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Biomedical subjects

G Serra

Publications and source records attributed to G Serra.

At least 145 records · Page 8Linked to original sources
PubMed1982

Effect of dopamine agonists and antagonists on DOPA formation in the substantia nigra.

The effect of different psychotropic drugs on the rate of DOPA accumulation after administration of a decarboxylase inhibitor (NSD 1015) was compared in the substantia nigra (SN) and caudate nucleus (CN) by a new radioenzymatic method. Inhibition of monoamine oxidase with pargyline or stimulation of dopamine (DA) receptors with apomorphine, N-n-propylnorapomorphine or D-amphetamine reduced DOPA formation in the CN and SN to the same extent. Vice versa, both inhibition of DA receptors with haloperidol or (-)sulpiride and depletion of DA concentration with reserpine enhanced DOPA formation to a greater extent in the CN than in the SN. Apomorphine antagonized not only the effect of haloperidol and (-)sulpiride, but also, and even more effectively, that of reserpine. The results indicate that DA synthesis in the SN is controlled by both end-product inhibition and DA receptor-mediated mechanisms.

Animals↗
PubMed1982

Uremic neuropathy: correlations between electroneurographic parameters and serum levels of parathyroid hormone and aluminum.

An electrophysiological investigation on 29 dialysis patients was performed with the aim of verifying whether serum parathyroid hormone (PTH) and aluminum (Al) levels may play a role in the pathogenesis of uremic neuropathy. All patients except 1 showed electrophysiological abnormalities. Both PTH and Al levels were found to be significantly correlated with the time on dialysis. On the contrary, the values of each single electroneurographic parameter did not show any correlation with the duration of dialysis, PTH levels and Al levels. The authors conclude that PTH and Al does not seem to play a role in the etiology of uremic neuropathy.

Adult↗
PubMed1981

Repeated electroconvulsive shock prevents the sedative effect of small doses of apomorphine.

Repeated electroconvulsive shock (ECS) (one shock daily for 8 days), but not single ECS, eliminates the sedative response to small doses of apomorphine (25--1000 microgram/kg) and potentiates the stimulant response to high doses (200 microgram/kg) of the drug in rats. This effect is observed 1 and 4 days after the last ECS. However, repeated ECS does not prevent the inhibitory effect of apomorphine on dopamine (DA) synthesis. The results suggest that repeated ECS may lead to the development of subsensitivity in DA receptors that mediate sedation and that these receptors are differentiated from those controlling DA synthesis.

Animals↗
PubMed1981

The diagnostic value of H-index in S1 root compression.

The H-index was studied in 42 healthy subjects and in 20 patients showing unilateral S1 root compression. When compared to the normal subjects, all patients showed a decreased H-index, or an increased difference in H-index between the sides or both. These results indicate that both parameters are valuable in the diagnosis of S1 root impairment due to intervertebral disc protrusion.

Adult↗
PubMed1981

Rapid cyclers and antidepressants.

434 bipolar manic-depressive patients were followed longitudinally. The course of the disease changed in many patients over the years. 67 cases became rapid cyclers (two or more cycles per year); in 40 of these cases (12 men and 28 women) the change of the course took place after intense or protracted use of antidepressant drugs. In their previous course these patients had not received antidepressant drugs. The common feature of the transformation of the previous course to a continuous circular one was the appearance for the first time in the course of the disease of hypomanic episodes after the depressions, or the accentuation of hypomanias that had been of milder intensity in previous recurrences. The patients who developed continuous circularity under antidepressant drug treatment were of highly energetic temperament. The hypothesis is advanced that these patients have latent hypomanias, which become clinically manifest under the action of antidepressants. The intensification of an underlying hypomanic process by the antidepressants would precipitate another depression and establish continuous circularity. The change to a rapid cyclical course was more frequent in middle-aged patients and in women.

Adolescent↗
PubMed1980

Effect of acute and chronic ethanol on dopamine synthesis in the caudate nucleus, substantia nigra and frontal cortex.

A single oral administration of 3.2 g/kg ethanol to normal rats increased 3,4-dihydroxyphenylacetic acid (DOPAC) content and DOPA formation in the caudate nucleus but had no effect in frontal cortex and substantia nigra and did not modify dopamine (DA) levels in any of the brain regions analyzed. Complete tolerance to the stimulant effect on DOPA formation developed after chronic ethanol-treatment (3.2 g/kg daily for 60 days). However ethanol administration to ethanol dependent rats produces a marked DA depletion and increases DOPAC concentration in the brain areas studied. The present results show that acute and chronic ethanol release DA stores, but only in the acute conditions DA depletion is compensated by enhanced synthesis.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

Effect of ethanol on the metabolism of regional brain dopamine.

Acute oral administration of ethanol (3.2g/kg) to rats increased (DOPAC) levels in the caudate nucleus, but had no effect on DOPAC levels in the substantia nigra and frontal cortex and failed to modify dopamine content in any of the above areas. On the other hand, the administration of the same dose of ethanol to rats which had been chronically treated with ethanol (3.2g/kg daily for 60 days), produced a decrease of DA content and a parallel increase of DOPAC levels in all areas studied. In chronically treated rats, 24 hrs after last ethanol administration dopamine levels in the frontal cortex were 60% higher than in controls. The results suggest that ethanol administration causes dopamine release in different brain areas.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

The fate of tritium-labeled reserpine in the chick embryo: a preliminary report.

After a single administration of EH-reserpine, 10 mugm 2.5 microCi, into the yolk of fertilized chicken eggs, gross radioactivity (reserpine plus degradation products) and the unchanged labeled drug, separated by thin layer chromatography, were assayed on the 8th and 19th day of incubation. Nanogram per gram concentrations of unchanged 3H-reserpine were recovered at both times. The 3H-reserpine recovered in the whole egg on the 8th day of incubation accounted for up to 20% of the administered dose. On the 19th day of incubation, brain showed the largest share (28%) of 3H-reserpine as a percentage of gross radioactivity of all organs investigated. Reserpine underwent considerable biodegradation in the developing chick embryo, but the concentrations of unchanged drug recovered in embryonal tissues throughout development were of the same order as those persisting in target organs of rats given a pharmacological dose of reserpine.

Animals↗