The effects of adenosine and of some adenosine analogues on the concanavalin A-or acetylcholine-induced histamine release from human adenoidal mast cells.

Histamine release induced by concanavalin A (Con A) or acetylcholine is enhanced by adenosine or the adenosine analogues PIA and NECA. The enhancement is not affected by preincubation with adenosine deaminase. The degree of the Con A-induced histamine release decreases with increasing incubation time. Under these conditions, the enhancing effect of adenosine on histamine release is either abolished or even reversed to inhibition.