PTGS2 and Parkinson disease: It seems that COX-2 and its major products, i.e. prostaglandins (PGs), have an important role in neurotransmitter release and PD-associated rigidity as reported in previous works (4, 5, 17, 22), suggesting that COX-2 causes increased levels of acetylcholine in brain via the production of PGE2 and increases in expression of cholinergic markers, such as choline acetyl transferase and vesicular acetylcholine transporter protein.