TY - JOUR
T1 - Adenosine receptors of human leukocytes-II. Characterization of an inhibitory p-site
AU - Marone, Gianni
AU - Petracca, Rosaria
AU - Vigorita, Sergio
AU - Casolaro, Vincenzo
PY - 1990/11/1
Y1 - 1990/11/1
N2 - We have investigated the effects of 2′,5′-dideoxyadenosine (DDA), 9′-β-D-arabinofurano-syladenine (ARA), and 9-β-D-xylofuranosyladenine (XFA), which have been classified as P-site adenosine agonists, on the cyclic adenosine 3′,5′-monophosphate (cAMP) metabolism of human lymphocytes and polymorphonuclear leukocytes (PMNs). DDA (10-5-2 × 10-4M), ARA and XFA caused a dose-dependent decrease in cAMP content of human lymphocytes. In addition to decreasing lymphocyte cAMP levels, DDA, ARA and XFA markedly inhibited the effects of many adenylate cyclase-stimulating agents including β-adrenergic stimuli, prostaglandin E1 (PGE1), histamine, adenosine, forskolin and cholera toxin. Theophylline and 3-isobutyl-1-methylxanthine, which are known antagonists of adenosine A1/Ri, and A2/Ra, receptors, did not modify the inhibiting effects of DDA. Mn2+ (1 mM) increased the sensitivity to inhibition of adenylate cyclase agonists by DDA. We also searched for the presence of adenosine P-sites in human PMNs. DDA caused a significant decrease of PMN cAMP levels only at the highest concentrations used (Z × 10-4M). In contrast, even low concentrations of DDA (10-6-10-4 M) concentration-dependently blocked the stimulatory effect of PGE1 and forskolin on PMN cAMP accumulation. The results support the existence of a purine P-site that regulates cAMP metabolism of human lymphocytes and PMNs.
AB - We have investigated the effects of 2′,5′-dideoxyadenosine (DDA), 9′-β-D-arabinofurano-syladenine (ARA), and 9-β-D-xylofuranosyladenine (XFA), which have been classified as P-site adenosine agonists, on the cyclic adenosine 3′,5′-monophosphate (cAMP) metabolism of human lymphocytes and polymorphonuclear leukocytes (PMNs). DDA (10-5-2 × 10-4M), ARA and XFA caused a dose-dependent decrease in cAMP content of human lymphocytes. In addition to decreasing lymphocyte cAMP levels, DDA, ARA and XFA markedly inhibited the effects of many adenylate cyclase-stimulating agents including β-adrenergic stimuli, prostaglandin E1 (PGE1), histamine, adenosine, forskolin and cholera toxin. Theophylline and 3-isobutyl-1-methylxanthine, which are known antagonists of adenosine A1/Ri, and A2/Ra, receptors, did not modify the inhibiting effects of DDA. Mn2+ (1 mM) increased the sensitivity to inhibition of adenylate cyclase agonists by DDA. We also searched for the presence of adenosine P-sites in human PMNs. DDA caused a significant decrease of PMN cAMP levels only at the highest concentrations used (Z × 10-4M). In contrast, even low concentrations of DDA (10-6-10-4 M) concentration-dependently blocked the stimulatory effect of PGE1 and forskolin on PMN cAMP accumulation. The results support the existence of a purine P-site that regulates cAMP metabolism of human lymphocytes and PMNs.
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U2 - 10.1016/0006-2952(90)90225-A
DO - 10.1016/0006-2952(90)90225-A
M3 - Article
C2 - 2173596
AN - SCOPUS:0025086064
SN - 0006-2952
VL - 40
SP - 1963
EP - 1973
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
IS - 9
ER -