This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Pharmacology), Subject name: Pharmacology
[{'content': 'Dopamine in dose concentration at <2mcg/kg/min acts predominantly on? \nSelect and explain. \nA. Beta-1, B. D-1, C. Alpha-1, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. D-1At low doses (<=2mg/kg/minute)stimulates dopaminergic receptors on renal blood vessels leading to vasodilation. DA infusion at this rate may increase renal blood flow and promote diuresis.At intermediate infusion rates (2-5mg/kg/min), (used in CHF, cardiogenic shock)Stimulates b1 receptors on heart increasing cardiac contractility. Also stimulates D1 receptorsAt higher infusion rates (5-15mg/kg/min), (used for shock with oliguria)Acts on a1, leading to vasoconstriction and rise in BP. Also stimulates D1 & b1 receptors', 'role': 'assistant'}]