Platelet Monoamine Oxidase Research Articles

Platelet monoamine oxidase B activity and vitamin B 12 in dementia

The activity of platelet monoamine oxidase B (MAO-B) was highly correlated with the severity of dementia in 39 patients suffering from probable dementia of the Alzheimer type and in 18 age-matched controls. There was no association between a low vitamin B 12 level and high MAO-B activity in our sample of patients, who are living in a geriatric hospital where the balanced nutrition of inpatients is controlled by diet assistants.

Platelet monoamine oxidase activity and temperament and personality in adolescent female substance abusers

Platelet monoamine oxidase (MAO) activities were compared between female adolescent substance abusers and normal control females. No differences were observed on this biochemical trait. The two groups were discriminable on psychosocial, and behavioral adjustment, personality traits measuring aggression, self control, and stress reactivity, and on the temperament constellations of difficult temperament index, dysrythmicity, and difficult affective temperament. Platelet MAO activity was associated with difficult affective temperament only in the substance abuse group but not in the controls, suggesting that this temperament variant and lower MAO activities may comprise one form of predisposition to substance abuse.

Platelet monoamine oxidase (MAO) activity: Personality, substance use, and the stress-response-dampening effect of alcohol.

Platelet monoamine oxidase (MAO) activity: Personality, substance use, and the stress-response-dampening effect of alcohol.

Brief Report

We investigated the possible relationship between schizophrenia, neuroleptic treatment, and platelet monoamine oxidase (MAO) activity. Platelet MAO activity was similar in neuroleptic-naive schizophrenic patients and healthy controls and was not affected by chronic (10-week) perphenazine treatment. A relationship between platelet MAO activity and central disturbances in schizophrenia remains uncertain.

Type A personalities tend to have low platelet monoamine oxidase activity

This study investigated whether there are relations between type A behaviours and the activity of monoamine oxidase (MAO) in blood platelets. Forty male nonsmokers completed the Jenkins Activity Survey (JAS) and had a blood sample drawn while at work. The JAS was scored in the traditional manner, yielding scores for ambitiousness (factor A), impatience (factor S), competitiveness (factor H) and job involvement (factor J). High scores on JAS scales were associated with low MAO activity in blood platelets; the correlation between platelet MAO activity and job involvement was significant. The findings agree with previous reports in showing relationships between MAO activity and certain personality traits and support the notion that low activity of MAO may contribute to sympathetic hyperreactivity in type A individuals.

Platelet monoamine oxidase (MAO) activity: Personality, substance use, and the stress-response-dampening effect of alcohol.

Platelet monoamine oxidase (MAO) activity: Personality, substance use, and the stress-response-dampening effect of alcohol.

Criminality and platelet monoamine oxidase activity in former juvenile delinquents as adults.

Platelet monoamine oxidase (MAO) activity was estimated in 70 former delinquent boys and 40 controls now aged 38-46 years. Platelet MAO activity was compared with their early criminal behaviour (before the age of 15) and their late registered criminality from the age of 15). Mean platelet MAO activity in subjects with both early and late criminality was significantly lower than that in former delinquents without late criminality. There was no significant difference in mean platelet MAO activity between controls and delinquents with early but no late criminality. When delinquents with early criminality were divided into a low and a high MAO group, the relative risk to be registered for late criminality was about 3.1 times higher for the subjects in the low MAO group. Thus, individuals with low platelet MAO activity run an increased risk of continued criminal behaviour.

Biochemical predictors of response to somatic antidepressant treatment

Ten years after the appearance of the first tricyclic antidepressant, a survey showed that only about two-thirds of depressed inpatients benefit from somatic treatment. The second-generation drugs and the selective reuptake inhibitors do not appear clinically more efficacious than the traditional tricyclic antidepressants. Along with the development of new drugs with alternative profiles of action, there have been many attempts to identify biologic tests and markers of affective disorders which could be useful in clarifying diagnosis and planning its treatment. This paper has reviewed studies of 11 biochemical predictor's - that is, dexa-methasone suppression test, thyrotropin-releasing hormone test, intravenous L-tryptophan test, 3-methoxy-4-hydroxyphenyl glycol, 5-hydroxyindoleacetic acid, precursor amino acids, amino acid transport into erythrocytes, platelet serotonin, platelet imipramine binding, platelet monoamine oxidase, and tyramine sulfate excretion - of antidepressant response and their application for clinical practice. Although some biochemical markers may be associated with antidepressant response in patient samples a reliable prediction of antidepressant response in individual patients is not available at present. On the basis of the state of knowledge of the biology of depression and the availability of treatments with various profiles of action, it is unsatisfactory that depression is not better treated. Improved and standardized methods for clinical description and diagnosis and for creating meaningful biochemical measures are needed.

Association of monoamine oxidase (MAO) activity with alcoholism and alcoholic subtypes.

A familial/genetic study of platelet monoamine oxidase (MAO) activity in alcoholics was carried out. MAO activities were determined using phenylethylamine (PEA) as substrate at Km concentration (1.2 microM) and at saturating concentration (12.0 microM). Complex segregation analysis of familial data indicated a single major gene mode of transmission of activity at both substrate concentrations. In addition, the present sample size (13 families, 108 members) proved sufficient to allow correlation analysis of enzyme activity with affection status and clinical subtypes of affecteds. MAO activity was significantly correlated with alcoholism at both Km and saturating substrate concentrations and a significant correlation between low MAO activity and Cloninger Type II alcoholism was seen at Km substrate concentration. These results confirm a hierarchical cosegregation of platelet MAO activity and alcoholism suggesting that MAO activity warrants continued status as a marker in alcoholism.

Are gender differences genetically related to catecholamine metabolism in schizophrenia?

Serum homovanillic acid (HVA) and norepinephrine (NE), serum dopamine-β-hydroxylase (DBH), platelet monoamine oxidase (MAO), and erythrocyte catechol-O-methyltransferase (COMT) have been measured in 86 healthy parents of schizophrenic patients and 36 normal control subjects. The t-test showed that serum HVA concentration was significantly higher in mothers of female patients than in mothers of male patients ( p < .05); Kruskal-Wallis analysis revealed a significant difference in erythrocyte COMT activity among the mothers of male patients, mothers of female patients and female control subjects ( H = 8.7, df = 2, p < .02); and the Mann-Whitney test demonstrated that erythrocyte COMT activity was significantly increased in mothers of male patients as compared with female control subjects ( p < .01), but there were no significant differences in the HVA concentration and COMT activity between the fathers of male and female patients, and male control subjects. There were no significant changes in serum NE concentration, serum DBH and platelet MAO activity in these subjects. The present study suggests that catecholamine metabolism in mothers of schizophrenic patients may play a genetic role in the gender differences of schizophrenia.

A genetic familial study of monoamine oxidase B activity and concentration in alcoholics.

Platelet monoamine oxidase B (MAO B) activity and concentration were studied in a small sample of alcoholic families (n = 8) and in 20 unrelated, nonalcoholic controls. Complex segregation analyses of familial data indicated that both activity and concentration are controlled by a single major gene locus with a multifactorial background effect accounting for 0-50% of the variance. When the alcoholic family members (n = 24) were compared with the controls, all determinations of activity display significant differences, whereas MAO B concentration levels showed no difference. These results indicated that the lowered MAO B activities frequently reported among alcoholics do not reflect a change in the number of MAO B macromolecules expressed in platelets, but could be caused by the presence of an inhibitor or by a polymorphic or variant form of the enzyme.

Migraine and depression: Biological aspects

There is a considerable overlap in migraine and depression incidence, and both conditions may be associated with low levels of 5-hydroxytryptamine (5-HT). During a migraine attack there is evidence for low levels of placelet 5-HT and possibly also low Vmax for 5-HT uptake; both these findings are also associated with the depressed state. Both conditions can be treated by tricyclic and monoamine oxidase inhibiting antidepressants. However, there are also clear differences: migraine attacks are brief and self limiting. Part of the migraine cascade occurs outside the blood brain barrier, presumably involving blood vessels and, unlike depression, migraine attacks can be ameliorated by drugs which only act peripherally. In addition, migraine patients, especially males, often have permanently low levels of platelet monoamine oxidase activity, whereas patients with unipolar depression tend to have raised levels of this marker. This low enzyme activity may reflect part of the vulnerability to migraine, often associated in the prodromal phase with agitation or hyperactivity. Migraine may form part of a family of brief recurrent self-limiting disorders, which involve disturbances of both mood and monoamines; during the headache phase of the attack, the links with depression are most apparent.

Platelet monoamine oxidase B activity in Parkinson's disease: a re-evaluation.

An increase in platelet monoamine oxidase (MAO) B activity in drug-free parkinsonians (n = 6) compared with healthy controls (n = 10) has been confirmed using both phenylethylamine (PEA) and dopamine as substrates, reaching statistical significance in the case of PEA oxidising activity (p < 0.05). Thus, certain reports of raised platelet MAO B activity towards PEA but decreased activity towards dopamine in parkinsonians, raising the possibility of the existence of an abnormal form of MAO B in this condition, cannot be supported.

Personality characteristics and platelet MAO activity in women with congenital adrenal hyperplasia (CAH)

Personality traits and platelet monoamine oxidase (MAO) activity were studied in 22 women, 17–34 years old, with prenatal virilization due to congenital adrenal hyperplasia (CAH) (21-hydroxylase deficiency) and 22 healthy controls. The CAH group differed significantly on two of the eight scales of the Karolinska Scales of Personality (KSP), which have earlier shown significant gender differences. Both differences were in the masculine direction, with a high, male level, score for Detachment and a lower score for Indirect Aggression. The Detachment scale reflects distance in social relations, and has earlier been shown to be strongly gender differentiating. There was no significant difference in platelet MAO activity between the CAH group and the controls. Although an influence of psychosocial factors cannot be excluded, the results suggest a possible association between prenatal androgen exposure and the high Detachment score for the CAH group. Gender differences in empathy, affiliation motivation, intimacy and maternal behavior may be relevant parallels.

Does amateur boxing lead to chronic brain damage? A review of some recent investigations.

Fifty former amateur boxers were examined and compared with two control groups of soccer players and track and field athletes. All subjects were interviewed regarding their sports career, medical history, and social variables. They underwent a physical and a neurologic examination. Personality traits were investigated and related to the platelet monoamine oxidase activity. Cerebral morphologic changes were evaluated using computed tomography and magnetic resonance imaging. Further, clinical neurophysiologic tests were made as well as neuropsychologic tests. No significant differences were found between the groups in any of the physical or neurologic examinations or in platelet monoamine oxidase activity. Socially, the boxers had a lower degree of education and had chosen less intellectual professions, but they were less impulsive and more socialized. The computed tomography images and magnetic resonance imaging studies showed no significant differences between the groups. There was a significantly higher incidence of slight or moderate electroencephalography deviations among the boxers. Neuropsychologically, the boxers had an inferior finger-tapping performance. Thus, no signs of serious chronic brain damage were found among any of the groups studied. However, the electroencephalography and finger-tapping differences between the groups might indicate slight brain dysfunction in some of the amateur boxers.

Low platelet gamma-aminobutyrate aminotransferase and monoamine oxidase activities in chronic alcoholic patients.

The activities of gamma-aminobutyrate aminotransferase (GABA-T) and monoamine oxidase (MAO) were estimated in blood platelets from 25 male chronic alcoholics and from 27 healthy male volunteers without histories of alcohol abuse. Based on clinical criteria, the alcoholics were classified into type 1 or type 2 alcoholism. The activity of GABA-T was found to be lower both in type 1 and type 2 alcoholics than in healthy volunteers. With regard to MAO, the platelet activity was found to be significantly lower only in type 2 alcoholics in concordance with previous reports. No significant correlation was found between the activities of GABA-T and MAO in the blood platelets of healthy volunteers. The inhibitory effect of 400 mM ethanol on the platelet MAO activity increased with decreasing concentrations of the substrate phenylethylamine. The degree of inhibition of ethanol on the platelet MAO activity, however, did not differ significantly between alcoholics and controls.

Monoamine oxidase and cortisol response in depression and schizophrenia

The relationship between hypothalamic-pituitary-adrenal (HPA) axis function and platelet monoamine oxidase (MAO) activity was examined in drug-free depressed ( n = 32) and schizophrenic ( n = 36) inpatients. HPA function was measured by determining plasma cortisol levels at 8:30 a.m. and 11 p.m. before, and 8:30 a.m., 4 p.m., and 11 p.m. after administration of 1 mg of dexamethasone (DEX). There was a significant correlation between platelet MAO activity and all post-DEX cortisol levels (8:30 a.m., 4 a.m., and 11 p.m.) in depressed patients, and MAO activity and pre-DEX cortisol levels (11 p.m.) in schizophrenic patients. MAO activity was significantly higher in depressed DST nonsuppressors than in suppressors, and there were more DST nonsuppressors in high-MAO groups as compared with low-MAO groups. Our results thus suggest a strong relationship between platelet MAO activity and HPA function in depressed patients. These biochemical markers are potentially useful in the identification of biochemically and clinically homogeneous subgroups of depressed patients.

Platelet monoamine oxidase in schizophrenia: a meta-analysis

We did a meta-analysis on all publications (English and other languages) concerned with platelet monoamine oxidase (MAO) in schizophrenia. Essentially, when patients were medicated with a neuroleptic, most studies found that schizophrenics had lower platelet MAO levels than controls. Administration of neuroleptic lowers MAO levels. MAO levels in drug-free schizophrenics were similar to controls. Only a minority of studies found drug-free schizophrenics had decreased platelet MAO levels.

Prediction of Suicidal Behavior from Biologic Tests

Biochemical studies related with suicidal behavior have mainly dealt with monoaminergic and corticosteroidal measures. We used some of these measures in a study of 61 suicide attempters who, except for occasional doses of benzodiazepines, had been medication free for a mean of 16 days. The monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylglycol were measured in lumbar cerebrospinal fluid (CSF). We found that violent suicide attempters (N = 18) had 5-hydroxyindoleacetic acid concentrations below the median of all patients, whereas the concentrations of 3-methoxy-4-hydroxyphenylglycol were mainly above the median. We found no significant differences between violent and nonviolent (N = 43) attempters concerning CSF homovanillic acid, 24-hour urinary norepinephrine-epinephrine and cortisol, activity of monoamine oxidase in platelets, or post-dexamethasone plasma cortisol. Four patients completed suicide, and 3 of them had CSF 5-hydroxyindoleacetic acid concentrations at or below the median. All completed suicides had CSF 3-methoxy-4-hydroxyphenylglycol concentrations above the median. Urinary measures and platelet monoamine oxidase activity of completed suicides were in the higher concentration ranges. Patients who repeated suicidal behavior after the index investigation had low 24-hour urinary cortisol levels more often than those who did not repeat. Because our subgroups of patients are small, we cannot draw any firm conclusions about the value of our CSF and urinary biochemical findings predicting suicidal behavior. However, our CSF findings in violent suicide attempters are similar to those observed in other studies.

Platelet monoamine oxidase (MAO) activity during an acute cluster headache episode : Aron D. Mosnaim, Shankar Huprikar, Marion E. Wolf, Seymour Diamond Chicago Medical School and N. Chicago VA Medical Center, Chicago, IL 60064

Platelet monoamine oxidase (MAO) activity during an acute cluster headache episode : Aron D. Mosnaim, Shankar Huprikar, Marion E. Wolf, Seymour Diamond Chicago Medical School and N. Chicago VA Medical Center, Chicago, IL 60064