An improved fluorimetric assay for brain monoamine oxidase

Morinan, Alun; Garratt, Helen M.

doi:10.1016/0160-5402(85)90021-x

Cited by 64 publications

(25 citation statements)

References 23 publications

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“…; II = 24) and, therefore, values for I;, could not be calculated.The slopes obtained for both CON(Fig. 1 )and ALC mice (data not shown) were almost identical, with a calculated E;, of 60.9 f 0.7 kJ/mol for CON and 60 6. f 0.4 kJ/mol for A L C mice (mean f s.E.M.…”

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confidence: 58%

Thermodynamic characteristics of brain monoamine oxidase in ethanol-tolerant mice

Morinan

1990

Biochemical Society Transactions

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lkpiir~tnetit of Hiologic~ul Sciericw. North Eust Siirrey College of Ti.c~lirrology, Krigurc. Korrd9 Ewell, I+.sotn K 7'1 7 3D.S. U. K .The use o f electron paramagnetic resonance and fluorcscence polarization spectroscopy has shown that there are decreases in synaptic plasma membrane fluidity following chronic ethanol administration t o rodents I 1 I. Such changes might have effects on the functioning o f synaptic proteins and. therefore. the membrane perturbation caused by ethanol may be involved in the drug's effects on neutrotransmission. and the development o f tolerance and dependence (21. T h e activity of membrane-bound enzymes is dependent on the physicochcmical state of their lipid environment and increases with temperature up t o a point where protein denaturation occurs [ 31. A linear relationship between enzyme activity and temperature can be derived, the Arrhenius Plot. from which the activation energy ( E J can be calculated. A discontinuity, o r break in the slope of this plot, is indicative of a lipid phase transition occurring at that temperature ( 7il). Therefore, the measurement o f 7;, can provide a useful index of the fluidity of the lipid microenvironment o f particular membrane-bound enzymes. In this study. the effect o f temperature on the mitochondria1 enzyme monoamine oxidase (MAO) in the brain of ethanol-tolerant mice was investigated.Male CFLP mice (20-30 g) were housed individually in NKP-M2 cages in a quiet room maintained on a 12 h light/ dark circle. One group of animals (ALC) were given 5%) (v/v) ethanol in the form of a chocolate-flavoured liquid diet for 7 days 141. while the other group (CON) were pair-fed an isocalorific diet with sucrose substituted for the ethanol. Locomotor activity in the Open Field (45 cm diameter, 14 cm wall height) was recorded over a 5 min period on day 7 of chronic ethanol treatment, and tolerance to the drug assessed by the method o f Ritzmann & Tabakoff 151. Twentyfour hours later, M A 0 was assayed in thc brain (excluding the pons/medulla oblongata and cerebellum) over a temperature range of 10-41°C using kynurarnine as the substrate (61. T h e concentrations of the monoamine neurotransmitters: dopamine. noradrenaline and 5-hydroxytryptamine (5-HT ) were also measured fluorimetrically after their isolation from deproteinized brain supernatants using Sephadex G-10 microcolumns [ 71. T h e concentration o f ethanol in the brain at the end o f the treatment period was quantified by gns-liquid chromatography using a Pye Series 104 Gas Chromatograph linked to a Philips PU-48 I 0 Computing Intcgrator. ALC mice exhibited hyperactivity in the Open Field, with activity counts of I 2 0 I f 0.3 (mean k s.E.M.; ti = 16) compared with a C O N value o f 7 5 Y f 6 6 (t=3.X0, I ' < O . O I ) . Chronic ethanol administration resulted in tolerance t o the hypothermic effect of an acute dose of ethanol. T h e decrease in rectal tcmperature of 1 .04 f 0.36"C (mean f s.E.M.; ti = 7) in A L C mice 30 min after an i.p. injection of ethanol (3 g/kg), was significantly ...

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confidence: 58%

Thermodynamic characteristics of brain monoamine oxidase in ethanol-tolerant mice

Morinan

1990

Biochemical Society Transactions

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“…4-Hydroxy-quinoline formed by the oxidation of kynuramine was measured fluorimetrically and the monoamine oxidase activity was expressed as 4-hydroxyquinoline formed/h/mg protein (Morinan and Garratt, 1985).…”

Section: Animalsmentioning

confidence: 99%

Neuroprotective effects of the antiparkinson drug Mucuna pruriens

Manyam

Dhanasekaran

Hare

2004

Phytotherapy Research

142

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Mucuna pruriens possesses significantly higher antiparkinson activity compared with levodopa in the 6-hydroxydopamine (6-OHDA) lesioned rat model of Parkinson's disease. The present study evaluated the neurorestorative effect of Mucuna pruriens cotyledon powder on the nigrostriatal tract of 6-OHDA lesioned rats. Mucuna pruriens cotyledon powder significantly increased the brain mitochondrial complex-I activity but did not affect the total monoamine oxidase activity (in vitro). Unlike synthetic levodopa treatment, Mucuna pruriens cotyledon powder treatment significantly restored the endogenous levodopa, dopamine, norepinephrine and serotonin content in the substantia nigra. Nicotine adenine dinucleotide (NADH) and coenzyme Q-10, that are shown to have a therapeutic benefit in Parkinson's disease, were present in the Mucuna pruriens cotyledon powder. Earlier studies showed that Mucuna pruriens treatment controls the symptoms of Parkinson's disease. This additional finding of a neurorestorative benefit by Mucuna pruriens cotyledon powder on the degenerating dopaminergic neurons in the substantia nigra may be due to increased complex-I activity and the presence of NADH and coenzyme Q-10.

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“…The concentrations of kynuramine were approximately equal to experimentally determined Km values (16 μM for MAO A; 8 μM for MAO B). The reaction was terminated by adding NaOH (0.5 M), and activity was determined by measuring fluorescence of 4-hydroxyquinoline (excitation, 320 nm; emission, 405 nm) using black, 96-well plates and a FluoStar Omega plate reader (BMG Labtech, Inc., Cary, NC, USA) (Morinan and Garratt, 1985). A linear standard curve of 4-hydroxyquinoline was used to quantify the product produced.…”

Section: Mao Inhibition By Fluorescence Kynuramine Assaymentioning

confidence: 99%

Inhibition of monoamine oxidase (MAO) by α-ethylphenethylamine and N,α-diethylphenethylamine, two compounds related to dietary supplements

Santillo

2014

Food and Chemical Toxicology

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An improved fluorimetric assay for brain monoamine oxidase

Cited by 64 publications

References 23 publications

Thermodynamic characteristics of brain monoamine oxidase in ethanol-tolerant mice

Thermodynamic characteristics of brain monoamine oxidase in ethanol-tolerant mice

Neuroprotective effects of the antiparkinson drug Mucuna pruriens

Inhibition of monoamine oxidase (MAO) by α-ethylphenethylamine and N,α-diethylphenethylamine, two compounds related to dietary supplements

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