Distribution of phenolsulphotransferase and monoamine oxidase in the common marmoset.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to V Glover.
Explore the source record for details and available documents.
In this study, urinary output of both neutral (tribulin) and basic monoamine oxidase inhibitory activity was measured in parkinsonian patients, other neurological patients and controls. No significant differences in output were found between these different groups. In general, tribulin output rose with age, in parallel with known changes in monoamine oxidase B activity.
A significantly higher proportion of patients with headache showed scores in the psychopathological range of the General Health Questionnaire (GHQ) compared with controls, with ratings particularly high on the anxiety and depression subscales. Across the whole group, there was a significant negative correlation between platelet monoamine oxidase (MAO) activity and GHQ score overall, and with the anxiety and depression subscales. There was a significant positive correlation between platelet MAO activity and urinary output of the endogenous MAO inhibitor, tribulin. Within the migraine group, there was a significant negative correlation between tribulin output and GHQ score. These findings suggest that the biochemical nature of the anxiety associated with migraine may differ from that in other conditions such as generalized anxiety disorder where high platelet MAO activity and high tribulin output have been reported.
Explore the source record for details and available documents.
Tyramine sulfoconjugation following an oral tyramine load was determined in 30 patients suffering from migraine and 14 controls not regularly suffering from headache. Reduced tyramine sulfoconjugation was found in those patients with a history of major depressive disorder compared with controls. When the patients with a history of major depression were removed from the analysis, no differences were found between diet-sensitive and non-diet sensitive migraine patients and controls.
1-Methyl-4-phenylpyridinium (MPP+) was taken up into human and rat striatal synaptosomes by a saturable system, similar to that for dopamine, with Km values of 0.24 and 0.17 microM, respectively, and similar Vmax values. Uptake of MPP+ and dopamine into both rat and human synaptosomes was inhibited by cocaine and amfonelic acid, with the latter being five to 10 times more potent than the former. MPP+ uptake was potently inhibited by dopamine in preparations from both species. In general, the characteristics of human and rat synaptosomal MPP+ uptake were very similar It seems unlikely that species differences in toxicity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine or reaction to dopamine uptake blockers stem from this system.
Two hours of cold restraint stress in rats resulted in significantly increased brain concentrations of endogenous monoamine oxidase inhibitor (tribulin). Young and old rats showed the same order of response. Tribulin levels were also increased by immobilisation stress alone but to a lesser extent.
This study describes the histochemical localisation of monoamine oxidase (MAO) in marmoset brain. No MAO A staining was observed but MAO B was found in many areas, with medium intensity of staining in the substantia nigra, and high intensity staining in the striatum and nucleus accumbens, among other regions. The high activity in the nigrostriatal tract, compared with the rat, may partially explain the greater sensitivity of the marmoset to MPTP toxicity. As in the rat, high activity was present in the raphe nuclei. However, unlike the rat, no enrichment of MAO B was observed in blood vessels or ventricular linings.
Patients with migraine who believed that red wine but not alcohol in general had a headache-provoking effect on them were challenged either with red wine or with a vodka and diluent mixture of equivalent alcohol content, both consumed cold out of dark bottles to disguise colour and flavour. The red wine, which had a negligible tyramine content, provoked a typical migraine attack in 9 of 11 such patients, whereas none of the 8 challenged with vodka had an attack. Neither red wine nor vodka provoked such episodes in other migrainous subjects or controls. These findings show that red wine contains a migraine-provoking agent that is neither alcohol nor tyramine.
Blood pressure and heart rate responses to oral tyramine have been measured in healthy volunteers before and after administration of the selective monoamine oxidase B inhibitor selegiline at high dosage (30 mg/day). Treatment brought about a 2 to 4-fold increase in tyramine sensitivity and a concomitant small but significant reduction in plasma 4-hydroxy-3-methoxyphenylglycol concentration, pointing to the emergence of some degree of monoamine oxidase A inhibition. It is suggested that patients treated with selegiline 30 mg/day or more should be placed on a tyramine-free diet.
Urinary output of an endogenous monoamine oxidase inhibitor and benzodiazepine receptor binding inhibitor (tribulin) was raised in a group of patients with generalised anxiety disorder compared with controls. Tribulin levels remained relatively constant in individual patients over the 6-week period of observation, mean values remaining high even after reduction of anxiety following non-drug behaviour therapy.
The histochemical distribution of monoamine oxidase A and B in rat brain was investigated using a coupled peroxidatic technique with benzylamine and tyramine as substrates and clorgyline and (-)-deprenyl as selective inhibitors. Benzylamine oxidase was absent in all areas. Both forms of monoamine oxidase were present, at low levels, in all areas; in addition several regions showed high activity of one or other form or both. Substantial activity of monoamine oxidase B was identified in the pineal gland, the lining of the ventricles, several hypothalamic regions, and the raphe nuclei. The locus coeruleus and interpeduncular nucleus possessed considerable type A activity. The substantia nigra and striatum showed no staining above the low general level, although the ventral tegmental area showed higher levels of both A and B. In general, noradrenaline-containing neuronal cell body areas showed monoamine oxidase A, and 5-hydroxytryptamine-rich areas monoamine oxidase B. There was no consistent enrichment of either in corresponding dopamine-rich regions. Monoamine oxidase thus appears to have a different role in these three types of neuron. The low level of monoamine oxidase B in the nigrostriatal tract may help to explain the resistance of the rat to MPTP toxicity.
Tribulin (endogenous monoamine oxidase inhibitor/benzodiazepine receptor binding inhibitor) output was measured in the urine of 18 patients with post-traumatic stress disorder (PTSD) and 13 controls. The level of the two inhibitory activities was highly significantly correlated in the group as a whole. There was no difference between output of either inhibitor in patients and controls. However, when the PTSD group was subdivided according to various psychometric ratings, a pattern of output did emerge. Levels of both inhibitory activities were higher in agitated compared with non-agitated subjects, and lower in extroverts compared with introverts. This finding supports the view that tribulin output is raised in conditions of greater arousal.
Purified tribulin, an endogenous monoamine oxidase (MAO) inhibitor, has been identified by direct probe insertion mass spectrometry as the indole-2,3-dione, isatin. A gas chromatographic-mass spectrometric assay for isatin has been developed and used to measure its relatively high concentrations in unpurified human urine, and in rat heart and brain. Isatin is a known compound with a broad range of biological activity; this is the first report of its presence in the animal body. Isatin is a potent inhibitor of MAO, particularly of MAO B (IC50, 3 microM), and also binds to central benzodiazepine receptors (IC50 against clonazepam, 123 microM).
Low platelet phenolsulphotransferase activity has been reported in adult patients with dietary sensitive migraine. Platelet activity of this enzyme was therefore measured in children having 'abdominal migraine' with probable dietary trigger and in controls. No significant difference was found in activity between the two groups. There was no significant correlation between platelet phenolsulphotransferase activity and age.
Urinary output of homovanillic acid and 4-hydroxy-3-methoxymandelic acid was decreased both in patients with panic attacks and in normal controls during lactate infusion, whereas that of tribulin (an endogenous monoamine oxidase inhibitor and benzodiazepine receptor binding inhibitor) was increased. There was no change in urinary excretion of any of these compounds during saline infusion. These findings provide further evidence of a link between tribulin output and stress and anxiety in man and point to its possible in vivo action as a monoamine oxidase inhibitor.
Several natural and synthetic food and drink constituents were tested in vitro for their inhibitory actions on phenolsulphotransferase P and M (PST P, PST M) and monoamine oxidase A and B (MAO A, MAO B). Cyanidin 3-rutinoside, a simple anthocyanin, (+)-catechin, a flavanol, and carmoisine, a synthetic food colorant, were found to be particularly potent, reversible inhibitors of PST P. All inhibited this enzyme by 100% at a concentration of 5 microM and had an IC50 in the microM range. The effects of these compounds on PST M and MAO A and B were less pronounced. There was a considerable difference in the inhibitory ability of different purified anthocyanins but all were selective for PST P. Several other phenolic food colorants were also found to be specific inhibitors of PST P, though less potent in their actions. Tartrazine, a non-phenolic food colorant, had little effect. The phenolic extracts from two red wines were also found selectively to inhibit PST P in vitro, suggesting that it is within this fraction that these inhibitors are to be found. PST is an important enzyme involved in the inactivation of a wide range of exogenous and endogenous phenols. If such a degree of inhibition were to occur in vivo, potentially toxic concentrations of some phenolic substrates might result.