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
[{'content': 'All of the following inflammatory mediators produce vasoconstriction except \nSelect and explain. \nA. Endothelin-1, B. Bradykinin, C. Thromboxane A2, D. Platelet activating factor', 'role': 'user'}, {'content': "Answer: B \nExplanation: Kinins including Bradykinin cause contraction of visceral smooth muscle, but they relax vascular smooth muscle NO, lowering blood pressure. Thromboxane A2 promotes platelet aggregation and vasoconstriction Platelet-activating factor (PAF), a cytokine secreted by neutrophils and monocytes as well as platelets. This compound also has inflammatory activity. It is an ether phospholipid, 1-alkyl-2acetylglyceryl-3-phosphorylcholine, which is produced from membrane lipids. It acts a G protein-coupled receptor to increase the production of arachidonic acid derivatives, including thromboxane A2 which cause vasoconstriction Endothelial cells produce endothelin-1, one of the most potent vasoconstrictor agents yet isolated Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:566", 'role': 'assistant'}]