What is the primary benefit of using selegiline in Parkinson's therapy?

Selegiline is primarily beneficial in Parkinson's therapy because it decreases dopamine metabolism in the central nervous system (CNS). It acts as a selective monoamine oxidase type B (MAO-B) inhibitor, which prevents the breakdown of dopamine, leading to increased levels of this neurotransmitter in the brain. This is particularly important in Parkinson's disease, where dopamine-producing neurons are progressively lost, resulting in a deficiency of dopamine that contributes to motor symptoms.

By inhibiting MAO-B, selegiline helps to prolong the effects of dopamine released from remaining neurons, thus aiding in symptom management. This mechanism can enhance the efficacy of other Parkinson's medications, such as levodopa, when used in combination.

In contrast, the options involving stimulation of dopamine release, enhancing peripheral levodopa absorption, or blocking acetylcholine receptors do not accurately reflect the primary action of selegiline in Parkinson's treatment. Selegiline does not stimulate the release of dopamine directly; instead, it preserves existing dopamine levels. It also does not impact the absorption of levodopa in the periphery and does not block acetylcholine receptors, as that action would involve addressing cholinergic mechanisms, which is not the focus of selegiline's therapeutic benefits.