• Changes in PPE-A mRNA levels in the striatum of the 6-OHDA-lesioned rat and MPTP-lesioned NHP killed in the off-state are inconsistent. |
• Striatal PPE-B mRNA levels are increased after chronic l-DOPA therapy in the 6-OHDA-lesioned rat and the MPTP-lesioned NHP, whether killed in the on- or off-state. |
• μ-Receptor levels are reduced in the striatum and GPi of dyskinetic NHPs killed in the on-state. |
• μ-Mediated signaling is overactive in the striatum and GPi of MPTP-lesioned NHPs killed in the on-state. |
• The selective μ antagonists cyprodine and ADL5510 in the MPTP-lesioned NHP reduce dyskinesia. |
• δ-Receptor levels are unchanged in the striatum of dyskinetic NHPs killed in the on-state. |
• δ-Mediated signaling is overactive in the striatum of MPTP-lesioned NHPs killed in the on-state. |
• The selective δ antagonist naltrindole reduces dyskinesia in the MPTP-lesioned NHP. |
• κ-Receptor levels are reduced in the GPe and GPi of dyskinetic NHPs killed in the on-state. |
• κ-Mediated signaling is overactive in the caudate nucleus and motor cortex of MPTP-lesioned NHPs killed in the on-state. |
• The selective κ agonist U50-488 reduces dyskinesia in the MPTP-lesioned NHP. |
• Morphine and meperidine alleviate dyskinesia in the MPTP-lesioned NHP. |
• Naloxone and naltrexone did not demonstrate convincing antidyskinetic efficacy in small clinical studies. |