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Biomedical subjects

E Costa

Publications and source records attributed to E Costa.

At least 667 records · Page 37Linked to original sources
PubMed1971

Effect of phenmetrazine, aminorex and ( ) p-chloramphetamine on the motor activity and turnover rate of brain catecholamines.

1. The minimal doses (mumol/kg i.v.) of phenmetrazine, (+/-)-p-chloramphetamine, and aminorex which increase motor activity are 5.6, 3.5, and 1.5, respectively. We detected stereotype behaviour neither in rats receiving intravenous doses 3 times greater nor in animals injected intraperitoneally with 44, 62 and 112 mumol/kg of (+/-)-p-chloramphetamine, aminorex and phenmatrazine, respectively.2. The latter doses of the three amphetamine congeners were tested for their action on tissue monoamine content. Only (+/-)-p-chloramphetamine decreased the concentration of tel-diencephalon 5-hydroxytryptamine (5-HT) and this decrease lasted longer than 24 hours. This and the other two amphetamine congeners failed to affect the concentration of noradrenaline (NA) in brain, heart and lung.3. Aminorex (1.5 mumol/kg i.v.) and (+/-)-p-chloramphetamine (3.5 mumol/kg i.v.) decreased the turnover time of striatum dopamine (DM) but failed to change the turnover time of tel-diencephalon and brainstem NA. Phenmetrazine (5.6 mumol/kg i.v.) changed neither the turnover time of striatum DM nor that of NA in the two brain areas assayed.

Amphetamine↗
PubMed1971

Action of fenfluramine on monoamine stores of rat tissues.

1. Fenfluramine is an anorexogenic agent used clinically because it is devoid of central stimulatory effects.2. In rats, fenfluramine causes a depletion of 5-hydroxytryptamine (5-HT) from the telencephalon + diencephalon which lasts longer than one might have expected from the biological half life of fenfluramine. The depleting effects of fenfluramine do not extend to brainstem, stomach and heart stores of 5-HT.3. Fenfluramine causes an increase in the turnover rate of tel-diencephalic 5-HT but such an acceleration could not be detected in the 5-HT stores of the brainstem.4. It is inferred that the effects of fenfluramine on brain 5-hydroxytryptamine may be related to the accumulation of a fenfluramine metabolite in 5-HT neurones.5. High doses of fenfluramine cause a depletion of catecholamine stores in brain and heart but the time course of this depletion is shorter than the depletion of brain 5-HT.

Animals↗
PubMed1970

Acetylcholine concentrations in rat brain: diurnal oscillation.

A diurnal oscillation of acetylcholine concentrations in rat brain has been demonstrated by gas chromatography. Peak concentrations occur at 2 hours of light, and a trough is seen at 6 hours of darkness. This pattern is observed only in grouped rats, and emerges after at least 18 days of prior conditioning in an environment with controlled light, humidity, and temperature.

Acetates↗