TL 333, a benzhydro[g]quinoline, stimulates both D-1 and D-2 dopamine receptors: implications for the selectivity of LY 141865 towards the D-2 receptor.

TL 333, (trans-N-ethyl-6,7-dihydroxyoctahydrobenzo[g]-quinoline), stimulates both D-1 and D-2 dopamine receptors. In contrast, LY 171555 (the active enantiomer of the selective D-2 agonist LY 141865) and LY 149632 stimulate only D-2 receptors. The structural differences between TL 333, LY 171555 and LY 149632 are discussed with regards to understanding the basis for the selective D-2 agonist activity of LY 171555 or LY 149632.