The effect of platelet-activating factor on histamine release from guinea pig peritoneal mast cells.

The effect of platelet-activating factor (PAF) on histamine release from the peritoneal mast cells of male guinea pigs at 4 weeks of age and one week of age (weaning) was investigated. PAF as well as compound 48/80 and concanavalin A were not found to release histamine from the mast cells of either age of guinea pigs. On the other hand, Ca2+ ionophore A23187 showed a significant, concentration-dependent histamine release from the mast cells obtained from guinea pig of either age group. PAF (3 x 10(-7) - 3 x 10(-6) g/ml) significantly inhibited the histamine release induced by Ca2+ ionophore A23187 from the mast cells of guinea pigs at one week of age, but not from those of the older ones. Such an inhibition was not seen with lyso-PAF in either age group. CV-3988, a PAF antagonist, neutralized the inhibitory effect of PAF on the A23187-induced histamine release from the mast cells of guinea pigs at one week of age. These results indicate that PAF does not have a histamine-liberating action on guinea pig peritoneal mast cells, and that PAF inhibits the effect of A23187 on histamine release from mast cells through activation of PAF receptor in guinea pigs at one week of age.