Mast cells contribute to PACAP-induced dermal oedema in mice

In the present study the effect of intradermal PACAP-injection on dermal oe dema in mice was investigated and the contribution of mast cells to this re sponse was assessed. The injection of PACAP 1-38 into the ears of C57BL/6 m ice evoked a dose-dependent response, which, after higher doses of PACAP 1- 38, lasted at least 24 h. Histological examination showed significant mast cell degranulation induced by PACAP. Using mast cell-deficient WBB6F(1)-Kit (W)/Kit(W-nu) mice and the congenic mice, we demonstrated that the the earl y phase (30 min to 6 h) of PACAP-induced ear swelling response was signific antly diminished in mast cell-deficient mice, suggesting that mast cell deg ranulation contributes to this phase of the response. When mast cell-defici ent WBB6F(1)-Kit(W)/Kit(W-nu) mice were locally and selectively reconstitut ed by adoptive mast cell transfer, the dermal oedema was almost equal to th at of control animals in the early phase of PACAP injection. These results show that mast cell degranulation contributes to PACAP-induced dermal oedem a in mice. (C) 1999 Elsevier Science B.V. All rights reserved.