Figure 5.

Effects of preincubation with ZK 138357 (10⁻⁵ M) and AH 6809 (10⁻⁷ M) on the inhibitory actions of PGD₂ (10⁻⁶ M) on anti-IgE induced histamine release from rat peritoneal mast cells. Ibuprofen (10⁻⁵ M) treated mast cells were exposed to anti-IgE and PGD₂ after 0, 5 or 10 min preincubation with the DP antagonists. For the ZK 138357 experiments, spontaneous histamine release was 9.8±1.0% (0 min), 11.5±1.1% (5 min) and 11.2±1.1% (10 min), whereas anti-IgE induced histamine release was 33.3±4.6% (0 min), 31.4±2.7% (5 min) and 31.6±3.1% (10 min). The corresponding values for the AH 6809 experiments were 13.9±1.1, 13.3±0.8, 13.9±1.5, 31.9±3.3, 31.7±3.0 and 31.8±4.4%. Results are given as means±s.e.mean for n=4.