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': 'Dopamine, in renal doses, in shock leads to: March 2009 \nSelect and explain. \nA. Reduction in peripheral re, B. Constriction of renal vasculature, C. Dilatation of renal vasculature, D. Increase in cardiac output', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C: Dilatation of renal vasculature Dopamine at "renal dose"/ low dosage binds D-lreceptors and effects in dilating blood vessels, increasing blood flow to renal, mesenteric, and coronary aeries; and increasing overall renal perfusion. Dopamine therefore has a diuretic effect, potentially increasing urine output. Intermediate dosages have a positive inotropic and chronotropic effect through increased beta-1 activation. It is used in patients with shock or hea failure to increase cardiac output and blood pressure. High dose is the "pressor" dose. This dose causes vasoconstriction, increases systemic vascular resistance, and increases blood pressure through alpha-1 receptor activation; but can cause the vessels in the kidneys to constrict to the point where they will become non-functional', 'role': 'assistant'}]