What is released from post-ganglionic neurons during the activation of the sympathetic nervous system?

During the activation of the sympathetic nervous system, post-ganglionic neurons primarily release norepinephrine. This neurotransmitter plays a crucial role in mediating the body's response to stress or emergency situations, often described as the "fight or flight" response.

In the sympathetic nervous system, pre-ganglionic neurons release acetylcholine, which then activates post-ganglionic neurons located in sympathetic ganglia. The activated post-ganglionic neurons release norepinephrine into the synaptic cleft, leading to a variety of physiological effects such as increased heart rate, bronchodilation, and heightened alertness.

While epinephrine is also involved in the sympathetic response, it is predominantly released from the adrenal medulla into the bloodstream rather than being released by post-ganglionic neurons. Dopamine and serotonin play roles in other neurotransmitter systems, primarily associated with different functions in the central nervous system and do not directly correlate with the actions of the sympathetic nervous system's post-ganglionic pathways. Thus, the release of norepinephrine is directly tied to sympathetic nervous system activation.