Ophthalmic acid as an alternative to dopamine in motor control

A research team from the University of California, Irvine has made a groundbreaking discovery by identifying a brain molecule called ophthalmic acid, which surprisingly acts like a neurotransmitter, similar to dopamine, in controlling movement. This finding offers a new potential treatment for Parkinson's disease and other movement disorders. The study, published in the October issue of Brain, shows that ophthalmic acid binds to calcium-sensing receptors in the brain, helping restore movement in Parkinson’s mouse models for over 20 hours. Currently, the main treatment, L-dopa, replaces lost dopamine but lasts only 2-3 hours, and its long-term use can cause side effects like uncontrollable muscle movements. What makes this discovery so important is that it challenges the long-standing belief that dopamine is the only neurotransmitter responsible for controlling movement. Ophthalmic acid not only improved movement but did so for much longer than L-dopa. This previously unknown pathway, involving ophthalmic acid and calcium-sensing receptors, could lead to new treatments for Parkinson’s and other movement disorders. Lead researcher Professor Amal Alachkar began exploring motor function outside of dopamine over 20 years ago, noticing that some Parkinson’s mice could still move without dopamine. In this study, the team analyzed hundreds of brain molecules and confirmed that ophthalmic acid works as an alternative neurotransmitter. One major challenge in Parkinson’s treatment is that many neurotransmitters can’t cross the blood-brain barrier, which is why L-dopa is used to boost dopamine levels in the brain. Now, the researchers are working on ways to either release ophthalmic acid in the brain or boost its natural production to further explore its role in movement control. The research team included several collaborators from UCI's School of Pharmacy & Pharmaceutical Sciences and the School of Medicine, and it was supported by a grant from the National Institute of Neurological Disorders and Stroke. Alachkar and her colleague Olivier Civelli also hold a provisional patent related to this discovery.