An 18-Year-Old Man, Who Was Recently Started on Risperidone Therapy

question 126

Multiple Choice

An 18-year-old man, who was recently started on risperidone therapy for schizophrenia, comes to the office due to involuntary deviation of his head.  On examination, the patient's head is tilted toward the right side and the chin is rotated to the left.  There is palpable tightening of the right sternocleidomastoid muscle.  It is determined that the patient is experiencing a medication-induced dystonic reaction due to motor neuron hyperactivity.  The persistent myocyte stimulation causes a substance to be released from the sarcoplasmic reticulum.  This substance most likely binds to which of the following proteins to cause this patient's symptoms?

• A)Actin
• B)Myosin
• C)Tropomyosin
• D)Troponin
• E)Protein kinase A

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Definitions:

Price Ceiling

A government-imposed limit on how high a price can be charged for a product, intended to protect consumers from high prices.

Price Floor

A government- or authority-imposed minimum price that can be charged for a good or service, often above the equilibrium price.

Quantity Control

Regulatory or business practices that limit the production, sale, or distribution of products to influence market prices or quality.

Quota Rent

The earnings that accrue to the license-holder from owning the right to import a limited quantity of goods under a quota system.