basophil

ST-1006, a potent histamine H4 receptor agonist (pKi: 7.94), exhibits significant anti-inflammatory and anti-pruritic effects. It is also a potent inducer of basophil migration.

Emedastine (LY188695) is a second generation, selective histamine H1 receptor antagonist with anti-allergic activity. Emedastine reversibly and competitively blocks histamine by binding to H1 receptors, thus blocking its downstream activity. As a result this agent interferes with mediator release from mast cells either by inhibiting calcium ion influx across mast cell basophil plasma membrane or by inhibiting intracellular calcium ion release within the cells. In addition, emedastine may also inhibit the late-phase allergic reaction mediated through leukotrienes or prostaglandins, or by producing an anti-platelet activating factor effect. Upon ocular administration, emedastine causes a dose-dependent inhibition of histamine-stimulated vascular permeability in the conjunctiva. Emedastine does not affect adrenergic, dopamine, or serotonin receptors.

R112 is an ATP-competitive inhibitor of Syk kinase. Ki=6 nM，IC50=226 nM.

Thapsigargicin (Thapsigargicine) acts as an activator for mast cells and leukocytes, prompting histamine release from rat peritoneal mast cells and human basophil leukocytes. Additionally, it elevates cytoplasmic free calcium levels in human blood platelets [1].

Tylogenin, a steroidal aglycone generated by acid hydrolysis from two seasonal glycosides occurring in Tylophora sylvatica, inhibits IgE-induced basophil mediator release for allergic reactions. In the rabbit basophil-dependent serotonin release (BDSR) assay system, the inhibitory activity of tylogenin was significantly greater than that of its parent glycosides, tylophoroside and acetyltylophoroside, and that of dexamethasone. The activity of tylogenin was found to increase with the incubation time. In the human leukocyte-dependent histamine release test model, the glycosides had only a minimal activity. In contrast, tylogenin, with a geom mean IC50 = 49 microM, exerted a significantly greater potency than dexamethasone. These results suggest that tylogenin could represent a new class of antiallergic agents.

N tau-methylhistamine is one of the histamine metabolites. N tau-methylhistamine in plasma and urine is a good parameter for histamine release, and the determination of this histamine metabolite is generally less hampered by possible artifacts (due to bas

FR-A 19, a Histamine H2 agonist, inhibits the release of IgE-mediated human basophil histamine in a nanomolar range. It has additional potent anti-allergic properties.