Question

How does negative feedback prevent further adrenergic transmission in the sympathetic nervous system?

a) Activation of autoreceptors on presynaptic terminals
b) Inhibition of adrenoreceptor synthesis
c) Blocking calcium channels
d) Increasing norepinephrine release

Answer 1

Negative feedback in the sympathetic nervous system prevents further adrenergic transmission through the activation of autoreceptors on presynaptic terminals, which inhibit the release of norepinephrine.

Step-by-step explanation:

Negative feedback in the sympathetic nervous system prevents further adrenergic transmission through the activation of autoreceptors on presynaptic terminals. Autoreceptors are receptors located on the presynaptic neurons themselves, and when they are stimulated by norepinephrine, they inhibit its further release.

For example, when norepinephrine is released from a sympathetic postganglionic fiber, it can bind to the autoreceptors on the presynaptic terminal, which then send signals to inhibit the release of more norepinephrine. This feedback mechanism helps maintain homeostasis and prevents excessive sympathetic nerve activity.