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
In the management of anaphylaxis, which action of adrenaline is not observed? 
Select and explain. 
A. Bronchodilation by beta-receptors, B. Cardiovascular effects of beta-receptors, C. Action on blood vessels by alpha-receptors, D. Action on presynaptic alpha-receptors
D: Action on presynaptic alpha-receptors
Answer: D: Action on presynaptic alpha-receptors 
Explanation: Ans: D. Action on presynaptic alpha-receptors(Ref: Goodman Gilman 12/e p209, 302, 308)Activation of presynaptic ?2 receptors inhibits the release of NE and other co-transmitters front peripheral sympathetic nerve endings.Activation of ?2 receptors in the pontomedullary region of the CNS inhibits sympathetic nervous system activity and leads to a full in blood pressure.Action on presynaptic alpha-receptors (a2 receptors) is not helpful in management of anaphylactic shock.