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
On increasing, vagal tone following occurs in pacemaker 
Select and explain. 
A. Increased Na+, increased slop, B. Decreased Na+, decreased slop, C. Increased Na+, decreased slop, D. Decreased Na+, increased slop
B: Decreased Na+, decreased slop
Answer: B: Decreased Na+, decreased slop 
Explanation: Na+ influx causes the pacemaker potential (prepotential). Due to vagal stimulation, the Na+ influx decreases, this leads to a decrease in the slop of prepotential.