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Biomedical subjects

G PEPEU

Publications and source records attributed to G PEPEU.

At least 19 recordsLinked to original sources
PubMed1964

MIDBRAIN HEMISECTION: EFFECT ON CORTICAL ACETYLCHOLINE IN THE CAT.

A midbrain hemisection in a midpontine pretrigeminal preparation of the cat causes an asymmetry in the electroencephalogram with a marked increase in the acetylcholine content of the cortex from the synchronized hemisphere. It is suggested that the increase in acetylcholine is related to the decrease of nervous activity caused by the hemisection.

Acetylcholine↗
PubMed1964

THE INFLUENCE OF CENTRALLY ACTING CHOLINOLYTIC DRUGS ON BRAIN ACETYLCHOLINE LEVELS.

A number of centrally acting cholinolytic drugs reduced levels of cerebral acetylcholine in the rat. Among its naturally occurring analogues, hyoscine had the greatest potency, producing a decrease of 31% at a dose of 0.63 mg/kg. Atropine methyl nitrate, which acts as a cholinolytic drug in the periphery, had no effect on brain acetylcholine levels. The fall in acetylcholine produced by hyoscine was greatest after 60 min and disappeared at about 120 min. The animals tended to show a partial tolerance to this effect of hyoscine when the drug was administered repeatedly. The reduction in acetylcholine after hyoscine was restricted to the cerebral hemispheres, and did not appear in subcortical regions of the brain. Hyoscine had no influence on the net synthesis of acetylcholine by acetone-extracted powder of rat brain. In a series of four synthetic cholinolytic drugs, only the two with conspicuous psychotomimetic actions in man produced a decrease in brain acetylcholine comparable to that seen with hyoscine and related alkaloids.

Acetylcholine↗
PubMed1962

Serotonin in the developing mammal.

Determinations have been made of the level of serotonin in various fetal and maternal tissues of goats and rabbits. In the goat, both fetal brain and blood were higher in serotonin content than comparable maternal tissues. Furthermore, in the goat fetal neocortical areas unexpectedly were found to be richer in serotonin than certain subcortical structures. In contrast to the goat, the rabbit was shown to have higher serotonin levels in maternal than in fetal blood. Moreover, when a large amount of serotonin was administered subcutaneously to pregnant rabbits, the fetuses began to die at a time when the maternal blood levels of serotonin had about doubled. This toxic action was shown to be due at least partially to the sensitivity of the umbilical vessels to the vasoconstrictor action of serotonin.

Animals↗
PubMed1962

Drug-induced changes in brain acetylcholine.

In rats, drug-induced depression of the central nervous system has been shown generally to be associated with an elevation in level of total acetylcholine in the brain. This generalization held true for a wide variety of depressant drugs with one notable exception: the subacute administration of reserpine, with which there was an increase in cerebral acetylcholine after the first dose, but a return to normal levels after subsequent doses, despite continued depression of the animals. Reduction in the level of total acetylcholine in the brain followed the administration of certain convulsants (pentylenetetrazole and 3,5-dimethylbutylethylbarbiturate); but no change was seen after the administration of several mildly exciting agents. The notable exceptions to this generalization were atropine and scopolamine, which significantly lowered brain acetylcholine in doses producing mild excitation in only some of the animals and no gross manifestations in the rest.

Acetylcholine↗