Separate purinoceptors mediate enhancement by adenosine of concanavalin A-induced mediator release and the cyclic AMP response in rat mast cells.

Adenosine caused a concentration-related enhancement of concanavalin A (Con A)-induced 5-hydroxytryptamine (5-HT) release from rat purified peritoneal mast cells. This was accompanied by an enhancement and prolongation of the cyclic AMP response to Con A. The cyclic AMP response but not enhancement of 5-HT release was blocked by 8-phenyltheophylline suggesting the two events to be unrelated. The effects of AMP and ADP, adenosine analogues and adenosine uptake inhibitors suggest the enhancement of 5-HT release to be mediated by a P1-cell surface purinoceptor which does not show the characteristics of either A1 or A2 subtypes.