Differences in affinity of agonist (NECA) or “antagonists” (ZM241385, XAC, istradefylline, SCH58261, preladenant, theophylline, and caffeine) at the active and inactive state StaRs. Data from Table 1 has been displayed as change (± S.E.M.) in pKi of active-state StaR (pKi StaR minus pKi A2A) compared with inactive-state StaR [pKi StaR2(1-316) minus pKi A2A(1-316)] for (A) GL0, (B) GL23, (C) GL26, and (D) GL31.