Dopamine beta-hydroxylase: biochemistry and molecular biology.

Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to norepinephrine (NE), and is known to exist in two forms: soluble and membrane-bound. It has been reported that the two forms are similar in their immunoreactivity, carbohydrate content, and binding affinities for various substrates, and are apparently dissimilar in subunit structures and hydrophilicity. Furthermore, added structural complexity is observed within sDBH itself.

Dopaminergic cells in the caudal A13 cell group express somatostatin-like immunoreactivity.

The caudal extension of the hypothalamic A13 dopamine cell group (A13c) was studied in the rat brain with immunohistochemical techniques using antibodies raised against the dopamine synthesizing enzymes tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). Adjacent sections revealed that the TH- and AADC-staining patterns exhibited a clear overlap with that for somatostatin (SOM). Employing a double-labelling method with SOM- and AADC-antisera and subsequent elution and restaining of the same section with TH-antiserum, it was found that all immunoreactivities occurred in the same cell bodies.

Catecholamine-synthesizing enzymes in the rat pituitary. An immunohistochemical study.

The catecholamine-containing nerve fibers of the rat pituitary were studied by immunohistochemical demonstration of the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). Immunohistochemical demonstration of TH confirms earlier catecholamine fluorescence histochemical studies showing a fine network of varicose fibers in both the intermediate and the neural lobe, with the most dense aggregation of fibers at the border between the lobes. DBH-immunoreactive fibers were much less in number, and confined to the neural lobe, where both vascular and parenchymal fibers were seen.

Pulmonary arterial pressure and plasma concentration of atrial natriuretic factor (ANF) in patients with heart disease.

To study the factors controlling the release of atrial natriuretic factor (ANF), we analyzed the peripheral plasma ANF concentration in 34 patients with heart disease who underwent cardiac catheterization. A significant positive correlation between plasma ANF concentration and pulmonary arterial pressure (systolic, r = 0.87; diastolic, r = 0.

Tyrosine hydroxylase is expressed by neocortical neurons after transplantation.

Tyrosine hydroxylase [TyrOHase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.

Tyrosine hydroxylase in the rat parabrachial region: ultrastructural localization and extrinsic sources of immunoreactivity.

We sought to determine the ultrastructural localization and the extrinsic sources of the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), in the lateral parabrachial region (PBR) of adult male rats. In the first portion of the study, a rabbit antiserum to TH was immunocytochemically localized in coronal sections through the lateral PBR from acrolein-fixed brains using the peroxidase-antiperoxidase method. Electron-microscopic analysis revealed that perikarya and dendrites with peroxidase immunoreactivity for TH constituted only 17% of the total labeled profiles.

Complete nucleotide and deduced amino acid sequence of bovine phenylethanolamine N-methyltransferase: partial amino acid homology with rat tyrosine hydroxylase.

We report here the isolation of a cDNA clone containing the full coding region of bovine phenylethanolamine N-methyltransferase (PNMTase, EC 2.1.1.

Postnatal developmental changes of tryptophan hydroxylase activity in serotonergic cell bodies and terminals of rat brain.

Tryptophan hydroxylase (TPH) is the rate limiting enzyme in serotonin biosynthesis, so its development is very important to the functional maturation of the serotonergic neurons. In the present study, we examined changes of TPH activity in serotonergic cell bodies and terminals of rat brain during postnatal development. TPH activity reached its peak in the cell body regions at 24 days after birth, while the enzyme activity in a terminal region rose to its plateau at day 30.

Physiological concentrations of human epidermal growth factor in biological fluids: use of a sensitive enzyme immunoassay.

A sandwich enzyme immunoassay for epidermal growth factor (EGF) has been developed which measures EGF concentrations in serum, urine, saliva, gastric and pancreatic juices without pretreatment. Sensitivity for human EGF is 500 fg/tube. Serum EGF concentration in normal males and females is 780 and 604 pg/ml, respectively.

Strain-specific differences in levels of the mRNA for the epinephrine synthesizing enzyme phenylethanolamine N-methyltransferase.

The activity of the epinephrine biosynthetic enzyme phenylethanolamine N-methyltransferase (PNMT, EC 2.1.1.

Specific lysis of noradrenergic synaptosomes by an antiserum to dopamine-beta-hydroxylase.

An antiserum to dopamine-beta-hydroxylase purified from bovine adrenal medulla, acting in the presence of complement, caused the release of 12% of lactate dehydrogenase, 20% of tyrosine hydroxylase activity, and 40% of noradrenaline (NA) content from synaptosomes prepared from rat brain cerebral cortex. Uptake of [3H]NA was reduced by 54%. Anti-serum alone or complement alone were without action.

Distribution of tyrosine hydroxylase and neuropeptide Y-like immunoreactive neurons in rabbit medulla oblongata, with attention to colocalization studies, presumptive adrenaline-synthesizing perikarya, and vagal preganglionic cells.

We studied the distribution, within the rabbit medulla oblongata, of neuronal cell bodies containing either tyrosine hydroxylase or neuropeptide Y-like immunoreactivity. Both avidin-biotin and immunofluorescence procedures were used. Because the two primary antibodies were raised in different species it was possible to perform simultaneous colocalization studies with the immunofluorescence procedure.

Strain differences in distribution of phenylethanolamine N-methyltransferase activity from rat brain and adrenal gland.

Phenylethanolamine N-methyltransferase (PNMT) activity was measured in adrenal glands and medulla oblongata from 4 inbred rat strains, Fischer 344, Buffalo, Lewis and Sprague-Dawley rats. Adrenal enzyme activity was markedly different among the strains with the highest in Fischer, followed by Sprague-Dawley, Lewis and Buffalo rats in decreasing order. In medulla oblongata, the PNMT activity of Buffalo rat was the lowest being about one half of that of the other strains.

Different charge forms of aromatic-L-amino-acid decarboxylase.

The isoelectric points (pI) of aromatic-L-amino-acid decarboxylase (AADC) from two species, rat and cow, were determined by chromatofocusing. The enzyme from both rat brain and adrenal has a pI of 5.5, while the bovine adrenal enzyme has a different pI of 5.

Effects of cyclic nucleotides, betazole hydrochloride and acetylcholine on pepsinogen secretion from isolated rabbit gastric mucosa.

The effects of dibutyryl cyclic AMP (db-cAMP), dibutyryl cyclic GMP (db-cGMP), betazole hydrochloride (betazole) and acetylcholine (ach.) on pepsinogen secretion from isolated rabbit gastric mucosa were studied using an organ culture system. The 10(-3) M db-cAMP, but not db-cGMP of any concentration, produced a significant enhancement of pepsinogen secretion into the culture medium.

Injury of nigral neurons exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine: a tyrosine hydroxylase immunocytochemical study in monkey.

Six monkeys treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine developed a Parkinsonian syndrome (rigidity, akinesia, flexed posture and tremor). In both high and low dose groups, neurons in the substantia nigra were selectively damaged. At high dose levels, nigral neurons were severely damaged, but because the monkeys died, the evolution of the pathology could not be studied.

Phenylethanolamine N-methyltransferase-containing neurons in rat retina: immunohistochemistry, immunochemistry, and molecular biology.

We sought to characterize in detail neurons in rat retina that contain phenylethanolamine N-methyltransferase (PNMT), the epinephrine biosynthetic enzyme. Cell bodies and processes of PNMT-containing neurons in retina were identified by immunohistochemistry. The coexistence of other catecholamine biosynthetic enzymes in the same cells was also investigated.

Ultrastructural localization of phenylethanolamine N-methyltransferase in sensory and motor nuclei of the vagus nerve.

The ultrastructural localization of phenylethanolamine N-methyltransferase (PNMT), the enzyme used in the final step in the synthesis of adrenaline, was examined in the medial nuclei of the solitary tracts (m-NTS) and in the dorsal motor nuclei of the vagus. Adult rats were anesthetized with Nembutal (50 mg/kg intraperitoneally), and the brains were fixed by vascular perfusion with a solution containing 3.75% acrolein and 2% paraformaldehyde in 0.

The adrenal: a new target organ of the calciotropic hormone 1,25-dihydroxyvitamin D3.

Target cells for 1,25-dihydroxyvitamin D3 were demonstrated in the adrenal medulla by frozen-section autoradiography. The appearance of these target cells was age-dependent in neonatal mice. Immunocytochemical staining for phenylethanolamine-N-methyltransferase revealed that both epinephrine and non-epinephrine cells concentrate 1,25-dihydroxyvitamin D3 in their nuclei.

Evidence that catecholamine-synthesizing perikarya in rat medulla oblongata do not contribute axons to the vagus nerve.

We attempted to confirm reports that medullary catecholamine-synthesizing neurons in the rat contribute axons to the vagus nerve. Vagal preganglionic neurons in the medulla were identified by the retrograde intra-axonal transport of Fast Blue from the cervical vagus. Catecholamine-synthesizing neurons were identified using a specific antibody against tyrosine hydroxylase.

Catecholaminergic neurites in senile plaques in prefrontal cortex of aged nonhuman primates.

Immunocytochemical studies, using a polyclonal antibody directed against tyrosine hydroxylase, identified catecholaminergic axons in prefrontal cortex of young and aged nonhuman primates. Aged monkeys, who showed cortical senile plaques in silver stains, had swollen tyrosine hydroxylase-immunoreactive axons in neocortex. Some of these abnormal processes were associated with deposits of amyloid (visualized by thioflavin-T fluorescence) and were similar in appearance to neurites demonstrated by silver impregnation methods.

Species-specific charge forms of phenylethanolamine N-methyltransferase.

Isoelectric points (pI) of phenylethanolamine N-methyltransferase (PNMT) from two species, cow and rat, were determined by chromatofocusing. Bovine PNMT has 5 different charge isozymes ranging from 5.4 to 6.