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The effect of a TXA2 receptor antagonist ON-579 on experimental allergic reactions
H Nagai1, H Kawasaki, H Takeda
1Department of Pharmacology, Gifu Pharmaceutical University, Japan.
Abstract:
The effect of a thromboxane A2 (TXA2) receptor antagonist, ON-579, on experimental allergic skin and airway reactions was studied in vivo. ON-579 at doses of 1 and 20 mg/kg clearly inhibited U-46619-induced increases in respiratory resistance (Rrs) in guinea pigs. ON-579 at doses of 1, 20 and 50 mg/kg inhibited the aerosolized antigen-induced biphasic increase in Rrs in guinea pigs. Moreover, ON-579 clearly inhibited repeated aeroantigen-induced airway hyperreactivity in guinea pigs. ON-579, however, did not have any significant effects on allergic cutaneous reactions in rats. These results suggest that ON-579 is a relatively selective TXA2 antagonist, especially in the airways, and indicate the efficacy of ON-579 on antigen-induced increase in airway resistance and antigen-induced airway hyperreactivity in guinea pigs.
Insights
The thromboxane A2 (TXA2) receptor antagonist ON-579 effectively reduced airway resistance and hyperreactivity in guinea pigs. ON-579 demonstrated selectivity for airway responses, not impacting skin reactions in rats.
Area of Science:
- Pharmacology
- Immunology
- Respiratory Medicine
Background:
- Thromboxane A2 (TXA2) plays a role in allergic reactions.
- Investigating novel antagonists for allergic airway diseases is crucial.
Purpose of the Study:
- To evaluate the efficacy of ON-579, a TXA2 receptor antagonist, in experimental allergic skin and airway reactions.
- To determine the selectivity of ON-579 in vivo.
Main Methods:
- In vivo studies using guinea pigs and rats.
- Administration of ON-579 at various doses.
- Assessment of respiratory resistance (Rrs) following U-46619 or aerosolized antigen challenge.
- Evaluation of allergic cutaneous reactions.
Main Results:
- ON-579 inhibited U-46619-induced increases in Rrs in guinea pigs.
- ON-579 suppressed aerosolized antigen-induced biphasic increases in Rrs.
- ON-579 reduced repeated aeroantigen-induced airway hyperreactivity.
- ON-579 showed no significant effect on allergic skin reactions in rats.
Conclusions:
- ON-579 acts as a selective TXA2 antagonist, particularly in the airways.
- ON-579 is effective against antigen-induced airway resistance and hyperreactivity.
- ON-579 shows potential for treating allergic airway diseases.
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