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Biomedical subjects

P Mandel

Publications and source records attributed to P Mandel.

At least 469 records · Page 26Linked to original sources
PubMed1976

The role of hippocampal cholinergic mechanisms in the aquisition of a barpress response.

The role of hippocampal cholinergic mechanisms in learning a bar-press response reinforced with food was investigated. Firstly, an interstrain comparison showed that mice having a low choline acetyltransferase activity in the dorsal hippocampus were quicker to associate the barpress with reinforcement. Secondly, when the activity of this enzyme was reduced by a subseizure electrical stimulation of the hippocampus learning was accelerated. It is suggested that acetylcholine availability at the hippocampal synapses slowed the apparition of these learned responses.

Acetylcholinesterase↗
PubMed1976

Action of di-n-propylacetate on the spontaneous and acquired behaviour in goldfish, mice and rats.

The action of n-dipropylacetate (nDPA) is related to the dose. In low doses, nDPA improved the number of conditioned responses with negative reinforcement. In higher doses, the drug inhibited spontaneous and conditioned behaviour. An nDPA produces an increase in gamma-aminobutyric acid (GABA) brain level, results are discussed in relation to the inhibitory action of GABA in the central nervous system.

Acetates↗
PubMed1976

Arylsulphatase A and 2',3'-cyclic nucleotide 3'-phosphohydrolase activities in the brains of myelin deficient mutant mice.

Arylsulphatase A and 2',3'-cyclic nucleotide 3'-phosphohydrolase activities of myelin deficient mutant mice brains were studied. The results indicated that there were no changes in arylsulphatase A activity of the developing mutant brain, whereas the activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase decreased considerably. The data obtained in this study suggest that in brain arylsulphatase A activity is localized in cells other than oligodendroglia.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1976

Cysteine sulphinate decarboxylase in chick and rat retina during development.

The activity, properties and developmental pattern of cysteine sulphinate decarboxylase (CSD) were studied in chick and rat retina. Retinal CSD shows properties similar to those of the enzyme in brain with respect to optimum pH, saturating substrate concentrations and stimulation by pyridoxal phosphate, CSD activity increased 3-fold from the 10th day of embryogenesis to hatching in chicks and in postnatal development in rats. The developmental pattern of CSD activity in both species is coincident with the functional maturation of visual function.

Aging↗
PubMed1976

[Presence of monogalactosyl diglyceride in the rat nerve sciatic].

We present a pattern of fractionation of total lipids, leading to the isolation of individual glycolipids, MGDG contains as sugars, a high quantity of galactose and a low level of glucose. The study of the fatty acids distribution shows: a) a high level of saturated short chains fatty acids, b) a high level of palmitic acid (C 16:0, 68% of the total).

Animals↗
PubMed1976

[Effects of sodium n-dipropylacetate on the GABA level in various areas of the mouse brain].

Regional brain GABA distribution studies show that after administration of sodium n dipropylacetate, a competitive inhibitor of GABA transaminase, the concentration of GABA increases in some regions i.e. Olfactory Bulbs, Hypothalamus, Cortex, Cerebellum. The GABA level remains unchanged in Caudate Nucleus, Pons Medulla, Hippocampus in our experimental conditions. These variations do not correlate with the initial GABA level.

Aminobutyrates↗
PubMed1976

[Guanyl cyclase activities in clonal lines of cultured astroblasts and neuroblasts].

Guanylate cyclase was found to be present in a number of astroblast and neuroblast clones. No correlations were observed between the enzyme activity and the nature of the clone. The enzyme shows a requirement for manganese ions and is stimulated by calcium. When the astroblast clone NN is cultured together with the neuroblast clone M1 for two months and the astroblast cells again isolated, a reduced guanylate cyclase activity was found.

Astrocytes↗
PubMed1976

[Dopamine beta hydroxylase. Value and limits of its study in neurology].

Plasma dopamine-beta-hydroxylase was studied in 96 subjects, 33 of them controls and 63 of them patients (Parkinson's disease, chronic chorea, torsion dystonia, postural tremor and epilepsy). Only the epileptics showed a significant decrease in the average level of dopamine-beta-hydroxylase activity in comparison with the controls. During the cold test, DBH did not vary except in one case. On the other hand, during epileptic attacks, DBH activity underwent considerable fluctuations. Therefore, except in special pathological conditions, such as epileptic attacks, measurement of plasma or serum DBH activity is of limited value for neurological pathology and is not a good indication of the activity of the sympathetic nervous system.

Amantadine↗