Biol. Pharm. Bull. 28(10) 1963—1965 (2005)

tissues including the skin, intestine, lung, heart, and dura mater in which actual membrane–membrane contacts were formed. Functional communication between mast cells and nerves has been shown to occur in physiological and pathological situations. In fact, psychological stress appears to activate mast cells and can exacerbate inflammatory responses. Dermal contacts between mast cells and nerves were increased in number in atopic dermatitis and since mast cells are also increased in number, they are able to maintain neurogenic inflammation through activation by substance P. The most direct evidence available for a bidirectional interaction has been obtained in a co-culture approach of mast cells and superior cervical ganglion (SCG) neurons. Our previous results showed that SCG neurite or mast cell (rat basophilic leukemia (RBL) cell line and bone marrow-derived mast cells (BMMCs)) activation can result in activation of the reciprocal cell type in the absence of any modulating or transducing effects of an intermediary cell. In addition, we found that N-cadherin was involved with the contact formation between nerves and mast cells in collaboration with bcatenin. However, it remains to be unclear how nerves influence responsibility to antigen in mast cells. In the present paper we have studied the calcium responses and FceRI expression in BMMCs which were co-cultured with SCG neurites in vitro. Mast cells are classified into two types. One is mucosal and another is connective tissue types. Both RBL cells (cultured mast cell lines) and BMMCs (primary cultured mast cells) belong to mucosal type mast cells. However, RBL cells are much more adhesive than BMMCs and would like to non-specifically stick to the supported matrigel-coated plate of glass dishes. RBL cells also have a malignant feature. In addition, nerves most commonly associated with mast cells in vivo contain substance P. Therefore, we used an in vitro co-culture approach comprising SCG and BMMCs to study calcium responses and FceRI expression in BMMCs which were associated with SCG neurites. The results gave useful information for calcium responses and FceRI expression in BMMCs when the co-culture approach was done between nerves and mast cells.