A dopamine antagonist would most likely lead to what effect in patients with Parkinson's disease?

• A. Increased mobility
• B. Decreased mobility and increased frequency of tremors
• C. Improvement in cognitive function
• D. Enhanced motor skills

Answer: (B)

In patients with Parkinson's disease, dopamine plays a crucial role in regulating movement and motor function. The disease is characterized by the degeneration of dopamine-producing neurons in the brain, leading to symptoms such as tremors, rigidity, and bradykinesia (slowed movement). A dopamine antagonist blocks the actions of dopamine, which can exacerbate the motor symptoms associated with the disease.

By inhibiting dopamine transmission, a dopamine antagonist would likely lead to decreased mobility and an increased frequency of tremors in these patients. This occurs because patients with Parkinson's already have a deficiency of dopamine, and blocking its action further compromises their ability to initiate and control movement, resulting in a worsening of their symptoms.

In contrast, increased mobility, improvement in cognitive function, or enhanced motor skills would not be expected outcomes when using a dopamine antagonist, as these actions would require adequate or increased dopamine activity, which the antagonist would inhibit. Therefore, decreased mobility and increased tremors are the anticipated effects in patients with Parkinson's disease when treated with a dopamine antagonist.