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P Brisson

Publications and source records attributed to P Brisson.

15 recordsLinked to original sources
PubMed1992

Long-term effects of constant light or darkness on chicken pineal hydroxyindole-O-methyltransferase expression: biochemical and cellular aspects.

1. Chickens kept in constant light, as opposed to constant darkness, display a twofold increase in the activity of pineal hydroxyindole-O-methyltransferase (HIOMT), the last acting enzyme in the melatonin pathway. 2. Using an immunological approach, we presently show that this regulation of HIOMT activity reflects changes in the concentration of a single molecular form of the enzyme protein (a 38 kDa polypeptide). Immunohistofluorescence indicates that these concentration changes concurrently affect modified photoreceptors and pinealocyte-like cells in the chicken pineal organ. 3. Together, the present data support the hypothesis that environmental lighting might regulate the expression of the HIOMT gene.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Distribution of arrestin-like protein and beta-subunit of GTP-binding proteins in quail choroid plexuses.

Monoclonal antibodies (Mabs) directed against retinal arrestin (S-antigen) were used to detect and characterize this protein in choroid plexus (CP) of quails maintained during eight days, either under long-day photoperiods or in constant darkness. Immunocytochemistry and Western blotting confirmed the presence and the distribution of an arrestin-like protein in quail CP. Arrestin-like immunoreactivities in CP were compared with those obtained with Mabs to beta 36-subunit of G proteins (G beta), alpha-subunit of transducin and rhodopsin. Rhodopsin-like and transducin-like proteins could not be detected in choroidal cells, whereas intense positive reactions were observed with anti-G beta and anti-arrestin Mabs. The strongest immunoreactivities were found in choroidal ependymocytes of the lateral and IIIrd ventricles. In CP epithelial cells lining the IVth ventricle, very weak or no immunoreactivity could be detected with Mabs to arrestin, while Mab against G beta subunit always provided a positive reaction. In quails maintained in constant darkness, arrestin- and G beta-immunoreactivities of CP epithelial cells displayed changes in cellular distribution and intensity (decrease or disappearance of the immunoreactions). The strong arrestin-like immunoreaction located in the apical region of ependymocytes suggests the preferential association of the protein with choroidal microvilli and a possible role in cerebrospinal fluid production assumed by CP cells.

Animals↗
PubMed1989

Pineal transducers in the course of evolution: molecular organization, rhythmic metabolic activity and role.

Data on the cell biology of pineal transducers (chief cells: typical and modified photoreceptors, pinealocytes) which belong to the paraneuron family, are reviewed in the vertebrate series. In spite of major changes throughout phylogeny, it is proposed that pineal chief cells share a common feature: they somehow transform the information derived from the light/dark cycle into daily rhythms of neural (an excitatory neurotransmitter) and/or hormonal (melatoninergic) output and appear invariably involved in the temporal organization of physiological and behavioral processes.

Animals↗
PubMed1988

Pineal-retinal molecular relationships; immunocytochemical evidence of calbindin-27 kDa in pineal transducers.

Calbindin-27 kDa immunocytochemical localization was studied concurrently in the pineal organ and retina from human as well as representatives of all vertebrate classes. Calbindin immunoreactivity was demonstrated in retinal cones (but not in rods) and in pineal transducers (cone-like and modified photoreceptor cells, pinealocytes) of a majority of amniotes. In contrast, no labelling was observed in anamniotes, except in retinal cones of the toad. Labelling was distributed through all cellular compartments (outer and inner segments, perikarya, pedicles or processes) of pineal transducers and retinal cones. Intra- and interspecific variations of calbindin contents are discussed.

Animals↗
PubMed1988

Synthesis of melatonin by the pineal modified photoreceptors of birds immunocytochemical localization of hydroxyindole-O-methyltransferase.

Photoperiodic control of several biological rhythms is exerted through the inhibitory effect of light on melatonin synthesis in the pineal organ. Hydroxyindole-O-methyltransferase (HIO-MT), the last acting-enzyme in melatonin biosynthesis, constitutes a specific marker of melatoninergic cells. In the present study, an antibody directed against chicken HIOMT was affinity-purified and used to identify melatoninergic cells in the pineal organ of chicken, quail, sparrow and blackbird. Regardless of the species, intense immunocytochemical reactions were observed in modified photoreceptors, whereas other cellular constituents (mostly glial cells) remained unlabeled. We conclude that modified photoreceptors synthesize melatonin in the avian pineal gland and are thus accountable for the translation of the photoperiodic input into hormonal output.

Acetylserotonin O-Methyltransferase↗
PubMed1987

Traumatic intraspinal pneumocele.

Traumatic intraspinal pneumocele (TIP) is a radiologic finding in which air is visualized within the spinal canal on routine cervical spine x-rays following a head injury. TIP may be the initial radiologic evidence of a severe central nervous system injury. The presence of TIP will alert a physician to the severity of the head injury, as well as the need for further radiologic investigations.

Air↗
PubMed1987

[Identification of a protein related to the S-antigen in choroid plexus in quails].

Using monoclonal and polyclonal antibody immuno-fluorescence, various areas of the quail diencephalon were tested immunocytochemically for the presence of S-antigen, which is a regulatory protein of retinal photoreceptors. In adult quail and embryos (from day 13 until hatching), S-antigen immunoreactivity was demonstrated in the cytoplasm of epithelial cells in the choroid plexus of the third ventricle. Similar data have previously been obtained in quail retinal photoreceptors. No labeling could be seen in the other investigated diencephalic areas, including the hypothalamus. Although an extraocular photoregulation of the reproductive cycle has previously been reported in birds, further investigations are needed before it can be concluded that the choroid plexus of the third ventricle is involved in this or other types of regulation.

Animals↗
PubMed1986

Pineal-retinal molecular relationships: distribution of "S-antigen" in the pineal complex.

The immunocytochemical localization of S-antigen, a specific protein first discovered in retinal photoreceptors, was studied in the pineal complex of vertebrates (eel, pike, frog, lizard, passerines, mouse, hamster) using monoclonal antibody immunofluorescence. S-antigen immunoreactivity was demonstrated concurrently in retinal photoreceptors and in most pineal phototransducers of all species, i.e. in pineal cells of the receptor series (cone-like, modified photoreceptor cells, pinealocytes) and in cone-like photoreceptors of the frog frontal organ and lizard parietal eye. The labelling was distributed either in all compartments of these cells, or restricted to outer segments. The functional significance of the S-antigen as well as some phylogenetic and ontogenic implication of this marker are discussed.

Anguilla↗
PubMed1984

S-antigen immunoreactivity in retinal rods and cones and pineal photosensitive cells.

The S-antigen is a protein of photoreceptors, mainly known for its autoantigenic properties in mammals, which is widely distributed in the retina of vertebrates and in photoreceptor organs of invertebrates. Using three monoclonal antibodies specific for different epitopes of S-antigen, this study complements our previous data on retinal rods and cones and presents new results on the photosensory cells of the pineal complex. Immunoreactivity was found in (i) retinal rods and cones, (ii) cone-like and modified photoreceptor cells, and pinealocytes of the pineal organ of vertebrates, (iii) cone-like photoreceptors of the frontal organ of the frog and of the third eye of the lizard. According to the species and the antibody used, some differences were found at the level of the cellular compartments of the pineal photoreceptor cells.

Animals↗
PubMed1980

Aminergic systems in pulmonate gastropod molluscs. III. Microspectrofluorometric characterization of the monoamines in the reproductive system.

Histochemical fluorescence (Falck-Hillarp) and microspectrofluorometric (MSF) methods were used to characterize different types of catecholamine-containing cellular elements located in the reproductive system of fresh-water snails (Bulinus truncatus, Planorbarius corneus) and land snails [Archachatina marginata, Helix (Cryptomphalus) aspersa]. Transverse sections through the genital tract display a common structural pattern of tubular differentiations: (1) an internal epithelium bordering the lumen and containing variable numbers of monoaminergic cells; (2) an enveloping sheath of connective and muscular tissue containing fine nerve fibers in the form of a network that exhibits a variable degree of density. MSF determinations showed that the formaldehyde-induced fluorophores of the intraepithelial aminergic cells belong to the following classes: (1) the DOPA/dopamine group in the duct of the albumen gland of B. truncatus and the carrefour of A. marginata; and (2) the norepinephrine/epinephrine group in the duct of the albumen gland and in the oviduct sac of P. corneus. In the reproductive systems of B. truncatus and P. corneus (duct of the albumen gland, oviduct sac, vagina), A. marginata and H. aspersa (duct of the fertilization pocket, origin of the receptaculum seminis, carrefour), the MSF analysis revealed norepinephrine/epinephrine-containing intramural nerve fibers. On the other hand, the small neurons in the vagina of B. truncatus belong to the DOPA/dopamine group.

Animals↗
PubMed1974

Percutaneous absorption.

Clinical effectiveness of topically applied medications depends on the ability of the active ingredient to leave its vehicle and penetrate into the epidermis. The stratum corneum is that layer of the epidermis which functionally is the most important in limiting percutaneous absorption, showing the characteristics of a composite semipermeable membrane. A mathematical expression of transepidermal diffusion may be derived from Fick's Law of mass transport; factors altering the rate of diffusion are discussed.

Administration, Topical↗