ABSTRACT
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.
Subject(s)
Acetylcholine/pharmacology , Adenosine/pharmacology , Concanavalin A/pharmacology , Histamine Release/drug effects , Mast Cells/metabolism , Adenoids/metabolism , Adenosine/analogs & derivatives , Adenosine-5'-(N-ethylcarboxamide) , Humans , In Vitro Techniques , Mast Cells/drug effects , Phenylisopropyladenosine/pharmacology , Receptors, Cell Surface/drug effects , Receptors, PurinergicABSTRACT
Mast cells from adenoid tissues of man do not form a homogeneous population but differ in size and ultrastructure. They degranulate on stimulation with specific antigen, ionophore A 23187, Concanavalin A and, under certain conditions, antihuman IgE or acetylcholine. Compound 48/80, dextran, purified C3a or C5a are ineffective. Adenosine exerts either an enhancing or inhibiting effect on the stimulated histamine release, depending on the actual conditions of the mast cells. The study of a range of known mast cell degranulation inhibitors revealed important differences between human adenoidal mast cells and human basophils or animal mast cell systems. The efficacies of the drugs or drug combinations so far tested correspond well with the established therapeutic effects in man.
