displacement curves obtained using n-ethylcarboxamidoadenosine ( neca ) and the r- and s-diastereoisomers of phenylisopropyl adenosine ( pia ) showed the [ 3h ] cha binding sites to have the pharmacological properties of a1-adenosine receptors , i.e . the order of potency for these derivatives was r-pia greater than neca greater than s-pia , in all regions tested .
C0050789
neca
C0001443
pia