Discussion
The role of striatal and nigral M1 and M4 muscarinic receptors in LID was investigated using a dual probe microdialysis approach (Mela et al. , 2012) by which M1 and M4 receptor preferential antagonists and a M4 receptor selective PAM were delivered through the microdialysis probe into the dorsolateral striatum or SNr, simultaneously with systemic L-DOPA administration.