Review Question - QID 215184

A 72-year-old man presents to his primary care physician with a 2-month history of increasing urinary hesitancy. He says that he now needs to strain when beginning to void and tends to dribble after he finishes urinating. Recently, he also started having episodes of nocturia and increased day-time urinary frequency. His past medical history is significant for hypertension but he is not currently taking any medications because he does not like the side effects of the ones he has tried. His physician says that there is a medication that addresses both of his problems; however, he immediately experiences lightheadedness after starting the medication. Which of the following molecular changes would most likely be caused by this medication?