Four conformationally defined analogs of amphetamine were synthesized and studied for their ability to potentiate the action of levarterenol on the isolated vas deferens from reserpine-treated rats. The compunds also were studied for indirect adrenergic agonist activity in the same test system. A definite stereochemical correlation was demonstrated in each case, the exo-isomers being considerably more active than their endo-counterparts both in potentiation and in indirect activity. The more active isomers of each pair correspond to an anti-periplanar conformation of amphetamine. The compounds are probably acting by inhibition of the neuronal amine uptake mechanism, since none of the compounds was a direct-acting agonist itself. These results are discussed in relationship to other previously reported, conformationally defined, amphetamine analogs.
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