Nitric oxide synthase converts the amino acid arginine into citrulline and nitric oxide.

一氧化氮合酶将氨基酸中的精氨酸转化为瓜氨酸和一氧化氮。

The acetylcholine bind to muscarinic receptors on endothelial cells, which activates the enzyme nitric oxide synthase.

乙酰胆碱与内皮细胞上的毒蕈碱受体结合，激活一氧化氮合酶。

So the neuro science project I'm working on involves the cellular signaling pathway of neuronal nitric oxide synthase.

我在做的这个神经学科项目涉及神经元一氧化氮合酶细胞信号传导通路。

Damaged parasympathetic nerve fibers can't release acetylcholine, so there's less nitric oxide synthase activation, and less nitric oxide is produced.

受损的副交感神经纤维不能释放乙酰胆碱，因此被激活的一氧化氮合酶较少，产生的一氧化氮也较少。

This happens because low testosterone levels are associated with lower levels of nitric oxide synthase, which causes less nitric oxide to be produced, and less smooth muscle relaxation.

这是因为低睾酮水平与较低水平的一氧化氮合酶有关，低睾酮水平导致一氧化氮产生不足，并减少平滑肌松弛。