This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Receptors on cell membrane that activate ion channel after binding with agonists are: 
Select and explain. 
A. Nicotinic cholinergic, B. Muscarinic cholinergic, C. Opioid mu receptors, D. GABA B receptors
A: Nicotinic cholinergic
Answer: A: Nicotinic cholinergic 
Explanation: Nicotinic cholinergic and GABAA are inotropic receptor (they are ion channel). Other receptors in the options are G­-protein coupled receptor; known as metabotropic receptor.