Melanostatin (MIF-1) is a naturally occurring neuropeptide acting as a positive allosteric modulator (PAM) of dopamine D<sub>2</sub> receptors (D<sub>2</sub>R), underscoring its potential for therapeutic use in central nervous system disorders associated with dopaminergic dysregulation, including depression, drug addiction, restless legs syndrome, tardive dyskinesia, and Parkinson's disease. The gene discussed is HERPUD1; the disease is depressive symptom measurement.