A research team from the University of California, Irvine is the first to reveal that a molecule in the brain – ophthalmic acid – unexpectedly acts like a neurotransmitter similar to dopamine in regulating motor function, offering a new therapeutic target for Parkinson's and other movement diseases. In the study, published in the October issue of the journal Brain , researchers observed that ophthalmic acid binds to and activates calcium-sensing receptors in the brain, reversing the movement impairments of Parkinson's mouse models for more than 20 hours. The disabling neurogenerative disease affects millions of people worldwide over the age of 50.
Symptoms, which include tremors, shaking and lack of movement, are caused by decreasing levels of dopamine in the brain as those neurons die. L-dopa, the front-line drug for treatment, acts by replacing the lost dopamine and has a duration of two to three hours. While initially successful, the effect of L-dopa fades over time, and its long-term use leads to dyskinesia – involuntary, erratic muscle movements in the patient's face, arms, legs and torso.
Our findings present a groundbreaking discovery that possibly opens a new door in neuroscience by challenging the more-than-60-year-old view that dopamine is the exclusive neurotransmitter in motor function control. Remarkably, ophthalmic acid not only enabled movement, but also far surpassed L-dopa in sustaining positive effects. The identification of the ophthalmic acid-calcium.
