MK-6884 is a M4 muscarinic receptor positive allosteric modulator (PAM) with a K i value of 0.19 nM. MK-6884 can be used for the research of the neurodegenerative diseases. MK-6884 can be conveniently radiolabeled with carbon-11 and as a positron emission tomography (PET) imaging agent In Vitro MK-6884 (compound 13; 0-22 µM) is a PAM of ACh function in a cell-based Ca 2+ mobilization assay, with an EC 50 of 27 nM. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo [ 11 C]MK-6884 (compound 13) shows non-displaceable binding potential (BP ND ) of 0.83 in rhesus monkeys . [ 11 C]MK-6884 (approximately 185 MBq, Form:Solid IC50& Target:mAChR4