1
|
Özçete ÖD, Banerjee A, Kaeser PS. Mechanisms of neuromodulatory volume transmission. Mol Psychiatry 2024:10.1038/s41380-024-02608-3. [PMID: 38789677 DOI: 10.1038/s41380-024-02608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
A wealth of neuromodulatory transmitters regulate synaptic circuits in the brain. Their mode of signaling, often called volume transmission, differs from classical synaptic transmission in important ways. In synaptic transmission, vesicles rapidly fuse in response to action potentials and release their transmitter content. The transmitters are then sensed by nearby receptors on select target cells with minimal delay. Signal transmission is restricted to synaptic contacts and typically occurs within ~1 ms. Volume transmission doesn't rely on synaptic contact sites and is the main mode of monoamines and neuropeptides, important neuromodulators in the brain. It is less precise than synaptic transmission, and the underlying molecular mechanisms and spatiotemporal scales are often not well understood. Here, we review literature on mechanisms of volume transmission and raise scientific questions that should be addressed in the years ahead. We define five domains by which volume transmission systems can differ from synaptic transmission and from one another. These domains are (1) innervation patterns and firing properties, (2) transmitter synthesis and loading into different types of vesicles, (3) architecture and distribution of release sites, (4) transmitter diffusion, degradation, and reuptake, and (5) receptor types and their positioning on target cells. We discuss these five domains for dopamine, a well-studied monoamine, and then compare the literature on dopamine with that on norepinephrine and serotonin. We include assessments of neuropeptide signaling and of central acetylcholine transmission. Through this review, we provide a molecular and cellular framework for volume transmission. This mechanistic knowledge is essential to define how neuromodulatory systems control behavior in health and disease and to understand how they are modulated by medical treatments and by drugs of abuse.
Collapse
Affiliation(s)
- Özge D Özçete
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Aditi Banerjee
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
| |
Collapse
|
2
|
Holt A. Radiochemical Assay of Monoamine Oxidase Activity. Methods Mol Biol 2023; 2558:45-61. [PMID: 36169855 DOI: 10.1007/978-1-0716-2643-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The activity of monoamine oxidase enzymes may be quantified by measuring the conversion of a radiolabeled amine substrate to a radiolabeled product that occurs during incubation of the substrate with the enzyme in an aqueous buffer. Described herein is an established discontinuous procedure in which separation of the substrate and product is achieved by extracting uncharged aldehydes into an organic solvent, while cationic amines remain in an acidified aqueous layer. Under assay conditions designed to ensure a pseudo-linear catalytic rate for the duration of the incubation, determination of radioactivity in the organic solvent by liquid scintillation counting facilitates estimation of an initial rate for amine turnover.
Collapse
Affiliation(s)
- Andrew Holt
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
3
|
Brain dopamine and serotonin differ in regulation and its consequences. Proc Natl Acad Sci U S A 2012; 109:11510-5. [PMID: 22778401 DOI: 10.1073/pnas.1201547109] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dopamine and serotonin (5-hydroxytryptamine or 5-HT) are neurotransmitters that are implicated in many psychological disorders. Although dopamine transmission in the brain has been studied extensively in vivo with fast scan cyclic voltammetry, detection of 5-HT using in vivo voltammetric methods has only recently been established. In this work we use two carbon-fiber microelectrodes to simultaneously measure dopamine release in the nucleus accumbens and 5-HT release in the substantia nigra pars reticulata, using a common stimulation in a single rat. We find that 5-HT release is profoundly restricted in comparison with dopamine release despite comparable tissue content levels. Using physiological and pharmacological analysis, we find that 5-HT transmission is mostly sensitive to uptake and metabolic degradation mechanisms. In contrast, dopamine transmission is constrained by synthesis and repackaging. Finally, we show that disruption of serotonergic regulatory mechanisms by simultaneous inhibition of uptake and metabolic degradation can have severe physiological consequences that mimic serotonin syndrome.
Collapse
|
4
|
Bârzu O. Measurement of oxygen consumption by the spectrophotometric oxyhemoglobin method. METHODS OF BIOCHEMICAL ANALYSIS 2006; 30:227-67. [PMID: 6330496 DOI: 10.1002/9780470110515.ch5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
5
|
Wojtczak AB, Brdiczka D, Wojtczak L. Is monoamine oxidase activity in the outer mitochondrial membrane influenced by the mitochondrial respiratory state? BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1229:249-55. [PMID: 7727501 DOI: 10.1016/0005-2728(95)00007-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Monoamine oxidase activity was measured in isolated rat liver mitochondria using the radiochemical assay with [14C]tyramine as substrate. With toluene as the extracting solvent the apparent activity in the resting state (State 4) was much higher than in the active state (State 3) in agreement with Smith and Reid (Smith, G.S. and Reid, R.A. (1978) Biochem. J. 176, 1011-1014). However, with ethyl acetate or diethyl ether as extracting solvents, the activity in both states was almost identical and several times higher than that measured with toluene. p-Hydroxyphenylacetaldehyde, p-hydroxyphenylacetalcohol and p-hydroxyphenylacetic acid were identified as final reaction products, the latter one being hardly extractable with toluene. It is concluded that monoamine oxidase activity is not influenced by the respiratory state of mitochondria and that differences found by Smith and Reid are due to different extractability of secondary reaction products. NADPH-dependent aldehyde reductase was tentatively identified in rat liver mitochondria, its specific activity amounting to about one fourth of that in the cytosol.
Collapse
Affiliation(s)
- A B Wojtczak
- Nencki Institute of Experimental Biology, Warsaw, Poland
| | | | | |
Collapse
|
6
|
Tipton KF, Singer TP. The radiochemical assay for monoamine oxidase activity. Problems and pitfalls. Biochem Pharmacol 1993; 46:1311-6. [PMID: 8240379 DOI: 10.1016/0006-2952(93)90093-c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- K F Tipton
- Department of Biochemistry, Trinity College, Dublin, Ireland
| | | |
Collapse
|
7
|
Elliott J, Callingham BA, Sharman DF. Semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Interactions with some naturally occurring amines and their structural analogues. Biochem Pharmacol 1989; 38:1507-15. [PMID: 2719723 DOI: 10.1016/0006-2952(89)90191-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The influence of a number of naturally occurring amines and their structural analogues has been examined on the metabolism of radiolabelled benzylamine (BZ) by the membrane bound semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Only primary monoamines were effective in reducing the deamination of BZ. In the phenylethylamine series, addition of hydroxyl groups to the benzene ring decreased their potency as inhibitors while addition of a hydroxyl group at the beta position increased the inhibitory potency. Stereoselectivity of action was shown with octopamine, the L-isomer being the more active form. Kinetic analysis of these interactions showed predominantly competitive inhibition and kynuramine had the lowest Ki of 5.4 microM. The aliphatic monoamines, isoamylamine and isobutylamine both competed with BZ. 5-Hydroxytryptamine (5-HT) was the only amine that inhibited non-competitively. Direct evidence for metabolism by SSAO of some of the competing amines such as isoamylamine, phenylethylamine, tyramine and tryptamine was obtained by fluorimetric or radiochemical assays. The inhibitors clorgyline and (E)-2-(3',4'-dimethoxyphenyl)-3-fluoroallylamine (MDL 72145) were used to characterise the amine oxidase activity responsible for the deamination. Octopamine and phenylethanolamine (PeOH) were not SSAO substrates and inhibited BZ metabolism in the fluorimetric assay. It is possible that the activity of SSAO is controlled by octopamine released from sympathetic nerve endings or 5-HT released from platelets.
Collapse
Affiliation(s)
- J Elliott
- Department of Pharmacology, University of Cambridge, U.K
| | | | | |
Collapse
|
8
|
Isaac L, Schoenbeck R, Bacher J, Skolnick P, Paul SM. Electroconvulsive shock increases endogenous monoamine oxidase inhibitor activity in brain and cerebrospinal fluid. Neurosci Lett 1986; 66:257-62. [PMID: 3725191 DOI: 10.1016/0304-3940(86)90028-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chronic daily administration of electroconvulsive shock (ECS) to cats resulted in a progressive elevation of seizure threshold which was accompanied by a sustained elevation in the activity of an endogenous monoamine oxidase inhibitor (EMAOI) present in cerebrospinal fluid (CSF). The increase in EMAOI activity in CSF following chronic ECS was observed maximally at 24-48 h. In rats, a single application of ECS resulted in a rapid but short-lasting increase in EMAOI activity present in the crude membrane fraction from brain. These findings demonstrate that both acute and chronic ECS modify the activity of an EMAOI in brain and CSF which may contribute to both the antidepressant and anticonvulsant effects of ECS treatment.
Collapse
|
9
|
Johnson M, Roberge AG. Difference in monoamine oxidase activity measured by either liquid ion exchange or ion exchange resin chromatography in rat and cat brain. Anal Biochem 1985; 149:183-90. [PMID: 4073474 DOI: 10.1016/0003-2697(85)90493-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cat and rat brain monoamine oxidase (MAO) activity was measured with a radioisotopic procedure and two extraction methods. Results indicated an underestimation of MAO activity when liquid ion exchange chromatography (LIEC) was used instead of an ion exchange chromatographic method (IEC) to separate the different products of the deaminated tyramine, phenylethylamine, or serotonin. MAO produced aldehydic products which may be found in the incubation medium and may be extracted with the substrate in the chloroform phase by the LIEC method. In cat brain, the resulting underestimation of the MAO activity was prevented by the addition of nicotinamide adenine dinucleotide (10(-3) M) in the incubation medium or by allowing a 2-h period between the end of incubation and the LIEC extraction procedure. In the rat brain, the same result was obtained by the addition of an equimolar mixture of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate in reduced form (NAD-NADPH, 10(-3) M). Using the IEC method, the NAD decreased only the deamination of tyramine and serotonin in rat brain. This study suggests that the use of an IEC method to evaluate MAO activity is more accurate for the estimation of the enzymatic activity.
Collapse
|
10
|
Nissinen E, Linko-Löppönen S, Männistö P. On-line radiochemical assay for monoamine oxidase utilizing high-performance liquid chromatography. JOURNAL OF PHARMACOLOGICAL METHODS 1984; 12:247-54. [PMID: 6443138 DOI: 10.1016/0160-5402(84)90010-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A fast and sensitive assay for the determination of monoamine oxidase activity was developed. The method is based on the separation and quantitation of 14C-labeled assay products by high-performance liquid chromatography, which is interfaced directly into a flow-through radioactivity detector. This allows on-line quantitation of the radioactive compounds with picomole sensitivity. The method makes possible the complete separation and detection of the deaminated products of monoamine oxidase A and B substrates benzylamine and 5-hydroxytryptamine, respectively. This assay has been applied to the measurement of monoamine oxidase A and B activities in rat brain.
Collapse
|
11
|
Kaul KL, Novak RF. Induction of rabbit hepatic microsomal cytochrome P-450 by imidazole: enhanced metabolic activity and altered substrate specificity. Arch Biochem Biophys 1984; 235:470-81. [PMID: 6517600 DOI: 10.1016/0003-9861(84)90220-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Pretreatment of rabbits with imidazole resulted in a twofold increase in hepatic microsomal cytochrome P-450 content, with the apparent induction of two or more distinct forms of the cytochrome [K. K. Hajek and R. F. Novak (1982) Biochem. Biophys. Res. Commun. 108, 664-672]. The metabolic properties of imidazole-induced microsomes have been compared to those of uninduced, phenobarbital- and beta-naphthoflavone-induced preparations. Metabolic activity was enhanced as a consequence of increased P-450 content and as a result of the presence of different forms of the cytochrome. When rates were expressed per nanomole P-450 the following were observed: (a) p-nitroanisole O-demethylation was comparable in all preparations; (b) N,N-dimethylaniline N-demethylation was comparable in imidazole- and beta-naphthoflavone-induced, and uninduced microsomes; (c) polycyclic aromatic hydrocarbon hydroxylase activity was approximately twofold greater in imidazole-induced relative to phenobarbital-induced microsomes, but was only one-half that of beta-naphthoflavone-induced microsomes; and (d) metabolism of N,N-dimethylnitrosamine was enhanced fivefold, alcohol oxidation increased three- to fivefold, and aniline hydroxylation was threefold greater in imidazole-induced microsomes compared to phenobarbital- or beta-naphthoflavone-induced preparations. Eadie-Scatchard analysis yielded a single Km value for dimethylnitrosamine N-demethylase activity in imidazole-induced microsomes; in contrast, both high- and low-Km values were obtained for phenobarbital- or beta-naphthoflavone-induced microsomal preparations. Dimethylnitrosamine N-demethylase activity was P-450 dependent; neither flavin monooxygenase nor monoamine oxidase appeared to contribute significantly to dimethylnitrosamine metabolism. Dimethyl sulfoxide was a competitive inhibitor of dimethylnitrosamine N-demethylase activity in imidazole-, phenobarbital-, and beta-naphthoflavone-induced microsomes. Dimethyl sulfoxide competitively inhibited ethanol oxidation in imidazole-induced microsomes; it was a noncompetitive inhibitor of ethanol oxidation in phenobarbital- or beta-naphthoflavone-induced microsomes.
Collapse
|
12
|
Mitra C, Guha SR. Shift in double-sigmoid MAO inhibition patterns in oxygen-saturated reaction mixture. Biochem Pharmacol 1983; 32:1803-5. [PMID: 6870925 DOI: 10.1016/0006-2952(83)90131-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
13
|
Mitra C, Guha SR. Differential activation of two monoamine oxidase types by oxygen. EXPERIENTIA 1983; 39:270-2. [PMID: 6825791 DOI: 10.1007/bf01955298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
14
|
Nelson TJ, Boor PJ. Allylamine cardiotoxicity--IV. Metabolism to acrolein by cardiovascular tissues. Biochem Pharmacol 1982; 31:509-14. [PMID: 7066019 DOI: 10.1016/0006-2952(82)90152-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Acrolein was detected in homogenates of rat aorta, lung, skeletal muscle, and heart incubated with allylamine. Semicarbazide and hydralazine, which protect against allylamine-induced myocardial injury in vivo in the rat, inhibited acrolein formation. Hydrogen peroxide, a product of oxidative deamination, was generated during allylamine oxidation. Acrolein was also produced from allylamine by bovine plasma amine oxidase and porcine kidney diamine oxidase but not by rat liver or brain homogenates. Allylamine competitively inhibited benzylamine oxidation in rat aorta, but pargyline-sensitive monoamine oxidase was not involved in acrolein production. The high activity in aorta, the competition with benzylamine, and the sensitivity to benzylamine oxidase inhibitors indicate that benzylamine oxidase is the active enzyme in oxidizing allylamine. The formation of acrolein may be the basis of the cardiotoxic action of allylamine.
Collapse
|
15
|
Moretti A, Caccia C, Calderini G, Menozzi M, Amico A. Studies on the mechanism of action of caroxazone, a new antidepressant drug. Biochem Pharmacol 1981; 30:2728-31. [PMID: 6170295 DOI: 10.1016/0006-2952(81)90549-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
16
|
Dziedzic JD, Wisniewski HM, Iqbal K. Monoamine oxidase activity in normal and Alzheimer brains. Ann Neurol 1981; 9:618-9. [PMID: 7259128 DOI: 10.1002/ana.410090621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
17
|
Uji A, Kawai S, Nagatsu T. Gas chromatographic determination of monoamine oxidase activity using mixed substrates. JOURNAL OF CHROMATOGRAPHY 1980; 221:155-60. [PMID: 7451618 DOI: 10.1016/s0378-4347(00)81018-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
18
|
Wibo M, Duong AT, Godfraind T. Subcellular location of semicarbazide-sensitive amine oxidase in rat aorta. EUROPEAN JOURNAL OF BIOCHEMISTRY 1980; 112:87-94. [PMID: 7449765 DOI: 10.1111/j.1432-1033.1980.tb04990.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
With tyramine as substrate, a considerable part of the amine oxidase activity of rat aorta was inhibited by 0.1 mM semicarbazide. The residual activity was little affected by 1 mM semicarbazide. Oxidation of 5-hydroxytryptamine was not inhibited by 0.1 mM semicarbazide. The subcellular location of the semicarbazide-sensitive and semicarbazide-resistant amine oxidases was investigated by analytical density gradient centrifugation. The semicarbazide-resistant enzyme was identified with the mitochondrial monoamine oxidase, located in the outer envelope of mitochondria. The semicarbazide-sensitive amine oxidase was ascribed to the plasma membrane because it was distributed like 5'-nucleotidase and (oligomycin-insensitive) Mg2+-ATPase in various fractionation experiments, and markedly shifted by digitonin towards higher equilibrium densities in sucrose gradient.
Collapse
|
19
|
Kobes RD, Wyatt RJ, Neckers LM. A sensitive and rapid fluorimetric assay for monoamine oxidase utilizing high pressure liquid chromatography. JOURNAL OF PHARMACOLOGICAL METHODS 1980; 3:305-10. [PMID: 6156366 DOI: 10.1016/0160-5402(80)90072-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A rapid and sensitive assay for the measurement of monoamine oxidase (MAO) activity was developed. This method utilizes high pressure liquid chromatography with fluorescence excitation at 280 nm and detection of 330 nm at pH 5.0 of indoleacetic acid and 5-hydroxyindoleacetic acid, the deaminated products of two substrates for MAO, tryptamine, and serotonin, respectively. The assay allows for the complete separation of metabolites from either of the two substrates. The method has been used to determine MAO activity in the frontal cortex and caudate nucleus of rat brain using tryptamine and serotonin as substrates. The ease and rapidity of this assay make it sutable for use where routine enzyme determinations are required.
Collapse
|
20
|
Mureşan L, Dânşoreanu M, Ana A, Bara A, Bârzu O. Cuvette and flow system for fast and sensitive spectrophotometric assays of oxygen consumption. Anal Biochem 1980; 104:44-50. [PMID: 7386882 DOI: 10.1016/0003-2697(80)90274-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
21
|
Fowler CJ, Oreland L, Marcusson J, Winblad B. Titration of human brain monoamine oxidase -A and -B by clorgyline and L-deprenil. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1980; 311:263-72. [PMID: 6771658 DOI: 10.1007/bf00569406] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The interaction of clorgyline and L-deprenil with the -A and -B forms of human brain monoamine oxidase (MAO) has been studied. Both compounds inhibit cerebrocortical MAO in a manner consistent with a 'suicide' inactivation of the enzyme. The interaction of clorgyline with the -A form of the enzyme appears to take place almost entirely at specific binding sites, and the conditions required for this inhibitor to 'titrate' the concentrations of MAO-A have been elucidated. L-Deprenil has also been used to titrate the concentration of the -B form of MAO in cerebrocortical homogenates, but there is a considerable degree of non-specific binding of this compound. The two inhibitors have been used to titrate the concentrations of the two enzyme forms in frontal cortex homogenates from different age groups. There was a significantly higher MAO-B activity for the age range 73--95 years than for the age range 2--63 years. No significant differences between the two age groups were found for MAO-A. The activity of MAO-A in the samples correlated very well with the concentration of this enzyme form. Titration of the B-form of the enzyme with L-deprenil indicated an increased enzyme concentration with age, although other factors, such as the non-specific binding of this compound, could contribute to this effect.
Collapse
|
22
|
Bârzu O, Dânşoreanu M. Spectrophotometric determination of H2O2-generating oxidases using oxyhemoglobin as oxygen donor and indicator. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1980; 11:121-6. [PMID: 6244202 DOI: 10.1016/0020-711x(80)90244-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. Spectrophotometric determination of oxygen uptake using oxyhemoglobin as oxygen donor and indicator was used for assay of H2O2-generating oxidases like monoamine oxidase and glucose oxidase. 2. In order to decompose H2O2 formed during the oxygen uptake, catalase and methanol (or ethanol) was added to the respiratory system. At pH values higher than 7.5 the oxydation of deoxygenated hemoglobin to methemoglobin was less than 3%. 2. Oxidases with low Km for oxygen can be assayed using the spectrophotometric method if suitable correction factors are introduced into the calculation of oxygen uptake. The correction factor represents the ratio of the rate of formation (or disappearance) of one of the reactants and the rate of oxyhemoglobin deoxygenation, measured under identical experimental conditions.
Collapse
|
23
|
Boor PJ, Nelson TJ. Allylamine cardiotoxicity: III. Protection by semicarbazide and in vivo derangements of monoamine oxidase. Toxicology 1980; 18:87-102. [PMID: 7256782 DOI: 10.1016/0300-483x(80)90072-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
24
|
Blank CL, Sasa S, Isernhagen R, Meyerson LR, Wassil D, Wong P, Modak AT, Stavinoha WB. Levels of norepinephrine and dopamine in mouse brain regions following microwave inactivation--rapid post-mortem degradation of striatal dopamine in decapitated animals. J Neurochem 1979; 33:213-9. [PMID: 37287 DOI: 10.1111/j.1471-4159.1979.tb11723.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
25
|
Salach JI. Monoamine oxidase from beef liver mitochondria: simplified isolation procedure, properties, and determination of its cysteinyl flavin content. Arch Biochem Biophys 1979; 192:128-37. [PMID: 434814 DOI: 10.1016/0003-9861(79)90078-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
26
|
Meyerson LR, McMurtrey KD, Davis VE. A rapid and sensitive potentiometric assay for monoamine oxidase using an ammonia-selective electrode. Anal Biochem 1978; 86:287-97. [PMID: 655389 DOI: 10.1016/0003-2697(78)90344-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
27
|
Fowler CJ, Callingham BA. Substrate-selective activation of rat liver mitochondrial monoamine oxidase by oxygen. Biochem Pharmacol 1978; 27:1995-2000. [PMID: 718722 DOI: 10.1016/0006-2952(78)90057-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
28
|
|
29
|
Fingerman M, Schultz RE, Bordlee BP, Dalton DP. Twenty-four-hour variation of 5-hydroxytryptophan decarboxylase and monoamine oxidase activities in the eyestalks of the fiddler crab, Uca pugilator. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C: COMPARATIVE PHARMACOLOGY 1978; 61C:171-5. [PMID: 30576 DOI: 10.1016/0306-4492(78)90129-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
30
|
Rao GH, Friedland M, Gerrard JM, White JG. The influence of metabolities on the assay of platelet serotonin. Thromb Res 1977; 10:791-802. [PMID: 196357 DOI: 10.1016/0049-3848(77)90136-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
31
|
Hayashi S, Murdock LL, Florey E. Octopamine metabolism in invertebrates (Locusta, Astacus, Helix): evidence for N-acetylation in arthropod tissues. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C: COMPARATIVE PHARMACOLOGY 1977; 58:183-91. [PMID: 23932 DOI: 10.1016/0306-4492(77)90102-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
32
|
|
33
|
Gabay S, Achee FM, Mentes G. Some parameters affecting the activity of monoamine oxidase in purified bovine brain mitochondria. J Neurochem 1976; 27:415-24. [PMID: 9476 DOI: 10.1111/j.1471-4159.1976.tb12263.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
34
|
Ekstedt B. Substrate specificity of the different forms of monoamine oxidase in rat liver mitochondria. Biochem Pharmacol 1976; 25:1133-8. [PMID: 938537 DOI: 10.1016/0006-2952(76)90359-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
35
|
|
36
|
|
37
|
Achee FM, Togulga G, Gabay S. Studies of monoamine oxidases: properties of the enzyme in bovine and rabbit brain mitochondria. J Neurochem 1974; 22:651-61. [PMID: 4407271 DOI: 10.1111/j.1471-4159.1974.tb04277.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
38
|
Jain M. A rapid, sensitive, radiometric procedure for the determination of human blood platelet monoamine oxidase activity. Clin Chim Acta 1973; 47:107-9. [PMID: 4747797 DOI: 10.1016/0009-8981(73)90066-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|