Showing papers on "Monoamine oxidase B published in 1969"

Multiple Forms of Rat Brain Monoamine Oxidase

Abstract: THE enzyme monoamine oxidase (monoamine : O2 oxido-reductase (deaminating), EC 1.4.3.4) (MAO) is likely to be concerned in the metabolism of known or suspected central nervous system transmitters such as nor adrenaline, dopamine and 5-hydroxytryptamine. In the therapy of depressive disease, drugs are used which are able to inhibit MAO and it is thought that they owe their beneficial effect to this ability and to the resulting accumulation of amines. It is found, however, that some compounds belonging to this group are considerably more effective therapeutically than others1,2 and no fully satisfactory explanation has been offered. We now offer an approach which we think in better accord with the characteristics of MAO.

Monoamine oxidase inhibition in the treatment of migraine.

Abstract: THE WIDESPREAD use of monoamine oxidase (MAO) inhibitors followed the simultaneous discovery that iproniazid phosphate caused euphoria in tuberculous patients1and inhibited monoamine oxidase.2Since then, they have formed an important group of antidepressant drugs. The clinically important monoamine oxidases are present in the granular fraction of most parenchymatous tissues of vertebrates where they deaminate several aliphatic and aromatic amines, including serotonin (5-hydroxytryptamine [5HT] ), dopamine, tryptamine, tyramine, and, to a lesser extent, epinephrine and norepinephrine. Administration of MAO inhibitors increases the concentration of these amines in many organs, including blood platelets, which contain about 99% of blood 5HT.3 Spontaneous migraine is associated with a fall in plasma 5HT and increased urinary excretion of both 5-hydroxyindole acetic acid (5HIAA)4,5and 5 HT (unpublished observations). Depletion of platelet 5HT by the intramuscular administration of reserpine induces migraine in susceptible individuals, and intravenous 5HT relieves-both spontaneous and reserpine-induced

Decreased monoamine oxidase activity in liver of iron-deficient rats.

Abstract: Chronic nutritional deficiency of iron in the rat results in a decrease of 18–31% in the monoamine oxidase activity of the liver. Prolonged feeding of a diet low in copper was without effect on the enzyme, although the concentration of ceruloplasmin in the plasma and of copper in the liver declined.Possible roles of iron in the action of monoamine oxidase are discussed. The inhibitory actions of three iron-chelating agents on monoamine oxidase preparations are consistent with a function of iron in the oxidation of monoamines.

Multiple forms of monoamine oxidase in the developing brain.

Abstract: MUCH attention has recently been centred on the biosynthesis and metabolism of the catecholamines and indole-alkylamines. Because the enzyme monoamine oxidase (monoamine : O2 oxidoreductase (deaminating), EC 1.4.3.4) is involved in the metabolism of both these classes of biogenic amines, and because of our interest in development1,2 we were prompted to investigate the nature of this enzyme and especially its activity in developing brain and other tissues of the maturing organism.

Flavins and monoamine oxidase activity in the brain, liver and kidney of the developing rat

Abstract: RECENT reports (NARA, IGAUE, Goms and YASUNOBU, 1966; IGAUE, Goms and YASUNOBU, 1967; ERWIN and HELLERMAN, 1967) indicate that tissue monoamine oxidase in the liver and kidney is a flavin enzyme. It was reported that brain monoamine oxidase may also be a flavoprotein (TIPTON, 1967). Since monoamine oxidase activity is supposed to have an important role in the development of the brain function during postnatal ontogony (KARKI, KUNTZMAN and BRODIE, 1962), several reports on the changes of monoamine oxidase activity and the concentration of the substrates, serotonin and norepinephrine, in the brain had appeared (NACHMIAS, 1960; KARKI et al., 1962; BENNETT and GIARMAN, 1965). However, the change of the concentration of the cofactor, flavins, in the brain during the development has not so far been reported to the authors’ knowledge. Present communication describes a study on the changes of the level of flavins and monoamine oxidase activity in the developing brain. Flavins and monoamine oxidase activity in the liver and kidney were examined at the same time. Female rats of Wistar strain were used for the experiment. The total amount of flavins was measured by the lumiflavin fluorescence method of YAGI (1956), and the activity of monoamine oxidase by the spectrophotometric assay of the disappearance of kynuramine (WEISSBACH, SMITH, DALY, WITKOP and UDENFRIEND, 1960). The level of flavins and monoamine oxidase activity in the brain, liver and kidney was measured in rats ranging in age from 2 days before birth to 120 days postnatal (adults). The level of flavins and monoamine oxidase activity increased at a rate which was markedly different in each organ (Fig. 1 and Fig. 2). The level of flavins in the brain of the new-born rat was 45 per cent of the adult value. The adult values in the brain were in good agreement with the earlier results (YAGI, 1954; NAGATSU, NAGATSUISHIBASHI, OKUDA and YAGI, 1967). The level did not increase significantly during 8 days after birth, then increased rapidly to reach the adult level at 20 days. The level of flavins in the liver of the new-born rat was 30 per cent of the adult value, and increased rapidly after birth until 10 days, and slowly later on. The level of flavins in the kidney of the new-born rat was 15 per cent of the adult value. The increase was slow initially until 10 days, then became rapid. The changes of monoamine oxidase activity in the brain showed a pattern similar to that described in previous reports (NACHMIAS, 1960; BENNETT and GIARMAN, 1965). A temporary halt in the development of monoamine oxidase activity was observed during the first week of postnatal life. This phenomenon was not observed in the liver or kidney. Monoamine oxidase activity in the liver showed a similar pattern of development to that in the brain except the absence of the temporary halt during the first week. On the other hand, the kidney showed a rapid increase in the enzyme activity only during 10 days after the birth, then the activity remained constant. A temporary halt in the development of flavins and monoamine oxidase activity during the first week of postnatal life is supposed to be specific in the brain. Since myelination of the rat brain occurs after 10 days of postnatal life (MATSUTANI, TSUKADA, MATSWAMA and SENDA, 1967), the rapid increase in flavin concentrations at this period is of physiological interest.

Determination of Monoamine Oxidase Activity in Human Blood Serum with 14C-Benzylamine and 14C-Tyramine as Substrates

Abstract: Two methods for determining monoamine oxidase in human serum with 14C-benzyIamine and 14C-tyramine as the substrates are described. The optimal experimental conditions for determination of the serum monoamine oxidase of patients with various clinical conditions are given.

Multiple substrate determination of monoamine oxidase distribution and iproniazid inhibition in rat brain.

Abstract: — —A variety of monoamine oxidase substrates (tyramine, dopamine, serotonin, tryptamine) have been used with and without Iproniazid inhibition to evaluate further the extent to which enzyme multiplicity may exist in various regions of rat brain. Levels of monoamine oxidase activity, as measured by ammonia production, were found to vary as a function of both brain area and kind of substrate used, in the absence as well as in the presence of Iproniazid, in vivo and in vitro. Similarity of substrate metabolizing patterns among the different brain areas, however, strongly suggests that only one kind of monoamine oxidase exists in rat brain.