This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Circulation, Subject name: Physiology
[{'content': 'True regarding endothelin-1 are all except: \nSelect and explain. \nA. Bronchodilatation, B. Vasoconstriction, C. Decreased GFR, D. Has inotropic effect', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Endothelin is a peptide that is released by damaged vascular endothelial cells of the kidneys, as well as by other tissues. It causes bronchoconstriction and not bronchodilatation. Biologic effects of endothelins: Hemodynamic effects: Contracts vascular smooth muscle; veins more sensitive than aeries. Cardiac effects: Positive inotropic and chronotropic effects on myocardium Intense vasoconstriction of coronary aeries Neuroendocrine effects: Increased plasma levels of ANP, renin, aldosterone, and catecholamines Modulates synaptic transmission Renal effects: Increases renal vascular resistance Decreases GFR, renal blood flow Increases Na+ reabsorption through hemodynamic actions, but decreases Na+ reabsroption through inhibition of Na+-K+ pump.', 'role': 'assistant'}]