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
Bezold-Jarisch reflex is mediated by: 
Select and explain. 
A. Serotonin, B. Angiotensin, C. Prostaglandin, D. Histamine
A: Serotonin
Answer: A: Serotonin 
Explanation: Answer- A. SerotoninThe Bezold-Jarisch reflex involves a variety of cardiovascular and neurological processes which cause hypopnea (excessively shallow breathing or an abnormally low respiratory rate) and bradycardia (abnormally low resting hea rate). Serotonin can elicit Bezold-Jarisch reflex.Bezold-Jarisch reflex responds to noxious ventricular stimuli sensed by chemoreceptors & mechanoreceptors within the LV wall by inducing the triad of hypotension bradycardia & coronary aery dilatation.Stimulation of aerial baroreceptors or ventricular baroreceptors by any of a host of chemicals-veratrum alkaloids, nicotine capsaicin, anti-histamine serotonin snake and insect venoms--can also trigger the Bezold- Jarisch reflex.