[Influence of indomethacin and clidanac on the blood pressure lowering effect of beta-blockers].

: In conscious rabbits, the intravenous administration of pindolol (1.25 mg/kg), propranolol (1 mg/kg) and alprenolol (2 mg/kg) induced a highly significant decrease of mean arterial blood pressure and significant bradycardia. In the same model, the intravenous administration of saline, indomethacin, and clidanac did not affect the mean arterial blood pressure and heart rate. Pretreatment with indomethacin and clidanac reduced the effect of these beta-blockers on the mean arterial blood pressure and had no effect on the heart rate. Treating of the guinea pig heart homogenate with 1 microM indomethacin or clidanac decreased the number of beta-adrenoceptors without changing their affinity. These results suggest that indomethacin and clidanac interfere with beta-adrenoceptor-mediated effects.