A client receives epinephrine for anaphylactic shock. The nurse should be aware of which mechanism by which epinephrine acts?

Question

1. Inhibiting reuptake of norepinephrine from the synaptic cleft
2. Indirectly, by promoting release of norepinephrine
3. Directly, by stimulating adrenergic receptors
4. Inhibiting destruction of norepinephrine by enzyme MAO

Answer 1

Correct Answer: 3
Rationale 1: Antidepressant imipramine and cocaine inhibit reuptake of NE from the synaptic cleft back to the presynaptic neuron.
Rationale 2: Epinephrine acts directly by stimulating adrenergic receptors. Ephedrine and amphetamine stimulate release of NE from its storage vesicles on the presynaptic neuron.
Rationale 3: Epinephrine acts directly by stimulating adrenergic receptors.
Rationale 4: Phenelzine (Nardil) is an example of an MAO inhibitor that inhibits destruction of norepinephrine.
Global Rationale: Epinephrine acts directly by stimulating adrenergic receptors. Ephedrine and amphetamine stimulate release of NE from its storage vesicles on the presynaptic neuron. Antidepressant imipramine and cocaine inhibit reuptake of NE from the synaptic cleft back to the presynaptic neuron. Phenelzine (Nardil) is an example of an MAO inhibitor that inhibits destruction of norepinephrine.