This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Muscarinic cholinergic agonists 
Select and explain. 
A. Decrease production of IP 3, B. Activate inhibitory G-proteins (Gi), C. Decrease release of intracellular calcium, D. Inhibit the activity of phospholipase C
B: Activate inhibitory G-proteins (Gi)
Answer: B: Activate inhibitory G-proteins (Gi) 
Explanation: In addition to activating inhibitory G-proteins (Gi), muscarinic cholinergic agonists stimulate the activity of phospholipase C, increase production of IP 3, and increase release of intracellular calcium. Ref:- KD Tripathi