The vesicular monoamine transporter is a specific presynaptic protein involved in the
transport of monoamines from the cytosol to storage vesicles of monoaminergic nerve
terminals. Recently, radioligands for this transporter have been developed and utilized for in
vivo positron emission tomographic (PET) imaging of monoaminergic nerve terminals in the
human brain. In this review, the characteristics of vesicular transport and storage that
provided the impetus for development of these radioligands are presented and discussed.