VU 0238429 is a selective positive allosteric modulator (PAM) of the M1 muscarinic acetylcholine receptor (M1 mAChR), primarily used in research settings to study the role of this receptor in the brain, particularly in neurological and psychiatric disorders. It enhances the activity of M1 mAChR without directly activating it, making it valuable for investigating conditions like schizophrenia, Alzheimer's disease, Parkinson's disease, and cognitive impairments. Researchers utilize it to explore potential therapeutic pathways, better understand underlying mechanisms, and support drug discovery. Its application is largely confined to preclinical studies as a research tool.