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)

In the lung, the contraction of smooth muscle, or bronchospasm, is generally caused by an immunologic insult resulting in mast cell degranulation and the release of histamine, slow reacting substances, and other mediators of inflammation (1). Although the immediate response is bronchospasm, continued activation of this sequence of events results in a chronic inflammatory disease. In the uterus, numerous conditions can result in smooth muscle contraction. One major pathophysiological syndrome associated with increased uterine tone and severe rhythmic contraction is primary dysmenorrhea (2). In this disease state, prostaglandins have been shown to play a major role in these contractions (3,4), and inhibitors of cyclooxygenase have proven beneficial in clinical practice (5). Both dysmenorrhea and cervical ripening have been likened to inflammatory reactions due to varying degrees of vasodilation, invasion by inflammatory cells, proliferation of fibroblasts and smooth muscle contraction (6,7). Metabolism of arachidonic acid (AA) via cyclooxygenase to prostaglandins and thromboxanes and via lipoxygenase to hydroxyeicosatetraenoic acids (HETEs) and leukotrienes is an integral part of both the acute and chronic inflammatory reaction in the lung or uterus. The material reviewed here examines the effect of endogenous leukotrienes on both the lung and uterus and suggests that other smooth muscles and pathophysiological states may be more involved with the lipoxygenase pathway of AA metabolism than previously believed.
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PMID:Smooth muscle contraction as a model to study the mediator role of endogenous lipoxygenase products of arachidonic acid. 642 Jun 33

Prostaglandin D2 is a secondary mast cell mediator that causes redness, chemosis, mucous discharge, and eosinophil chemotaxis in the eye. It may play an important role in allergic ocular disease. Although histamine is a key mediator of allergic inflammation, antihistamine therapy provides only symptomatic relief. We added aspirin therapy to the treatment regimen of three patients with vernal conjunctivitis. Aspirin acetylates the enzyme cyclooxygenase, thereby preventing the formation of prostaglandin D2. Within two weeks after initiation of aspirin therapy, we noted dramatic improvement in conjunctival and episcleral redness and resolution of keratitis and limbal infiltration. We recommend a trial of oral aspirin as adjunctive therapy for intractable cases of vernal conjunctivitis.
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PMID:Aspirin therapy in vernal conjunctivitis. 657 38

We have investigated some aspects of the regulation of production of rat platelet activating factor (PAF)2 in vitro. Suspensions of unseparated (PLC1), mast cell-depleted (PLC2), or mast cell (MC)-enriched rat peritoneal lavage cells (PLC) were analyzed for PAF content by extraction at alkaline pH. PAF activity extracted from PLC1 varied inversely with viable cell concentration: at 1 X 10(6) cells/ml, 32 +/- 9.3 PAF units, decreasing to 11.2 +/- 9.5 units at 10 X 10(6) cells/ml, and no activity at higher concentrations. Incubation of PLC1 in Tyrode's buffer or acetylsalicylic acid (ASA), but not salicylate, resulted in a time-dependent loss of PAF activity. Mean PAF activity of PLC2 was similar to that in PLC1, while no PAF activity was extractable from MC. Co-incubation with MC extracts inhibited PAF activity of PLC1 extracts in a dose-dependent fashion. Ultracentrifugation of PAF-containing samples led to a loss of all PAF activity in PLC1 extracts, suggesting the association of PAF activity with subcellular components. PAF appears to be derived from a non-MC population of rat PLC, is not extractable from rat PLC in the presence of ASA and is inhibited by MC extracts. These studies suggest that ASA regulates PAF availability unrelated to its effect on cyclooxygenase and that MC membrane products directly inhibit PAF activity from rat PLC.
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PMID:Platelet activating factor: regulation by mast cells and aspirin. 671 91

Anti-IgE-dependent activation of rat and human mast cells resulted in the preferential generation of the cyclooxygenase products prostaglandin D2 (PGD2) and prostaglandin I2 (PGI2) in the rat and PGD2 in the human. The average net generation of PGD2, determined by gas chromatography-mass spectrometry, was 13.1 ng/10(6) purified rat mast cells and 39.5 ng/10(6) dispersed, enriched human mast cells. After IgE-dependent activation, there was a linear relationship between the net quantities of PGD2 generated and of histamine secreted from dispersed human pulmonary cells when the number of mast cells was varied but the total number of cells was held constant, indicating that it is the number of mast cells participating in IgE-dependent activation, rather than total mast cell number, that determines PGD2 generation. A linear relationship was also shown between PGD2 generation, determined by radioimmunoassay, and the release of the granule marker beta-hexosaminidase from purified rat mast cells on the dose-response portion of the plot of their response to anti-IgE challenge. With higher concentrations of anti-IgE, PGD2 generation from rat mast cells plateaued, whereas net percent beta-hexosaminidase release increased further. In kinetic studies of rat mast cells activated with anti-IgE, the onset (1 to 2 min) and time of maximum generation (5 to 10 min) for PGD2 were delayed relative to the onset (15 to 30 sec) and completion (1 to 2 min) of beta-hexosaminidase release. Thus, the extracellular appearance of PGD2 during IgE-dependent mast cell activation represents a response additional to the secretion of granule-associated mediators.
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PMID:Prostaglandin D2 generation after activation of rat and human mast cells with anti-IgE. 680 26

Highly purified porcine phospholipase A2 induced noncytotoxic rat cell degranulation, as indicated by release of histamine without release of the cytoplasmic marker lactate dehydrogenase. Ultrastructural studies using transmission, scanning, and freeze fracture electron microscopic techniques indicated that phospholipase A2-induced degranulation was comparable to that caused by other mast cell secretagogues. Secretory changes noted were fusion of perigranular and plasma membranes, formation of vacuoles containing less electron-dense granules, and exocytosis of the altered granules through pores in the plasma membrane, without alteration in other intracellular organelles. The earliest consistent feature of the exocytotic process (within 1 minute) was the formation of plasma membrane bulges overlying cytoplasmic granules, with depletion of intramembranous particles from the bulges and a reduction in surface microridges. Phospholipase A2-induced mast cell degranulation was blocked by the phospholipase inhibitor 4-bromophenacyl bromide and by eicosa-5,8,11,14-tetraynoic acid (ETYA) but not by indomethacin. Since ETYA inhibits both the cyclooxygenase and lipoxygenase pathways of arachidonic acid metabolism and indomethacin only the cyclooxygenase pathway, these findings are compatible with the mediation of phospholipase A2-induced mast cell degranulation by a lipoxygenase product of the released arachidonic acid ETYA, however, may inhibit phospholipase activity directly and thus affect degranulation by phospholipase A2 in this way. These studies indicate that phospholipase A2 can induce mast cell degranulation and provides evidence that is compatible with, but not proof of, mediation of this process by a lipoxygenase product of arachidonic acid metabolism.
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PMID:Phospholipase A2-induced rat mast cell secretion. Role of arachidonic acid metabolites. 681 79

It has been shown that the major cyclooxygenase product in rat basophilic leukemia (RBL-1) cells and in normal rat mast cells is prostaglandin D2. In RBL-1 cells, prostaglandin D2 is isomerase activity was found in the 150 000 X g microsomal pellet as well as the supernatant fraction. Incubation of RBL-1 microsomes with arachidonic acid without cofactors yielded 17.5 +/- 2% prostaglandin E2 and 9.1 +/- 1.4% prostaglandin D2. The cyclooxygenase activity was enhanced (25%) by epinephrine and the addition of reduced glutathione led to a marked increase in prostaglandin D2 synthesis (3-fold). Incubations with arachidonic acid, glutathione and epinephrine gave the maximum conversion to prostaglandin D2, yielding 7 +/- 0.4% prostaglandin E2 and 35.6 +/- 3.5% prostaglandin D2. Incubations with [14C]prostaglandin H2 to bypass cyclooxygenase confirmed the presence and glutathione dependence of the prostaglandin D2 isomerase in the microsomal fraction and also revealed the presence of the same enzyme in the 150 000 X g supernant. In contrast to RBL-1 cells, incubations of microsomes and supernatant from normal rat mast cells with [14C]-arachidonic acid and [14C]prostaglandin H2 localized the prostaglandin D2 isomerase activity in the soluble fraction. Similar to the enzyme in the RBL-1 cells, the mast cell enzyme was glutathione dependent.
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PMID:Enzymatic formation of prostaglandin D2 by rat basophilic leukemia cells and normal rat mast cells. 737 31

Photoactivation of intravascular dyes with high doses of light is a technique used clinically to treat tumors. This procedure results in arteriolar constriction, mast cell degranulation, platelet thrombus formation, and, ultimately, microvascular stasis. In vivo microscopy was utilized in the current study to examine if the endothelial release of prostaglandins and nitric oxide could participate in the microvascular effects of photoactivation. Diameter changes and thrombus formation of arterioles and venules of the cremaster muscle of male Sprague-Dawley rats were quantitated during continuous light activation of intravascular fluorescein isothiocyanate conjugated to bovine serum albumin. Vasoconstriction and thrombus development were assessed separately, using the relationships between the width of the red blood cell column, the inner wall diameter, and the thickness of the plasma layer. Venular photoactivation resulted in thrombus growth which reached 30% of the maximum size by 16.8 +/- 3.71 min and a subsequent growth rate of 6.2 +/- 1.64 microns/min. In arterioles, 30% thrombus growth occurred at 14.0 +/- 2.02 min with a growth rate of 3.0 +/- 0.57 microns/min. Continuous arteriolar photoactivation led to a vasoconstriction of 34.4 +/- 6.87% of the initial vessel diameter. Thirty percent of the maximal constriction occurred after 10.6 +/- 1.26 min of photoactivation. Constriction proceeded at a rate of 3.8 +/- 1.32 microns/min. Topically applied mefenamic acid (a cyclooxygenase inhibitor) and Nw-nitro-L-arginine methyl ester (L-NAME, a nitric oxide synthase inhibitor) each enhanced both the arteriolar and the venular thrombus growth due to photoactivation. Photoactivation-induced arteriolar constriction was augmented by L-NAME and inhibited by mefenamic acid. These data suggest that the photoactivation of intravascular dyes is accompanied both by the release of nitric oxide, which inhibits thrombus development and arteriolar constriction, and by the release of cyclooxygenase products, which inhibit thrombus growth and induce vasoconstriction. Rats treated with busulfan to induce thrombocytopenia exhibited a 90% decrease in circulating platelets. In these animals, photoactivation caused significantly delayed thrombus growth in arterioles and venules, while arteriolar constriction remained unaltered, suggesting that the vasoconstrictor prostanoid is not of platelet origin.
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PMID:Involvement of nitric oxide and cyclooxygenase products in photoactivation-induced microvascular occlusion. 751 91

To study cytokine regulation of the 5-lipoxygenase (5-LO)/leukotriene (LT) synthase pathway we have developed mouse bone marrow-derived mast cells (BMMC) that minimally express each protein of the pathway by using a novel culture system, lacking interleukin (IL)-3. When mouse bone marrow cells were cultured for 5 weeks with 100 ng/ml c-kit ligand (KL) and 10 units/ml IL-10, a population of > 95% mast cells was obtained. These cells generated 8.3 +/- 4.5 ng of LTC4/10(6) cells and 8.1 +/- 2.4 ng of prostaglandin (PG) D2/10(6) cells after IgE-dependent activation. When these BMMC were cultured for 2-5 weeks more with 100 units/ml IL-3 in the continued presence of KL and IL-10, the IgE-dependent generation of LTC4 and PGD2 increased to 212 +/- 36 and 25.5 +/- 8.6 ng/10(6) cells, respectively. The dramatic increase in the IgE-dependent generation of LTC4 in response to IL-3 was accompanied by a concomitant increase in expression of 5-LO and 5-LO-activating protein and preceded the increased expression of cytosolic phospholipase A2 and LTC4 synthase. The recognition that IL-3 up-regulates the expression of each protein of the 5-LO pathway for the generation of LTC4 contrasts with our recent finding that KL up-regulates the expression of cytosolic phospholipase A2, prostaglandin endoperoxide synthase-1, and hematopoietic PGD2 synthase and increases the IgE-dependent generation of PGD2 in BMMC developed from bone marrow with IL-3. Thus, developmentally segregated regulation of the prostanoid and cysteinyl leukotriene pathways in lineage-related committed mast cell progenitors reveals the pleiotropism of this effector cell of allergic inflammation, a cytokine/growth factor basis for preferential expression of pathways of eicosanoid biosynthesis, and the particular role of IL-3 in regulating the expression of the proteins of the 5-LO/LTC4 synthase pathway.
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PMID:Interleukin-3 regulates development of the 5-lipoxygenase/leukotriene C4 synthase pathway in mouse mast cells. 755 81

Colonic smooth muscle function may be altered in food protein hypersensitivity reactions and could contribute to the clinical manifestation of diarrhea. To characterize such functional changes and elucidate the mediators and mechanisms involved. Hooded-Lister rats were sensitized by intraperitoneal injection of egg albumin (10 micrograms), and controls were sham sensitized with saline. Fourteen days later the contractility of longitudinally oriented distal colonic segments (mucosa intact) were studied in standard tissue baths in response to antigen (Ag) or other agents. After Ag exposure, a contractile response was documented in animals that were sensitized [specific immunoglobulin E (IgE) antibody levels > or = 1:64] and was specific for the sensitizing Ag. Mast cell involvement was suggested by a significant reduction in the number of granulated mucosal mast cells in sensitized tissues after Ag challenge and in the magnitude of the Ag-induced contractile response in the presence of mast cell stabilizers. The antigen-induced response was significantly and independently inhibited by both cyclooxygenase and lipoxygenase enzyme inhibitors and by leukotriene D4 and platelet activating factor receptor antagonists. The Ag-induced response was resistant to histamine and the 5-hydroxytryptamine antagonists, atropine and tetrodotoxin. These results suggest that the food protein-induced contraction of colonic longitudinal smooth muscle in the sensitized rat is due to IgE-mediated mast cell activation with the subsequent production and release of membrane-derived mediators that, in vitro, act directly on the smooth muscle.
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PMID:Intestinal anaphylaxis: mediation of the response of colonic longitudinal muscle in rat. 776 60

In continuing experiments to determine the ionic basis of inhibitory presynaptic modulation, rat cortical synaptosomes were employed and receptor-activated K+ efflux was determined with a K+ sensitive electrode. When synaptosomes were sub-optimally depolarized by veratridine, the addition of agents that activated purinergic, alpha 2-adrenergic, muscarinic and opioid receptors all promoted K+ efflux. With 2-chloroadenosine as a model inhibitory presynaptic modulator, the increased K+ efflux evoked by this agent was blocked by the cyclooxygenase inhibitor indomethacin suggesting that arachidonic acid or its metabolites was an intermediary in opening the channel. When arachidonic acid and PGE2 were tested, both promoted K+ efflux that was inhibited by dendrotoxin and mast cell degranulating peptide, two agents that are known to inhibit a delayed rectifier K+ current. Our results suggest that via eicosanoid second messengers, inhibitory presynaptic modulators open a sub-class of K channels that hyperpolarize nerve terminals, therefore less Ca2+ would enter per nerve impulse and thus the evoked release of neurotransmitters would be decreased.
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PMID:Presynaptic modulation by eicosanoids in cortical synaptosomes. 782 77


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