Abstract
The in vivo effects of prostaglandins on the immediate type allergic reactions were investigated on the capillary permeability in the rat. The following result were obtained.
1) The increased capillary permeability provoked in the skin by the intravenous injection (i. v. inj.) of chemical mediators (H, 5-HT, BK) was significantly suppressed by the subcutaneous injection (s.c. inj.) of PGE1 or PGE2, whereas it was enhanced by the s.c. inj. of PGF2α.
2) The increase on capillary permeability provoked in the skin by s.c. inj. of 5-HT was inhibited by 95% when PGE1 was administered 10 min before the challenging injection by 89% when administered 60 min before. But when administered 120 min or more before, the inhibitory effect of PGE1 was significantly reduced.
3) Forty-eight h passive cutaneous anaphylaxis (48 h PCA) was significantly suppressed by the s.c. inj. of PGE1 and PGE2.
4) Reversed PCA using sheep anti-rat IgE serum was significantly suppressed by the s.c. inj. of PGE1, but was enhanced by s.c. inj. of PGF2α.
5) Using the modified method of the air bleb, the effects by s.c. administration of PGE1 were examined on the leakage of the dye exudated into air bleb after the provoking injection of sheep anti-rat IgE serum into the bleb. Results obtained indicated that it was remarkably suppressed by the administration of anti-rat IgE serum. However, the more prolonged was the time of PGE1 administration after the challenging injection, the more reduced was the inhibiting effect.
6) From the microscopic examination in the extention samples of the bleb's wall, provoked by compound 48/80 immediately before i. v. inj. of colloidal carbon in the tail vein, the administration of PGE1 remarkably suppressed vasoexpansion and the leakage of carbon from venules.
