The role of SPECT imaging of the dopaminergic system in translational research on Parkinson's disease.

Imaging of the dopaminergic system with single photon emission computed tomography (SPECT), and particularly of the dopamine transporter (DAT) located in the striatum, is a well accepted tool in clinical practice to confirm or exclude loss of nigrostriatal dopamine (DA) neurons in patients suspected to suffer from Parkinson's disease (PD). SPECT techniques were developed successfully to image neurotransmitter systems, including the presynaptic DAT and postsynaptic dopamine D2/3 receptors, in rat and mouse models of PD. Here we review the results of preclinical SPECT studies of the dopaminergic system in rat and mouse models of PD. Initially, SPECT studies in animal models of PD were performed to validate that micro-SPECT is able to accurately assess parts of the dopaminergic system in small animals in-vivo. However, more recently, micro-SPECT DAT is increasingly used as a research tool to support the interpretation of human DAT SPECT studies in PD, including clinical trials examining the effects of potential neuroprotective drugs. Translational research with SPECT is an interesting development which may further increase our understanding of the pathophysiology and treatment of PD.