This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Most potent cardiac stimulant among the following is? 
Select and explain. 
A. Adrenaline, B. Noradrenaline, C. Ephedrine, D. Salbutamol
A: Adrenaline
Answer: A: Adrenaline 
Explanation: Epinephrine (adrenaline) is an agonist at both a and b receptors. It is, therefore, a very potent vasoconstrictor and cardiac stimulant. Noradrenaline acts mainly on alpha receptors salbutamol acts on beta 2 receptors beta 1 receptors are located on hea Katzung 12e pg:140