Researchers from the Champalimaud Foundation shed light on the puzzling relationship between dopamine and rest tremor in Parkinson's disease, finding that preserved dopamine in certain brain regions may actually contribute to tremor symptoms, challenging common beliefs. Parkinson's disease (PD) is a progressive neurological disorder known for its characteristic motor symptoms: tremor, rigidity, and slowness of movement. Among these, rest tremor-;a shaking that occurs when muscles are relaxed-;is one of the most recognisable yet least understood.
A new study from the Champalimaud Foundation published in npj Parkinson's Disease , led by the Neural Circuits Dysfunction Lab in collaboration with the Neuropsychiatry and Nuclear Medicine Labs, offers fresh insights into the complex relationship between rest tremor and dopamine, a chemical messenger that plays a key role in coordinating movement. The dopamine paradox Dopamine loss in brain regions like the putamen, associated with movement regulation, is a well-established hallmark of PD. However, while some patients experience significant tremor relief with dopamine replacement therapies like L-DOPA, others see little to no improvement, or even a worsening of symptoms.
Tremor is a common and often debilitating symptom for PD patients, but it has always been a bit of a puzzle. We know dopamine is involved, but the way it affects tremor isn't as direct as with other motor symptoms". Marcelo Mendonça, one of the study's lead authors.
