A well-known drug used to treat hyperactive children boosts the potency of another drug that reduces Parkinson’s disease symptoms, an Oregon Health & Science University study has found. Scientists at the OHSU Parkinson Center of Oregon found that methylphenidate, known commercially as Ritalin, bolsters the effects of levodopa, a drug converted in the brain to dopamine. Methylphenidate inhibits the reabsorption of dopamine into nerve cells, increasing the neurotransmitter’s potency. Parkinson’s disease is caused by a deficiency of nerve cells that produce dopamine. A parallel study by Parkinson center researchers found that paroxetine, a popular antidepressant best known under the brand name Paxil, doesn’t augment the effects of levodopa and has little benefit in reducing physical symptoms of Parkinson’s disease. Paroxetine is a selective serotonin reuptake inhibitor, or SSRI, a class of antidepressants that block the reabsorption of another neurotransmitter, serotonin, into nerve cells. Researchers studied it because laboratory evidence has suggested the serotonin transporter, the system through which serotonin is reabsorbed into nerve cells, may take up dopamine as well.
