Is seems like to me that it should mean they are 'bioisosteric' if they have the same biological effect as each other with the same two different functional groups in the same places in two otherwise identical molecules. Clearly, they are both powerful CNS stimulants. But, upon closer inspection, MPH may be a pure NT reuptake inhibitor, while desoxypipadrol may be a NT releaser.
Is the mode of that action really the deciding factor? Mightn't it depend on how close you are splitting hairs when settling on a definition for "biological effect" (i.e., in a general sense, yes, they are both powerful CNS stimulants, but on a more hair splitting level, one is possibly a releaser while the other is a reuptake inhibitor?).
Which leads me to the question: Is it possible for a molecule to be both a releaser and a reuptake inhibitor in varying degrees at the same time? In other words, why (or does) this dichotomy have to a be an all or nothing proposition? Seems like I remember reading here somewhere maybe by you, aced126, that releasers are also reuptake inhibitors in so far as they have to fill DAT or SERT or whatever long enough to reverse NT flow anyway.
Must the means and ends match? Why not just the ends? I guess I'm just the kind of guy who focuses on the end results and tries his best to ignore the intermediary mechanism which gives rise to that end. To me, the ends often justify the means, but maybe I'm a Machiavellian psychopath with a small penis, a psychiatric diagnosis or two, an inability to currently procure real MDMA or LSD (which was once my forte of sorts back when we still bought Schedule I drugs on the streets, at rave parties, and in dorm rooms) and a fairly robust ice methamphetamine habit, I dunno.