PDE5A and pulmonary arterial hypertension: PDE2 inhibitors are used to treat heart failure and pulmonary hypertension (Bubb et al, 2014), PDE5 inhibitors are known for their ability to treat erectile dysfunction and are thought to have benefits in Alzheimer’s disease (Adesuyan et al, 2024), and PDE10 inhibitors are used to explore treatments for Huntington’s disease and schizophrenia (Halene and Siegel, 2007).