PROTO-1 is primarily used in research settings as a selective antagonist for the dopamine D3 receptor. It has been instrumental in studies examining the role of dopamine signaling in behavioral disorders, addiction, and psychiatric conditions such as schizophrenia and depression. Due to its high selectivity for the D3 receptor subtype over D2, it allows scientists to isolate and study specific dopaminergic pathways without broad interference across multiple receptor types.

In preclinical models, PROTO-1 has demonstrated potential in reducing drug-seeking behavior, particularly in substance use disorders involving opioids and psychostimulants. Its application in neuroimaging studies also enables the development of receptor-specific tracers, aiding in the visualization and quantification of D3 receptor expression in the brain.

Additionally, PROTO-1 serves as a valuable pharmacological tool in validating new therapeutic targets and in the early-stage screening of compounds aimed at modulating dopaminergic activity. Its use contributes to the advancement of targeted treatments for neurological and psychiatric diseases with fewer side effects.