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Biomedical subjects

E Costa

Publications and source records attributed to E Costa.

At least 649 records · Page 36Linked to original sources
PubMed1972

Gas chromatographic-mass spectrometric assay of four indole alkylamines of rat pineal.

Gas chromatography-mass spectrometry was used to quantitate serotonin, N-acetylserotonin, 5-methoxytryptamine, and melatonin in single rat pineal glands. After gas chromatographic separation, the ion density of specific fragments of each indole was measured with mass spectrometry. Sensitivity of this indole assay is of the order of 10(-12) to 10(-13) mole. Routinely, specificity is based on gas chromatographic retention time and the recording of the ion density generated by specific fragments. Absolute identification of the extracted indoles was based on multiple ion detection.

Animals↗
PubMed1972

Norepinephrine and dopamine: assay by mass fragmentography in the picomole range.

Gas chromatography-mass spectrometry makes possible the simultaneous measurement of norepinephrine and dopamine in concentrations of 0.1-milligram tissue samples. Specificity of the assay is confirmed both by the retention time of the compound and by the mass to charge ratio of the fragments recorded. The sensitivity is of the order of 0.5 picomole, and linearity of the response is maintained up to at least 200 picomoles.

Animals↗
PubMed1972

Effects of amphetamine on the turnover rate of brain catecholamines and motor activity.

1. Rats receiving (+)-amphetamine (either 0.3 or 0.2 mg/kg, i.v.) are anorexic. Only the former dose increases their motor activity. Both doses fail to change dopamine (DM) and noradrenaline (NA) concentrations in striatum and teldiencephalon. The turnover rate of striatal DM is increased only by 0.3 mg/kg of (+)-amphetamine; neither dose changes NA turnover rate in teldiencephalon.2. (-)-Amphetamine (1 mg/kg, i.v.) causes anorexia and hyperthermia in rats but it changes neither the steady-state concentration nor the turnover rate of striatal DM and tel-diencephalic NA. Motor activity is not increased by this dose of (-)-amphetamine.3. Cocaine (3 mg/kg, i.v.) increases motor activity and accelerates the turnover rate of striatal DM. This drug neither accelerates turnover rate of teldiencephalic NA nor causes anorexia.4. These observations suggest that the acceleration of striatal DM turnover rate elicited by (+)-amphetamine and cocaine may be associated with an effect on motor activity. In contrast, the increase of motor activity seems unrelated to the effects of these drugs on noradrenergic tracts of the teldiencephalon.

Animals↗