Parkinson's disease is a common neurodegenerative disease that primarily affects the central nervous system, causing symptoms such as muscle stiffness, tremors, and movement disorders. At present, the methods of Parkinson's disease are relatively diverse, among which the combined use of rasagiline and levodopa is considered the best partner. 
1. The mechanism of action of rasagiline
Rasagiline is a selective monoamine oxidase B (MAO-B) inhibitor that increases the concentration of dopamine by inhibiting MAO-B enzyme activity. Dopamine is an important neurotransmitter that is involved in functions such as controlling movement and mood in the brain. In people with Parkinson's disease, levels of dopamine are usually low, leading to the appearance of symptoms. Rasagiline works by preventing the MAO-B enzyme from degrading dopamine, thereby increasing the amount of dopamine present. This way of increasing dopamine is relatively safe and does not lead to an excess of dopamine. Therefore, the use of rasagiline can improve muscle stiffness, tremors, and other movement disorder symptoms in patients with Parkinson's disease. 
2. Mechanism of action of levodopa
Levodopa is a prodrug of dopamine that increases dopamine levels by replenishing dopamine in the brain. Dopamine plays an important role as a neurotransmitter in the brain and is involved in regulating functions such as movement and mood. Patients with Parkinson's disease have symptoms due to a lack of dopamine. Levodopa can be converted into dopamine by brain cells, which increases dopamine levels. This method can quickly and effectively replenish dopamine and improve the symptoms of movement disorders in patients with Parkinson's disease. 
3. Rasagiline and levodopa have a better effect
Rasagiline and levodopa have different mechanisms of action, and they complement each other to significantly improve the best results. Rasagiline increases the amount of dopamine by inhibiting the activity of the MAO-B enzyme;Levodopa increases dopamine levels by supplementing dopamine. Rasagiline and levodopa can also enhance each other's effects. Rasagiline can inhibit the metabolism of levodopa, prolong its half-life in the body, and thus prolong the duration of its efficacy. In addition, rasagiline can also reduce levodopa-induced movement disorders and mood swings. 