Serum dopamine- -hydroxylase (D H) activity and affective states

Serum dopamine-beta-hydroxylase activity in clinical subtypes of depression

Serum dopamine-beta-hydroxylase (DBH) activity was determined in male adult psychiatric patients (n = 280) and age-matched male healthy controls (n = 100). Patients included in the study had no history of previous or current exposure to psychoactive drugs and were diagnosed according to Research Diagnostic Criteria. A significant decrease in serum DBH activity was noted in patients with psychotic major depressive disorder (n = 50) as compared with controls. In acute schizophrenics (n = 100), nonpsychotic major depressives (n = 45) and patients with manic disorder (n = 85), mean DBH activity did not differ significantly from the control values.

Serum dopamine-beta-hydroxylase activity in patients with major depressive disorders

The dopamine-beta-hydroxylase (DBH) activity in serum was assayed in 32 acutely ill inpatients with major disorder and in 33 healthy control subjects. Twenty-six of these patients were also studied in a state of remission. The DBH activity was compared to the serum levels (studied during a 24 h period) of T4, T3, TSH, prolactin and melatonin as well as to the outcome of the dexamethasone suppression and TRH test and to various clinical symptoms, as estimated by different rating procedures. No significant differences in DBH activity were found between the acutely ill patients, patients in remission, or normal subjects. Thus, the determination of the activity does not seem to be of practical importance as a laboratory diagnostic tool for major depressive disorder. A significant positive correlation was found between the DBH activity and the TSH levels, estimated by several parameters during the 24 h period, in the acutely ill patients, whereas no significant correlation was found in patients in remission or in the normal subjects. No significant correlation was found between the DBH activity in any group and the other laboratory or clinical parameters. The mechanism behind the significant correlation between the DBH activity and TSH levels remains to be clarified.

A comprehensive study of chronic schizophrenic patients. II: Biological, neuropsychological, and clinical correlates of CT abnormality

There are numerous reports of lateral cerebral ventricle enlargement on computed tomography (CT) in schizophrenics, but the significance and its relationship to traditional notions of organicity remain unclear. Therefore we studied a subgroup of chronic schizophrenics who had lateral ventriculomegaly (and also cortical hyperdensity) on a battery of relevant biological, neuro-psychological, and clinical parameters such as electroencephalogram (EEG), platelet monoamine oxidase (MAO) and serum dopamine-beta-hydroxylase (DBH) activity, the Halstead Reitan Neuropsychological Battery (HRB), premorbid personality adjustment, drug response, positive and negative symptoms, employment history, and family history. Our findings support the notion that there is an "organic" subgroup of schizophrenia that has 1) CT structural abnormalities such as lateral ventricle enlargement and cortical hyperdensity; and cerebral dysfunction or deficits as evidenced by 2) an increased incidence of abnormal EEGs and also 3) greater impairment on neuropsychological tests. The biochemical measures, platelet MAO and serum DBH activity, nor any of the clinical measures could differentiate between the subgroups. The implications of these findings for the subtyping of schizophrenia are discussed.

Studies on biogenic amine metabolizing enzymes (DBH, COMT, MAO) and pathogenesis of affective illness. I. Plasma dopamine-beta-hydroxylase activity in endogenous depression

On the basis of studies carried out with a group of 47 patients with endogenous depressive illness, lower plasma activity of dopamine-beta-hydroxylase (DBH) was found as compared with a control group (31 healthy persons). Lower DBH activity particularly characterized bipolar patients. Lowest DBH activity was found in patients with a family history of psychiatric disorders, in particular, affective illness (in comparison with the control group the difference was statistically significant, P less than 0.05). It was noticed, that in a period of remission or significant improvement the enzymatic activity increases, although in some cases the level of activity is still lower than in the control group. There was a correlation between activity of the enzyme and clinical course of the illness and susceptibility to antidepressive drugs. Most of the observed phenomena are related to male patients. On the basis of these studies and data supplied by corresponding literature, concerning in particular the effects of DBH inhibitors (fusaric acid, disulfiram), the authors consider that changes in DBH activity may play a role in the pathogenesis of depression and that DBH deserves further studies, also of genetic nature.

Schizophrenia: dopamine beta-hydroxylase activity and treatment response

Cerebrospinal fluid levels of dopamine beta-hydroxylase, found to be relatively constant over time in individual patients, were significantly lower in schizophrenic patients who became nonpsychotic during neuroleptic treatment than in those who remained psychotic. Dopamine beta-hydroxylase activity may delineate a subgroup of patients who have a dopamine-sensitive brain disorder.

Depression, antidepressants, and plasma DBH

Plasma levels of dopamine-beta-hydroxylase (DBH) were determined in 16 unmedicated patients with major depressive episodes (nonpsychotic) and in an equal number of normal subjects, before and after 4 weeks of treatment with tricyclic antidepressants. Some eight patients were treated with amitriptyline, and the remainder received desipramine. The controls remained medication free during the entire experimental period. Degrees of depression were quantified before and after treatment with the Hamilton Rating Scale of Depression (HRSD). There were no significant differences between the depressed patients and the controls on levels of DBH. Similarly, there were no within-group, pre-posttreatment differences on the enzyme levels in either group. Pre- and posttreatment HRSD scores did not correlate with corresponding plasma DBH levels. Plasma levels of amitriptyline, nortriptyline (product of amitriptyline in the body), and desipramine at the end of 4 weeks of treatment also failed to correlate with the enzyme levels.

Dopamine-beta-hydroxylase and its apparent endogenous inhibitory activity in the plasma of some psychiatric patients

The "apparent" and "absolute" levels of dopamine-beta-hydroxylase (DBH) in 62 psychiatric patients and 20 healthy control subjects have been investigated. No significant differences could be detected between control subjects and patients diagnosed as schizophrenic, unipolar depressive and bipolar depressive, when DBH was assayed in the presence of the anti-inhibitors Cu++ and N-ethylmaleimide (i.e., "absolute" DBH activity). In the absence of these anti-inhibitors, however, the levels of plasma DBH (i.e., "apparent" DBH activity) were considerably reduced in all cases, with the schizophrenic group also being significantly reduced (p less than 0.02) in comparison with the control group.

Reassessing the bipolar-unipolar dichotomy

This paper is a critical review of the literature on the dichotomous classification of affective disorders into unipolar and bipolar types. The majority of genetic studies show significant overlap in the liability to develop two forms of illness, and the majority of lithium studies show a similar clinical responsiveness of both groups to both acute and maintenance treatment. Biological studies comparing the two groups are difficult to interpret as most have compared manics to depressives without controlling for motor activity, excitement, and other state-dependent clinical variables. Viewed in light of our research findings in a recent genetic study of affective states, we believe these data suggest that the separation of affective disorders by polarity may have been premature, and that the search for heterogeneity should now be carried out using alternative strategies.

Dopamine beta-hydroxylase in health and disease

DBH is a copper-containing oxygenase that catalyzes the hydroxylation of the beta carbon of a wide variety of phenylethylamine derivatives using molecular oxygen ascorbate as cofactors. It is a glycoprotein with a molecular weight of 290,000 and consists of four identical subunits, each with a single copper atom and 5% carbohydrate by weight. The enzyme is a constituent of catecholamine storage vesicles in chromaffin cell and adrenergic neurons in the peripheral and central nervous system where it functions to synthesize noradrenaline from dopamine. Although endogenous inhibitors have been isolated, they have not been demonstrated to have a physiological function, and the kinetics of the enzyme in vitro and in vivo suggest that the enzyme is not a rate limiting step in catecholamine synthesis under normal conditions. DBH exists in both a soluble form within vesicles and as a constituent of their membranes with its active site directed inward. The significance of the partition of the enzyme into soluble and membrane forms is not understood, although the soluble form has a fivefold greater homospecific activity. DBH has been one of the most intensively investigated enzymes in neurochemistry for several reasons. It is a readily assayable constitutent of catecholamine storage vesicles and, as such, provides a convenient biochemical marker for subcellular fractionation work and studies of the cellular regulation of catecholamine synthesis, storage, and release. The adrenal medulla is a rich source of the enzyme for purification, and the purified enzyme is highly antigenic, thereby enabling the use of several immunological techniques to study the cellular dynamics of the enzyme and the organelles in which it is located. These include radioimmunoassay, immunohistochemistry, and cytochemistry. This review firstly summarizes the present state of knowledge concerning the molecular properties of DBH. It then describes the tissue, cellular, and subcellular localization of the enzyme and its physiological regulation. The remainder of the review concentrates on those aspects of research on DBH in which the authors have participated that have led to general advances such as the development of the concept of homospecific activity, the introduction of immunohistochemistry for the localization of enzymes involved in transmitter metabolism, the release of macromolecules from synaptic vesicles during the process of exocytosis, the use of antibodies to DBH administered in vivo to study the fate of synaptic vesicle membranes and to produce specific immunological lesions of noradrenergic nerves in the peripheral and central nervous system, the genetic, environmental, and physiological determinants of serum DBH activity as an index of sympathetic function in animals and man, and the question of its diagnostic value in disease.

Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients

The peripheral interactions of amphetamine with antipsychotic agents may elucidate some central mechanisms by which these drugs affect the behavioral responses to amphetamine. The authors studied the effects of intravenous amphetamine on plasma levels of norepinephrine (NE), dopamine-beta-hydroxylase (DBH), pulse rate, and blood pressure in schizophrenic patients. Amphetamine increased plasma NE, pulse rate, and blood pressure without significantly changing plasma DBH. DBH activity was similar in drug-free schizophrenic and normal subjects. Neither pimozide nor lithium altered these amphetamine effects nor changed any of the cardiovascular parameters measured in the drug-free subjects. Pimozide and lithium alter behavior and the behavioral effects of amphetamine, but neurotransmitters other than NE may be involved.

Some neuroendocrine parameters in bipolar and unipolar depression

There is mounting evidence showing that some pituitary and hypothalamic hormones play an important role in the affective disorders and may directly affect brain function and behavior. This report briefly reviews some recent endocrinological studies in affective illness with special reference to bipolar and unipolar form of illness. Data on prolactin and growth hormone response to levodopa in bipolar and unipolar illness presented. Preliminary data on plasma dopamine beta hydroxylase activity measured over a 24-h period are illustrated in patients suffering from bipolar and unipolar illnesses as compared to controls. The significance of these results is discussed in relation to biogenic amine dysfunction in the major affective disorders.

Serum dopamine-beta-hydroxylase in psychiatric patients and normals. Effect of d-amphetamine and haloperidol

Serum dopamine-beta-hydroxylase activity was estimated in groups of normals and of psychiatric patients, using a thin layer radiochromatographic method. The percentage of patients with schizophrenic and with depressive symptomatology was higher in the population with high enzyme activities. In addition, d-amphetamine given to normals caused an increase in the serum activity while haloperidol caused the opposite effect. The activity in serum is interpreted as a loss in the enzyme from the place it acts physiologically, with possible influence on the noradrenaline synthesis rate.

Plasma dopamine beta hydroxylase activity in affective disorders

Plasma dopamine beta hydroxylase (DBH) activity was measured in patients with affective disorders and in their relatives. The groups studied had wide distributions of values for plasma DBH activity. No significant difference of plasma DBH activity was found between unipolar and bipolar patients, nor between patients given lithium or placebo. Exercise on a treadmill at 40 degrees or 10 degrees C elicited a different pattern of response for plasma DBH activity in three patients as compared to control subjects. In familial studies we found the values of plasma DBH activity to be almost identical in monozygotic twin pairs and quite similar in dizygotic twin pairs. All pairs, however, were discordant for affective illness. There was also a marked similarity of plasma DBH activity in 15 pairs of the same sex sibs discordant for affective illness. These studies suggest that the resting level of plasma DBH activity is not related to affective illness but is genetically determined.

Dopamine beta-hydroxylase activity in brains of chronic schizophrenic patients

Postmorten brain specimens from nine chronic schizophrenic patients and nine control were assayed for activity of dopamine beta-hydroxylase, the enzyme responsible for the conversion of dopamine to norepinephrine. Unlike the results of previous reports, there was no statistically significant difference in enzyme activity between the patient and control groups. There were, however, significant negative correlations between dopamin beta-hydroxylase activity and the tim spent in the morgue before autopsy, and between enzyme activity of schizophrenics and dosage of chlorpromazine or its equivalent.

Human circulating dopamine-beta-hydroxylase and epilepsy

The activity of circulatory dopamine-beta-hydroxylase (DBH) in humans is shown to be lower in some epileptic subjects than in normal subjects. The activity of the enzymes was found to be dramatically low in subjects who experienced an epileptic seizure 24 hrs before DBH activity was determined. The activity varied through the course of epileptic seizures induced by a convulsant drugs and these variations might be due to the "en masse" changes of the sympathetic nervous system.

A genetic study of plasma dopamine beta hydroxylase activity in man

Plasma dopamine beta hydroxylase (DBH) activity was determined in MZ twins and in siblings of both sexes. The enzyme activities were found to be virtually identical in MZ twins. DBH activity was less similar in same-sex sibs, but still significantly correlated. These results indicate that plasma DBH activity is genetically determined.