Similarly, a recent study identified β2-adrenoreceptor (β2AR) agonists as negative regulators of the aSyn gene expression, and an association was found between the use of β2AR agonist salbutamol, a brain-penetrant asthma medication, and a reduced risk of developing PD (Mittal et al., 2017). This evidence concerns the gene ADRB2 and Parkinson disease.