DBH Activity Research Articles

肥満と血清Ｄｏｐａｍｉｎｅ‐β‐ｈｙｄｒｏｘｙｌａｓｅ活性

The relationship between obesity index and serum dopamine-β-hydroxylase (DBH) activity, which was considered to be a useful index as a sympathetic nerve activity, was examined on 55 males and 61 females over 19 years old who lived in Shiramine-village, Ishikawa Prefecture. The results obtained were as follows. 1) Frequency of obese persons, whose obesity indexes were over +10%, in females 2) Significant negative correlation between obesity index and serum DBH activity was observed in females. However, there was no significant correlations between them in males.was significantly high, compared with that in males. 3) The serum DBH activities in the obese females under 39 years old were significantly low, compared with that in non-obese females . The serum DBH activities in nonobese females tended to decrease with age. However, in obese females, the changes of the serum DBH activities with age were not observed. These results suggests that the sympathetic nerve activity in obese females might be depressed from youth.

Effect of Diabetic Hyperglycemia and Other Sugars on Plasma Dopamine-β-Hydroxylase Activity

The plasma glycoprotein, dopamine-beta-hydroxylase (DBH), is present in markedly increased amounts in experimental, streptozocin (STZ)-diabetic rats, reaching a maximum at about the first week and maintaining a plateau for several months afterward. High glycemia values are observed simultaneously. Insulin treatment is observed to keep the glycemia and plasma DBH activity values at levels seen in control rats. The heterologous half-life of DBH in STZ-diabetic rats is significantly increased compared with that of control animals. The glucose analogue, 2-deoxy-D-glucose, has a similar effect on plasma DBH activity levels, eliciting high glycemia values. In STZ-diabetic animals, this increase is more significant, as if it were the additive effect of the two sugars. Other sugars that can compete for glycoprotein catabolic receptors can also modulate the plasma DBH activity levels. The lack of effect of galactose on DBH levels, together with the induced increase of DBH by alpha-methyl-D-mannoside and, to a lesser extent, by inulin, suggest an important rate for the mannose/glucose/N-acetyl glucosamine/fructose receptor in the catabolic clearance of DBH from plasma and explain the abnormal values seen for DBH in diabetes mellitus.

Biochemical markers in the study of clinical effects and extrapyramidal side effects of neuroleptics

Neuroleptic treatment was instituted in 20 female schizophrenic patients, who had not received neuroleptics for at least the preceding 3 months. Both the therapeutic response to neuroleptics and the development of parkinsonian side effects were monitored in these patients. In addition, plasma dopamine-β-hydroxylase (DBH) and platelet monoamine oxidase (MAO) activities were measured. None of the neuroleptic responders developed parkinsonian symptoms. During the course of the 28-day treatment, there was a significant decrease in platelet MAO activity. There was a tendency for responders without parkinsonian symptoms to have lower plasma DBH activity than did nonresponders with parkinsonian symptoms.

Influence of sex steroids on the catecholamine biosynthesis in chromaffin tissue from rainbow trout, Salmo gairdneri

The in vitro activities of dopamine-β-hydroxylase (DBH) and phenylethanolamine- N-methyl transferase (PNMT) were determined in the chromaffin tissue (head kidney) of sex steroid-treated rainbow trout, Salmo gairdneri. In addition, the DBH and PNMT activities were measured in fish at different sexual states. Steroid treatment increased the wet weight of the head kidney, while both DBH and PNMT activities decreased. Although no sex difference in the enzyme activities was detected, a possible correlation between DBH and PNMT activities and increased GSI values was indicated. The presented data suggest that changes in sex steroids during development may affect the catecholamine synthesis in the chromaffin tissue in S. gairdneri.

A sensitive fluorometric assay for dopamine-β-hydroxylase activity by high-performance liquid chromatography

A sensitive and specific fluorometric assay for dopamine-β-hydroxylase (DBH) activity is described. The main natural substrate, dopamine (DA), was used and incubated under optimal conditions. Norepinephrine (NE) formed enzymatically from DA was isolated by an aluminum oxide column and was analyzed by high-performance liquid chromatography (HPLC) with trihydroxyindole fluorescence. Epinephrine (EN) was added to the incubation mixture as an internal standard after incubation, and this assay was therefore highly reproducible. HPLC conditions were settled to elute the product, NE, prior to the substrate, DA, and the internal standard, EN, between NE and DA. Only catecholamines produced significant peaks, and therefore, this assay is highly specific. We applied this method to measure the DBH activity in human serum and cerebrospinal fluid.

Dopamine-β-hydroxylase activities in serum and cerebrospinal fluid of aged and demented patients

Age-related changes in dopamine-β-hydroxylase (DBH) activities in serum and cerebrospinal fluid (CSF) were determined. In normal subjects, serum DBH activity increased gradually from the 3rd to the 8th decade, but decreased prominently in the 9th decade. DBH activity in CSF did not differ between younger and older subjects. Serum DBH activity decreased significantly in senile dementia of Alzheimer's type (SDAT, 12.2 ± 8.8 nmoles/min/ml , P < 0.05), but not in multi-infarct dementia (MID, 13.9 ± 9.1 nmoles/min/ml ) compared to control subjects ( 17.1 ± 9.5 nmoles/min/ml ). The decrease of serum DBH in SDAT was more prominent in patients with severe dementia and/or severe brain atrophy. DBH activity in CSF was much lower than that in serum and did not correlate with each other. DBH activity in CSF obained from SDAT patients ( 1.60 ± 0.94 nmoles/h/ml ) and from MID patients ( 2.01 ± 0.99 nmoles/h/ml ) were both lower than that from other neurological diseases without dementia ( 4.04 ± 3.81 nmoles/h/ml ). DBH in CSF from SDAT patients was significantly lower ( P < 0.05) than that from controls, but that from MID did not differ from controls. Noradrenergic nervous dysfunction is partly associated with pathophysiology and life expectancy of senile dementia of Alzheimer's type (SDAT).

Simultaneous evaluation of the catecholamine pathway and three opioid peptide producing systems in human pheochromocytomas

Tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) activities, dopamine (DA), noradrenaline (NA), adrenaline (A), met 5-enkephalin (Met-Enk), leu 5-enkephalin (Leu-Enk), dynorphin (Dyn) and β-endorphin (β-end) were measured simultaneously in ten human pheochromocytomas = 1. 1- TH activity was highly variable, from 22 to 2220 U/g tissue. 2. 2- DBH activity, in contrast, was rather constant, from 96 to 582 U/g. 3. 3- Catecholamines (A and NA) concentrations showed only small variations. 4. 4- The four opioid peptides were detected in all cases and exhibited a wide range of tissue concentrations (Enk ⪢ Dyn > β-end). 5. 5- Met-Enk and Leu-Enk concentrations were highly correlated; no correlation was observed with the other opioid peptides. 6. 6- A very strong correlation was observed between enkephalins concentrations and both catecholamines concentrations and DBH activities. These results are discussed in term of the significance of the co-localization of these various biologically active substances, principally with regard to the possible regulation of catecholamine synthesis by opioid peptides and conversely.

Adrenaline and noradrenaline neurons in rat lower brain stem: anatomical and pharmacological neurochemistry.

Since there was no study available on the comparative anatomical neurochemistry of the noradrenaline (NA) and adrenaline (A) containing neurons of the lower brain stem, we studied the distribution of the activities of the three major catecholamines (CA)-synthesizing enzymes in coronal sections of the rat medulla oblongata dissected into microcubes. In the dorso-medial region, there was a 1500 micron rostro-caudal difference in the localization of the peak of PNMT activity compared with the peaks of TH and DBH activities. This result led to a new microdissection technique allowing the preferential microdissection of the C2 A neurons versus the A2 NA neurons. The response of these two populations of CA neurons was then studied after a sustained decrease in blood pressure induced in young SHR by a 14 days dihydralazine treatment. The C2 adrenergic region exhibited an overall increase in TH, DBH and PNMT activity (+69%, +45% and +33%; p less than 0.01 respectively) while the A2 noradrenergic region was unaffected. Thus, the NA and A neurons of the rat dorso-medial lower brain stem do not seem to exhibit the same biochemical response after a prolonged hypotension. This preliminary result favors the hypothesis of a different functional role for the neighboring A2 and C2 neurons in central control of blood pressure.

Plasma dopamine-beta-hydroxylase in neuroblastoma.

Serum and plasma dopamine-beta-hydroxylase (DBH, E. C. 1. 14. 17. 1.) activity has been measured by several investigators in order to assess its value for the diagnosis of neural crest tumours. In children with neuroblastoma both elevated and normal values have been reported (Goldstein et al., 1972; Brewster et al., 1979). Recently Eldeeb et al. (1983) published evidence indicating that the DBH activity is related neither to the disease state nor to the urinary catecholamine output. These authors concluded that this enzyme has no diagnostic value and is poorly correlated to tumour growth. As shown below our results support the conclusions of Eldeeb et al. (1983) and suggest that the procedure used to determine serum DBH activities might be inadequate. For DBH assays a convenient spectrophotometric method, initially described by Nagatsu & Udenfriend (1972), has been widely used. The inability to detect low DBH activity levels in laboratory animals or in humans with genetically low DBH activity demonstrates, however, that this method lacks sensitivity. In addition strong interindividual variability was noticed (Weinshilboum, 1978). The original description of Nagatsu and Udenfriend's assay prescribes incubation of 2-50pl human serum or plasma diluted with water to 400p1 in a standard incubation mixture containing sodium acetate buffer (1moll-', pH, 5.0) 200p1; sodium fumarate (0.2 mol l-1) 50 pl; pargyline (20mmoll-') 50p; catalase (lmgml-') 50ul (= 1500 U); tyramine-HCl (0.4 mol -') 50 I1 and Nethylmaleimide (0.2 mol I1) 150 p1. A sample of a boiled enzyme preparation is run as a blank. After incubation at 37°C for 60min in a water bath with continuous shaking, the reaction is stopped by adding 0.2 ml of 3M trichloracetic acid. The mixture is centrifugated at 2000rpm for 10min. The supernatant is then transferred to a small column of Dowex 50 (H+, mesh 200-400) packed volume 0.2 ml which has been prepared in a

Time course study of changes in the activity of the catecholamine synthesizing enzymes in the rat medulla oblongata after intraventricular injection of 6-hydroxydopamine

Recent data have shown that 5 days after intraventricular injection of 6-hydroxydopamine (6-OHDA), the tyrosine hydroxylase activity (TH) was increased within the locus coeruleus (LC). We sought to determine if such an alteration occurs within the A1 and A2 noradrenergic (NA) and C1 and C2 adrenergic (A) neurons of the rat medulla oblongata. The TH activity within the cell bodies was significantly increased 2 days after 6-OHDA injection with a maximum at 5 days (LC, + 109%, P < 0.001;A1-C1, +40%, P < 0.01;A 2-C 2; + 24%, P < 0.01) while a significant decrease was present 21 days after 6-OHDA. Conversely, dopamine-β-hydroxylase (DBH) activity exhibited a decrease which was maximal at 21 days (LC, −41%;A1-C1, −33%,A2-C2, −35%, P < 0.001). Both the TH (−47% at 5 days) and the DBH (−82% at 12 days) activities were decreased within the terminals of the tractus intermediolateralis (TIML). The phenylethanolamine-N-methyltransferase (PNMT) activity was never altered in the cell bodies nor in the terminals analyzed. These data demonstrate that the NA neurons of the rat medulla oblongata and of the LC exhibit a similar pattern of response to the neurotoxin 6-OHDA. Conversely, the lack of change in the PNMT activity confirms the hypothesis of a resistance of the A neurons to 6-OHDA or questions the validity of the PNMT as an A marker.

Effects of hypophysectomy and cortisol on the catecholamine biosynthesis and catecholamine content in chromaffin tissue from rainbow trout, Salmo gairdneri

The in vitro activities of dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) were determined in the chromaffin tissue of hypophysectomized and cortisol-treated rainbow trout, Salmo gairdneri. In addition, the content of adrenaline and noradrenaline was estimated. DBH activity increased after both hypophysectomy and cortisol administration. The increased activity after hypophysectomy was restored with administration of pituitary extract, ADP. The PNMT activity seemed to increase slightly after hypophysectomy, while the activity remained unchanged after cortisol administration. A small decrease in catecholamine content was seen after hypophysectomy or treatment with cortisol but the A NA ratio was not changed. A regulation of the biosynthesis of catecholamines in trout chromaffin tissue is suggested and discussed in relation to mammalian conditions.

CSF dopamine beta-hydroxylase in schizophrenia.

Dopamine beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine, was measured in the CSF of 30 schizophrenic patients and 27 normal controls. The CSF DBH activity in the patients was not significantly different from that in controls. Levels of CSF DBH activity in individual patients were highly constant over time and were not influenced by clinical state or neuroleptic treatment. Low levels of DBH in CSF did significantly relate to good social and sexual functioning, good prognosis, less symptoms between hospitalizations, and excellent clinical response to neuroleptic treatment. We speculate from these data that low brain DBH activity may produce a type of vulnerability to psychotic decompensation and thereby influence the clinical course, although it does not cause schizophrenia, in general. Low CSF DBH activity may delineate a "reactive" subgroup from the heterogenous population of patients with diagnoses of schizophrenia.

Comparative analysis of indices of central dopaminergic functions in man

Various postulated indices of central dopaminergic activity - cerebrospinal fluid (CSF) dopamine (DA), dihydroxy-phenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), plasma NA, serum prolactin, serum dopamine-β-hydroxylase (DBH), and platelet monoamine oxidase (MAO) activity - were measured in 30 drug-free inpatients. The mean values and the ranges were similar to those described in the literature. Plasma NA showed significant positive correlation with age. Significant positive correlation was found between CSF DA and its metabolites DOPAC and HVA. Serum DBH activity showed a slight but significant inverse correlation with CSF DA and its two metabolites. CSF NA showed a significant positive correlation with CSF DOPAC, but only in females. Serum DBH activity had no significant correlation either with CSF or with plasma NA levels. These findings suggest that either CSF HVA or DOPAC and DA may be useful indicators of DA metabolism in humans. Serum DBH activity may be in relationship with the central dopaminergic functions.

DBH inhibitory factors of brain tissue.

In vivo turnover of NA in the brain is considerably high, but in vitro only a low activity of the enzyme DBH is detectable. It is supposed that this effect is brought about by endogenous enzyme inhibitors. It was demonstrated that the addition of rat brain homogenate, as well as different subcellular fractions from rat brain, inhibit the human serum DBH. Inhibitory activity is resistant to heat and acid but does not seem to be uniformly distributed within the cell. Pretreatment of brain homogenate with pronase reduced its inhibitory activity. In conclusion, pronase sensitive peptides are partially responsible for the inhibitory potency of tissue homogenates.

Distribution of tyrosine hydroxylase, dopamine-β-hydroxylase and phenylethanolamine-N-methyltransferase activities in coronal sections of the rat lower brainstem

The activities of the three major catecholamines synthesizing enzymes were determined on supernatants from microcubes dissected out from 500 μm thick coronal sections of the rat lower brainstem. The microcubes exhibiting significant or high enzymatic activities represented only one-third of the microcubes analyzed and were generally localized either in the dorso-medial or in the ventro-lateral region of the lower brainstem. In the ventro-lateral region, referred to as the A 1-C 1 region, the rostro-caudal distribution of the enzymatic activities exhibited a small difference between the maximal TH and DBH activities and the maximum PNMT activity located 500 μm more rostrally. Conversely, in the dorso-medoal region, referred to as the A 2-C 2 region, there was a much larger rostro-caudal difference (about 1500 μm) between the peaks of TH and DBH activities and the more rostral peak of PNMT activity. Such a distribution suggests a separation between the adrenaline (A) and the noradrenaline (NA) containing neurons within the dorso-medial region. According to the results of this study, a preferential microdissection of the A versus NA neurons seems possible in the A 2–C 2 region of the rat medulla oblongata.

Serum dopamine β-hydroxylase activity in non-human primates: phylogenetic and genetic implications

1. Serum dopamine β-hydroxylase (DBH) activity is one to two orders of magnitude higher in man than in any other species previously studied. The high levels of human serum DBH are associated with the inherited allele DBH H. 2. DBH activity was measured in serum from gorillas, chimpanzees, orangutans, gibbons, rhesus monkeys and squirrel monkeys in an attempt to determine how recently in the course of evolution the allele DBH H had originated. 3. Of the non-human primates tested, only gorillas had high levels of serum DBH activity comparable to those found in man. 4. The genetic polymorphism responsible for elevated serum DBH in man is probably of very recent evolutionary origin.

The effect of pentylenetetrazol on the levels of dopamine-β-hydroxylase in the cerebrospinal fluid of rabbits: A dose-dependent relationship

The effect of various doses of pentylenetetrazol (PTZ) on the levels of dopamine-β-hydroxylase (DβH) and acetylcholinesterase (AChE) in the CSF of rabbits was studied. The drug augments in a dose-dependent manner the DβH activity but causes only a small and dose-independent increase in AChE. This suggests that PTZ-induced convulsions are associated with an increase in central noradrenergic activity but not by an increase in central cholinergic activity.

Reduced serum dopamine-beta-hydroxylase activity in paranoid schizophrenics.

The serum dopamine-beta-hydroxylase activity of 134 carefully selected paranoid schizophrenic patients was compared with that of 118 normal controls. Significantly reduced serum DBH activity found in the schizophrenic group in comparison to the control group could not be brought into relationship with the patients' age, nor with neuroleptic treatment. Manic depressive patients showed values similar to the normal control group. It is discussed that mainly genetically determined low serum DBH activity may be related to the hyperdopaminergic pathomechanism of paranoid schizophrenia.

An Attempt to Evaluate Autonomic Nervous Functions in Workers Exposed to Vibration : Respiratory Arrhythmia and Serum DBH Activities

An Attempt to Evaluate Autonomic Nervous Functions in Workers Exposed to Vibration : Respiratory Arrhythmia and Serum DBH Activities

Stress-induced changes in in vivo and in vitro dopamine-β-hydroxylase activity in spontaneously hypertensive rats

The in vivo dopamine-β-hydroxylase (DBH) activity in peripheral tissues of the whole animal and the in vitro DBH activity in serum, adrenal glands, peripheral sympathetically innervated tissue, and brain were examined in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) at 12 weeks of age before and after daily immobilization stress. In vitro DBH activity did not differ significantly between SHR and WKY before stress, but in vivo DBH activity in SHR was significantly lower than that in WKY. After repeated immobilization stress, in vivo DBH activity was significantly elevated only in SHR but not in WKY. In vitro DBH activity in serum, adrenal gland, vas deferens, and brain was also significantly increased in SHR, whereas that in WKY was increased only in adrenal glands. These results suggest that SHR at 12 weeks of age, when hypertension is established, may have even lower sympathetic nerve activity than WKY, and that after repeated stress the response of the sympatho-adrenal system is higher in SHR than in WKY.