Parallels between behavioral and neurochemical variability in the rat vacuous chewing movement model of tardive dyskinesia

Upregulation of dopamine D3, not D2, receptors correlates with tardive dyskinesia in a primate model

“…However, those data failed to explain TD occurrence in a fraction of APD‐exposed human subjects, and the delay necessary for induction. Protracted (6‐8 months) APD treatments in rats have produced increased striatal D2 binding, mRNA levels, and affinity to ligands, but unchanged D2 binding has also been reported . Furthermore, in some chronic rat experiments, striatal D2 receptor density and mRNA levels were found to be similar between animals with or without oral TD‐like movements.…”

“…Protracted (6‐8 months) APD treatments in rats have produced increased striatal D2 binding, mRNA levels, and affinity to ligands, but unchanged D2 binding has also been reported . Furthermore, in some chronic rat experiments, striatal D2 receptor density and mRNA levels were found to be similar between animals with or without oral TD‐like movements. Positron emission tomography (PET) studies did not show a difference in D2 receptor density between APD‐treated patients with or without TD, and no post‐mortem evidence for striatal dopamine D2 receptor upregulation was found in TD patients …”