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': 'Which of the following combinations will show vasomotor reversal of Dale \nSelect and explain. \nA. Phentolamine followed by adrenaline, B. Propanalol followed by adrenaline, C. Phentolamine followed by nor adrenaline, D. Propanalol followed by nor adrenaline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Adrenaline leads to increased BP by acting on\xa0α1 - receptors, and\xa0 vasodilation by action on\xa0β2 receptors. If it is administered after Phentolamine (α1 - blocker) it can lead to only vasodilation, which is termed as "Vasomotor reversal of Dale".', 'role': 'assistant'}]