Cis- and trans-4-n-Propyl-1,2,3,4,4a,5,6,10b-octahydrobenzo(f)quinolines

Cis- and trans-4-n-Propyloctahydrobenzo(f)quinolines 4a,b were prepared for further assessment of dopaminergic effects of non-oxygenated dopamine congeners. The trans isomer 4b exhibited marked dopamine-like effects in the cat cardioaccelerator nerve assay and in a rat rotation model. Compound 4b produced dose-related lowering of blood pressure in the cat. The cis isomer 4a was inactive in these assays. Both compounds were inactive in a dopamine binding assay, but both appeared active in a spiroperidol binding assay. Both compounds are active alpha 1- and alpha 2-adrenoceptor antagonists. Compound 4b provides evidence that alpha 2-adrenoceptors and dopamine receptors are different entities, since this compound is an alpha 2 antagonist and a dopamine receptor agonist at presynaptic sites.