Regarding the sympathetic pathway... Which neurotransmitter is released by preganglionic neurons? Which neurotransmitter is released by postganglionic neurons? To what types of receptors do these neurotransmitters bind? What is the effect of the neurotransmitter on the target cells? Choose the appropriate key terms from the following list: ACh, NE, nicotinic, muscarinic, alpha-1, alpha-2, beta-1, beta-2, excitatory, inhibitory.

Answer 1

In the sympathetic nervous system:

1. Preganglionic neurons release the neurotransmitter ACh (acetylcholine).
2. Postganglionic neurons release the neurotransmitter NE (norepinephrine).

The neurotransmitter binding occurs as follows:

• ACh released by preganglionic neurons binds to nicotinic receptors on postganglionic neurons, which generally has an excitatory effect on those neurons.
• NE released by postganglionic neurons binds to alpha-1, alpha-2, beta-1, and beta-2 adrenergic receptors on target cells, with effects that can be either excitatory or inhibitory depending on the specific receptor and the target tissue.

Overall, the sympathetic nervous system's activation tends to prepare the body for "fight or flight" responses, affecting various systems in ways that facilitate increased alertness, energy availability, and physiological readiness.