This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'Hea rate is decreased by \nSelect and explain. \nA. Propanolol, B. Isoprenaline, C. Dopamine, D. Dobutamine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ref; KD Tripathi Pharmacology 6th edition (page no;136) Propranolol is a beta blocker which decreases hea rate, force of contraction (at relatively higher doses) and cardiac output (c.o.). beta blocker inhibits adrenergic responses mediated through the beta receptors. Isoprenaline,Dobutamine,Dopamine are adrenergic drugs , which are cardiac stimulators so increases hea rate', 'role': 'assistant'}]