Notes: ML-137 is a positive allosteric modulator (PAM) of M1 muscarinic acetylcholine receptors (mAChRs).{68783} It is selective for M1 over M2-M5 mAChRs at 30 µM. ML-137 potentiates ACh-induced activation of the M1 muscarinic receptor (EC50 = 0.83 µM).