Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Histamine N-Methyltransferase”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

Conformationally restricted analogs of histamine H1 receptor antagonists: trans and cis-1-benzyl-3-dimethylamino-6-phenylpiperidine.

The syntheses of trans- and cis-1-benzyl-3-dimethylamino-6-phenylpiperidine (1 and 2) are described. Compounds 1 and 2 were found to be inhibitors to histamine, acetylcholine, and barium chloride induced contractions of the isolated guinea pig ileum. Compounds 1 and 2 do not exhibit appreciable stereoselectivity in their ability to inhibit smooth muscle contractions. The cis compound 2 is a more effective inhibitor of histamine N-methyltransferase than the trans isomer 1.

Acetylcholine↗
PubMed1977

Delayed cold-induced urticaria: a dominantly inherited disorder.

A delayed cutaneous response to cold, characterized by areas of erythematous, edematous deep swelling at 9 to 18 hr after experimental ice challenge, was recognized in a 10-yr-old boy and several members of his family. Biopsy of the cold-induced lesion showed edema and an infiltrate of mononuclear cells; mast cells were normal, and immunoglobulins, complement factors, and fibrin were not detected by immunofluorescence techniques. Local cold challenge did not release histamine or induce alterations in the complement system or the enzymes, histaminase, and histamine methyl transferase. The delayed cutaneous response to cold could not be passively transferred with serum or tissue extracts to monkey skin. Family studies suggested an autosomal-dominant mode of inheritance.

Amine Oxidase (Copper-Containing)↗
PubMed1978

A clinical study of concanavalin A-induced histamine release utilizing a single isotopic enzymatic assay of histamine.

Concanavalin A (Con A)-induced histamine release from cells of subjects with extrinsic asthma, intrinsic asthma or urticaria and normal individuals was examined utilizing a single isotopic enzymatic assay for histamine. Maximum histamine release by Con A occurred with 0.9 to 4.5 microgram/ml. The mean percentage of maximum histamine release by Con A from cells of donors with extrinsic asthma was 36(+/- 19.3)% while that from cells of normal individuals was 21.4(+/- 23.7)%. However, there was no significant difference between the two groups. The higher reactivity to Con A of cells from individuals with intrinsic asthma or urticaria was not observed compared to that of the normal group. The histamine release by Con A was not correlated with IgE level in the plasma (r = 0.35). It was observed that compound 48/80 inhibited the enzymatic reaction in the isotopic, enzymatic assay.

Asthma↗
PubMed1978

[Histamine and its role in peptic gastric diseases: the discovery of histamine-H2-receptor antagonists].

For the definition of histamine receptors the following prerequisites must be fulfilled: (1) Course of dose-response curves according to the mass-action law; (2) parallel displacement of these curves to the right in the presence of antagonists; (3) inhibition only by specific histamine antagonists; (4) slope of a Schild-plot not significantly different from unity. For H2-receptors these prerequisites could ideally be fulfilled, especially by the development of highly specific H2-receptor antagonists. However, this new class of compounds acts not only by mere competitive inhibition of histamine at its H2-receptor, but also by activating the metabolism of this secretagogue. A further explanation of the action of H2-receptor antagonists in the treatment of chronic duodenal ulcer may be given by studying the pathogenetic role played by histamine in the development of this disease: duodenal ulcer patients showed an increased liberation of histamine from mucosal mast cell stores as well as a decreased activity of histamine methyltransferase (i. e. longer action of histamine!). The rise in histamine content and histamine methyltransferase activity after vagotomy may be the basis for a biochemical explanation of the acid-reducing effect of this operation.

Animals↗
PubMed1979

An improved radioenzymatic assay for histamine in human plasma, whole blood, urine, and gastric juice.

A radioenzymatic method suitable for the assay of histamine in human blood, urine, plasma, and gastric juice is described. It differs from earlier methods by use of a histamine methyltransferase preparation from pig brain, of high activity tritiated S-adenosylmethionine, and of a heat precipitation step to reduce the previously noted interference from plasma constituents. The method is simpler than those requiring solvent extraction and concentration of histamine, gives recoveries in the range 80-120%, and so sliminates the need for internal standardisation. The method is sensitive and precise with coefficients of variation for blood, urine, and plasma of 5%, 6%, and 13% respectively. The mean +/- standard deviation for normal human plasma histamine is 5 +/- 4 nmol/l, for whole blood 559 +/- 193 nmol/l, and for urine 229 +/- 128 nmol/24h.

Animals↗
PubMed1976

Effect of surgical isolation of the hypothalamus on its neurotransmitter content.

The concentrations of norepinephrine, dopamine-beta-hydroxylase, dopamine, tyrosine hydroxylase, phenylethanolamine-N-methyltransferase, serotonin, tryptophan hydroxylase, histamine, glutamic acid decarboxylase, and choline acetyltransferase were determined in selected hypothalamic nuclei and in the median eminence after deafferentation of the medial basal hypothalamus. Norepinephrine and dopamine-beta-hydroxylase fell markedly while dopamine and tyrosine hydroxylase did not. Serotonin also decreased in all regions studied; histamine decreased in none. Choline acetyltransferase, phenylethanolamine-N-methyltransferase, and glutamic acid decarboxylase declined in some areas, but not in others.

Animals↗
PubMed1976

Distribution of releasing factors, biogenic amines, and related enzymes in the bovine median eminence.

The bovine median eminence was dissected into eight different subdivisions: rostral, anterior internal, anterior external, middle external medial, middle external lateral, middle internal medial, middle internal lateral, and caudal. Thyrotropin-releasing hormone (TRH) was found in the highest concentrations in the middle external medial and lateral subdivisions; luteinizing hormone-releasing hormone (LHRH) was concentrated in the middle external lateral and anterior internal subdivisions. Among the various neurotransmitters and enzymes assayed, only dopamine and choline acetyltransferase were present in highest concentrations in the same subdivisions of the bovine median eminence found to be rich in TRH and LHRH. The distributions of norepinephrine, dopamine-beta-hydroxylase, serotonin, tryptophan hydroxylase, phenylethanolamine-N-methyltransferase, glutamic acid decarboxylase, and histamine appeared to correlate poorly with the major distributions of TRH and LHRH. These findings suggest that at the level of the median eminence, central neuroendocrine regulation of TRH and LHRH release may involve an interaction only with dopamine and acetylcholine.

Animals↗