A 44-Year-Old Man with Progressive Dyspnea Is Diagnosed with Dilated

A 44-year-old man with progressive dyspnea is diagnosed with dilated cardiomyopathy.  Despite optimal medical therapy, he continues to have symptoms and disease progression is noted.  He undergoes cardiac transplantation after a suitable donor becomes available.  Permission is obtained from the patient to study his diseased heart for intracellular calcium regulation.  Microelectrodes placed into cardiac muscle cells detect a rapid decrease in cytoplasmic calcium level immediately preceding relaxation.  Which of the following proteins is most likely responsible for the observed change in electrolyte levels?

A) Calmodulin
B) Na⁺/Ca²⁺ exchanger
C) Ryanodine receptors
D) Troponin C
E) Voltage-dependent calcium channels

Correct Answer:

Verified

Unlock this answer now
Get Access to more Verified Answers free of charge

Access For Free