Question 198

Question:

A 76-year-old man with a history of prostatic hypertrophy has the recent onset of increased difficulty urinating. Symptoms began shortly after he started taking a nasal decongestant orally for cold symptoms. Which of the following types of receptors is most likely to be involved in these adverse effects?

Correct Answer: A.  alpha1-Adrenergic

Nasal decongestants are alpha1-adrenergic stimulants that cause smooth muscle contraction, reducing vascular congestion. Benign prostatic hyperplasia is partly due to proliferation of smooth muscle in the bladder neck, urethra, and prostate. Therefore alpha1 blockade is one of the main symptomatic treatments to relieve smooth muscle tension. Main effects of beta2 adrenergic stimulation (Answer B) include bronchodilation and vasodilation. Both sympathetic and parasympathetic ganglionic receptors are nicotinic (Answer C), hence the complex autonomic effects of nicotine. Nicotinic receptor stimulation at the neuromuscular junction (Answer D) causes skeletal muscle contraction, which is not involved in BPH. Serotonergic receptors (Answer E) are not involved in BPH.