This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
Mediator present in mast cells is 
Select and explain. 
A. Histamine, B. Encephalin, C. Calmodulin, D. None of these
A: Histamine
Answer: A: Histamine 
Explanation: Mast cells release several different substances. Among them areHistamineSlow-reacting substance of anaphylaxis (which is a mixture of leukotrienes)Eosinophilic chemotactic factorBradykininRef: Guyton and Hall textbook of medical physiology 13th edition. Page:554