This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
Relaxation of mesangial cells is caused by 
Select and explain. 
A. Histamine, B. Dopamine, C. Angiotension 2, D. Vasopressin
B: Dopamine
Answer: B: Dopamine 
Explanation: Dopamine causes relaxation of mesangial cells. Other three are agents causing contraction.Ref: Ganong&;s Review of Medical Physiology, 23rd edition, page no: 646