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: Pharmacology
[{'content': 'Tegaserod acts at the following receptor: \nSelect and explain. \nA. Histamine, B. Serotonin, C. Thromboxane, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tegaserod is a serotonin 5-HT4 paial agonist that has high affinity for 5-HT4 receptors but no appreciable binding to 5-HT3 or dopamine receptors. Tegaserod was approved for the treatment of patients with chronic constipation and IBS with predominant constipation. Ref: Katzung 11th edition Chapter 60.', 'role': 'assistant'}]