The stimulation of rat brain monoamine oxidase by dietary lithium chloride.

Lithium chloride administered to rats in drinking water for 30 days caused an increase of whole brain monoamine oxidase specific activity to approximately 140% of control. Carboxylesterase and formyltetrahydrofolate synthetase activities were not affected by Li+ either in vivo or in vitro.     

The stimulation of rat brain monoamine oxidase by dietary lithium chloride

Summary Lithium chloride administered to rats in drinking water for 30 days caused an increase of whole brain monoamine oxidase specific activity to approximately 140% of control. Carboxylesterase and formyltetrahydrofolate synthetase activities were not affected by Li⁺ either in vivo or in vitro.Contribution of the Nevada Agricultural Experiment Station (Reno), Journal Series No. 439.     

Monoamine oxidase activity in rat erythrocytes: Evidence for its localization in reticulocyte mitochondria

Summary During growth of young rats, monoamine oxidase activity in erythrocyte membrane preparations decreases more rapidly than reticulocyte concentrations in the respective blood samples. Since reticulocytes lose their mitochondria prior to the substantia reticulo-filamentosa, the non-linear correlation between monoamine oxidase activity and reticulocyte counts indicates that erythrocyte monoamine oxidase is located in reticulocyte mitochondria.This work was supported by a grant from the Deutsche Forschungsgemeinschaft.     

Monoacylcadaverines as substrates for both monoamine oxidase and diamine oxidase; low rates of activity

Summary Monoacetylcadaverine and monopropionylcadaverine were found to be substrates for both rat liver monoamine oxidase and hog kidney diamine oxidase, but all the K_m-values for the oxidases were very high. The amines were common substrates for type A and type B monoamine oxidase.     

Inhibition par les sels de tetrazolium de l'activité monoamine-oxydasique d'une suspension mitochondriale de cerveau de mouton

Summary 5 tetrazolium salts used in electronic microscopy are non-competitive inhibitors of monoaminoxidasic activity of a sheep's brain mitochondrial suspension. This inhibition indicates that special caution must be taken in using these salts for detection of monoamine oxidase in optic or electronic microscopy.     

Identification of type A monoamine oxidase in mouse and rabbit liver mitochondria

Summary Type A monoamine oxidase was identified in liver mitochondria of mouse and rabbit. 5-Hydroxytryptamine was a common substrate for type A and type B monoamine oxidase in these enzyme preparations where its concentration was 1.0 mM.     

Abschwächung der Noradrenalin-Wirkung auf die isolierte Aorta bei Hemmung der Monoaminoxydase

Summary Twenty hours after pretreatment of rabbits with the monoamine oxidase inhibitor N₂-isopropyl-isonicotinic acid hydrazide (IIH) the norepinephrine induced contraction of the isolated aorta was significantly reduced; the 5-hydroxytryptamine sensitivity could not be changed significantly. Isonicotinic acid hydrazide (INH), a weak monoamine oxidase inhibitor, had no significant effect on the norepinephrine and 5-hydroxytryptamine sensitivity of the aorta.     

Chlorodimeform and its effect on monoamine oxidase activity in the cattle tickBoophilus microplus

Summary The action of the acaricide, chlorodimeform and its metabolite, N-desmethylchlorodimeform, on the activity monoamine oxidase (MAO) from the cattle tick,Boophilus microplus, were studied, Both compounds were found to be potent in vitro and in vivo inhibitors of the enzyme. However the inhibition of MAO does not seem to be related to the toxic action of the acaricide.     

Histochemical remarks on monoamine oxidase and acetylcholinesterase in some regions of amphibian brain

Summary The histochemical localization of monoamine oxidase and acetylcholinesterase has been studied in the cerebellum, optic tectum and telencephalon of three amphibian species. For acetylcholinesterase in particular, different histochemical methods and selective inhibitors have been used in order to investigate the actual nature of enzymatic activity revealed.     

Occurrence of mitochondrial monoamine oxidase in human semen.

Mitochondrial monoamine oxidase (MAO) was found in human semen, showing its Km and Vmax values of 91.7 microM and 290 pmoles/mg of protein/60 min, respectively, with kynuramine as substrate. A major part of the activity was due to type A MAO.     

Differential activation of two monoamine oxidase types by oxygen

Summary The stimulation of rat brain monoamine oxidase activity by oxygen is shown to be type-selective, type B being much more strongly stimulated than type A.Pargyline and clorgyline were gift samples from Abbott Laboratories, USA and May and Baker Ltd, England respectively     

In vitro biosynthesis of octopamine by the nervous system and the heart of the mollusc gastropode Helix pomatia (author's transl)]

The tyrosine is decarboxylated in vitro by the central nervous tissue and by the intracardiac nervous tissue of Helix pomatia by aromatic amino-acid decarboxylase. The tyramine obtained is then partially transformed into octopamine by tyramine-beta-hydroxylase. The inhibition of monoamine oxidase favours apparition of the 2 amines. The monoamine oxidase seems able to regulate their synthese and to assure their inactivation.     

Histochemische Untersuchungen über den Einfluss von Iproniazid (Marsilid) auf die durch Reserpin erzeugte Freisetzung von Adrenalin und Noradrenalin aus dem Nebennierenmark

Summary A single injection of 10 mg/kg reserpine causes marked decrease of catecholamine in the medulla of the adrenal gland of rats. Histochemically, this can be shown by the disappearance of chromaffinity and of the potassium iodate reaction. After pretreatment with 100 mg/kg of iproniazid, reserpine injection induces little or no decrease in the histochemical reactions of adrenalin and noradrenalin. In animals pretreated with equimolar doses of isoniazid, however, histochemical catecholamine reactions are well preserved in all cells of the adrenal medulla. These results suggest that monoamine oxidase plays a part in the reserpine-induced release of catecholamine.     

Cadmium-induced inhibition of brain monoamine oxidase in the freshwater catfish

Summary The freshwater catfishClarias batrachus (L.), exposed to 50 ppm of cadmium (Cd) chloride for a period of 135 days exhibited marked inhibition of brain monoamine oxidase (MAO) (p<0.001). The retarded gonadal growth observed in the present study suggests that Cd may be capable of creating imbalance in the aminergic activity of the hypothalamus, which modulates the secretion and release of gonadotropins.Acknowledgment. Financial assistance from the Council of Scientific and Industrial Research of India made this work possible.     

Occurrence of mitochondrial monoamine oxidase in human semen

Summary Mitochondrial monoamine oxidase (MAO) was found in human semen, showing its K_m and V_max values of 91.7 M and 290 pmoles/mg of protein/60 min, respectively, with kynuramine as substrate. A major part of the activity was due to type A MAO.     

Effects of thyroidectomy on monoamine oxidase activities toward tyramine and serotonin in the circumventricular nuclei of the rat.

Following thyroidectomy, monoamine oxidase (MAO) activities toward tyramine decreased significantly by 20% in the nucleus periventricularis and the nucleus arcuatus among the 3 hypothalamic nuclei of the rat, while MAO activity toward serotonin decreased significantly by 10% only in the nucleus periventricularis. It is suggested that thyroidectomy induced selective changes on the multiple forms of MAO in the discrete circumventricular nuclei.     

Effects of thyroidectomy on monoamine oxidase activities toward tyramine and serotonin in the circumventricular nuclei of the rat

Summary Following thyroidectomy, monoamine oxidase (MAO) activities toward tyramine decreased significantly by 20% in the nucleus periventricularis and the nucleus arcuatus among the 3 hypothalamic nuclei of the rat, while MAO activity toward serotonin decreased significantly by 10% only in the nucleus periventricularis. It is suggested that thyroidectomy induced selective changes on the multiple forms of MAO in the discrete circumventricular nuclei.     

Chlorodimeform and its effect on monoamine oxidase activity in the cattle tick, Boophilus microplus.

The action of the acaricide, chlorodimeform and its metabolite. N-desmethylchlorodimeform, on the activity monoamine oxidase (MAO) from the cattle tick, Boophilus microplus, were studied. Both compounds were found to be potent in vitro and in vivo inhibitors of the enzyme. However the inhibition of MAO does not seem to be related to the toxic action of the acaricide.     

Oxidation of synephrine by type A and type B monoamine oxidase.

Synephrine (SP) was found to be a substrate for monoamine oxidase (MAO) in rat brain mitochondria, showing the Km and Vmax values of 250 microM and 32.6 nmoles/mg of protein/30 min respectively. The inhibition studies showed that the SP oxidation was carried out by both type A and type B MAO and a major part of the activity was due to type A MAO.     

Biosynthèse in vitro d'octopamine par le système nerveux et le cœur du mollusque gastéropodeHelix pomatia

Summary The tyrosine is decarboxylated in vitro by the central nervous tissue and by the intracardiac nervous tissue ofHelix pomatia by aromatic amino-acid decarboxylase. The tyramine obtained is the partially transformed into octopamine by tyramine--hydroxylase. The inhibition of monoamine oxidase favours apparition of the 2 amines. The monoamine oxidase seems able to regulate their synthese and to assure their inactivation.

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Biosynthèse in vitro d'octopamine par le système nerveux et le cur du mollusque gastéropodeHelix pomatia