AEMCA Practice Exam

What is the role of Alpha 2 receptors when stimulated?

1. Increases norepinephrine release

2. Inhibits the release of norepinephrine

3. Causes bronchial dilation

4. Increases heart rate

The correct answer is: Inhibits the release of norepinephrine

Alpha 2 receptors, when stimulated, play a key role in the modulation of neurotransmitter release in the sympathetic nervous system. Their primary function is to inhibit the release of norepinephrine, which leads to a decrease in sympathetic outflow. This is often referred to as a negative feedback mechanism, where the stimulation of these receptors reduces the activity of neurons that release norepinephrine, ultimately leading to decreased peripheral resistance and lower blood pressure. This inhibition is crucial in various physiological responses, particularly in situations where reducing sympathetic tone can be beneficial, such as in the management of hypertension or during sedation. Therefore, the choice indicating the inhibition of norepinephrine release accurately reflects the function of Alpha 2 receptors, emphasizing their important regulatory role in the autonomic nervous system.