ANTIALLERGIC ACTIVITY OF 6-(2-CYCLOHEXYLETHYL)-[1,3,4]THIADIAZOLO-[3,2-A]-1,2,3-TRIAZOLO-[4,5-D]PYRIMIDIN-9(3H)-ONE (DS-4574) IN RATS

The antiallergic activity of DS-4574 was evaluated in several commonly used rat models for allergic diseases. In passive cutaneous anaphylaxis, DS-4574 given intravenously and orally induced dose-dependent inhibition with ID50 values of 0.55 and 2.8 mg/kg, respectively. In contrast, this compound had no antagonistic activity against the histamine- and serotonin-induced cutaneous vascular permeability. In lung anaphylaxis, DS-4574 inhibited pulmonary function changes induced by the antigen in a dose-dependent manner when it was given intravenously and orally, the ID50 values being 0.04 and 0.89 mg/kg, respectively. DS-4574 also inhibited antigen-induced histamine and leukotriene release in passive peritoneal anaphylaxis following oral administration. In addition, this compound prevented antigen-induced histamine release in passively sensitized mast cells in vitro. These potent activities of DS-4574 in in vivo and in vitro models of immediate-type hypersensitivity reactions suggest that this compound could be useful in the treatment of allergic diseases including asthma.