A 64-year-old man presents with a tremor in his legs and arms. He says he has had the tremor for "many years", but it has worsened in the last year. The tremor is more prominent at rest and nearly disappears on movement. His daughter mentions that his movements have become slower. The patient is afebrile and vital signs are within normal limits. On physical examination, the patient is hunched over and his face is expressionless throughout examination. There is a "pillrolling" resting tremor that is accentuated when the patient is asked to clench the contralateral hand and alleviated by finger nose testing. When asked to walk across the room, the patient has difficulty taking the first step, has a stooped posture and takes short rapid shuffling steps. A doctor initiates pharmacotherapy and the drug of first line, levodopa, is prescribed. Which of the following is the most likely mechanism of action of this drug?

Питання КРОК 1 (медицина) · тест з варіантами та поясненням · Medus

EN: A 64-year-old man presents with a tremor in his legs and arms. He says he has had the tremor for "many years", but it has worsened in the last year. The tremor is more prominent at rest and nearly disappears on movement. His daughter mentions that his movements have become slower. The patient is afebrile and vital signs are within normal limits. On physical examination, the patient is hunched over and his face is expressionless throughout examination. There is a "pillrolling" resting tremor that is accentuated when the patient is asked to clench the contralateral hand and alleviated by finger nose testing. When asked to walk across the room, the patient has difficulty taking the first step, has a stooped posture and takes short rapid shuffling steps. A doctor initiates pharmacotherapy and the drug of first line, levodopa, is prescribed. Which of the following is the most likely mechanism of action of this drug?

Варіанти відповідей

1. Stimulation of dopamine production
2. Inhibition of M2-cholinergic receptors
3. Cholinesterase inhibition
4. Activation of M2-cholinergic receptors

Answer options (EN)

1. Stimulation of dopamine production
2. Inhibition of M2-cholinergic receptors
3. Cholinesterase inhibition
4. Activation of M2-cholinergic receptors

Правильна відповідь

Stimulation of dopamine production

Пояснення

Леводопа - попередник дофаміну; у мозку вона перетворюється на дофамін і компенсує його дефіцит при хворобі Паркінсона. Саме стимуляція (відновлення) дофамінергічної передачі пояснює терапевтичний ефект. М-холінергічні рецептори та холінестераза не є мішенню леводопи.

Зустрічається в буклетах

• 2019 рік (English)
• 2022 рік, 1 день (English)

Усі буклети КРОК 1 · Підготовка до КРОК