Adenylate cyclase, cyclic AMP and IgE-mediated desensitization in rat mast cells.
Rat peritoneal mast cells were desensitized up to 100% with 1-4 additions of suboptimal concentrations of anti-rat IgE over 60-90 min. Desensitized cells rechallenged with anti-IgE showed a 2- to 10-fold increase in cAMP during the initial 1-5 min. Membrane preparations from desensitized cells showed up to a 100-fold rise in cyclase activity following incubation with anti-IgE, compared to a 5- to 10-fold rise in control cells. Control and desensitized cell membranes rechallenged with anti-IgE showed nearly identical levels of phosphodiesterase activation. We conclude that following desensitization, repetitive low levels of anti-IgE binding induce atypically high and sustained activation of adenylate cyclase which may reflect primary or secondary regulatory events in the development of desensitization.
D000262:Adenylyl Cyclases / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D000242:Cyclic AMP / Q000494:pharmacology*; D003888:Desensitization, Immunologic; D004789:Enzyme Activation; D005260:Female; D007073:Immunoglobulin E / Q000494:pharmacology*; D008407:Mast Cells / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D051381:Rats; D011919:Rats, Inbred Strains
D007073:Immunoglobulin E; D000242:Cyclic AMP; D000262:Adenylyl Cyclases