Evidence for an adenosine A2/Ra receptor on human basophils.
5'-N-ethylcarboxamideadenosine (NECA) greater than 2-chloroadenosine greater than adenosine greater than (-)-N6-(R-phenyl-isopropyl)-adenosine greater than (+)-N6-(S-phenylisopropyl)-adenosine, in that order of potency, inhibited in vitro antigen-induced histamine release from human basophils in a dose-dependent fashion. Inhibition occurred only during the first stage of antigen-induced histamine release and the nucleosides failed to inhibit the release caused by the Ca2+ ionophore, A23187. 6-nitrobenzylthioinosine and dipyridamole, which inhibit adenosine uptake, and erythro-9-(2-hydroxy-3-nonyl)adenine, which blocks adenosine metabolism, did not impair the inhibition caused by NECA and adenosine. 8-phenyltheophylline and theophylline, two competitive antagonists of adenosine receptors, blocked the inhibition caused by NECA and adenosine. These data suggest that NECA and other adenosine analogs activate a specific cell surface adenosine receptor which possesses properties similar to those of an adenosine A2/Ra receptor.
Marone
G
G
Vigorita
S
S
Antonelli
C
C
Torella
G
G
Genovese
A
A
Condorelli
M
M
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D000262:Adenylyl Cyclases / Q000378:metabolism; D001491:Basophils / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects*; D006801:Humans; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011983:Receptors, Purinergic; D013329:Structure-Activity Relationship; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D013868:Thioinosine / Q000031:analogs & derivatives / Q000494:pharmacology
D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D019830:Adenosine-5'-(N-ethylcarboxamide); D000001:Calcimycin; D013868:Thioinosine; D013806:Theophylline; C028322:8-phenyltheophylline; D000262:Adenylyl Cyclases; C001789:4-nitrobenzylthioinosine; D000241:Adenosine