Mast cell desensitization to IgE fails to induce a parallel adenosine receptor desensitization.
Desensitization induced by challenge of mast cells with antigen is specific for IgE-dependent signals. During the secretory process mast cells release adenosine, which can induce a desensitization of adenosine receptors. To determine whether adenosine receptors may be desensitized from a previous antigen challenge, mast cells were sensitized with anti-DNP IgE antibody, challenged with DNP-BSA antigen, returned to culture overnight, resensitized, and rechallenged. Previously challenged cells exhibited increased spontaneous beta-hexosaminidase release, but adenosine retained its ability to augment beta-hexosaminidase release. Adenosine enhanced A23187-stimulated release of beta-hexosaminidase in control and previously challenged cells. Leukotriene C4 generation followed a similar pattern. Mastoparan, a direct G protein activator and mast cells secretagogue, produced a doubling of beta-hexosaminidase release in previously challenged cells. Results using other G protein activators were equivocal. Degranulation alone is insufficient to induce adenosine receptor hyposensitization. Whether the hyperresponsiveness to mastoparan is a consequence of uncoupling of IgE receptors from G proteins remains uncertain.
Marquardt
D L
DL
Department of Medicine, University of California, San Diego School of Medicine.
Lwin
A
A
Walker
L L
LL
D000241:Adenosine / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001854:Bone Marrow Cells; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D003888:Desensitization, Immunologic; D019204:GTP-Binding Proteins / Q000378:metabolism; D007073:Immunoglobulin E / Q000276:immunology*; D007202:Indicators and Reagents; D036341:Intercellular Signaling Peptides and Proteins; D017997:Leukotriene C4 / Q000378:metabolism; D008407:Mast Cells / Q000201:enzymology / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D012710:Serum Albumin, Bovine / Q000276:immunology; D019311:Staurosporine; D014862:Wasp Venoms / Q000494:pharmacology; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
D000470:Alkaloids; D007202:Indicators and Reagents; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D018047:Receptors, Purinergic P1; D014862:Wasp Venoms; D012710:Serum Albumin, Bovine; D017997:Leukotriene C4; D007073:Immunoglobulin E; D000001:Calcimycin; C037500:mastoparan; D011493:Protein Kinase C; D001619:beta-N-Acetylhexosaminidases; D019204:GTP-Binding Proteins; D019311:Staurosporine; D000241:Adenosine