Selectivity of agonists and antagonists at D2dopamine receptors compared to D1 and S2receptors

The common dopamine agonists (dopamine, apomorphine, ADTN, and N‐propylnorapomorphine) are not selective D1 or D2 dopamine receptors, affecting both simultaneously. SK&F 38393 is selective for D1, while bromocriptine and (D2)D2LYD2171555 are selective for D2. The neuroleptic with the highest D2/S2 selectivity is eticlopride with an affinity 3,200‐fold higher for the D2 dopamine receptor compared to the S2 serotonin receptor. Such selective neuroleptics may be clinically useful and may also help in measuring the elevated D2 density in vivo by positron emission tomography in the brains of schizophrensis.