layers II, III and V, while layer I was devoid of signal. In area 17 and 18 layer IV stood out by its low PKC beta signal. In sharp contrast, layer IV of area 19 was indiscernible from the superficial layers because of an evenly high signal. In the dLGN of the adult cat PKC beta 1 and PKC beta 2 mRNAs were distributed rather homogeneously over the different layers, but the expression levels for PKC beta 1 were clearly higher than those for PKC beta 2.

Animals↗

Distribution of beta-endorphin-like-immunoreactive structures in the chicken and quail brain as demonstrated with a new homologous antibody directed against a synthetic peptide.

A polyclonal rabbit antibody was raised against a synthetic peptide fragment located at the C-terminal end of turkey beta-endorphin (beta-END) and used to analyze the distribution of beta-END-immunoreactive-like structures in the quail and chicken brain. Three major groups of immunopositive cells were detected in the preoptic area-hypothalamus complex. A thin layer of immunopositive cells was parallel and adjacent to the ventral edge of the brain in the preoptic and anterior hypothalamic region, a more numerous group of immunoreactive perikarya was located along the walls of the third ventricle in these same regions, and, finally, a few scattered cells were found in a more lateral position on both the internal and external sides of the tip of the fasciculus prosencephali lateralis. The periventricular cell population extended in the caudal direction until the posterior hypothalamus. Labelled fibers were always associated with these immunoreactive perikarya, and they were also found in the adjacent hypothalamic regions. A dense innervation of the median eminence was also detected. These data are compared with previous studies in mammals and birds that had identified more restricted populations of immunoreactive cells and the possible sources of the observed discrepancy are discussed. The functional significance of the present data is also briefly analyzed.

Animals↗

Immunocytochemical localization of L-dopa and dopamine in the brain of the chicken (Gallus domesticus).

A light microscopic immunocytochemical study, with antisera against dihydroxyphenylalanine (L-DOPA) and dopamine (DA), revealed the dopaergic and dopaminergic systems in the brain of the chicken (Gallus domesticus). L-DOPA- and DA-immunoreactive (ir) elements are similarly distributed throughout the entire brain. Virtually all regions of the brain contained a dense innervation by L-DOPA- and DA-immunopositive varicose fibers. The neuronal cell bodies immunoreactive for the two monoamines were confined to more restricted regions, the hypothalamus, the midbrain and the brainstem. In the hypothalamus, DA- and L-DOPA-ir neurons were subdivided into a medial periventricular and a lateral group. The medial group starts at the level of the anterior commissure, in the ventral part of the nucleus periventricularis hypothalami, and continues in a more dorsal periventricular position caudally into the dorsal tuberal hypothalamic region. Densely labeled cerebrospinal fluid contacting cells can be observed in the paraventricular organ. The lateral group consists of immunopositive neurons loosely arranged in the lateral hypothalamic area and in the nucleus mamillaris lateralis. Most of the dopaminergic cell groups, identified in the hypothalamus of mammals, could be observed in the chicken, with the exception of the tuberoinfundibular group. The majority of L-DOPA- and DA-ir perikarya is, however, situated in the mesencephalic tegmentum, in the area ventralis of Tsai and in the nucleus tegmenti pedunculo-pontinus, pars compacta, the avian homologues of, respectively, the ventral tegmental area and the substantia nigra of mammals. In the pons, dense groups of cells are found in the locus coeruleus and in the nucleus subcoeruleus ventralis and dorsalis. A few labeled cells appear in and around the nucleus olivaris superior in the most caudal part of the metencephalic tegmentum. In the medulla oblongata, L-DOPA- and DA-ir cells can be seen at the level of the nucleus of the solitary tract and in a ventrolateral complex. A comparison with tyrosine hydroxylase (TH) immunocytochemistry revealed TH-immunopositive neurons greatly outnumbering the cells exhibiting DA and L-DOPA immunoreactivity. These results are discussed in relation to catecholaminergic systems previously reported in avian species and in the mammalian brain.

Aging↗

Distribution of immediate early gene zif-268, c-fos, c-jun and jun-D mRNAs in the adult cat with special references to brain region related to vision.

The distribution of immediate early gene zif-268, c-fos, c-jun and jun-D mRNAs was investigated in the visual cortex, dorsal lateral geniculate nucleus and hippocampus of the adult cat brain with in situ hybridization. In area 17, zif-268, c-jun and jun-D were found predominantly in layers II-III and VI, while c-fos mRNA was abundant in layer VI. In area 18, the zif-268, c-fos and c-jun labelling pattern was identical to that of area 17, this was not true for jun-D. In area 19, only c-jun retained the lamination pattern of areas 17 and 18, while zif-268, c-fos and jun-D were homogeneously distributed. In the dorsal lateral geniculate nucleus, only c-fos and jun-D resulted in labelling. In the pyramidal layer of hippocampus, zif-268 was found in CA1-4, c-jun in CA1-3, and jun-D in CA2-4. In the dentate gyrus, c-jun was abundant, jun-D moderate and zif-268 faint. C-fos labelling was absent in the hippocampal formation.

Animals↗