PSB-10
# PSB-10

PSB-10 is a drug which acts as a selective antagonist for the adenosine $A_3$ receptor $(k_i$ value at human $A_3$ receptor is 0.44 nM), with high selectivity over the other three adenosine receptor subtypes $(k_i$ values at human $A_1,$ $A_{2A}$ and $A_{2B}$ receptors are 4.1, 3.3 and 30 μM). Further pharmacological experiments in a $[^{35}S]GTPγS$ binding assay using $hA_3-CHO-cells$ indicated that PSB-10 acts as an inverse agonist $(IC_{50}$ = 4 nM). It has been shown to produce antiinflammatory effects in animal studies. Simple xanthine derivatives such as caffeine and DPCPX have generally low affinity for the $A_3$ subtype and must be extended by expanding the ring system and adding an aromatic group to give high $A_3$ affinity and selectivity. The affinity towards adenosine $A_3$ subtype was measured against the radioligand PSB-11.

