A 65-year-old man with Parkinson disease for 8 years presents with wearing-off symptoms appearing 2 hours before his next levodopa dose. Vitals: BP 128/76, HR 82, RR 16, Temp 37°C, SpO2 98%. Recent MRI brain shows no structural lesions. He denies dyskinesias. His neurologist adds entacapone to his regimen. Which of the following best describes the mechanism of action of this added medication?

1. A)Irreversible inhibition of dopamine receptors
2. B)Stimulation of NMDA receptors in the basal ganglia
3. C)Inhibition of GABA transaminase to increase striatal GABA
4. D)Blockade of muscarinic receptors in the periphery only
5. E)Inhibition of catechol-O-methyltransferase to decrease levodopa metabolismGABARITO