Inhibition of synaptosomal accumulation of l-norepinephrine II: N-aryloxyalkylphentermines, quaternary d-amphetamines, and 3-aryloxypropylamines.

The inhibitory potencies of a series of N-substituted phentermines on the synaptosomal uptake of l-norepinephrine were found to be similar to those of the corresponding amphetamines. Quaternization of N, N-dimenthyl-d-amphetamine diminished, but did not abolish, its inhibitory potency, indicating that a permanently charged cation is also effective. Since the addition of an aromatic moiety at the end of a four-atom chain originating at the nitrogen of amphetamine or phentermine significantly increased inhibitor strength, several 3-aryloxypropylamines and 4-phenylbutylamine were tested, but they were much weaker inhibitors than dl-amphetamine. Thus, the observed increase in inhibitor potency apparently was not simply the result of a specific interaction of the "nonmimic" portion of the N-substituted amphetamines or phentermines.