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A Oblin

Publications and source records attributed to A Oblin.

24 records · Page 2Linked to original sources
PubMed1984

Involvement of the D-2 dopamine receptor in the neuroleptic-induced decrease in nigral substance P.

Repeated treatment with, but not single administration of drugs which impair dopaminergic transmission produced a consistent reduction in substance P immunoreactivity in the rat substantia nigra. This effect appears to be related to the D-2 dopamine receptor function as the blockade of this receptor subtype by selective antagonists produced effects qualitatively similar to those produced by drugs lacking selectivity for different subclasses of dopamine receptors.

Animals↗
PubMed1983

Influence of lithium on biochemical manifestations of striatal dopamine target cell supersensitivity induced by prolonged haloperidol treatment.

The effects of prolonged treatment with dietary lithium and/or haloperidol (infused by means of osmotic minipumps) on biochemical parameters indicative of striatal dopamine target cell supersensitivity have been investigated in the rat. When given concomitantly with haloperidol, lithium failed to prevent the fall of striatal dopamine metabolites observed 2 days following withdrawal and the tolerance to the elevation of dopamine metabolites in response to challenge with the neuroleptic during withdrawal. Prolonged treatment with lithium also failed to modify the changes in nigral dihydroxyphenylacetic acid levels and in striatal acetylcholine levels which occur under chronic neuroleptic treatment. Chronic dietary lithium alone consistently elevated substance P levels in substantia nigra. The usual decrease in nigral levels of the peptide that occurs in response to chronic treatment with haloperidol was prevented in animals treated concomitantly with lithium. These data suggest that the mechanism whereby lithium stabilizes dopaminergic supersensitivity does not seem to involve an action of the compound on the neuronal mechanisms regulating the activity of the nigro-striatal dopaminergic system or on striatal cholinergic neurons but may be related to the restoration of normal striato-nigral substance P ergic transmission.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Solid-phase radioimmunoassay for substance P.

The solid-phase immunoassay for quantification of substance P has been developed. The assay is based on the repartition of anti-substance P antibodies between the insoluble phase-immobilized substance P and the free peptide. The immobilized substance P-antibody complex is then quantified with 125I-protein A. The method allowed detection of 10 pg of substance P. The values of substance P concentration obtained by the present method in different regions of the rat brain were comparable to those obtained by standard radioimmunoassay with 125I-tyr-8-substance P as tracer. The described solid-phase radioimmunoassay is a simple, sensitive, and reliable technique for quantification of substance P-like immunoreactivity in biological samples.

Animals↗
PubMed1978

Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells.

An experimental study has been carried out using different biological and biochemical in vivo and in vitro tests for assessing the toxicity of natural UICC (A) chrysotile and SO2-sorbed UICC (A) chrysotile and for detecting a possible synergistic effect. For in vivo studies, rabbits received an intratracheal injection of chrysotile fibers suspended in physiological saline (PS). The control group received only PS; all animals were sacrificed after 68 hr. The alveolar free cells were harvested by pulmonary lavage. The results have shown that chrysotile induces a decrease in the free cell population but there was no significant difference in the number of viable cells or in the nature of cells harvested between the two chrysotile groups. Enzymatic activities of the alveolar macrophages from animals injected with SO2-sorbed chrysotile showed a significant increase of the enzymes LDH and acid phosphatases. The LDH increase could be related to the affinity of the enzyme regarding some chemical forms of SO2. In vitro studies using alveolar macrophages harvested by pulmonary lavage have shown no differences between the two chrysotile groups when cell viability and enzyme release were studied. The toxic effect was due to chrysotile fibers (decrease of 38% in cell viability and increase in cellular enzyme release when compared with control). When rabbit red blood cells were used, both natural and SO2 chrysotile fibers showed the same hemolytic activity. The failure to detect high differences between the two chrysotile groups may be related to the chemical form of sorbed SO2.

Acetylglucosaminidase↗
PubMed1978

Biological effects of chrysolite after SO2 sorption. iii. effects on the biochemical components of alveolar washing.

The short-term effects of chrysotile asbestos before and after SO2 sorption are studied in the rabbit after intratracheal injection of low doses of these pollutants. Chrysotile, as well as SO2-chrysotile, induces an increase in the unsaturated fatty acid content of lung surfactant, which is similar to that observed in the respiratory distress syndrome of the newborn, and an increase in the protein level of pulmonary washings which may be explained by an increase of the permeability of the blood-air barrier. These soluble proteins can interact with the surfacant and thus decrease its tensio-active properites.

Animals↗