Meanwhile, several studies using toxin-induced rodent models of PD have shown that inhibition of PARP rescues the degeneration of dopaminergic neurons in the substantia nigra pars compacta.16, 17, 18 PARPs are major NAD+-consuming nuclear proteins involved in repairing single-strand breaks in the DNA of healthy cells. The gene discussed is PARP1; the disease is Parkinson disease.