Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The inhibitory effects of clonidine and guanfacine on antigen-induced histamine release from human basophils and mast cells and on bronchial muscle tension were compared. Clonidine, but not guanfacine inhibited the antigen-induced histamine release from human basophils and mast cell preparations. This effect of clonidine was prevented by an H2-antagonist, cimetidine. Clonidine and guanfacine, like norepinephrine, inhibited the twitch contraction of electrically stimulated human segmental bronchi by stimulation of alpha 2-adrenoceptors. Clonidine and guanfacine had no effects on the basal bronchial muscle tone, but in very high concentrations they could reduce a carbacholine-induced bronchial tone. It is suggested that the inhibitory effects of clonidine on allergic reactions and on exicitatory nerve transmission in human airways may be useful in the treatment of asthmatic patients.
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PMID:Comparison of the effects of clonidine and guanfacine on the histamine liberation from human mast cells and basophils and on the human bronchial smooth muscle activity. 244 13

We examined agmatine and imidazoline derivatives as putative ligands of trimeric G protein in rat peritoneal mast cells. Agmatine induced a concentration-dependent and pertussis toxin-sensitive secretion of histamine (exocytosis) and arachidonate. Clonidine and idazoxan had no effect. Blockage of Gbetagamma dimers by a specific anti-Gbeta antibody inhibited exocytosis elicited by agmatine and mastoparan. The G protein antagonist [p-Glu(5),D-Trp(7,9,10)]substance P-(5-11) prevented both mastoparan- and agmatine-induced exocytosis when it was allowed to reach its intracellular targets by streptolysin-O permeabilisation. In intact cells, this response was prevented by both the removal of sialic acid residues by neuraminidase and by [D-Pro(4),D-Trp(7,9,10)]substance P-(4-11) acting at the mast cell surface. Exocytosis was restored by permeabilisation of the plasma membrane with streptolysin-O. These results suggest that agmatine might have several molecular targets, exerting its neurotransmitter function at low concentrations (i.e., with high affinity) through membrane receptors and at high concentrations (i.e., with weak affinity) through direct G protein activation.
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PMID:Agmatine: a mastoparan-like activity related to direct activation of heterotrimeric G proteins. 1179 Mar 74