Regarding the parasympathetic 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.

Question

GPT-4o mini · Answer

In the parasympathetic pathway: 1. **Preganglionic neurons** release the neurotransmitter **ACh (acetylcholine)**. 2. **Postganglionic neurons** also release **ACh (acetylcholine)**. 3. The neurotransmitter released by preganglionic neurons (ACh) binds to **nicotinic receptors** on postganglionic neurons. The ACh released by postganglionic neurons binds to **muscarinic receptors** on target cells. 4. The effect of ACh on the target cells varies but is generally considered **excitatory** for smooth muscles and **inhibitory** for cardiac muscles. Thus, the complete answer is: - Preganglionic neurotransmitter: **ACh** - Postganglionic neurotransmitter: **ACh** - Receptor for preganglionic ACh: **nicotinic** - Receptor for postganglionic ACh: **muscarinic** - Effect on target cells: Generally **excitatory** (smooth muscle) or **inhibitory** (cardiac muscle).