From what I've gathered, compounds such as amphetamine, ephedrine and tyramine are taken into noradrenergic (and dopaminergic) cells via the uptake transporters, then when in the cytosol they get taken into the synaptic vesicles via the vesicular monoamine uptake transporter. Like that, they displace the norepinephrine or dopamine inside these vesicles, forcing them out into the cytosol. Some of the norepinephrine is destroyed by MAO while some of it is transported into the synaptic cleft via the uptake transporter, in exchange for the amphetamine or other drug. Is this the primary way that amphetamines cause the release of norepinephrine, dopamine and other monoamines from cells? I'd imagine then that the comedown caused by amphetamines is a result of depleted norepinephrine and dopamine (since much of it gets destroyed by MAO after its forced out of the vesicle by the drug).