the a1 subtype specific agonists cyclohexyladenosine and r-phenylisopropyladenosine had inhibitory effects at lower concentrations than adenosine and s-phenylisopropyladenosine , suggesting the relevance of presynaptic inhibitory adenosine receptors of the a1 subtype .
C0001443
adenosine
C0031484
phenylisopropyladenosine