Which of the following can be blocked by atropine, a muscarinic receptor blocker?: (A) Increased blood pressure caused by nicotine, (B) Increased skeletal muscle strength caused by neostigmine, an acetycholine esterase inhibitor, (C) Bradycardia caused by infusion of acetylcholine, (D) All of these
Answer is C. Atropine is a muscarinic antagonist. Muscarinic antagonists competitively inhibit the effect of acetylcholine at muscarinic receptors. Bradycardia caused by infusion of acetylcholine- can be blocked by atropine