Spontaneous histamine release from isolarted Mastcells was found to be independent of cal­cium in the concentration range up to 1 m. mole/lit. Phosphatidyl serine do not change the effect of calcium on spontaneous release. The activation of anaphyla.ctic histamine release by calcium is potentiated by phosphatidyl serine but the laitter can't do so w1th strontium.  Mastcells, pretreated with AT...

the effects of some histaminergic agents were evaluated on stress- induced immunosuppression in immunized nale rats. in rat immunized with sheep red blood cells ( srbcs). restraint stress (rs) prevented the booster-induced rise in anti-srbc antibody titre and cell immunity response. intracerebroventicular (i.c>v) injection of histamine (150 µg/rat) induced a similar effect with rs. pretreatment...

Histamine is an β–imidazolylethylamine derivative that is present in essentially all mammalian tissues. The major physiological actions of histamine are centered on the cardiovascular system, nonvascular smooth muscle, exocrine glands and the adrenal medulla. In a general sense, histamine plays an important role as a “chemical messenger” component of the various pathways that have evolved in mu...

Using oxygen uptake as an index of the physiological response of isolated parietal cells, the interactions between histamine and gastrin and between histamine and carbamylcholine and the effects of atropine and metiamide on these interactions have been studied. Parietal cells were isolated from canine fundic mucosa by sequential exposure of separated mucosa to collagenase and EDTA. In previous ...

Data presented in this study support the finding that cotton and flax dusts contain agents which potentiate the formation or accumulation of histamine or both in the lungs of guinea pigs exposed to dust, and that such agents are present at much higher levels in cotton dust than in flax dust. The potentiating effect may be through the recruitment of mast cells into the lung. Both cotton and flax...

The role of cyclic AMP in histamine release induced by human leukocyte lysates was investigated. Leukocytes were incubated with leukocyte lysates prepared by ultrasonic disruption, and histamine was determined fluorimetrically. Several cyclic AMP-active agents had a marked inhibitory effect on histamine release. Theophylline and isoproterenol produced 50% inhibition at concentrations of less th...

Each of the four agents, ovomucoid, dextran, 48/80, and testis extract, when injected beneath the skin of the dorsa of the paws of rats produces a local vascular injury characterized by a protein-rich edema. Each agent also produces damage to mast cells. Either 5-hydroxytryptamine or histamine produces a response similar in the gross to that elicited by the agents which damage mast cells; howev...

We have previously reported that imatinib, a c-Abl inhibitor, reduces caveolae-mediated endocytosis of endothelial cells and inhibits the extravasation IgG in steady state. However, target signaling pathway behind this mechanism remains unclear. Here, we established an vitro culture system using human dermal microvascular (HDMEC) to mimic IgG. Thrombin histamine increased translocation through ...

The early phase of the ConA-induced inflammatory ascites was studied, with special reference to histamine. Concanavalin A (ConA), a cell-surface binding lectin was injected i.p. (25 mg/kg bw) to mice. After 1 h the animals were killed, the ascitic fluid collected and measured. Other agents were injected s.c., 10 min before the ConA-challenge. Exogenous histamine markedly inhibited the ConA-indu...