L-threo-3,4-dihydroxyphenylserine,a noradrenaline precursor,inhibits dopamine release and metabolism in the rat striatum in vivo

The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on dopamine (DA) release and metabolism in the striatum was studied in freely moving rats by intracerebral microdialysis techniques. The DA level as well as the levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly decreased 140 min after the administration of L-threo-DOPS (50 mg/kg intraperitoneally). The results suggest that L-threo-DOPS inhibits the release and metabolism of DA in the striatum.     

L-threo-3,4-dihydroxyphenylserine, a noradrenaline precursor, inhibits dopamine release and metabolism in the rat striatum in vivo.

The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on dopamine (DA) release and metabolism in the striatum was studied in freely moving rats by intracerebral microdialysis techniques. The DA level as well as the levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly decreased 140 min after the administration of L-threo-DOPS (50 mg/kg intraperitoneally). The results suggest that L-threo-DOPS inhibits the release and metabolism of DA in the striatum.     

Changes in cellular noradrenaline fluorescence in the denervated rat superior cerical ganglion

Summary The microfluorimetrical investigation showed that in the principal perikarya of the rat superior cervical ganglion, after inhibition of noradrenaline-synthesis and unilateral preganglionic axotomy, the fluorescence of newly synthesized noradrenaline was most intense at the periphery of the perikarya of the intact side.The authors are deeply indebted to Mr H. Petermann, and to Mr B. Rombach, Ciba-Geigy Ltd. for their mathematical support.     

Diurnal fluctuation of sensitivity to noradrenaline in the rat and thyroid adrenal interaction

Summary Diurnal fluctuation of the sensitivity to noradrenaline, which disappeared after thyroidectomy, was restored after novotyrol treatment. Dexamethasone treatment did not result in the restoration of the diurnal fluctuation of noradrenaline calorigenic action in adrenalectomized animals.     

Stress-induced increase in noradrenaline release in the rat hypothalamus assessed by intracranial microdialysis

Summary The hypothalamic microdialysis of conscious rats was used to investigate the effects of immobilization stress (20 min) on extracellular noradrenaline(NA) levels. The stress significantly increased NA levels relative to basal efflux by 106% and this elevation continued for 40 min after release from stress.     

Stress-induced increase in noradrenaline release in the rat hypothalamus assessed by intracranial microdialysis

The hypothalamic microdialysis of conscious rats was used to investigate the effects of immobilization stress (20 min) on extracellular noradrenaline (NA) levels. The stress significantly increased NA levels relative to basal efflux by 106% and this elevation continued for 40 min after release from stress.     

Distribution of noradrenaline in the genital organs of the female rat with a remark on dopamine in the cervix and vagina

Zusammenfassung Durch Bestimmung des organeigenen Noradrenalingehalts wird die adrenergische Innervation der weiblichen Geschlechtsorgane der Ratte untersucht. Die Hauptmenge des Noradrenalins (0,3µg/g) wird im Tuba uterina gefunden, der vierfache Betrag von Uterusinhalt. Daneben wurde Dopamin in Cervix und Vagina nachgewiesen.

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This work has been supported by Stiftelsen Therese och Johan Anderssons Minne and by the Swedish Medical Research Council, project No. B68-14X-2323-01.     

Binding of 5-hydroxytryptamine and noradrenaline by rat lung

Résumé Après injection i.v. de 5-hydroxatryptamine-C¹⁴ et de noradrénaline-H³ à des rats, on a préparé et centrifugé des homogénates de leurs poumons dans un gradient linéaire de sucrose. Après sacrifice immédiat ces deux amines sont retrouvées dans une grande fraction de particules pulmonaires sédimentant dans 1M de sucrose. Après 30 min les poumons des rat offrent un pic additionel de noradrénaline-H³ correspondant à une densité de sucrose de 0.4 à 0.5.

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This work was supported in part by Grant No. 13315 from the U.S. Public Health Service and by Grant No. 435 from the Connecticut Heart Association. Assistance provided by Ayerst Laboratories and Astra Laboratories is also gratefully acknowledged.     

In vivo degradation of noradrenaline by MAO A in locus coeruleus of the rat

Depletion of noradrenaline in locus coeruleus neurons after reserpinization was prevented by clorgyline, a selective inhibitor of MAO A, but not by deprenyl, a selective inhibitor of MAO B. Only MAO A is therefore responsible for the degradation of homoneuronal noradrenaline in locus coeruleus nerve cells.     

Depletion and repletion of noradrenaline in adrenergic nerves of the rat after decaborane treatment

Zusammenfassung Mit Hilfe der Fluoreszenz-Technik werden die Veränderungen in sympathischen Fasern der Ratteniris nach Noradrenalin-Depletion durch Boron-Hydrid Decarboran (Dopa-Dekarboxylase-Hemmer) analysiert.

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This work has been supported by grants from the Swedish Medical Research Council under project No. B70-14x-97-06B, B70-14x-711-05B and Knut and Alice Wallenberg Foundation.     

Increased cardiac noradrenaline turnover in the rat after acute exposure to environmental heat

Summary In male rats, the cardiac turnover of noradrenaline is significantly increased on acute exposure to an environmental temperature of 32°C, when compared to control experiments performed at 23°C.Supported by a grant from the Deutsche Forschungsgemeinschaft.     

Evidence of diurnal fluctuation of sensitivity to noradrenaline in the rat — the role of the thyroid

Summary The capacity for heat production, under the influence of the same amount of noradrenaline, in the rat was significantly higher in the evening (20.00 h) than in the morning (07.00 h). Thyroidectomy produces not only a lower level of heat production, but also a complete disappearance of the differences between the morning and the evening experiments.